Merge branch 'x86/urgent' into x86/asm, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/Documentation/x86/orc-unwinder.txt b/Documentation/x86/orc-unwinder.txt
new file mode 100644
index 0000000..af0c9a4
--- /dev/null
+++ b/Documentation/x86/orc-unwinder.txt
@@ -0,0 +1,179 @@
+ORC unwinder
+============
+
+Overview
+--------
+
+The kernel CONFIG_ORC_UNWINDER option enables the ORC unwinder, which is
+similar in concept to a DWARF unwinder. The difference is that the
+format of the ORC data is much simpler than DWARF, which in turn allows
+the ORC unwinder to be much simpler and faster.
+
+The ORC data consists of unwind tables which are generated by objtool.
+They contain out-of-band data which is used by the in-kernel ORC
+unwinder. Objtool generates the ORC data by first doing compile-time
+stack metadata validation (CONFIG_STACK_VALIDATION). After analyzing
+all the code paths of a .o file, it determines information about the
+stack state at each instruction address in the file and outputs that
+information to the .orc_unwind and .orc_unwind_ip sections.
+
+The per-object ORC sections are combined at link time and are sorted and
+post-processed at boot time. The unwinder uses the resulting data to
+correlate instruction addresses with their stack states at run time.
+
+
+ORC vs frame pointers
+---------------------
+
+With frame pointers enabled, GCC adds instrumentation code to every
+function in the kernel. The kernel's .text size increases by about
+3.2%, resulting in a broad kernel-wide slowdown. Measurements by Mel
+Gorman [1] have shown a slowdown of 5-10% for some workloads.
+
+In contrast, the ORC unwinder has no effect on text size or runtime
+performance, because the debuginfo is out of band. So if you disable
+frame pointers and enable the ORC unwinder, you get a nice performance
+improvement across the board, and still have reliable stack traces.
+
+Ingo Molnar says:
+
+ "Note that it's not just a performance improvement, but also an
+ instruction cache locality improvement: 3.2% .text savings almost
+ directly transform into a similarly sized reduction in cache
+ footprint. That can transform to even higher speedups for workloads
+ whose cache locality is borderline."
+
+Another benefit of ORC compared to frame pointers is that it can
+reliably unwind across interrupts and exceptions. Frame pointer based
+unwinds can sometimes skip the caller of the interrupted function, if it
+was a leaf function or if the interrupt hit before the frame pointer was
+saved.
+
+The main disadvantage of the ORC unwinder compared to frame pointers is
+that it needs more memory to store the ORC unwind tables: roughly 2-4MB
+depending on the kernel config.
+
+
+ORC vs DWARF
+------------
+
+ORC debuginfo's advantage over DWARF itself is that it's much simpler.
+It gets rid of the complex DWARF CFI state machine and also gets rid of
+the tracking of unnecessary registers. This allows the unwinder to be
+much simpler, meaning fewer bugs, which is especially important for
+mission critical oops code.
+
+The simpler debuginfo format also enables the unwinder to be much faster
+than DWARF, which is important for perf and lockdep. In a basic
+performance test by Jiri Slaby [2], the ORC unwinder was about 20x
+faster than an out-of-tree DWARF unwinder. (Note: That measurement was
+taken before some performance tweaks were added, which doubled
+performance, so the speedup over DWARF may be closer to 40x.)
+
+The ORC data format does have a few downsides compared to DWARF. ORC
+unwind tables take up ~50% more RAM (+1.3MB on an x86 defconfig kernel)
+than DWARF-based eh_frame tables.
+
+Another potential downside is that, as GCC evolves, it's conceivable
+that the ORC data may end up being *too* simple to describe the state of
+the stack for certain optimizations. But IMO this is unlikely because
+GCC saves the frame pointer for any unusual stack adjustments it does,
+so I suspect we'll really only ever need to keep track of the stack
+pointer and the frame pointer between call frames. But even if we do
+end up having to track all the registers DWARF tracks, at least we will
+still be able to control the format, e.g. no complex state machines.
+
+
+ORC unwind table generation
+---------------------------
+
+The ORC data is generated by objtool. With the existing compile-time
+stack metadata validation feature, objtool already follows all code
+paths, and so it already has all the information it needs to be able to
+generate ORC data from scratch. So it's an easy step to go from stack
+validation to ORC data generation.
+
+It should be possible to instead generate the ORC data with a simple
+tool which converts DWARF to ORC data. However, such a solution would
+be incomplete due to the kernel's extensive use of asm, inline asm, and
+special sections like exception tables.
+
+That could be rectified by manually annotating those special code paths
+using GNU assembler .cfi annotations in .S files, and homegrown
+annotations for inline asm in .c files. But asm annotations were tried
+in the past and were found to be unmaintainable. They were often
+incorrect/incomplete and made the code harder to read and keep updated.
+And based on looking at glibc code, annotating inline asm in .c files
+might be even worse.
+
+Objtool still needs a few annotations, but only in code which does
+unusual things to the stack like entry code. And even then, far fewer
+annotations are needed than what DWARF would need, so they're much more
+maintainable than DWARF CFI annotations.
+
+So the advantages of using objtool to generate ORC data are that it
+gives more accurate debuginfo, with very few annotations. It also
+insulates the kernel from toolchain bugs which can be very painful to
+deal with in the kernel since we often have to workaround issues in
+older versions of the toolchain for years.
+
+The downside is that the unwinder now becomes dependent on objtool's
+ability to reverse engineer GCC code flow. If GCC optimizations become
+too complicated for objtool to follow, the ORC data generation might
+stop working or become incomplete. (It's worth noting that livepatch
+already has such a dependency on objtool's ability to follow GCC code
+flow.)
+
+If newer versions of GCC come up with some optimizations which break
+objtool, we may need to revisit the current implementation. Some
+possible solutions would be asking GCC to make the optimizations more
+palatable, or having objtool use DWARF as an additional input, or
+creating a GCC plugin to assist objtool with its analysis. But for now,
+objtool follows GCC code quite well.
+
+
+Unwinder implementation details
+-------------------------------
+
+Objtool generates the ORC data by integrating with the compile-time
+stack metadata validation feature, which is described in detail in
+tools/objtool/Documentation/stack-validation.txt. After analyzing all
+the code paths of a .o file, it creates an array of orc_entry structs,
+and a parallel array of instruction addresses associated with those
+structs, and writes them to the .orc_unwind and .orc_unwind_ip sections
+respectively.
+
+The ORC data is split into the two arrays for performance reasons, to
+make the searchable part of the data (.orc_unwind_ip) more compact. The
+arrays are sorted in parallel at boot time.
+
+Performance is further improved by the use of a fast lookup table which
+is created at runtime. The fast lookup table associates a given address
+with a range of indices for the .orc_unwind table, so that only a small
+subset of the table needs to be searched.
+
+
+Etymology
+---------
+
+Orcs, fearsome creatures of medieval folklore, are the Dwarves' natural
+enemies. Similarly, the ORC unwinder was created in opposition to the
+complexity and slowness of DWARF.
+
+"Although Orcs rarely consider multiple solutions to a problem, they do
+excel at getting things done because they are creatures of action, not
+thought." [3] Similarly, unlike the esoteric DWARF unwinder, the
+veracious ORC unwinder wastes no time or siloconic effort decoding
+variable-length zero-extended unsigned-integer byte-coded
+state-machine-based debug information entries.
+
+Similar to how Orcs frequently unravel the well-intentioned plans of
+their adversaries, the ORC unwinder frequently unravels stacks with
+brutal, unyielding efficiency.
+
+ORC stands for Oops Rewind Capability.
+
+
+[1] https://lkml.kernel.org/r/20170602104048.jkkzssljsompjdwy@suse.de
+[2] https://lkml.kernel.org/r/d2ca5435-6386-29b8-db87-7f227c2b713a@suse.cz
+[3] http://dustin.wikidot.com/half-orcs-and-orcs
diff --git a/arch/um/include/asm/unwind.h b/arch/um/include/asm/unwind.h
new file mode 100644
index 0000000..7ffa543
--- /dev/null
+++ b/arch/um/include/asm/unwind.h
@@ -0,0 +1,8 @@
+#ifndef _ASM_UML_UNWIND_H
+#define _ASM_UML_UNWIND_H
+
+static inline void
+unwind_module_init(struct module *mod, void *orc_ip, size_t orc_ip_size,
+ void *orc, size_t orc_size) {}
+
+#endif /* _ASM_UML_UNWIND_H */
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 781521b..9b30212 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -73,7 +73,6 @@
select ARCH_USE_QUEUED_RWLOCKS
select ARCH_USE_QUEUED_SPINLOCKS
select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
- select ARCH_WANT_FRAME_POINTERS
select ARCH_WANTS_DYNAMIC_TASK_STRUCT
select ARCH_WANTS_THP_SWAP if X86_64
select BUILDTIME_EXTABLE_SORT
@@ -157,6 +156,7 @@
select HAVE_MEMBLOCK
select HAVE_MEMBLOCK_NODE_MAP
select HAVE_MIXED_BREAKPOINTS_REGS
+ select HAVE_MOD_ARCH_SPECIFIC
select HAVE_NMI
select HAVE_OPROFILE
select HAVE_OPTPROBES
@@ -167,7 +167,7 @@
select HAVE_PERF_REGS
select HAVE_PERF_USER_STACK_DUMP
select HAVE_REGS_AND_STACK_ACCESS_API
- select HAVE_RELIABLE_STACKTRACE if X86_64 && FRAME_POINTER && STACK_VALIDATION
+ select HAVE_RELIABLE_STACKTRACE if X86_64 && FRAME_POINTER_UNWINDER && STACK_VALIDATION
select HAVE_STACK_VALIDATION if X86_64
select HAVE_SYSCALL_TRACEPOINTS
select HAVE_UNSTABLE_SCHED_CLOCK
diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index cd20ca0..71a48a3 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -305,8 +305,6 @@
Some of these sanity checks may slow down kernel entries and
exits or otherwise impact performance.
- This is currently used to help test NMI code.
-
If unsure, say N.
config DEBUG_NMI_SELFTEST
@@ -358,4 +356,61 @@
The current power state can be read from
/sys/kernel/debug/punit_atom/dev_power_state
+choice
+ prompt "Choose kernel unwinder"
+ default FRAME_POINTER_UNWINDER
+ ---help---
+ This determines which method will be used for unwinding kernel stack
+ traces for panics, oopses, bugs, warnings, perf, /proc/<pid>/stack,
+ livepatch, lockdep, and more.
+
+config FRAME_POINTER_UNWINDER
+ bool "Frame pointer unwinder"
+ select FRAME_POINTER
+ ---help---
+ This option enables the frame pointer unwinder for unwinding kernel
+ stack traces.
+
+ The unwinder itself is fast and it uses less RAM than the ORC
+ unwinder, but the kernel text size will grow by ~3% and the kernel's
+ overall performance will degrade by roughly 5-10%.
+
+ This option is recommended if you want to use the livepatch
+ consistency model, as this is currently the only way to get a
+ reliable stack trace (CONFIG_HAVE_RELIABLE_STACKTRACE).
+
+config ORC_UNWINDER
+ bool "ORC unwinder"
+ depends on X86_64
+ select STACK_VALIDATION
+ ---help---
+ This option enables the ORC (Oops Rewind Capability) unwinder for
+ unwinding kernel stack traces. It uses a custom data format which is
+ a simplified version of the DWARF Call Frame Information standard.
+
+ This unwinder is more accurate across interrupt entry frames than the
+ frame pointer unwinder. It also enables a 5-10% performance
+ improvement across the entire kernel compared to frame pointers.
+
+ Enabling this option will increase the kernel's runtime memory usage
+ by roughly 2-4MB, depending on your kernel config.
+
+config GUESS_UNWINDER
+ bool "Guess unwinder"
+ depends on EXPERT
+ ---help---
+ This option enables the "guess" unwinder for unwinding kernel stack
+ traces. It scans the stack and reports every kernel text address it
+ finds. Some of the addresses it reports may be incorrect.
+
+ While this option often produces false positives, it can still be
+ useful in many cases. Unlike the other unwinders, it has no runtime
+ overhead.
+
+endchoice
+
+config FRAME_POINTER
+ depends on !ORC_UNWINDER && !GUESS_UNWINDER
+ bool
+
endmenu
diff --git a/arch/x86/configs/tiny.config b/arch/x86/configs/tiny.config
index 4b429df..550cd50 100644
--- a/arch/x86/configs/tiny.config
+++ b/arch/x86/configs/tiny.config
@@ -1,3 +1,5 @@
CONFIG_NOHIGHMEM=y
# CONFIG_HIGHMEM4G is not set
# CONFIG_HIGHMEM64G is not set
+CONFIG_GUESS_UNWINDER=y
+# CONFIG_FRAME_POINTER_UNWINDER is not set
diff --git a/arch/x86/entry/Makefile b/arch/x86/entry/Makefile
index 9976fce..af28a8a 100644
--- a/arch/x86/entry/Makefile
+++ b/arch/x86/entry/Makefile
@@ -2,7 +2,6 @@
# Makefile for the x86 low level entry code
#
-OBJECT_FILES_NON_STANDARD_entry_$(BITS).o := y
OBJECT_FILES_NON_STANDARD_entry_64_compat.o := y
CFLAGS_syscall_64.o += $(call cc-option,-Wno-override-init,)
diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h
index 05ed3d3..640aafe 100644
--- a/arch/x86/entry/calling.h
+++ b/arch/x86/entry/calling.h
@@ -1,4 +1,5 @@
#include <linux/jump_label.h>
+#include <asm/unwind_hints.h>
/*
@@ -112,6 +113,7 @@ For 32-bit we have the following conventions - kernel is built with
movq %rdx, 12*8+\offset(%rsp)
movq %rsi, 13*8+\offset(%rsp)
movq %rdi, 14*8+\offset(%rsp)
+ UNWIND_HINT_REGS offset=\offset extra=0
.endm
.macro SAVE_C_REGS offset=0
SAVE_C_REGS_HELPER \offset, 1, 1, 1, 1
@@ -136,6 +138,7 @@ For 32-bit we have the following conventions - kernel is built with
movq %r12, 3*8+\offset(%rsp)
movq %rbp, 4*8+\offset(%rsp)
movq %rbx, 5*8+\offset(%rsp)
+ UNWIND_HINT_REGS offset=\offset
.endm
.macro RESTORE_EXTRA_REGS offset=0
@@ -145,6 +148,7 @@ For 32-bit we have the following conventions - kernel is built with
movq 3*8+\offset(%rsp), %r12
movq 4*8+\offset(%rsp), %rbp
movq 5*8+\offset(%rsp), %rbx
+ UNWIND_HINT_REGS offset=\offset extra=0
.endm
.macro RESTORE_C_REGS_HELPER rstor_rax=1, rstor_rcx=1, rstor_r11=1, rstor_r8910=1, rstor_rdx=1
@@ -167,6 +171,7 @@ For 32-bit we have the following conventions - kernel is built with
.endif
movq 13*8(%rsp), %rsi
movq 14*8(%rsp), %rdi
+ UNWIND_HINT_IRET_REGS offset=16*8
.endm
.macro RESTORE_C_REGS
RESTORE_C_REGS_HELPER 1,1,1,1,1
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 6d078b8..64b233a 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -36,6 +36,7 @@
#include <asm/smap.h>
#include <asm/pgtable_types.h>
#include <asm/export.h>
+#include <asm/frame.h>
#include <linux/err.h>
.code64
@@ -43,9 +44,10 @@
#ifdef CONFIG_PARAVIRT
ENTRY(native_usergs_sysret64)
+ UNWIND_HINT_EMPTY
swapgs
sysretq
-ENDPROC(native_usergs_sysret64)
+END(native_usergs_sysret64)
#endif /* CONFIG_PARAVIRT */
.macro TRACE_IRQS_IRETQ
@@ -134,6 +136,7 @@
*/
ENTRY(entry_SYSCALL_64)
+ UNWIND_HINT_EMPTY
/*
* Interrupts are off on entry.
* We do not frame this tiny irq-off block with TRACE_IRQS_OFF/ON,
@@ -169,6 +172,7 @@
pushq %r10 /* pt_regs->r10 */
pushq %r11 /* pt_regs->r11 */
sub $(6*8), %rsp /* pt_regs->bp, bx, r12-15 not saved */
+ UNWIND_HINT_REGS extra=0
/*
* If we need to do entry work or if we guess we'll need to do
@@ -223,6 +227,7 @@
movq EFLAGS(%rsp), %r11
RESTORE_C_REGS_EXCEPT_RCX_R11
movq RSP(%rsp), %rsp
+ UNWIND_HINT_EMPTY
USERGS_SYSRET64
1:
@@ -316,6 +321,7 @@
/* rcx and r11 are already restored (see code above) */
RESTORE_C_REGS_EXCEPT_RCX_R11
movq RSP(%rsp), %rsp
+ UNWIND_HINT_EMPTY
USERGS_SYSRET64
opportunistic_sysret_failed:
@@ -343,6 +349,7 @@
DISABLE_INTERRUPTS(CLBR_ANY)
TRACE_IRQS_OFF
popq %rax
+ UNWIND_HINT_REGS extra=0
jmp entry_SYSCALL64_slow_path
1:
@@ -351,6 +358,7 @@
.macro ptregs_stub func
ENTRY(ptregs_\func)
+ UNWIND_HINT_FUNC
leaq \func(%rip), %rax
jmp stub_ptregs_64
END(ptregs_\func)
@@ -367,6 +375,7 @@
* %rsi: next task
*/
ENTRY(__switch_to_asm)
+ UNWIND_HINT_FUNC
/*
* Save callee-saved registers
* This must match the order in inactive_task_frame
@@ -406,6 +415,7 @@
* r12: kernel thread arg
*/
ENTRY(ret_from_fork)
+ UNWIND_HINT_EMPTY
movq %rax, %rdi
call schedule_tail /* rdi: 'prev' task parameter */
@@ -413,6 +423,7 @@
jnz 1f /* kernel threads are uncommon */
2:
+ UNWIND_HINT_REGS
movq %rsp, %rdi
call syscall_return_slowpath /* returns with IRQs disabled */
TRACE_IRQS_ON /* user mode is traced as IRQS on */
@@ -440,13 +451,102 @@
ENTRY(irq_entries_start)
vector=FIRST_EXTERNAL_VECTOR
.rept (FIRST_SYSTEM_VECTOR - FIRST_EXTERNAL_VECTOR)
+ UNWIND_HINT_IRET_REGS
pushq $(~vector+0x80) /* Note: always in signed byte range */
- vector=vector+1
jmp common_interrupt
.align 8
+ vector=vector+1
.endr
END(irq_entries_start)
+.macro DEBUG_ENTRY_ASSERT_IRQS_OFF
+#ifdef CONFIG_DEBUG_ENTRY
+ pushfq
+ testl $X86_EFLAGS_IF, (%rsp)
+ jz .Lokay_\@
+ ud2
+.Lokay_\@:
+ addq $8, %rsp
+#endif
+.endm
+
+/*
+ * Enters the IRQ stack if we're not already using it. NMI-safe. Clobbers
+ * flags and puts old RSP into old_rsp, and leaves all other GPRs alone.
+ * Requires kernel GSBASE.
+ *
+ * The invariant is that, if irq_count != -1, then the IRQ stack is in use.
+ */
+.macro ENTER_IRQ_STACK regs=1 old_rsp
+ DEBUG_ENTRY_ASSERT_IRQS_OFF
+ movq %rsp, \old_rsp
+
+ .if \regs
+ UNWIND_HINT_REGS base=\old_rsp
+ .endif
+
+ incl PER_CPU_VAR(irq_count)
+ jnz .Lirq_stack_push_old_rsp_\@
+
+ /*
+ * Right now, if we just incremented irq_count to zero, we've
+ * claimed the IRQ stack but we haven't switched to it yet.
+ *
+ * If anything is added that can interrupt us here without using IST,
+ * it must be *extremely* careful to limit its stack usage. This
+ * could include kprobes and a hypothetical future IST-less #DB
+ * handler.
+ *
+ * The OOPS unwinder relies on the word at the top of the IRQ
+ * stack linking back to the previous RSP for the entire time we're
+ * on the IRQ stack. For this to work reliably, we need to write
+ * it before we actually move ourselves to the IRQ stack.
+ */
+
+ movq \old_rsp, PER_CPU_VAR(irq_stack_union + IRQ_STACK_SIZE - 8)
+ movq PER_CPU_VAR(irq_stack_ptr), %rsp
+
+#ifdef CONFIG_DEBUG_ENTRY
+ /*
+ * If the first movq above becomes wrong due to IRQ stack layout
+ * changes, the only way we'll notice is if we try to unwind right
+ * here. Assert that we set up the stack right to catch this type
+ * of bug quickly.
+ */
+ cmpq -8(%rsp), \old_rsp
+ je .Lirq_stack_okay\@
+ ud2
+ .Lirq_stack_okay\@:
+#endif
+
+.Lirq_stack_push_old_rsp_\@:
+ pushq \old_rsp
+
+ .if \regs
+ UNWIND_HINT_REGS indirect=1
+ .endif
+.endm
+
+/*
+ * Undoes ENTER_IRQ_STACK.
+ */
+.macro LEAVE_IRQ_STACK regs=1
+ DEBUG_ENTRY_ASSERT_IRQS_OFF
+ /* We need to be off the IRQ stack before decrementing irq_count. */
+ popq %rsp
+
+ .if \regs
+ UNWIND_HINT_REGS
+ .endif
+
+ /*
+ * As in ENTER_IRQ_STACK, irq_count == 0, we are still claiming
+ * the irq stack but we're not on it.
+ */
+
+ decl PER_CPU_VAR(irq_count)
+.endm
+
/*
* Interrupt entry/exit.
*
@@ -485,17 +585,7 @@
CALL_enter_from_user_mode
1:
- /*
- * Save previous stack pointer, optionally switch to interrupt stack.
- * irq_count is used to check if a CPU is already on an interrupt stack
- * or not. While this is essentially redundant with preempt_count it is
- * a little cheaper to use a separate counter in the PDA (short of
- * moving irq_enter into assembly, which would be too much work)
- */
- movq %rsp, %rdi
- incl PER_CPU_VAR(irq_count)
- cmovzq PER_CPU_VAR(irq_stack_ptr), %rsp
- pushq %rdi
+ ENTER_IRQ_STACK old_rsp=%rdi
/* We entered an interrupt context - irqs are off: */
TRACE_IRQS_OFF
@@ -515,10 +605,8 @@
ret_from_intr:
DISABLE_INTERRUPTS(CLBR_ANY)
TRACE_IRQS_OFF
- decl PER_CPU_VAR(irq_count)
- /* Restore saved previous stack */
- popq %rsp
+ LEAVE_IRQ_STACK
testb $3, CS(%rsp)
jz retint_kernel
@@ -561,6 +649,7 @@
INTERRUPT_RETURN
ENTRY(native_iret)
+ UNWIND_HINT_IRET_REGS
/*
* Are we returning to a stack segment from the LDT? Note: in
* 64-bit mode SS:RSP on the exception stack is always valid.
@@ -633,6 +722,7 @@
orq PER_CPU_VAR(espfix_stack), %rax
SWAPGS
movq %rax, %rsp
+ UNWIND_HINT_IRET_REGS offset=8
/*
* At this point, we cannot write to the stack any more, but we can
@@ -654,6 +744,7 @@
*/
.macro apicinterrupt3 num sym do_sym
ENTRY(\sym)
+ UNWIND_HINT_IRET_REGS
ASM_CLAC
pushq $~(\num)
.Lcommon_\sym:
@@ -740,6 +831,8 @@
.macro idtentry sym do_sym has_error_code:req paranoid=0 shift_ist=-1
ENTRY(\sym)
+ UNWIND_HINT_IRET_REGS offset=8
+
/* Sanity check */
.if \shift_ist != -1 && \paranoid == 0
.error "using shift_ist requires paranoid=1"
@@ -763,6 +856,7 @@
.else
call error_entry
.endif
+ UNWIND_HINT_REGS
/* returned flag: ebx=0: need swapgs on exit, ebx=1: don't need it */
.if \paranoid
@@ -860,6 +954,7 @@
* edi: new selector
*/
ENTRY(native_load_gs_index)
+ FRAME_BEGIN
pushfq
DISABLE_INTERRUPTS(CLBR_ANY & ~CLBR_RDI)
SWAPGS
@@ -868,8 +963,9 @@
2: ALTERNATIVE "", "mfence", X86_BUG_SWAPGS_FENCE
SWAPGS
popfq
+ FRAME_END
ret
-END(native_load_gs_index)
+ENDPROC(native_load_gs_index)
EXPORT_SYMBOL(native_load_gs_index)
_ASM_EXTABLE(.Lgs_change, bad_gs)
@@ -892,14 +988,12 @@
ENTRY(do_softirq_own_stack)
pushq %rbp
mov %rsp, %rbp
- incl PER_CPU_VAR(irq_count)
- cmove PER_CPU_VAR(irq_stack_ptr), %rsp
- push %rbp /* frame pointer backlink */
+ ENTER_IRQ_STACK regs=0 old_rsp=%r11
call __do_softirq
+ LEAVE_IRQ_STACK regs=0
leaveq
- decl PER_CPU_VAR(irq_count)
ret
-END(do_softirq_own_stack)
+ENDPROC(do_softirq_own_stack)
#ifdef CONFIG_XEN
idtentry xen_hypervisor_callback xen_do_hypervisor_callback has_error_code=0
@@ -923,14 +1017,14 @@
* Since we don't modify %rdi, evtchn_do_upall(struct *pt_regs) will
* see the correct pointer to the pt_regs
*/
+ UNWIND_HINT_FUNC
movq %rdi, %rsp /* we don't return, adjust the stack frame */
-11: incl PER_CPU_VAR(irq_count)
- movq %rsp, %rbp
- cmovzq PER_CPU_VAR(irq_stack_ptr), %rsp
- pushq %rbp /* frame pointer backlink */
+ UNWIND_HINT_REGS
+
+ ENTER_IRQ_STACK old_rsp=%r10
call xen_evtchn_do_upcall
- popq %rsp
- decl PER_CPU_VAR(irq_count)
+ LEAVE_IRQ_STACK
+
#ifndef CONFIG_PREEMPT
call xen_maybe_preempt_hcall
#endif
@@ -951,6 +1045,7 @@
* with its current contents: any discrepancy means we in category 1.
*/
ENTRY(xen_failsafe_callback)
+ UNWIND_HINT_EMPTY
movl %ds, %ecx
cmpw %cx, 0x10(%rsp)
jne 1f
@@ -970,11 +1065,13 @@
pushq $0 /* RIP */
pushq %r11
pushq %rcx
+ UNWIND_HINT_IRET_REGS offset=8
jmp general_protection
1: /* Segment mismatch => Category 1 (Bad segment). Retry the IRET. */
movq (%rsp), %rcx
movq 8(%rsp), %r11
addq $0x30, %rsp
+ UNWIND_HINT_IRET_REGS
pushq $-1 /* orig_ax = -1 => not a system call */
ALLOC_PT_GPREGS_ON_STACK
SAVE_C_REGS
@@ -1020,6 +1117,7 @@
* Return: ebx=0: need swapgs on exit, ebx=1: otherwise
*/
ENTRY(paranoid_entry)
+ UNWIND_HINT_FUNC
cld
SAVE_C_REGS 8
SAVE_EXTRA_REGS 8
@@ -1047,6 +1145,7 @@
* On entry, ebx is "no swapgs" flag (1: don't need swapgs, 0: need it)
*/
ENTRY(paranoid_exit)
+ UNWIND_HINT_REGS
DISABLE_INTERRUPTS(CLBR_ANY)
TRACE_IRQS_OFF_DEBUG
testl %ebx, %ebx /* swapgs needed? */
@@ -1068,6 +1167,7 @@
* Return: EBX=0: came from user mode; EBX=1: otherwise
*/
ENTRY(error_entry)
+ UNWIND_HINT_FUNC
cld
SAVE_C_REGS 8
SAVE_EXTRA_REGS 8
@@ -1152,6 +1252,7 @@
* 0: user gsbase is loaded, we need SWAPGS and standard preparation for return to usermode
*/
ENTRY(error_exit)
+ UNWIND_HINT_REGS
DISABLE_INTERRUPTS(CLBR_ANY)
TRACE_IRQS_OFF
testl %ebx, %ebx
@@ -1161,6 +1262,7 @@
/* Runs on exception stack */
ENTRY(nmi)
+ UNWIND_HINT_IRET_REGS
/*
* Fix up the exception frame if we're on Xen.
* PARAVIRT_ADJUST_EXCEPTION_FRAME is guaranteed to push at most
@@ -1234,11 +1336,13 @@
cld
movq %rsp, %rdx
movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
+ UNWIND_HINT_IRET_REGS base=%rdx offset=8
pushq 5*8(%rdx) /* pt_regs->ss */
pushq 4*8(%rdx) /* pt_regs->rsp */
pushq 3*8(%rdx) /* pt_regs->flags */
pushq 2*8(%rdx) /* pt_regs->cs */
pushq 1*8(%rdx) /* pt_regs->rip */
+ UNWIND_HINT_IRET_REGS
pushq $-1 /* pt_regs->orig_ax */
pushq %rdi /* pt_regs->di */
pushq %rsi /* pt_regs->si */
@@ -1255,6 +1359,7 @@
pushq %r13 /* pt_regs->r13 */
pushq %r14 /* pt_regs->r14 */
pushq %r15 /* pt_regs->r15 */
+ UNWIND_HINT_REGS
ENCODE_FRAME_POINTER
/*
@@ -1409,6 +1514,7 @@
.rept 5
pushq 11*8(%rsp)
.endr
+ UNWIND_HINT_IRET_REGS
/* Everything up to here is safe from nested NMIs */
@@ -1424,6 +1530,7 @@
pushq $__KERNEL_CS /* CS */
pushq $1f /* RIP */
INTERRUPT_RETURN /* continues at repeat_nmi below */
+ UNWIND_HINT_IRET_REGS
1:
#endif
@@ -1473,6 +1580,7 @@
* exceptions might do.
*/
call paranoid_entry
+ UNWIND_HINT_REGS
/* paranoidentry do_nmi, 0; without TRACE_IRQS_OFF */
movq %rsp, %rdi
@@ -1510,17 +1618,19 @@
END(nmi)
ENTRY(ignore_sysret)
+ UNWIND_HINT_EMPTY
mov $-ENOSYS, %eax
sysret
END(ignore_sysret)
ENTRY(rewind_stack_do_exit)
+ UNWIND_HINT_FUNC
/* Prevent any naive code from trying to unwind to our caller. */
xorl %ebp, %ebp
movq PER_CPU_VAR(cpu_current_top_of_stack), %rax
- leaq -TOP_OF_KERNEL_STACK_PADDING-PTREGS_SIZE(%rax), %rsp
+ leaq -PTREGS_SIZE(%rax), %rsp
+ UNWIND_HINT_FUNC sp_offset=PTREGS_SIZE
call do_exit
-1: jmp 1b
END(rewind_stack_do_exit)
diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c
index 7241537..e0bb46c 100644
--- a/arch/x86/ia32/ia32_signal.c
+++ b/arch/x86/ia32/ia32_signal.c
@@ -226,7 +226,7 @@ static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs,
if (ksig->ka.sa.sa_flags & SA_ONSTACK)
sp = sigsp(sp, ksig);
/* This is the legacy signal stack switching. */
- else if ((regs->ss & 0xffff) != __USER32_DS &&
+ else if (regs->ss != __USER32_DS &&
!(ksig->ka.sa.sa_flags & SA_RESTORER) &&
ksig->ka.sa.sa_restorer)
sp = (unsigned long) ksig->ka.sa.sa_restorer;
diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
index 1c18d83..a62a12c 100644
--- a/arch/x86/include/asm/elf.h
+++ b/arch/x86/include/asm/elf.h
@@ -126,15 +126,15 @@ do { \
pr_reg[4] = regs->di; \
pr_reg[5] = regs->bp; \
pr_reg[6] = regs->ax; \
- pr_reg[7] = regs->ds & 0xffff; \
- pr_reg[8] = regs->es & 0xffff; \
- pr_reg[9] = regs->fs & 0xffff; \
+ pr_reg[7] = regs->ds; \
+ pr_reg[8] = regs->es; \
+ pr_reg[9] = regs->fs; \
pr_reg[11] = regs->orig_ax; \
pr_reg[12] = regs->ip; \
- pr_reg[13] = regs->cs & 0xffff; \
+ pr_reg[13] = regs->cs; \
pr_reg[14] = regs->flags; \
pr_reg[15] = regs->sp; \
- pr_reg[16] = regs->ss & 0xffff; \
+ pr_reg[16] = regs->ss; \
} while (0);
#define ELF_CORE_COPY_REGS(pr_reg, regs) \
diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h
index 48febf0..1310e1f 100644
--- a/arch/x86/include/asm/io.h
+++ b/arch/x86/include/asm/io.h
@@ -69,6 +69,9 @@ build_mmio_write(__writeb, "b", unsigned char, "q", )
build_mmio_write(__writew, "w", unsigned short, "r", )
build_mmio_write(__writel, "l", unsigned int, "r", )
+#define readb readb
+#define readw readw
+#define readl readl
#define readb_relaxed(a) __readb(a)
#define readw_relaxed(a) __readw(a)
#define readl_relaxed(a) __readl(a)
@@ -76,6 +79,9 @@ build_mmio_write(__writel, "l", unsigned int, "r", )
#define __raw_readw __readw
#define __raw_readl __readl
+#define writeb writeb
+#define writew writew
+#define writel writel
#define writeb_relaxed(v, a) __writeb(v, a)
#define writew_relaxed(v, a) __writew(v, a)
#define writel_relaxed(v, a) __writel(v, a)
@@ -88,13 +94,15 @@ build_mmio_write(__writel, "l", unsigned int, "r", )
#ifdef CONFIG_X86_64
build_mmio_read(readq, "q", unsigned long, "=r", :"memory")
+build_mmio_read(__readq, "q", unsigned long, "=r", )
build_mmio_write(writeq, "q", unsigned long, "r", :"memory")
+build_mmio_write(__writeq, "q", unsigned long, "r", )
-#define readq_relaxed(a) readq(a)
-#define writeq_relaxed(v, a) writeq(v, a)
+#define readq_relaxed(a) __readq(a)
+#define writeq_relaxed(v, a) __writeq(v, a)
-#define __raw_readq(a) readq(a)
-#define __raw_writeq(val, addr) writeq(val, addr)
+#define __raw_readq __readq
+#define __raw_writeq __writeq
/* Let people know that we have them */
#define readq readq
@@ -119,6 +127,7 @@ static inline phys_addr_t virt_to_phys(volatile void *address)
{
return __pa(address);
}
+#define virt_to_phys virt_to_phys
/**
* phys_to_virt - map physical address to virtual
@@ -137,6 +146,7 @@ static inline void *phys_to_virt(phys_addr_t address)
{
return __va(address);
}
+#define phys_to_virt phys_to_virt
/*
* Change "struct page" to physical address.
@@ -169,11 +179,14 @@ static inline unsigned int isa_virt_to_bus(volatile void *address)
* else, you probably want one of the following.
*/
extern void __iomem *ioremap_nocache(resource_size_t offset, unsigned long size);
+#define ioremap_nocache ioremap_nocache
extern void __iomem *ioremap_uc(resource_size_t offset, unsigned long size);
#define ioremap_uc ioremap_uc
extern void __iomem *ioremap_cache(resource_size_t offset, unsigned long size);
+#define ioremap_cache ioremap_cache
extern void __iomem *ioremap_prot(resource_size_t offset, unsigned long size, unsigned long prot_val);
+#define ioremap_prot ioremap_prot
/**
* ioremap - map bus memory into CPU space
@@ -193,8 +206,10 @@ static inline void __iomem *ioremap(resource_size_t offset, unsigned long size)
{
return ioremap_nocache(offset, size);
}
+#define ioremap ioremap
extern void iounmap(volatile void __iomem *addr);
+#define iounmap iounmap
extern void set_iounmap_nonlazy(void);
@@ -203,53 +218,6 @@ extern void set_iounmap_nonlazy(void);
#include <asm-generic/iomap.h>
/*
- * Convert a virtual cached pointer to an uncached pointer
- */
-#define xlate_dev_kmem_ptr(p) p
-
-/**
- * memset_io Set a range of I/O memory to a constant value
- * @addr: The beginning of the I/O-memory range to set
- * @val: The value to set the memory to
- * @count: The number of bytes to set
- *
- * Set a range of I/O memory to a given value.
- */
-static inline void
-memset_io(volatile void __iomem *addr, unsigned char val, size_t count)
-{
- memset((void __force *)addr, val, count);
-}
-
-/**
- * memcpy_fromio Copy a block of data from I/O memory
- * @dst: The (RAM) destination for the copy
- * @src: The (I/O memory) source for the data
- * @count: The number of bytes to copy
- *
- * Copy a block of data from I/O memory.
- */
-static inline void
-memcpy_fromio(void *dst, const volatile void __iomem *src, size_t count)
-{
- memcpy(dst, (const void __force *)src, count);
-}
-
-/**
- * memcpy_toio Copy a block of data into I/O memory
- * @dst: The (I/O memory) destination for the copy
- * @src: The (RAM) source for the data
- * @count: The number of bytes to copy
- *
- * Copy a block of data to I/O memory.
- */
-static inline void
-memcpy_toio(volatile void __iomem *dst, const void *src, size_t count)
-{
- memcpy((void __force *)dst, src, count);
-}
-
-/*
* ISA space is 'always mapped' on a typical x86 system, no need to
* explicitly ioremap() it. The fact that the ISA IO space is mapped
* to PAGE_OFFSET is pure coincidence - it does not mean ISA values
@@ -341,13 +309,38 @@ BUILDIO(b, b, char)
BUILDIO(w, w, short)
BUILDIO(l, , int)
+#define inb inb
+#define inw inw
+#define inl inl
+#define inb_p inb_p
+#define inw_p inw_p
+#define inl_p inl_p
+#define insb insb
+#define insw insw
+#define insl insl
+
+#define outb outb
+#define outw outw
+#define outl outl
+#define outb_p outb_p
+#define outw_p outw_p
+#define outl_p outl_p
+#define outsb outsb
+#define outsw outsw
+#define outsl outsl
+
extern void *xlate_dev_mem_ptr(phys_addr_t phys);
extern void unxlate_dev_mem_ptr(phys_addr_t phys, void *addr);
+#define xlate_dev_mem_ptr xlate_dev_mem_ptr
+#define unxlate_dev_mem_ptr unxlate_dev_mem_ptr
+
extern int ioremap_change_attr(unsigned long vaddr, unsigned long size,
enum page_cache_mode pcm);
extern void __iomem *ioremap_wc(resource_size_t offset, unsigned long size);
+#define ioremap_wc ioremap_wc
extern void __iomem *ioremap_wt(resource_size_t offset, unsigned long size);
+#define ioremap_wt ioremap_wt
extern bool is_early_ioremap_ptep(pte_t *ptep);
@@ -365,6 +358,9 @@ extern bool xen_biovec_phys_mergeable(const struct bio_vec *vec1,
#define IO_SPACE_LIMIT 0xffff
+#include <asm-generic/io.h>
+#undef PCI_IOBASE
+
#ifdef CONFIG_MTRR
extern int __must_check arch_phys_wc_index(int handle);
#define arch_phys_wc_index arch_phys_wc_index
diff --git a/arch/x86/include/asm/module.h b/arch/x86/include/asm/module.h
index e3b7819..9eb7c71 100644
--- a/arch/x86/include/asm/module.h
+++ b/arch/x86/include/asm/module.h
@@ -2,6 +2,15 @@
#define _ASM_X86_MODULE_H
#include <asm-generic/module.h>
+#include <asm/orc_types.h>
+
+struct mod_arch_specific {
+#ifdef CONFIG_ORC_UNWINDER
+ unsigned int num_orcs;
+ int *orc_unwind_ip;
+ struct orc_entry *orc_unwind;
+#endif
+};
#ifdef CONFIG_X86_64
/* X86_64 does not define MODULE_PROC_FAMILY */
diff --git a/arch/x86/include/asm/orc_lookup.h b/arch/x86/include/asm/orc_lookup.h
new file mode 100644
index 0000000..91c8d86
--- /dev/null
+++ b/arch/x86/include/asm/orc_lookup.h
@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef _ORC_LOOKUP_H
+#define _ORC_LOOKUP_H
+
+/*
+ * This is a lookup table for speeding up access to the .orc_unwind table.
+ * Given an input address offset, the corresponding lookup table entry
+ * specifies a subset of the .orc_unwind table to search.
+ *
+ * Each block represents the end of the previous range and the start of the
+ * next range. An extra block is added to give the last range an end.
+ *
+ * The block size should be a power of 2 to avoid a costly 'div' instruction.
+ *
+ * A block size of 256 was chosen because it roughly doubles unwinder
+ * performance while only adding ~5% to the ORC data footprint.
+ */
+#define LOOKUP_BLOCK_ORDER 8
+#define LOOKUP_BLOCK_SIZE (1 << LOOKUP_BLOCK_ORDER)
+
+#ifndef LINKER_SCRIPT
+
+extern unsigned int orc_lookup[];
+extern unsigned int orc_lookup_end[];
+
+#define LOOKUP_START_IP (unsigned long)_stext
+#define LOOKUP_STOP_IP (unsigned long)_etext
+
+#endif /* LINKER_SCRIPT */
+
+#endif /* _ORC_LOOKUP_H */
diff --git a/arch/x86/include/asm/orc_types.h b/arch/x86/include/asm/orc_types.h
new file mode 100644
index 0000000..9c9dc57
--- /dev/null
+++ b/arch/x86/include/asm/orc_types.h
@@ -0,0 +1,107 @@
+/*
+ * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _ORC_TYPES_H
+#define _ORC_TYPES_H
+
+#include <linux/types.h>
+#include <linux/compiler.h>
+
+/*
+ * The ORC_REG_* registers are base registers which are used to find other
+ * registers on the stack.
+ *
+ * ORC_REG_PREV_SP, also known as DWARF Call Frame Address (CFA), is the
+ * address of the previous frame: the caller's SP before it called the current
+ * function.
+ *
+ * ORC_REG_UNDEFINED means the corresponding register's value didn't change in
+ * the current frame.
+ *
+ * The most commonly used base registers are SP and BP -- which the previous SP
+ * is usually based on -- and PREV_SP and UNDEFINED -- which the previous BP is
+ * usually based on.
+ *
+ * The rest of the base registers are needed for special cases like entry code
+ * and GCC realigned stacks.
+ */
+#define ORC_REG_UNDEFINED 0
+#define ORC_REG_PREV_SP 1
+#define ORC_REG_DX 2
+#define ORC_REG_DI 3
+#define ORC_REG_BP 4
+#define ORC_REG_SP 5
+#define ORC_REG_R10 6
+#define ORC_REG_R13 7
+#define ORC_REG_BP_INDIRECT 8
+#define ORC_REG_SP_INDIRECT 9
+#define ORC_REG_MAX 15
+
+/*
+ * ORC_TYPE_CALL: Indicates that sp_reg+sp_offset resolves to PREV_SP (the
+ * caller's SP right before it made the call). Used for all callable
+ * functions, i.e. all C code and all callable asm functions.
+ *
+ * ORC_TYPE_REGS: Used in entry code to indicate that sp_reg+sp_offset points
+ * to a fully populated pt_regs from a syscall, interrupt, or exception.
+ *
+ * ORC_TYPE_REGS_IRET: Used in entry code to indicate that sp_reg+sp_offset
+ * points to the iret return frame.
+ *
+ * The UNWIND_HINT macros are used only for the unwind_hint struct. They
+ * aren't used in struct orc_entry due to size and complexity constraints.
+ * Objtool converts them to real types when it converts the hints to orc
+ * entries.
+ */
+#define ORC_TYPE_CALL 0
+#define ORC_TYPE_REGS 1
+#define ORC_TYPE_REGS_IRET 2
+#define UNWIND_HINT_TYPE_SAVE 3
+#define UNWIND_HINT_TYPE_RESTORE 4
+
+#ifndef __ASSEMBLY__
+/*
+ * This struct is more or less a vastly simplified version of the DWARF Call
+ * Frame Information standard. It contains only the necessary parts of DWARF
+ * CFI, simplified for ease of access by the in-kernel unwinder. It tells the
+ * unwinder how to find the previous SP and BP (and sometimes entry regs) on
+ * the stack for a given code address. Each instance of the struct corresponds
+ * to one or more code locations.
+ */
+struct orc_entry {
+ s16 sp_offset;
+ s16 bp_offset;
+ unsigned sp_reg:4;
+ unsigned bp_reg:4;
+ unsigned type:2;
+} __packed;
+
+/*
+ * This struct is used by asm and inline asm code to manually annotate the
+ * location of registers on the stack for the ORC unwinder.
+ *
+ * Type can be either ORC_TYPE_* or UNWIND_HINT_TYPE_*.
+ */
+struct unwind_hint {
+ u32 ip;
+ s16 sp_offset;
+ u8 sp_reg;
+ u8 type;
+};
+#endif /* __ASSEMBLY__ */
+
+#endif /* _ORC_TYPES_H */
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 028245e..0b03d655 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -22,6 +22,7 @@ struct vm86;
#include <asm/nops.h>
#include <asm/special_insns.h>
#include <asm/fpu/types.h>
+#include <asm/unwind_hints.h>
#include <linux/personality.h>
#include <linux/cache.h>
@@ -684,6 +685,7 @@ static inline void sync_core(void)
unsigned int tmp;
asm volatile (
+ UNWIND_HINT_SAVE
"mov %%ss, %0\n\t"
"pushq %q0\n\t"
"pushq %%rsp\n\t"
@@ -693,6 +695,7 @@ static inline void sync_core(void)
"pushq %q0\n\t"
"pushq $1f\n\t"
"iretq\n\t"
+ UNWIND_HINT_RESTORE
"1:"
: "=&r" (tmp), "+r" (__sp) : : "cc", "memory");
#endif
diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h
index 2b5d686..a29f828 100644
--- a/arch/x86/include/asm/ptrace.h
+++ b/arch/x86/include/asm/ptrace.h
@@ -9,6 +9,20 @@
#ifdef __i386__
struct pt_regs {
+ /*
+ * NB: 32-bit x86 CPUs are inconsistent as what happens in the
+ * following cases (where %seg represents a segment register):
+ *
+ * - pushl %seg: some do a 16-bit write and leave the high
+ * bits alone
+ * - movl %seg, [mem]: some do a 16-bit write despite the movl
+ * - IDT entry: some (e.g. 486) will leave the high bits of CS
+ * and (if applicable) SS undefined.
+ *
+ * Fortunately, x86-32 doesn't read the high bits on POP or IRET,
+ * so we can just treat all of the segment registers as 16-bit
+ * values.
+ */
unsigned long bx;
unsigned long cx;
unsigned long dx;
@@ -16,16 +30,22 @@ struct pt_regs {
unsigned long di;
unsigned long bp;
unsigned long ax;
- unsigned long ds;
- unsigned long es;
- unsigned long fs;
- unsigned long gs;
+ unsigned short ds;
+ unsigned short __dsh;
+ unsigned short es;
+ unsigned short __esh;
+ unsigned short fs;
+ unsigned short __fsh;
+ unsigned short gs;
+ unsigned short __gsh;
unsigned long orig_ax;
unsigned long ip;
- unsigned long cs;
+ unsigned short cs;
+ unsigned short __csh;
unsigned long flags;
unsigned long sp;
- unsigned long ss;
+ unsigned short ss;
+ unsigned short __ssh;
};
#else /* __i386__ */
diff --git a/arch/x86/include/asm/rmwcc.h b/arch/x86/include/asm/rmwcc.h
index 661dd30..045f992 100644
--- a/arch/x86/include/asm/rmwcc.h
+++ b/arch/x86/include/asm/rmwcc.h
@@ -1,45 +1,56 @@
#ifndef _ASM_X86_RMWcc
#define _ASM_X86_RMWcc
+#define __CLOBBERS_MEM "memory"
+#define __CLOBBERS_MEM_CC_CX "memory", "cc", "cx"
+
#if !defined(__GCC_ASM_FLAG_OUTPUTS__) && defined(CC_HAVE_ASM_GOTO)
/* Use asm goto */
-#define __GEN_RMWcc(fullop, var, cc, ...) \
+#define __GEN_RMWcc(fullop, var, cc, clobbers, ...) \
do { \
asm_volatile_goto (fullop "; j" #cc " %l[cc_label]" \
- : : "m" (var), ## __VA_ARGS__ \
- : "memory" : cc_label); \
+ : : [counter] "m" (var), ## __VA_ARGS__ \
+ : clobbers : cc_label); \
return 0; \
cc_label: \
return 1; \
} while (0)
-#define GEN_UNARY_RMWcc(op, var, arg0, cc) \
- __GEN_RMWcc(op " " arg0, var, cc)
+#define __BINARY_RMWcc_ARG " %1, "
-#define GEN_BINARY_RMWcc(op, var, vcon, val, arg0, cc) \
- __GEN_RMWcc(op " %1, " arg0, var, cc, vcon (val))
#else /* defined(__GCC_ASM_FLAG_OUTPUTS__) || !defined(CC_HAVE_ASM_GOTO) */
/* Use flags output or a set instruction */
-#define __GEN_RMWcc(fullop, var, cc, ...) \
+#define __GEN_RMWcc(fullop, var, cc, clobbers, ...) \
do { \
bool c; \
asm volatile (fullop ";" CC_SET(cc) \
- : "+m" (var), CC_OUT(cc) (c) \
- : __VA_ARGS__ : "memory"); \
+ : [counter] "+m" (var), CC_OUT(cc) (c) \
+ : __VA_ARGS__ : clobbers); \
return c; \
} while (0)
-#define GEN_UNARY_RMWcc(op, var, arg0, cc) \
- __GEN_RMWcc(op " " arg0, var, cc)
-
-#define GEN_BINARY_RMWcc(op, var, vcon, val, arg0, cc) \
- __GEN_RMWcc(op " %2, " arg0, var, cc, vcon (val))
+#define __BINARY_RMWcc_ARG " %2, "
#endif /* defined(__GCC_ASM_FLAG_OUTPUTS__) || !defined(CC_HAVE_ASM_GOTO) */
+#define GEN_UNARY_RMWcc(op, var, arg0, cc) \
+ __GEN_RMWcc(op " " arg0, var, cc, __CLOBBERS_MEM)
+
+#define GEN_UNARY_SUFFIXED_RMWcc(op, suffix, var, arg0, cc) \
+ __GEN_RMWcc(op " " arg0 "\n\t" suffix, var, cc, \
+ __CLOBBERS_MEM_CC_CX)
+
+#define GEN_BINARY_RMWcc(op, var, vcon, val, arg0, cc) \
+ __GEN_RMWcc(op __BINARY_RMWcc_ARG arg0, var, cc, \
+ __CLOBBERS_MEM, vcon (val))
+
+#define GEN_BINARY_SUFFIXED_RMWcc(op, suffix, var, vcon, val, arg0, cc) \
+ __GEN_RMWcc(op __BINARY_RMWcc_ARG arg0 "\n\t" suffix, var, cc, \
+ __CLOBBERS_MEM_CC_CX, vcon (val))
+
#endif /* _ASM_X86_RMWcc */
diff --git a/arch/x86/include/asm/unwind.h b/arch/x86/include/asm/unwind.h
index e667649..e9f793e 100644
--- a/arch/x86/include/asm/unwind.h
+++ b/arch/x86/include/asm/unwind.h
@@ -12,11 +12,14 @@ struct unwind_state {
struct task_struct *task;
int graph_idx;
bool error;
-#ifdef CONFIG_FRAME_POINTER
- bool got_irq;
- unsigned long *bp, *orig_sp;
+#if defined(CONFIG_ORC_UNWINDER)
+ bool signal, full_regs;
+ unsigned long sp, bp, ip;
struct pt_regs *regs;
- unsigned long ip;
+#elif defined(CONFIG_FRAME_POINTER_UNWINDER)
+ bool got_irq;
+ unsigned long *bp, *orig_sp, ip;
+ struct pt_regs *regs;
#else
unsigned long *sp;
#endif
@@ -24,16 +27,20 @@ struct unwind_state {
void __unwind_start(struct unwind_state *state, struct task_struct *task,
struct pt_regs *regs, unsigned long *first_frame);
-
bool unwind_next_frame(struct unwind_state *state);
-
unsigned long unwind_get_return_address(struct unwind_state *state);
+unsigned long *unwind_get_return_address_ptr(struct unwind_state *state);
static inline bool unwind_done(struct unwind_state *state)
{
return state->stack_info.type == STACK_TYPE_UNKNOWN;
}
+static inline bool unwind_error(struct unwind_state *state)
+{
+ return state->error;
+}
+
static inline
void unwind_start(struct unwind_state *state, struct task_struct *task,
struct pt_regs *regs, unsigned long *first_frame)
@@ -43,22 +50,7 @@ void unwind_start(struct unwind_state *state, struct task_struct *task,
__unwind_start(state, task, regs, first_frame);
}
-static inline bool unwind_error(struct unwind_state *state)
-{
- return state->error;
-}
-
-#ifdef CONFIG_FRAME_POINTER
-
-static inline
-unsigned long *unwind_get_return_address_ptr(struct unwind_state *state)
-{
- if (unwind_done(state))
- return NULL;
-
- return state->regs ? &state->regs->ip : state->bp + 1;
-}
-
+#if defined(CONFIG_ORC_UNWINDER) || defined(CONFIG_FRAME_POINTER_UNWINDER)
static inline struct pt_regs *unwind_get_entry_regs(struct unwind_state *state)
{
if (unwind_done(state))
@@ -66,20 +58,46 @@ static inline struct pt_regs *unwind_get_entry_regs(struct unwind_state *state)
return state->regs;
}
-
-#else /* !CONFIG_FRAME_POINTER */
-
-static inline
-unsigned long *unwind_get_return_address_ptr(struct unwind_state *state)
-{
- return NULL;
-}
-
+#else
static inline struct pt_regs *unwind_get_entry_regs(struct unwind_state *state)
{
return NULL;
}
+#endif
-#endif /* CONFIG_FRAME_POINTER */
+#ifdef CONFIG_ORC_UNWINDER
+void unwind_init(void);
+void unwind_module_init(struct module *mod, void *orc_ip, size_t orc_ip_size,
+ void *orc, size_t orc_size);
+#else
+static inline void unwind_init(void) {}
+static inline
+void unwind_module_init(struct module *mod, void *orc_ip, size_t orc_ip_size,
+ void *orc, size_t orc_size) {}
+#endif
+
+/*
+ * This disables KASAN checking when reading a value from another task's stack,
+ * since the other task could be running on another CPU and could have poisoned
+ * the stack in the meantime.
+ */
+#define READ_ONCE_TASK_STACK(task, x) \
+({ \
+ unsigned long val; \
+ if (task == current) \
+ val = READ_ONCE(x); \
+ else \
+ val = READ_ONCE_NOCHECK(x); \
+ val; \
+})
+
+static inline bool task_on_another_cpu(struct task_struct *task)
+{
+#ifdef CONFIG_SMP
+ return task != current && task->on_cpu;
+#else
+ return false;
+#endif
+}
#endif /* _ASM_X86_UNWIND_H */
diff --git a/arch/x86/include/asm/unwind_hints.h b/arch/x86/include/asm/unwind_hints.h
new file mode 100644
index 0000000..5e02b11
--- /dev/null
+++ b/arch/x86/include/asm/unwind_hints.h
@@ -0,0 +1,103 @@
+#ifndef _ASM_X86_UNWIND_HINTS_H
+#define _ASM_X86_UNWIND_HINTS_H
+
+#include "orc_types.h"
+
+#ifdef __ASSEMBLY__
+
+/*
+ * In asm, there are two kinds of code: normal C-type callable functions and
+ * the rest. The normal callable functions can be called by other code, and
+ * don't do anything unusual with the stack. Such normal callable functions
+ * are annotated with the ENTRY/ENDPROC macros. Most asm code falls in this
+ * category. In this case, no special debugging annotations are needed because
+ * objtool can automatically generate the ORC data for the ORC unwinder to read
+ * at runtime.
+ *
+ * Anything which doesn't fall into the above category, such as syscall and
+ * interrupt handlers, tends to not be called directly by other functions, and
+ * often does unusual non-C-function-type things with the stack pointer. Such
+ * code needs to be annotated such that objtool can understand it. The
+ * following CFI hint macros are for this type of code.
+ *
+ * These macros provide hints to objtool about the state of the stack at each
+ * instruction. Objtool starts from the hints and follows the code flow,
+ * making automatic CFI adjustments when it sees pushes and pops, filling out
+ * the debuginfo as necessary. It will also warn if it sees any
+ * inconsistencies.
+ */
+.macro UNWIND_HINT sp_reg=ORC_REG_SP sp_offset=0 type=ORC_TYPE_CALL
+#ifdef CONFIG_STACK_VALIDATION
+.Lunwind_hint_ip_\@:
+ .pushsection .discard.unwind_hints
+ /* struct unwind_hint */
+ .long .Lunwind_hint_ip_\@ - .
+ .short \sp_offset
+ .byte \sp_reg
+ .byte \type
+ .popsection
+#endif
+.endm
+
+.macro UNWIND_HINT_EMPTY
+ UNWIND_HINT sp_reg=ORC_REG_UNDEFINED
+.endm
+
+.macro UNWIND_HINT_REGS base=%rsp offset=0 indirect=0 extra=1 iret=0
+ .if \base == %rsp && \indirect
+ .set sp_reg, ORC_REG_SP_INDIRECT
+ .elseif \base == %rsp
+ .set sp_reg, ORC_REG_SP
+ .elseif \base == %rbp
+ .set sp_reg, ORC_REG_BP
+ .elseif \base == %rdi
+ .set sp_reg, ORC_REG_DI
+ .elseif \base == %rdx
+ .set sp_reg, ORC_REG_DX
+ .elseif \base == %r10
+ .set sp_reg, ORC_REG_R10
+ .else
+ .error "UNWIND_HINT_REGS: bad base register"
+ .endif
+
+ .set sp_offset, \offset
+
+ .if \iret
+ .set type, ORC_TYPE_REGS_IRET
+ .elseif \extra == 0
+ .set type, ORC_TYPE_REGS_IRET
+ .set sp_offset, \offset + (16*8)
+ .else
+ .set type, ORC_TYPE_REGS
+ .endif
+
+ UNWIND_HINT sp_reg=sp_reg sp_offset=sp_offset type=type
+.endm
+
+.macro UNWIND_HINT_IRET_REGS base=%rsp offset=0
+ UNWIND_HINT_REGS base=\base offset=\offset iret=1
+.endm
+
+.macro UNWIND_HINT_FUNC sp_offset=8
+ UNWIND_HINT sp_offset=\sp_offset
+.endm
+
+#else /* !__ASSEMBLY__ */
+
+#define UNWIND_HINT(sp_reg, sp_offset, type) \
+ "987: \n\t" \
+ ".pushsection .discard.unwind_hints\n\t" \
+ /* struct unwind_hint */ \
+ ".long 987b - .\n\t" \
+ ".short " __stringify(sp_offset) "\n\t" \
+ ".byte " __stringify(sp_reg) "\n\t" \
+ ".byte " __stringify(type) "\n\t" \
+ ".popsection\n\t"
+
+#define UNWIND_HINT_SAVE UNWIND_HINT(0, 0, UNWIND_HINT_TYPE_SAVE)
+
+#define UNWIND_HINT_RESTORE UNWIND_HINT(0, 0, UNWIND_HINT_TYPE_RESTORE)
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* _ASM_X86_UNWIND_HINTS_H */
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index a01892b..287eac7 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -126,11 +126,9 @@
obj-$(CONFIG_TRACING) += tracepoint.o
obj-$(CONFIG_SCHED_MC_PRIO) += itmt.o
-ifdef CONFIG_FRAME_POINTER
-obj-y += unwind_frame.o
-else
-obj-y += unwind_guess.o
-endif
+obj-$(CONFIG_ORC_UNWINDER) += unwind_orc.o
+obj-$(CONFIG_FRAME_POINTER_UNWINDER) += unwind_frame.o
+obj-$(CONFIG_GUESS_UNWINDER) += unwind_guess.o
###
# 64 bit specific files
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index dbce3cc..f13b4c0 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -94,6 +94,9 @@ void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
if (stack_name)
printk("%s <%s>\n", log_lvl, stack_name);
+ if (regs && on_stack(&stack_info, regs, sizeof(*regs)))
+ __show_regs(regs, 0);
+
/*
* Scan the stack, printing any text addresses we find. At the
* same time, follow proper stack frames with the unwinder.
@@ -118,10 +121,8 @@ void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
* Don't print regs->ip again if it was already printed
* by __show_regs() below.
*/
- if (regs && stack == ®s->ip) {
- unwind_next_frame(&state);
- continue;
- }
+ if (regs && stack == ®s->ip)
+ goto next;
if (stack == ret_addr_p)
reliable = 1;
@@ -144,6 +145,7 @@ void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
if (!reliable)
continue;
+next:
/*
* Get the next frame from the unwinder. No need to
* check for an error: if anything goes wrong, the rest
@@ -153,7 +155,7 @@ void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
/* if the frame has entry regs, print them */
regs = unwind_get_entry_regs(&state);
- if (regs)
+ if (regs && on_stack(&stack_info, regs, sizeof(*regs)))
__show_regs(regs, 0);
}
@@ -265,7 +267,7 @@ int __die(const char *str, struct pt_regs *regs, long err)
#ifdef CONFIG_X86_32
if (user_mode(regs)) {
sp = regs->sp;
- ss = regs->ss & 0xffff;
+ ss = regs->ss;
} else {
sp = kernel_stack_pointer(regs);
savesegment(ss, ss);
diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c
index e5f0b40..4f04814 100644
--- a/arch/x86/kernel/dumpstack_32.c
+++ b/arch/x86/kernel/dumpstack_32.c
@@ -37,7 +37,7 @@ static bool in_hardirq_stack(unsigned long *stack, struct stack_info *info)
* This is a software stack, so 'end' can be a valid stack pointer.
* It just means the stack is empty.
*/
- if (stack < begin || stack > end)
+ if (stack <= begin || stack > end)
return false;
info->type = STACK_TYPE_IRQ;
@@ -62,7 +62,7 @@ static bool in_softirq_stack(unsigned long *stack, struct stack_info *info)
* This is a software stack, so 'end' can be a valid stack pointer.
* It just means the stack is empty.
*/
- if (stack < begin || stack > end)
+ if (stack <= begin || stack > end)
return false;
info->type = STACK_TYPE_SOFTIRQ;
diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c
index 3e1471d..225af41 100644
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -55,7 +55,7 @@ static bool in_exception_stack(unsigned long *stack, struct stack_info *info)
begin = end - (exception_stack_sizes[k] / sizeof(long));
regs = (struct pt_regs *)end - 1;
- if (stack < begin || stack >= end)
+ if (stack <= begin || stack >= end)
continue;
info->type = STACK_TYPE_EXCEPTION + k;
@@ -78,7 +78,7 @@ static bool in_irq_stack(unsigned long *stack, struct stack_info *info)
* This is a software stack, so 'end' can be a valid stack pointer.
* It just means the stack is empty.
*/
- if (stack < begin || stack > end)
+ if (stack <= begin || stack > end)
return false;
info->type = STACK_TYPE_IRQ;
diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index 1f85ee8..0332664 100644
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -457,12 +457,9 @@
/* The vector number is in pt_regs->gs */
cld
- pushl %fs /* pt_regs->fs */
- movw $0, 2(%esp) /* clear high bits (some CPUs leave garbage) */
- pushl %es /* pt_regs->es */
- movw $0, 2(%esp) /* clear high bits (some CPUs leave garbage) */
- pushl %ds /* pt_regs->ds */
- movw $0, 2(%esp) /* clear high bits (some CPUs leave garbage) */
+ pushl %fs /* pt_regs->fs (__fsh varies by model) */
+ pushl %es /* pt_regs->es (__esh varies by model) */
+ pushl %ds /* pt_regs->ds (__dsh varies by model) */
pushl %eax /* pt_regs->ax */
pushl %ebp /* pt_regs->bp */
pushl %edi /* pt_regs->di */
@@ -479,9 +476,8 @@
/* Load the vector number into EDX */
movl PT_GS(%esp), %edx
- /* Load GS into pt_regs->gs and clear high bits */
+ /* Load GS into pt_regs->gs (and maybe clobber __gsh) */
movw %gs, PT_GS(%esp)
- movw $0, PT_GS+2(%esp)
movl %esp, %eax /* args are pt_regs (EAX), trapnr (EDX) */
call early_fixup_exception
@@ -493,10 +489,10 @@
popl %edi /* pt_regs->di */
popl %ebp /* pt_regs->bp */
popl %eax /* pt_regs->ax */
- popl %ds /* pt_regs->ds */
- popl %es /* pt_regs->es */
- popl %fs /* pt_regs->fs */
- popl %gs /* pt_regs->gs */
+ popl %ds /* pt_regs->ds (always ignores __dsh) */
+ popl %es /* pt_regs->es (always ignores __esh) */
+ popl %fs /* pt_regs->fs (always ignores __fsh) */
+ popl %gs /* pt_regs->gs (always ignores __gsh) */
decl %ss:early_recursion_flag
addl $4, %esp /* pop pt_regs->orig_ax */
iret
diff --git a/arch/x86/kernel/ldt.c b/arch/x86/kernel/ldt.c
index a870910..f0e64db 100644
--- a/arch/x86/kernel/ldt.c
+++ b/arch/x86/kernel/ldt.c
@@ -21,6 +21,25 @@
#include <asm/mmu_context.h>
#include <asm/syscalls.h>
+static void refresh_ldt_segments(void)
+{
+#ifdef CONFIG_X86_64
+ unsigned short sel;
+
+ /*
+ * Make sure that the cached DS and ES descriptors match the updated
+ * LDT.
+ */
+ savesegment(ds, sel);
+ if ((sel & SEGMENT_TI_MASK) == SEGMENT_LDT)
+ loadsegment(ds, sel);
+
+ savesegment(es, sel);
+ if ((sel & SEGMENT_TI_MASK) == SEGMENT_LDT)
+ loadsegment(es, sel);
+#endif
+}
+
/* context.lock is held for us, so we don't need any locking. */
static void flush_ldt(void *__mm)
{
@@ -32,6 +51,8 @@ static void flush_ldt(void *__mm)
pc = &mm->context;
set_ldt(pc->ldt->entries, pc->ldt->nr_entries);
+
+ refresh_ldt_segments();
}
/* The caller must call finalize_ldt_struct on the result. LDT starts zeroed. */
diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c
index f67bd32..62e7d70 100644
--- a/arch/x86/kernel/module.c
+++ b/arch/x86/kernel/module.c
@@ -35,6 +35,7 @@
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/setup.h>
+#include <asm/unwind.h>
#if 0
#define DEBUGP(fmt, ...) \
@@ -213,7 +214,7 @@ int module_finalize(const Elf_Ehdr *hdr,
struct module *me)
{
const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL,
- *para = NULL;
+ *para = NULL, *orc = NULL, *orc_ip = NULL;
char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
@@ -225,6 +226,10 @@ int module_finalize(const Elf_Ehdr *hdr,
locks = s;
if (!strcmp(".parainstructions", secstrings + s->sh_name))
para = s;
+ if (!strcmp(".orc_unwind", secstrings + s->sh_name))
+ orc = s;
+ if (!strcmp(".orc_unwind_ip", secstrings + s->sh_name))
+ orc_ip = s;
}
if (alt) {
@@ -248,6 +253,10 @@ int module_finalize(const Elf_Ehdr *hdr,
/* make jump label nops */
jump_label_apply_nops(me);
+ if (orc && orc_ip)
+ unwind_module_init(me, (void *)orc_ip->sh_addr, orc_ip->sh_size,
+ (void *)orc->sh_addr, orc->sh_size);
+
return 0;
}
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index c6d6dc5..efc5eeb 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -68,7 +68,7 @@ void __show_regs(struct pt_regs *regs, int all)
if (user_mode(regs)) {
sp = regs->sp;
- ss = regs->ss & 0xffff;
+ ss = regs->ss;
gs = get_user_gs(regs);
} else {
sp = kernel_stack_pointer(regs);
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index c3169be..e04941f 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -69,8 +69,7 @@ void __show_regs(struct pt_regs *regs, int all)
unsigned int fsindex, gsindex;
unsigned int ds, cs, es;
- printk(KERN_DEFAULT "RIP: %04lx:%pS\n", regs->cs & 0xffff,
- (void *)regs->ip);
+ printk(KERN_DEFAULT "RIP: %04lx:%pS\n", regs->cs, (void *)regs->ip);
printk(KERN_DEFAULT "RSP: %04lx:%016lx EFLAGS: %08lx", regs->ss,
regs->sp, regs->flags);
if (regs->orig_ax != -1)
@@ -279,6 +278,9 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
struct tss_struct *tss = &per_cpu(cpu_tss, cpu);
unsigned prev_fsindex, prev_gsindex;
+ WARN_ON_ONCE(IS_ENABLED(CONFIG_DEBUG_ENTRY) &&
+ this_cpu_read(irq_count) != -1);
+
switch_fpu_prepare(prev_fpu, cpu);
/* We must save %fs and %gs before load_TLS() because
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 3486d04..ecab322 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -115,6 +115,7 @@
#include <asm/microcode.h>
#include <asm/mmu_context.h>
#include <asm/kaslr.h>
+#include <asm/unwind.h>
/*
* max_low_pfn_mapped: highest direct mapped pfn under 4GB
@@ -1310,6 +1311,8 @@ void __init setup_arch(char **cmdline_p)
if (efi_enabled(EFI_BOOT))
efi_apply_memmap_quirks();
#endif
+
+ unwind_init();
}
#ifdef CONFIG_X86_32
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index cc30a74..e044423 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -256,7 +256,7 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
sp = current->sas_ss_sp + current->sas_ss_size;
} else if (IS_ENABLED(CONFIG_X86_32) &&
!onsigstack &&
- (regs->ss & 0xffff) != __USER_DS &&
+ regs->ss != __USER_DS &&
!(ka->sa.sa_flags & SA_RESTORER) &&
ka->sa.sa_restorer) {
/* This is the legacy signal stack switching. */
diff --git a/arch/x86/kernel/step.c b/arch/x86/kernel/step.c
index 5f25cfb..5ee6638 100644
--- a/arch/x86/kernel/step.c
+++ b/arch/x86/kernel/step.c
@@ -13,7 +13,7 @@ unsigned long convert_ip_to_linear(struct task_struct *child, struct pt_regs *re
unsigned long addr, seg;
addr = regs->ip;
- seg = regs->cs & 0xffff;
+ seg = regs->cs;
if (v8086_mode(regs)) {
addr = (addr & 0xffff) + (seg << 4);
return addr;
diff --git a/arch/x86/kernel/unwind_frame.c b/arch/x86/kernel/unwind_frame.c
index b9389d7..7574ef5 100644
--- a/arch/x86/kernel/unwind_frame.c
+++ b/arch/x86/kernel/unwind_frame.c
@@ -10,20 +10,22 @@
#define FRAME_HEADER_SIZE (sizeof(long) * 2)
-/*
- * This disables KASAN checking when reading a value from another task's stack,
- * since the other task could be running on another CPU and could have poisoned
- * the stack in the meantime.
- */
-#define READ_ONCE_TASK_STACK(task, x) \
-({ \
- unsigned long val; \
- if (task == current) \
- val = READ_ONCE(x); \
- else \
- val = READ_ONCE_NOCHECK(x); \
- val; \
-})
+unsigned long unwind_get_return_address(struct unwind_state *state)
+{
+ if (unwind_done(state))
+ return 0;
+
+ return __kernel_text_address(state->ip) ? state->ip : 0;
+}
+EXPORT_SYMBOL_GPL(unwind_get_return_address);
+
+unsigned long *unwind_get_return_address_ptr(struct unwind_state *state)
+{
+ if (unwind_done(state))
+ return NULL;
+
+ return state->regs ? &state->regs->ip : state->bp + 1;
+}
static void unwind_dump(struct unwind_state *state)
{
@@ -66,15 +68,6 @@ static void unwind_dump(struct unwind_state *state)
}
}
-unsigned long unwind_get_return_address(struct unwind_state *state)
-{
- if (unwind_done(state))
- return 0;
-
- return __kernel_text_address(state->ip) ? state->ip : 0;
-}
-EXPORT_SYMBOL_GPL(unwind_get_return_address);
-
static size_t regs_size(struct pt_regs *regs)
{
/* x86_32 regs from kernel mode are two words shorter: */
diff --git a/arch/x86/kernel/unwind_guess.c b/arch/x86/kernel/unwind_guess.c
index 039f367..4f0e17b 100644
--- a/arch/x86/kernel/unwind_guess.c
+++ b/arch/x86/kernel/unwind_guess.c
@@ -19,6 +19,11 @@ unsigned long unwind_get_return_address(struct unwind_state *state)
}
EXPORT_SYMBOL_GPL(unwind_get_return_address);
+unsigned long *unwind_get_return_address_ptr(struct unwind_state *state)
+{
+ return NULL;
+}
+
bool unwind_next_frame(struct unwind_state *state)
{
struct stack_info *info = &state->stack_info;
diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c
new file mode 100644
index 0000000..570b70d
--- /dev/null
+++ b/arch/x86/kernel/unwind_orc.c
@@ -0,0 +1,582 @@
+#include <linux/module.h>
+#include <linux/sort.h>
+#include <asm/ptrace.h>
+#include <asm/stacktrace.h>
+#include <asm/unwind.h>
+#include <asm/orc_types.h>
+#include <asm/orc_lookup.h>
+#include <asm/sections.h>
+
+#define orc_warn(fmt, ...) \
+ printk_deferred_once(KERN_WARNING pr_fmt("WARNING: " fmt), ##__VA_ARGS__)
+
+extern int __start_orc_unwind_ip[];
+extern int __stop_orc_unwind_ip[];
+extern struct orc_entry __start_orc_unwind[];
+extern struct orc_entry __stop_orc_unwind[];
+
+static DEFINE_MUTEX(sort_mutex);
+int *cur_orc_ip_table = __start_orc_unwind_ip;
+struct orc_entry *cur_orc_table = __start_orc_unwind;
+
+unsigned int lookup_num_blocks;
+bool orc_init;
+
+static inline unsigned long orc_ip(const int *ip)
+{
+ return (unsigned long)ip + *ip;
+}
+
+static struct orc_entry *__orc_find(int *ip_table, struct orc_entry *u_table,
+ unsigned int num_entries, unsigned long ip)
+{
+ int *first = ip_table;
+ int *last = ip_table + num_entries - 1;
+ int *mid = first, *found = first;
+
+ if (!num_entries)
+ return NULL;
+
+ /*
+ * Do a binary range search to find the rightmost duplicate of a given
+ * starting address. Some entries are section terminators which are
+ * "weak" entries for ensuring there are no gaps. They should be
+ * ignored when they conflict with a real entry.
+ */
+ while (first <= last) {
+ mid = first + ((last - first) / 2);
+
+ if (orc_ip(mid) <= ip) {
+ found = mid;
+ first = mid + 1;
+ } else
+ last = mid - 1;
+ }
+
+ return u_table + (found - ip_table);
+}
+
+#ifdef CONFIG_MODULES
+static struct orc_entry *orc_module_find(unsigned long ip)
+{
+ struct module *mod;
+
+ mod = __module_address(ip);
+ if (!mod || !mod->arch.orc_unwind || !mod->arch.orc_unwind_ip)
+ return NULL;
+ return __orc_find(mod->arch.orc_unwind_ip, mod->arch.orc_unwind,
+ mod->arch.num_orcs, ip);
+}
+#else
+static struct orc_entry *orc_module_find(unsigned long ip)
+{
+ return NULL;
+}
+#endif
+
+static struct orc_entry *orc_find(unsigned long ip)
+{
+ if (!orc_init)
+ return NULL;
+
+ /* For non-init vmlinux addresses, use the fast lookup table: */
+ if (ip >= LOOKUP_START_IP && ip < LOOKUP_STOP_IP) {
+ unsigned int idx, start, stop;
+
+ idx = (ip - LOOKUP_START_IP) / LOOKUP_BLOCK_SIZE;
+
+ if (unlikely((idx >= lookup_num_blocks-1))) {
+ orc_warn("WARNING: bad lookup idx: idx=%u num=%u ip=%lx\n",
+ idx, lookup_num_blocks, ip);
+ return NULL;
+ }
+
+ start = orc_lookup[idx];
+ stop = orc_lookup[idx + 1] + 1;
+
+ if (unlikely((__start_orc_unwind + start >= __stop_orc_unwind) ||
+ (__start_orc_unwind + stop > __stop_orc_unwind))) {
+ orc_warn("WARNING: bad lookup value: idx=%u num=%u start=%u stop=%u ip=%lx\n",
+ idx, lookup_num_blocks, start, stop, ip);
+ return NULL;
+ }
+
+ return __orc_find(__start_orc_unwind_ip + start,
+ __start_orc_unwind + start, stop - start, ip);
+ }
+
+ /* vmlinux .init slow lookup: */
+ if (ip >= (unsigned long)_sinittext && ip < (unsigned long)_einittext)
+ return __orc_find(__start_orc_unwind_ip, __start_orc_unwind,
+ __stop_orc_unwind_ip - __start_orc_unwind_ip, ip);
+
+ /* Module lookup: */
+ return orc_module_find(ip);
+}
+
+static void orc_sort_swap(void *_a, void *_b, int size)
+{
+ struct orc_entry *orc_a, *orc_b;
+ struct orc_entry orc_tmp;
+ int *a = _a, *b = _b, tmp;
+ int delta = _b - _a;
+
+ /* Swap the .orc_unwind_ip entries: */
+ tmp = *a;
+ *a = *b + delta;
+ *b = tmp - delta;
+
+ /* Swap the corresponding .orc_unwind entries: */
+ orc_a = cur_orc_table + (a - cur_orc_ip_table);
+ orc_b = cur_orc_table + (b - cur_orc_ip_table);
+ orc_tmp = *orc_a;
+ *orc_a = *orc_b;
+ *orc_b = orc_tmp;
+}
+
+static int orc_sort_cmp(const void *_a, const void *_b)
+{
+ struct orc_entry *orc_a;
+ const int *a = _a, *b = _b;
+ unsigned long a_val = orc_ip(a);
+ unsigned long b_val = orc_ip(b);
+
+ if (a_val > b_val)
+ return 1;
+ if (a_val < b_val)
+ return -1;
+
+ /*
+ * The "weak" section terminator entries need to always be on the left
+ * to ensure the lookup code skips them in favor of real entries.
+ * These terminator entries exist to handle any gaps created by
+ * whitelisted .o files which didn't get objtool generation.
+ */
+ orc_a = cur_orc_table + (a - cur_orc_ip_table);
+ return orc_a->sp_reg == ORC_REG_UNDEFINED ? -1 : 1;
+}
+
+#ifdef CONFIG_MODULES
+void unwind_module_init(struct module *mod, void *_orc_ip, size_t orc_ip_size,
+ void *_orc, size_t orc_size)
+{
+ int *orc_ip = _orc_ip;
+ struct orc_entry *orc = _orc;
+ unsigned int num_entries = orc_ip_size / sizeof(int);
+
+ WARN_ON_ONCE(orc_ip_size % sizeof(int) != 0 ||
+ orc_size % sizeof(*orc) != 0 ||
+ num_entries != orc_size / sizeof(*orc));
+
+ /*
+ * The 'cur_orc_*' globals allow the orc_sort_swap() callback to
+ * associate an .orc_unwind_ip table entry with its corresponding
+ * .orc_unwind entry so they can both be swapped.
+ */
+ mutex_lock(&sort_mutex);
+ cur_orc_ip_table = orc_ip;
+ cur_orc_table = orc;
+ sort(orc_ip, num_entries, sizeof(int), orc_sort_cmp, orc_sort_swap);
+ mutex_unlock(&sort_mutex);
+
+ mod->arch.orc_unwind_ip = orc_ip;
+ mod->arch.orc_unwind = orc;
+ mod->arch.num_orcs = num_entries;
+}
+#endif
+
+void __init unwind_init(void)
+{
+ size_t orc_ip_size = (void *)__stop_orc_unwind_ip - (void *)__start_orc_unwind_ip;
+ size_t orc_size = (void *)__stop_orc_unwind - (void *)__start_orc_unwind;
+ size_t num_entries = orc_ip_size / sizeof(int);
+ struct orc_entry *orc;
+ int i;
+
+ if (!num_entries || orc_ip_size % sizeof(int) != 0 ||
+ orc_size % sizeof(struct orc_entry) != 0 ||
+ num_entries != orc_size / sizeof(struct orc_entry)) {
+ orc_warn("WARNING: Bad or missing .orc_unwind table. Disabling unwinder.\n");
+ return;
+ }
+
+ /* Sort the .orc_unwind and .orc_unwind_ip tables: */
+ sort(__start_orc_unwind_ip, num_entries, sizeof(int), orc_sort_cmp,
+ orc_sort_swap);
+
+ /* Initialize the fast lookup table: */
+ lookup_num_blocks = orc_lookup_end - orc_lookup;
+ for (i = 0; i < lookup_num_blocks-1; i++) {
+ orc = __orc_find(__start_orc_unwind_ip, __start_orc_unwind,
+ num_entries,
+ LOOKUP_START_IP + (LOOKUP_BLOCK_SIZE * i));
+ if (!orc) {
+ orc_warn("WARNING: Corrupt .orc_unwind table. Disabling unwinder.\n");
+ return;
+ }
+
+ orc_lookup[i] = orc - __start_orc_unwind;
+ }
+
+ /* Initialize the ending block: */
+ orc = __orc_find(__start_orc_unwind_ip, __start_orc_unwind, num_entries,
+ LOOKUP_STOP_IP);
+ if (!orc) {
+ orc_warn("WARNING: Corrupt .orc_unwind table. Disabling unwinder.\n");
+ return;
+ }
+ orc_lookup[lookup_num_blocks-1] = orc - __start_orc_unwind;
+
+ orc_init = true;
+}
+
+unsigned long unwind_get_return_address(struct unwind_state *state)
+{
+ if (unwind_done(state))
+ return 0;
+
+ return __kernel_text_address(state->ip) ? state->ip : 0;
+}
+EXPORT_SYMBOL_GPL(unwind_get_return_address);
+
+unsigned long *unwind_get_return_address_ptr(struct unwind_state *state)
+{
+ if (unwind_done(state))
+ return NULL;
+
+ if (state->regs)
+ return &state->regs->ip;
+
+ if (state->sp)
+ return (unsigned long *)state->sp - 1;
+
+ return NULL;
+}
+
+static bool stack_access_ok(struct unwind_state *state, unsigned long addr,
+ size_t len)
+{
+ struct stack_info *info = &state->stack_info;
+
+ /*
+ * If the address isn't on the current stack, switch to the next one.
+ *
+ * We may have to traverse multiple stacks to deal with the possibility
+ * that info->next_sp could point to an empty stack and the address
+ * could be on a subsequent stack.
+ */
+ while (!on_stack(info, (void *)addr, len))
+ if (get_stack_info(info->next_sp, state->task, info,
+ &state->stack_mask))
+ return false;
+
+ return true;
+}
+
+static bool deref_stack_reg(struct unwind_state *state, unsigned long addr,
+ unsigned long *val)
+{
+ if (!stack_access_ok(state, addr, sizeof(long)))
+ return false;
+
+ *val = READ_ONCE_TASK_STACK(state->task, *(unsigned long *)addr);
+ return true;
+}
+
+#define REGS_SIZE (sizeof(struct pt_regs))
+#define SP_OFFSET (offsetof(struct pt_regs, sp))
+#define IRET_REGS_SIZE (REGS_SIZE - offsetof(struct pt_regs, ip))
+#define IRET_SP_OFFSET (SP_OFFSET - offsetof(struct pt_regs, ip))
+
+static bool deref_stack_regs(struct unwind_state *state, unsigned long addr,
+ unsigned long *ip, unsigned long *sp, bool full)
+{
+ size_t regs_size = full ? REGS_SIZE : IRET_REGS_SIZE;
+ size_t sp_offset = full ? SP_OFFSET : IRET_SP_OFFSET;
+ struct pt_regs *regs = (struct pt_regs *)(addr + regs_size - REGS_SIZE);
+
+ if (IS_ENABLED(CONFIG_X86_64)) {
+ if (!stack_access_ok(state, addr, regs_size))
+ return false;
+
+ *ip = regs->ip;
+ *sp = regs->sp;
+
+ return true;
+ }
+
+ if (!stack_access_ok(state, addr, sp_offset))
+ return false;
+
+ *ip = regs->ip;
+
+ if (user_mode(regs)) {
+ if (!stack_access_ok(state, addr + sp_offset,
+ REGS_SIZE - SP_OFFSET))
+ return false;
+
+ *sp = regs->sp;
+ } else
+ *sp = (unsigned long)®s->sp;
+
+ return true;
+}
+
+bool unwind_next_frame(struct unwind_state *state)
+{
+ unsigned long ip_p, sp, orig_ip, prev_sp = state->sp;
+ enum stack_type prev_type = state->stack_info.type;
+ struct orc_entry *orc;
+ struct pt_regs *ptregs;
+ bool indirect = false;
+
+ if (unwind_done(state))
+ return false;
+
+ /* Don't let modules unload while we're reading their ORC data. */
+ preempt_disable();
+
+ /* Have we reached the end? */
+ if (state->regs && user_mode(state->regs))
+ goto done;
+
+ /*
+ * Find the orc_entry associated with the text address.
+ *
+ * Decrement call return addresses by one so they work for sibling
+ * calls and calls to noreturn functions.
+ */
+ orc = orc_find(state->signal ? state->ip : state->ip - 1);
+ if (!orc || orc->sp_reg == ORC_REG_UNDEFINED)
+ goto done;
+ orig_ip = state->ip;
+
+ /* Find the previous frame's stack: */
+ switch (orc->sp_reg) {
+ case ORC_REG_SP:
+ sp = state->sp + orc->sp_offset;
+ break;
+
+ case ORC_REG_BP:
+ sp = state->bp + orc->sp_offset;
+ break;
+
+ case ORC_REG_SP_INDIRECT:
+ sp = state->sp + orc->sp_offset;
+ indirect = true;
+ break;
+
+ case ORC_REG_BP_INDIRECT:
+ sp = state->bp + orc->sp_offset;
+ indirect = true;
+ break;
+
+ case ORC_REG_R10:
+ if (!state->regs || !state->full_regs) {
+ orc_warn("missing regs for base reg R10 at ip %p\n",
+ (void *)state->ip);
+ goto done;
+ }
+ sp = state->regs->r10;
+ break;
+
+ case ORC_REG_R13:
+ if (!state->regs || !state->full_regs) {
+ orc_warn("missing regs for base reg R13 at ip %p\n",
+ (void *)state->ip);
+ goto done;
+ }
+ sp = state->regs->r13;
+ break;
+
+ case ORC_REG_DI:
+ if (!state->regs || !state->full_regs) {
+ orc_warn("missing regs for base reg DI at ip %p\n",
+ (void *)state->ip);
+ goto done;
+ }
+ sp = state->regs->di;
+ break;
+
+ case ORC_REG_DX:
+ if (!state->regs || !state->full_regs) {
+ orc_warn("missing regs for base reg DX at ip %p\n",
+ (void *)state->ip);
+ goto done;
+ }
+ sp = state->regs->dx;
+ break;
+
+ default:
+ orc_warn("unknown SP base reg %d for ip %p\n",
+ orc->sp_reg, (void *)state->ip);
+ goto done;
+ }
+
+ if (indirect) {
+ if (!deref_stack_reg(state, sp, &sp))
+ goto done;
+ }
+
+ /* Find IP, SP and possibly regs: */
+ switch (orc->type) {
+ case ORC_TYPE_CALL:
+ ip_p = sp - sizeof(long);
+
+ if (!deref_stack_reg(state, ip_p, &state->ip))
+ goto done;
+
+ state->ip = ftrace_graph_ret_addr(state->task, &state->graph_idx,
+ state->ip, (void *)ip_p);
+
+ state->sp = sp;
+ state->regs = NULL;
+ state->signal = false;
+ break;
+
+ case ORC_TYPE_REGS:
+ if (!deref_stack_regs(state, sp, &state->ip, &state->sp, true)) {
+ orc_warn("can't dereference registers at %p for ip %p\n",
+ (void *)sp, (void *)orig_ip);
+ goto done;
+ }
+
+ state->regs = (struct pt_regs *)sp;
+ state->full_regs = true;
+ state->signal = true;
+ break;
+
+ case ORC_TYPE_REGS_IRET:
+ if (!deref_stack_regs(state, sp, &state->ip, &state->sp, false)) {
+ orc_warn("can't dereference iret registers at %p for ip %p\n",
+ (void *)sp, (void *)orig_ip);
+ goto done;
+ }
+
+ ptregs = container_of((void *)sp, struct pt_regs, ip);
+ if ((unsigned long)ptregs >= prev_sp &&
+ on_stack(&state->stack_info, ptregs, REGS_SIZE)) {
+ state->regs = ptregs;
+ state->full_regs = false;
+ } else
+ state->regs = NULL;
+
+ state->signal = true;
+ break;
+
+ default:
+ orc_warn("unknown .orc_unwind entry type %d\n", orc->type);
+ break;
+ }
+
+ /* Find BP: */
+ switch (orc->bp_reg) {
+ case ORC_REG_UNDEFINED:
+ if (state->regs && state->full_regs)
+ state->bp = state->regs->bp;
+ break;
+
+ case ORC_REG_PREV_SP:
+ if (!deref_stack_reg(state, sp + orc->bp_offset, &state->bp))
+ goto done;
+ break;
+
+ case ORC_REG_BP:
+ if (!deref_stack_reg(state, state->bp + orc->bp_offset, &state->bp))
+ goto done;
+ break;
+
+ default:
+ orc_warn("unknown BP base reg %d for ip %p\n",
+ orc->bp_reg, (void *)orig_ip);
+ goto done;
+ }
+
+ /* Prevent a recursive loop due to bad ORC data: */
+ if (state->stack_info.type == prev_type &&
+ on_stack(&state->stack_info, (void *)state->sp, sizeof(long)) &&
+ state->sp <= prev_sp) {
+ orc_warn("stack going in the wrong direction? ip=%p\n",
+ (void *)orig_ip);
+ goto done;
+ }
+
+ preempt_enable();
+ return true;
+
+done:
+ preempt_enable();
+ state->stack_info.type = STACK_TYPE_UNKNOWN;
+ return false;
+}
+EXPORT_SYMBOL_GPL(unwind_next_frame);
+
+void __unwind_start(struct unwind_state *state, struct task_struct *task,
+ struct pt_regs *regs, unsigned long *first_frame)
+{
+ memset(state, 0, sizeof(*state));
+ state->task = task;
+
+ /*
+ * Refuse to unwind the stack of a task while it's executing on another
+ * CPU. This check is racy, but that's ok: the unwinder has other
+ * checks to prevent it from going off the rails.
+ */
+ if (task_on_another_cpu(task))
+ goto done;
+
+ if (regs) {
+ if (user_mode(regs))
+ goto done;
+
+ state->ip = regs->ip;
+ state->sp = kernel_stack_pointer(regs);
+ state->bp = regs->bp;
+ state->regs = regs;
+ state->full_regs = true;
+ state->signal = true;
+
+ } else if (task == current) {
+ asm volatile("lea (%%rip), %0\n\t"
+ "mov %%rsp, %1\n\t"
+ "mov %%rbp, %2\n\t"
+ : "=r" (state->ip), "=r" (state->sp),
+ "=r" (state->bp));
+
+ } else {
+ struct inactive_task_frame *frame = (void *)task->thread.sp;
+
+ state->sp = task->thread.sp;
+ state->bp = READ_ONCE_NOCHECK(frame->bp);
+ state->ip = READ_ONCE_NOCHECK(frame->ret_addr);
+ }
+
+ if (get_stack_info((unsigned long *)state->sp, state->task,
+ &state->stack_info, &state->stack_mask))
+ return;
+
+ /*
+ * The caller can provide the address of the first frame directly
+ * (first_frame) or indirectly (regs->sp) to indicate which stack frame
+ * to start unwinding at. Skip ahead until we reach it.
+ */
+
+ /* When starting from regs, skip the regs frame: */
+ if (regs) {
+ unwind_next_frame(state);
+ return;
+ }
+
+ /* Otherwise, skip ahead to the user-specified starting frame: */
+ while (!unwind_done(state) &&
+ (!on_stack(&state->stack_info, first_frame, sizeof(long)) ||
+ state->sp <= (unsigned long)first_frame))
+ unwind_next_frame(state);
+
+ return;
+
+done:
+ state->stack_info.type = STACK_TYPE_UNKNOWN;
+ return;
+}
+EXPORT_SYMBOL_GPL(__unwind_start);
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index c8a3b61..f05f00a 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -24,6 +24,7 @@
#include <asm/asm-offsets.h>
#include <asm/thread_info.h>
#include <asm/page_types.h>
+#include <asm/orc_lookup.h>
#include <asm/cache.h>
#include <asm/boot.h>
@@ -148,6 +149,8 @@
BUG_TABLE
+ ORC_UNWIND_TABLE
+
. = ALIGN(PAGE_SIZE);
__vvar_page = .;
diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c
index 0ea8afc..fb2ddcd 100644
--- a/arch/x86/mm/extable.c
+++ b/arch/x86/mm/extable.c
@@ -142,7 +142,7 @@ void __init early_fixup_exception(struct pt_regs *regs, int trapnr)
* undefined. I'm not sure which CPUs do this, but at least
* the 486 DX works this way.
*/
- if ((regs->cs & 0xFFFF) != __KERNEL_CS)
+ if (regs->cs != __KERNEL_CS)
goto fail;
/*
diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
index 7ef015e..b4531e3 100644
--- a/include/asm-generic/io.h
+++ b/include/asm-generic/io.h
@@ -915,6 +915,9 @@ extern void ioport_unmap(void __iomem *p);
#endif /* CONFIG_GENERIC_IOMAP */
#endif /* CONFIG_HAS_IOPORT_MAP */
+/*
+ * Convert a virtual cached pointer to an uncached pointer
+ */
#ifndef xlate_dev_kmem_ptr
#define xlate_dev_kmem_ptr xlate_dev_kmem_ptr
static inline void *xlate_dev_kmem_ptr(void *addr)
@@ -954,6 +957,14 @@ static inline void *bus_to_virt(unsigned long address)
#ifndef memset_io
#define memset_io memset_io
+/**
+ * memset_io Set a range of I/O memory to a constant value
+ * @addr: The beginning of the I/O-memory range to set
+ * @val: The value to set the memory to
+ * @count: The number of bytes to set
+ *
+ * Set a range of I/O memory to a given value.
+ */
static inline void memset_io(volatile void __iomem *addr, int value,
size_t size)
{
@@ -963,6 +974,14 @@ static inline void memset_io(volatile void __iomem *addr, int value,
#ifndef memcpy_fromio
#define memcpy_fromio memcpy_fromio
+/**
+ * memcpy_fromio Copy a block of data from I/O memory
+ * @dst: The (RAM) destination for the copy
+ * @src: The (I/O memory) source for the data
+ * @count: The number of bytes to copy
+ *
+ * Copy a block of data from I/O memory.
+ */
static inline void memcpy_fromio(void *buffer,
const volatile void __iomem *addr,
size_t size)
@@ -973,6 +992,14 @@ static inline void memcpy_fromio(void *buffer,
#ifndef memcpy_toio
#define memcpy_toio memcpy_toio
+/**
+ * memcpy_toio Copy a block of data into I/O memory
+ * @dst: The (I/O memory) destination for the copy
+ * @src: The (RAM) source for the data
+ * @count: The number of bytes to copy
+ *
+ * Copy a block of data to I/O memory.
+ */
static inline void memcpy_toio(volatile void __iomem *addr, const void *buffer,
size_t size)
{
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index da0be9a..fffc9bd 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -680,6 +680,31 @@
#define BUG_TABLE
#endif
+#ifdef CONFIG_ORC_UNWINDER
+#define ORC_UNWIND_TABLE \
+ . = ALIGN(4); \
+ .orc_unwind_ip : AT(ADDR(.orc_unwind_ip) - LOAD_OFFSET) { \
+ VMLINUX_SYMBOL(__start_orc_unwind_ip) = .; \
+ KEEP(*(.orc_unwind_ip)) \
+ VMLINUX_SYMBOL(__stop_orc_unwind_ip) = .; \
+ } \
+ . = ALIGN(6); \
+ .orc_unwind : AT(ADDR(.orc_unwind) - LOAD_OFFSET) { \
+ VMLINUX_SYMBOL(__start_orc_unwind) = .; \
+ KEEP(*(.orc_unwind)) \
+ VMLINUX_SYMBOL(__stop_orc_unwind) = .; \
+ } \
+ . = ALIGN(4); \
+ .orc_lookup : AT(ADDR(.orc_lookup) - LOAD_OFFSET) { \
+ VMLINUX_SYMBOL(orc_lookup) = .; \
+ . += (((SIZEOF(.text) + LOOKUP_BLOCK_SIZE - 1) / \
+ LOOKUP_BLOCK_SIZE) + 1) * 4; \
+ VMLINUX_SYMBOL(orc_lookup_end) = .; \
+ }
+#else
+#define ORC_UNWIND_TABLE
+#endif
+
#ifdef CONFIG_PM_TRACE
#define TRACEDATA \
. = ALIGN(4); \
@@ -866,7 +891,7 @@
DATA_DATA \
CONSTRUCTORS \
} \
- BUG_TABLE
+ BUG_TABLE \
#define INIT_TEXT_SECTION(inittext_align) \
. = ALIGN(inittext_align); \
diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index bdb80c4..310f51d 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -201,17 +201,6 @@
#endif
#endif
-#ifdef CONFIG_STACK_VALIDATION
-#define annotate_unreachable() ({ \
- asm("%c0:\t\n" \
- ".pushsection .discard.unreachable\t\n" \
- ".long %c0b - .\t\n" \
- ".popsection\t\n" : : "i" (__LINE__)); \
-})
-#else
-#define annotate_unreachable()
-#endif
-
/*
* Mark a position in code as unreachable. This can be used to
* suppress control flow warnings after asm blocks that transfer
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index eca8ad7..109b146 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -185,8 +185,34 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
#endif
/* Unreachable code */
+#ifdef CONFIG_STACK_VALIDATION
+#define annotate_reachable() ({ \
+ asm("%c0:\n\t" \
+ ".pushsection .discard.reachable\n\t" \
+ ".long %c0b - .\n\t" \
+ ".popsection\n\t" : : "i" (__LINE__)); \
+})
+#define annotate_unreachable() ({ \
+ asm("%c0:\n\t" \
+ ".pushsection .discard.unreachable\n\t" \
+ ".long %c0b - .\n\t" \
+ ".popsection\n\t" : : "i" (__LINE__)); \
+})
+#define ASM_UNREACHABLE \
+ "999:\n\t" \
+ ".pushsection .discard.unreachable\n\t" \
+ ".long 999b - .\n\t" \
+ ".popsection\n\t"
+#else
+#define annotate_reachable()
+#define annotate_unreachable()
+#endif
+
+#ifndef ASM_UNREACHABLE
+# define ASM_UNREACHABLE
+#endif
#ifndef unreachable
-# define unreachable() do { } while (1)
+# define unreachable() do { annotate_reachable(); do { } while (1); } while (0)
#endif
/*
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 98fe715..32a48e7 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -374,6 +374,9 @@
pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure
that runtime stack traces are more reliable.
+ This is also a prerequisite for generation of ORC unwind data, which
+ is needed for CONFIG_ORC_UNWINDER.
+
For more information, see
tools/objtool/Documentation/stack-validation.txt.
@@ -1121,7 +1124,7 @@
bool
depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
select STACKTRACE
- select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE && !ARC && !SCORE
+ select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE && !ARC && !SCORE && !X86
select KALLSYMS
select KALLSYMS_ALL
@@ -1540,7 +1543,7 @@
depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
depends on !X86_64
select STACKTRACE
- select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC && !SCORE
+ select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC && !SCORE && !X86
help
Provide stacktrace filter for fault-injection capabilities
@@ -1549,7 +1552,7 @@
depends on DEBUG_KERNEL
depends on STACKTRACE_SUPPORT
depends on PROC_FS
- select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC
+ select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC && !X86
select KALLSYMS
select KALLSYMS_ALL
select STACKTRACE
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 4a9a2ce..80ed148 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -258,10 +258,14 @@
__objtool_obj := $(objtree)/tools/objtool/objtool
-objtool_args = check
+objtool_args = $(if $(CONFIG_ORC_UNWINDER),orc generate,check)
+
ifndef CONFIG_FRAME_POINTER
objtool_args += --no-fp
endif
+ifdef CONFIG_GCOV_KERNEL
+objtool_args += --no-unreachable
+endif
# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory
# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file
@@ -276,6 +280,11 @@
endif # SKIP_STACK_VALIDATION
endif # CONFIG_STACK_VALIDATION
+# Rebuild all objects when objtool changes, or is enabled/disabled.
+objtool_dep = $(objtool_obj) \
+ $(wildcard include/config/orc/unwinder.h \
+ include/config/stack/validation.h)
+
define rule_cc_o_c
$(call echo-cmd,checksrc) $(cmd_checksrc) \
$(call cmd_and_fixdep,cc_o_c) \
@@ -298,13 +307,13 @@
endif
# Built-in and composite module parts
-$(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_obj) FORCE
+$(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
$(call cmd,force_checksrc)
$(call if_changed_rule,cc_o_c)
# Single-part modules are special since we need to mark them in $(MODVERDIR)
-$(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_obj) FORCE
+$(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
$(call cmd,force_checksrc)
$(call if_changed_rule,cc_o_c)
@{ echo $(@:.o=.ko); echo $@; \
@@ -399,7 +408,7 @@
endif
endif
-$(obj)/%.o: $(src)/%.S $(objtool_obj) FORCE
+$(obj)/%.o: $(src)/%.S $(objtool_dep) FORCE
$(call if_changed_rule,as_o_S)
targets += $(real-objs-y) $(real-objs-m) $(lib-y)
diff --git a/tools/objtool/Build b/tools/objtool/Build
index 6f2e198..749becd 100644
--- a/tools/objtool/Build
+++ b/tools/objtool/Build
@@ -1,6 +1,9 @@
objtool-y += arch/$(SRCARCH)/
objtool-y += builtin-check.o
+objtool-y += builtin-orc.o
objtool-y += check.o
+objtool-y += orc_gen.o
+objtool-y += orc_dump.o
objtool-y += elf.o
objtool-y += special.o
objtool-y += objtool.o
diff --git a/tools/objtool/Documentation/stack-validation.txt b/tools/objtool/Documentation/stack-validation.txt
index 17c1195..6a1af43 100644
--- a/tools/objtool/Documentation/stack-validation.txt
+++ b/tools/objtool/Documentation/stack-validation.txt
@@ -11,9 +11,6 @@
It enforces a set of rules on asm code and C inline assembly code so
that stack traces can be reliable.
-Currently it only checks frame pointer usage, but there are plans to add
-CFI validation for C files and CFI generation for asm files.
-
For each function, it recursively follows all possible code paths and
validates the correct frame pointer state at each instruction.
@@ -23,6 +20,10 @@
instructions). Similarly, it knows how to follow switch statements, for
which gcc sometimes uses jump tables.
+(Objtool also has an 'orc generate' subcommand which generates debuginfo
+for the ORC unwinder. See Documentation/x86/orc-unwinder.txt in the
+kernel tree for more details.)
+
Why do we need stack metadata validation?
-----------------------------------------
@@ -93,37 +94,14 @@
or at the very end of the function after the stack frame has been
destroyed. This is an inherent limitation of frame pointers.
-b) 100% reliable stack traces for DWARF enabled kernels
+b) ORC (Oops Rewind Capability) unwind table generation
- (NOTE: This is not yet implemented)
+ An alternative to frame pointers and DWARF, ORC unwind data can be
+ used to walk the stack. Unlike frame pointers, ORC data is out of
+ band. So it doesn't affect runtime performance and it can be
+ reliable even when interrupts or exceptions are involved.
- As an alternative to frame pointers, DWARF Call Frame Information
- (CFI) metadata can be used to walk the stack. Unlike frame pointers,
- CFI metadata is out of band. So it doesn't affect runtime
- performance and it can be reliable even when interrupts or exceptions
- are involved.
-
- For C code, gcc automatically generates DWARF CFI metadata. But for
- asm code, generating CFI is a tedious manual approach which requires
- manually placed .cfi assembler macros to be scattered throughout the
- code. It's clumsy and very easy to get wrong, and it makes the real
- code harder to read.
-
- Stacktool will improve this situation in several ways. For code
- which already has CFI annotations, it will validate them. For code
- which doesn't have CFI annotations, it will generate them. So an
- architecture can opt to strip out all the manual .cfi annotations
- from their asm code and have objtool generate them instead.
-
- We might also add a runtime stack validation debug option where we
- periodically walk the stack from schedule() and/or an NMI to ensure
- that the stack metadata is sane and that we reach the bottom of the
- stack.
-
- So the benefit of objtool here will be that external tooling should
- always show perfect stack traces. And the same will be true for
- kernel warning/oops traces if the architecture has a runtime DWARF
- unwinder.
+ For more details, see Documentation/x86/orc-unwinder.txt.
c) Higher live patching compatibility rate
@@ -211,7 +189,7 @@
function, add proper frame pointer logic using the FRAME_BEGIN and
FRAME_END macros. Otherwise, if it's not a callable function, remove
its ELF function annotation by changing ENDPROC to END, and instead
- use the manual CFI hint macros in asm/undwarf.h.
+ use the manual unwind hint macros in asm/unwind_hints.h.
If it's a GCC-compiled .c file, the error may be because the function
uses an inline asm() statement which has a "call" instruction. An
@@ -231,8 +209,8 @@
If the error is for an asm file, and the instruction is inside (or
reachable from) a callable function, the function should be annotated
with the ENTRY/ENDPROC macros (ENDPROC is the important one).
- Otherwise, the code should probably be annotated with the CFI hint
- macros in asm/undwarf.h so objtool and the unwinder can know the
+ Otherwise, the code should probably be annotated with the unwind hint
+ macros in asm/unwind_hints.h so objtool and the unwinder can know the
stack state associated with the code.
If you're 100% sure the code won't affect stack traces, or if you're
@@ -258,7 +236,7 @@
instructions aren't allowed in a callable function, and are most
likely part of the kernel entry code. They should usually not have
the callable function annotation (ENDPROC) and should always be
- annotated with the CFI hint macros in asm/undwarf.h.
+ annotated with the unwind hint macros in asm/unwind_hints.h.
6. file.o: warning: objtool: func()+0x26: sibling call from callable instruction with modified stack frame
@@ -272,7 +250,7 @@
If the instruction is not actually in a callable function (e.g.
kernel entry code), change ENDPROC to END and annotate manually with
- the CFI hint macros in asm/undwarf.h.
+ the unwind hint macros in asm/unwind_hints.h.
7. file: warning: objtool: func()+0x5c: stack state mismatch
@@ -288,8 +266,8 @@
Another possibility is that the code has some asm or inline asm which
does some unusual things to the stack or the frame pointer. In such
- cases it's probably appropriate to use the CFI hint macros in
- asm/undwarf.h.
+ cases it's probably appropriate to use the unwind hint macros in
+ asm/unwind_hints.h.
8. file.o: warning: objtool: funcA() falls through to next function funcB()
diff --git a/tools/objtool/Makefile b/tools/objtool/Makefile
index 0e2765e..6976c73 100644
--- a/tools/objtool/Makefile
+++ b/tools/objtool/Makefile
@@ -25,7 +25,8 @@
all: $(OBJTOOL)
INCLUDES := -I$(srctree)/tools/include -I$(srctree)/tools/arch/$(HOSTARCH)/include/uapi
-CFLAGS += -Wall -Werror $(EXTRA_WARNINGS) -Wno-switch-default -Wno-switch-enum -fomit-frame-pointer -O2 -g $(INCLUDES)
+WARNINGS := $(EXTRA_WARNINGS) -Wno-switch-default -Wno-switch-enum -Wno-packed
+CFLAGS += -Wall -Werror $(WARNINGS) -fomit-frame-pointer -O2 -g $(INCLUDES)
LDFLAGS += -lelf $(LIBSUBCMD)
# Allow old libelf to be used:
@@ -52,6 +53,9 @@
diff -I'^#include' arch/x86/insn/inat.h ../../arch/x86/include/asm/inat.h >/dev/null && \
diff -I'^#include' arch/x86/insn/inat_types.h ../../arch/x86/include/asm/inat_types.h >/dev/null) \
|| echo "warning: objtool: x86 instruction decoder differs from kernel" >&2 )) || true
+ @(test -d ../../kernel -a -d ../../tools -a -d ../objtool && (( \
+ diff ../../arch/x86/include/asm/orc_types.h orc_types.h >/dev/null) \
+ || echo "warning: objtool: orc_types.h differs from kernel" >&2 )) || true
$(QUIET_LINK)$(CC) $(OBJTOOL_IN) $(LDFLAGS) -o $@
diff --git a/tools/objtool/arch.h b/tools/objtool/arch.h
index 21aeca8..b0d7dc3 100644
--- a/tools/objtool/arch.h
+++ b/tools/objtool/arch.h
@@ -31,8 +31,9 @@
#define INSN_RETURN 6
#define INSN_CONTEXT_SWITCH 7
#define INSN_STACK 8
-#define INSN_NOP 9
-#define INSN_OTHER 10
+#define INSN_BUG 9
+#define INSN_NOP 10
+#define INSN_OTHER 11
#define INSN_LAST INSN_OTHER
enum op_dest_type {
diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c
index a36c2eb..7841e5d 100644
--- a/tools/objtool/arch/x86/decode.c
+++ b/tools/objtool/arch/x86/decode.c
@@ -271,7 +271,7 @@ int arch_decode_instruction(struct elf *elf, struct section *sec,
case 0x8d:
if (rex == 0x48 && modrm == 0x65) {
- /* lea -disp(%rbp), %rsp */
+ /* lea disp(%rbp), %rsp */
*type = INSN_STACK;
op->src.type = OP_SRC_ADD;
op->src.reg = CFI_BP;
@@ -281,6 +281,30 @@ int arch_decode_instruction(struct elf *elf, struct section *sec,
break;
}
+ if (rex == 0x48 && (modrm == 0xa4 || modrm == 0x64) &&
+ sib == 0x24) {
+
+ /* lea disp(%rsp), %rsp */
+ *type = INSN_STACK;
+ op->src.type = OP_SRC_ADD;
+ op->src.reg = CFI_SP;
+ op->src.offset = insn.displacement.value;
+ op->dest.type = OP_DEST_REG;
+ op->dest.reg = CFI_SP;
+ break;
+ }
+
+ if (rex == 0x48 && modrm == 0x2c && sib == 0x24) {
+
+ /* lea (%rsp), %rbp */
+ *type = INSN_STACK;
+ op->src.type = OP_SRC_REG;
+ op->src.reg = CFI_SP;
+ op->dest.type = OP_DEST_REG;
+ op->dest.reg = CFI_BP;
+ break;
+ }
+
if (rex == 0x4c && modrm == 0x54 && sib == 0x24 &&
insn.displacement.value == 8) {
@@ -382,20 +406,27 @@ int arch_decode_instruction(struct elf *elf, struct section *sec,
case 0x0f:
- if (op2 >= 0x80 && op2 <= 0x8f)
+ if (op2 >= 0x80 && op2 <= 0x8f) {
+
*type = INSN_JUMP_CONDITIONAL;
- else if (op2 == 0x05 || op2 == 0x07 || op2 == 0x34 ||
- op2 == 0x35)
+
+ } else if (op2 == 0x05 || op2 == 0x07 || op2 == 0x34 ||
+ op2 == 0x35) {
/* sysenter, sysret */
*type = INSN_CONTEXT_SWITCH;
- else if (op2 == 0x0d || op2 == 0x1f)
+ } else if (op2 == 0x0b || op2 == 0xb9) {
+
+ /* ud2 */
+ *type = INSN_BUG;
+
+ } else if (op2 == 0x0d || op2 == 0x1f) {
/* nopl/nopw */
*type = INSN_NOP;
- else if (op2 == 0xa0 || op2 == 0xa8) {
+ } else if (op2 == 0xa0 || op2 == 0xa8) {
/* push fs/gs */
*type = INSN_STACK;
diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c
index 365c34e..57254f5 100644
--- a/tools/objtool/builtin-check.c
+++ b/tools/objtool/builtin-check.c
@@ -29,7 +29,7 @@
#include "builtin.h"
#include "check.h"
-bool nofp;
+bool no_fp, no_unreachable;
static const char * const check_usage[] = {
"objtool check [<options>] file.o",
@@ -37,7 +37,8 @@ static const char * const check_usage[] = {
};
const struct option check_options[] = {
- OPT_BOOLEAN('f', "no-fp", &nofp, "Skip frame pointer validation"),
+ OPT_BOOLEAN('f', "no-fp", &no_fp, "Skip frame pointer validation"),
+ OPT_BOOLEAN('u', "no-unreachable", &no_unreachable, "Skip 'unreachable instruction' warnings"),
OPT_END(),
};
@@ -52,5 +53,5 @@ int cmd_check(int argc, const char **argv)
objname = argv[0];
- return check(objname, nofp);
+ return check(objname, no_fp, no_unreachable, false);
}
diff --git a/tools/objtool/builtin-orc.c b/tools/objtool/builtin-orc.c
new file mode 100644
index 0000000..4c6b5c9
--- /dev/null
+++ b/tools/objtool/builtin-orc.c
@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * objtool orc:
+ *
+ * This command analyzes a .o file and adds .orc_unwind and .orc_unwind_ip
+ * sections to it, which is used by the in-kernel ORC unwinder.
+ *
+ * This command is a superset of "objtool check".
+ */
+
+#include <string.h>
+#include <subcmd/parse-options.h>
+#include "builtin.h"
+#include "check.h"
+
+
+static const char *orc_usage[] = {
+ "objtool orc generate [<options>] file.o",
+ "objtool orc dump file.o",
+ NULL,
+};
+
+extern const struct option check_options[];
+extern bool no_fp, no_unreachable;
+
+int cmd_orc(int argc, const char **argv)
+{
+ const char *objname;
+
+ argc--; argv++;
+ if (!strncmp(argv[0], "gen", 3)) {
+ argc = parse_options(argc, argv, check_options, orc_usage, 0);
+ if (argc != 1)
+ usage_with_options(orc_usage, check_options);
+
+ objname = argv[0];
+
+ return check(objname, no_fp, no_unreachable, true);
+
+ }
+
+ if (!strcmp(argv[0], "dump")) {
+ if (argc != 2)
+ usage_with_options(orc_usage, check_options);
+
+ objname = argv[1];
+
+ return orc_dump(objname);
+ }
+
+ usage_with_options(orc_usage, check_options);
+
+ return 0;
+}
diff --git a/tools/objtool/builtin.h b/tools/objtool/builtin.h
index 34d2ba7..dd52606 100644
--- a/tools/objtool/builtin.h
+++ b/tools/objtool/builtin.h
@@ -18,5 +18,6 @@
#define _BUILTIN_H
extern int cmd_check(int argc, const char **argv);
+extern int cmd_orc(int argc, const char **argv);
#endif /* _BUILTIN_H */
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 2c6d748..4f0c4ae 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -33,11 +33,11 @@ struct alternative {
};
const char *objname;
-static bool nofp;
+static bool no_fp;
struct cfi_state initial_func_cfi;
-static struct instruction *find_insn(struct objtool_file *file,
- struct section *sec, unsigned long offset)
+struct instruction *find_insn(struct objtool_file *file,
+ struct section *sec, unsigned long offset)
{
struct instruction *insn;
@@ -59,19 +59,6 @@ static struct instruction *next_insn_same_sec(struct objtool_file *file,
return next;
}
-static bool gcov_enabled(struct objtool_file *file)
-{
- struct section *sec;
- struct symbol *sym;
-
- for_each_sec(file, sec)
- list_for_each_entry(sym, &sec->symbol_list, list)
- if (!strncmp(sym->name, "__gcov_.", 8))
- return true;
-
- return false;
-}
-
#define func_for_each_insn(file, func, insn) \
for (insn = find_insn(file, func->sec, func->offset); \
insn && &insn->list != &file->insn_list && \
@@ -100,7 +87,6 @@ static bool gcov_enabled(struct objtool_file *file)
static bool ignore_func(struct objtool_file *file, struct symbol *func)
{
struct rela *rela;
- struct instruction *insn;
/* check for STACK_FRAME_NON_STANDARD */
if (file->whitelist && file->whitelist->rela)
@@ -113,11 +99,6 @@ static bool ignore_func(struct objtool_file *file, struct symbol *func)
return true;
}
- /* check if it has a context switching instruction */
- func_for_each_insn(file, func, insn)
- if (insn->type == INSN_CONTEXT_SWITCH)
- return true;
-
return false;
}
@@ -259,6 +240,11 @@ static int decode_instructions(struct objtool_file *file)
if (!(sec->sh.sh_flags & SHF_EXECINSTR))
continue;
+ if (strcmp(sec->name, ".altinstr_replacement") &&
+ strcmp(sec->name, ".altinstr_aux") &&
+ strncmp(sec->name, ".discard.", 9))
+ sec->text = true;
+
for (offset = 0; offset < sec->len; offset += insn->len) {
insn = malloc(sizeof(*insn));
if (!insn) {
@@ -310,7 +296,7 @@ static int decode_instructions(struct objtool_file *file)
}
/*
- * Find all uses of the unreachable() macro, which are code path dead ends.
+ * Mark "ud2" instructions and manually annotated dead ends.
*/
static int add_dead_ends(struct objtool_file *file)
{
@@ -319,9 +305,20 @@ static int add_dead_ends(struct objtool_file *file)
struct instruction *insn;
bool found;
+ /*
+ * By default, "ud2" is a dead end unless otherwise annotated, because
+ * GCC 7 inserts it for certain divide-by-zero cases.
+ */
+ for_each_insn(file, insn)
+ if (insn->type == INSN_BUG)
+ insn->dead_end = true;
+
+ /*
+ * Check for manually annotated dead ends.
+ */
sec = find_section_by_name(file->elf, ".rela.discard.unreachable");
if (!sec)
- return 0;
+ goto reachable;
list_for_each_entry(rela, &sec->rela_list, list) {
if (rela->sym->type != STT_SECTION) {
@@ -354,6 +351,48 @@ static int add_dead_ends(struct objtool_file *file)
insn->dead_end = true;
}
+reachable:
+ /*
+ * These manually annotated reachable checks are needed for GCC 4.4,
+ * where the Linux unreachable() macro isn't supported. In that case
+ * GCC doesn't know the "ud2" is fatal, so it generates code as if it's
+ * not a dead end.
+ */
+ sec = find_section_by_name(file->elf, ".rela.discard.reachable");
+ if (!sec)
+ return 0;
+
+ list_for_each_entry(rela, &sec->rela_list, list) {
+ if (rela->sym->type != STT_SECTION) {
+ WARN("unexpected relocation symbol type in %s", sec->name);
+ return -1;
+ }
+ insn = find_insn(file, rela->sym->sec, rela->addend);
+ if (insn)
+ insn = list_prev_entry(insn, list);
+ else if (rela->addend == rela->sym->sec->len) {
+ found = false;
+ list_for_each_entry_reverse(insn, &file->insn_list, list) {
+ if (insn->sec == rela->sym->sec) {
+ found = true;
+ break;
+ }
+ }
+
+ if (!found) {
+ WARN("can't find reachable insn at %s+0x%x",
+ rela->sym->sec->name, rela->addend);
+ return -1;
+ }
+ } else {
+ WARN("can't find reachable insn at %s+0x%x",
+ rela->sym->sec->name, rela->addend);
+ return -1;
+ }
+
+ insn->dead_end = false;
+ }
+
return 0;
}
@@ -874,6 +913,99 @@ static int add_switch_table_alts(struct objtool_file *file)
return 0;
}
+static int read_unwind_hints(struct objtool_file *file)
+{
+ struct section *sec, *relasec;
+ struct rela *rela;
+ struct unwind_hint *hint;
+ struct instruction *insn;
+ struct cfi_reg *cfa;
+ int i;
+
+ sec = find_section_by_name(file->elf, ".discard.unwind_hints");
+ if (!sec)
+ return 0;
+
+ relasec = sec->rela;
+ if (!relasec) {
+ WARN("missing .rela.discard.unwind_hints section");
+ return -1;
+ }
+
+ if (sec->len % sizeof(struct unwind_hint)) {
+ WARN("struct unwind_hint size mismatch");
+ return -1;
+ }
+
+ file->hints = true;
+
+ for (i = 0; i < sec->len / sizeof(struct unwind_hint); i++) {
+ hint = (struct unwind_hint *)sec->data->d_buf + i;
+
+ rela = find_rela_by_dest(sec, i * sizeof(*hint));
+ if (!rela) {
+ WARN("can't find rela for unwind_hints[%d]", i);
+ return -1;
+ }
+
+ insn = find_insn(file, rela->sym->sec, rela->addend);
+ if (!insn) {
+ WARN("can't find insn for unwind_hints[%d]", i);
+ return -1;
+ }
+
+ cfa = &insn->state.cfa;
+
+ if (hint->type == UNWIND_HINT_TYPE_SAVE) {
+ insn->save = true;
+ continue;
+
+ } else if (hint->type == UNWIND_HINT_TYPE_RESTORE) {
+ insn->restore = true;
+ insn->hint = true;
+ continue;
+ }
+
+ insn->hint = true;
+
+ switch (hint->sp_reg) {
+ case ORC_REG_UNDEFINED:
+ cfa->base = CFI_UNDEFINED;
+ break;
+ case ORC_REG_SP:
+ cfa->base = CFI_SP;
+ break;
+ case ORC_REG_BP:
+ cfa->base = CFI_BP;
+ break;
+ case ORC_REG_SP_INDIRECT:
+ cfa->base = CFI_SP_INDIRECT;
+ break;
+ case ORC_REG_R10:
+ cfa->base = CFI_R10;
+ break;
+ case ORC_REG_R13:
+ cfa->base = CFI_R13;
+ break;
+ case ORC_REG_DI:
+ cfa->base = CFI_DI;
+ break;
+ case ORC_REG_DX:
+ cfa->base = CFI_DX;
+ break;
+ default:
+ WARN_FUNC("unsupported unwind_hint sp base reg %d",
+ insn->sec, insn->offset, hint->sp_reg);
+ return -1;
+ }
+
+ cfa->offset = hint->sp_offset;
+ insn->state.type = hint->type;
+ }
+
+ return 0;
+}
+
static int decode_sections(struct objtool_file *file)
{
int ret;
@@ -904,6 +1036,10 @@ static int decode_sections(struct objtool_file *file)
if (ret)
return ret;
+ ret = read_unwind_hints(file);
+ if (ret)
+ return ret;
+
return 0;
}
@@ -947,6 +1083,30 @@ static bool has_valid_stack_frame(struct insn_state *state)
return false;
}
+static int update_insn_state_regs(struct instruction *insn, struct insn_state *state)
+{
+ struct cfi_reg *cfa = &state->cfa;
+ struct stack_op *op = &insn->stack_op;
+
+ if (cfa->base != CFI_SP)
+ return 0;
+
+ /* push */
+ if (op->dest.type == OP_DEST_PUSH)
+ cfa->offset += 8;
+
+ /* pop */
+ if (op->src.type == OP_SRC_POP)
+ cfa->offset -= 8;
+
+ /* add immediate to sp */
+ if (op->dest.type == OP_DEST_REG && op->src.type == OP_SRC_ADD &&
+ op->dest.reg == CFI_SP && op->src.reg == CFI_SP)
+ cfa->offset -= op->src.offset;
+
+ return 0;
+}
+
static void save_reg(struct insn_state *state, unsigned char reg, int base,
int offset)
{
@@ -1032,6 +1192,9 @@ static int update_insn_state(struct instruction *insn, struct insn_state *state)
return 0;
}
+ if (state->type == ORC_TYPE_REGS || state->type == ORC_TYPE_REGS_IRET)
+ return update_insn_state_regs(insn, state);
+
switch (op->dest.type) {
case OP_DEST_REG:
@@ -1051,7 +1214,7 @@ static int update_insn_state(struct instruction *insn, struct insn_state *state)
regs[CFI_BP].base = CFI_BP;
regs[CFI_BP].offset = -state->stack_size;
state->bp_scratch = false;
- } else if (!nofp) {
+ } else if (!no_fp) {
WARN_FUNC("unknown stack-related register move",
insn->sec, insn->offset);
@@ -1222,7 +1385,7 @@ static int update_insn_state(struct instruction *insn, struct insn_state *state)
}
/* detect when asm code uses rbp as a scratch register */
- if (!nofp && insn->func && op->src.reg == CFI_BP &&
+ if (!no_fp && insn->func && op->src.reg == CFI_BP &&
cfa->base != CFI_BP)
state->bp_scratch = true;
break;
@@ -1323,6 +1486,10 @@ static bool insn_state_match(struct instruction *insn, struct insn_state *state)
break;
}
+ } else if (state1->type != state2->type) {
+ WARN_FUNC("stack state mismatch: type1=%d type2=%d",
+ insn->sec, insn->offset, state1->type, state2->type);
+
} else if (state1->drap != state2->drap ||
(state1->drap && state1->drap_reg != state2->drap_reg)) {
WARN_FUNC("stack state mismatch: drap1=%d(%d) drap2=%d(%d)",
@@ -1346,7 +1513,7 @@ static int validate_branch(struct objtool_file *file, struct instruction *first,
struct insn_state state)
{
struct alternative *alt;
- struct instruction *insn;
+ struct instruction *insn, *next_insn;
struct section *sec;
struct symbol *func = NULL;
int ret;
@@ -1361,6 +1528,8 @@ static int validate_branch(struct objtool_file *file, struct instruction *first,
}
while (1) {
+ next_insn = next_insn_same_sec(file, insn);
+
if (file->c_file && insn->func) {
if (func && func != insn->func) {
WARN("%s() falls through to next function %s()",
@@ -1378,13 +1547,54 @@ static int validate_branch(struct objtool_file *file, struct instruction *first,
}
if (insn->visited) {
- if (!!insn_state_match(insn, &state))
+ if (!insn->hint && !insn_state_match(insn, &state))
return 1;
return 0;
}
- insn->state = state;
+ if (insn->hint) {
+ if (insn->restore) {
+ struct instruction *save_insn, *i;
+
+ i = insn;
+ save_insn = NULL;
+ func_for_each_insn_continue_reverse(file, func, i) {
+ if (i->save) {
+ save_insn = i;
+ break;
+ }
+ }
+
+ if (!save_insn) {
+ WARN_FUNC("no corresponding CFI save for CFI restore",
+ sec, insn->offset);
+ return 1;
+ }
+
+ if (!save_insn->visited) {
+ /*
+ * Oops, no state to copy yet.
+ * Hopefully we can reach this
+ * instruction from another branch
+ * after the save insn has been
+ * visited.
+ */
+ if (insn == first)
+ return 0;
+
+ WARN_FUNC("objtool isn't smart enough to handle this CFI save/restore combo",
+ sec, insn->offset);
+ return 1;
+ }
+
+ insn->state = save_insn->state;
+ }
+
+ state = insn->state;
+
+ } else
+ insn->state = state;
insn->visited = true;
@@ -1423,7 +1633,7 @@ static int validate_branch(struct objtool_file *file, struct instruction *first,
/* fallthrough */
case INSN_CALL_DYNAMIC:
- if (!nofp && func && !has_valid_stack_frame(&state)) {
+ if (!no_fp && func && !has_valid_stack_frame(&state)) {
WARN_FUNC("call without frame pointer save/setup",
sec, insn->offset);
return 1;
@@ -1461,6 +1671,14 @@ static int validate_branch(struct objtool_file *file, struct instruction *first,
return 0;
+ case INSN_CONTEXT_SWITCH:
+ if (func && (!next_insn || !next_insn->hint)) {
+ WARN_FUNC("unsupported instruction in callable function",
+ sec, insn->offset);
+ return 1;
+ }
+ return 0;
+
case INSN_STACK:
if (update_insn_state(insn, &state))
return -1;
@@ -1474,7 +1692,7 @@ static int validate_branch(struct objtool_file *file, struct instruction *first,
if (insn->dead_end)
return 0;
- insn = next_insn_same_sec(file, insn);
+ insn = next_insn;
if (!insn) {
WARN("%s: unexpected end of section", sec->name);
return 1;
@@ -1484,6 +1702,27 @@ static int validate_branch(struct objtool_file *file, struct instruction *first,
return 0;
}
+static int validate_unwind_hints(struct objtool_file *file)
+{
+ struct instruction *insn;
+ int ret, warnings = 0;
+ struct insn_state state;
+
+ if (!file->hints)
+ return 0;
+
+ clear_insn_state(&state);
+
+ for_each_insn(file, insn) {
+ if (insn->hint && !insn->visited) {
+ ret = validate_branch(file, insn, state);
+ warnings += ret;
+ }
+ }
+
+ return warnings;
+}
+
static bool is_kasan_insn(struct instruction *insn)
{
return (insn->type == INSN_CALL &&
@@ -1507,8 +1746,13 @@ static bool ignore_unreachable_insn(struct instruction *insn)
/*
* Ignore any unused exceptions. This can happen when a whitelisted
* function has an exception table entry.
+ *
+ * Also ignore alternative replacement instructions. This can happen
+ * when a whitelisted function uses one of the ALTERNATIVE macros.
*/
- if (!strcmp(insn->sec->name, ".fixup"))
+ if (!strcmp(insn->sec->name, ".fixup") ||
+ !strcmp(insn->sec->name, ".altinstr_replacement") ||
+ !strcmp(insn->sec->name, ".altinstr_aux"))
return true;
/*
@@ -1580,15 +1824,6 @@ static int validate_reachable_instructions(struct objtool_file *file)
if (insn->visited || ignore_unreachable_insn(insn))
continue;
- /*
- * gcov produces a lot of unreachable instructions. If we get
- * an unreachable warning and the file has gcov enabled, just
- * ignore it, and all other such warnings for the file. Do
- * this here because this is an expensive function.
- */
- if (gcov_enabled(file))
- return 0;
-
WARN_FUNC("unreachable instruction", insn->sec, insn->offset);
return 1;
}
@@ -1613,15 +1848,15 @@ static void cleanup(struct objtool_file *file)
elf_close(file->elf);
}
-int check(const char *_objname, bool _nofp)
+int check(const char *_objname, bool _no_fp, bool no_unreachable, bool orc)
{
struct objtool_file file;
int ret, warnings = 0;
objname = _objname;
- nofp = _nofp;
+ no_fp = _no_fp;
- file.elf = elf_open(objname);
+ file.elf = elf_open(objname, orc ? O_RDWR : O_RDONLY);
if (!file.elf)
return 1;
@@ -1629,8 +1864,9 @@ int check(const char *_objname, bool _nofp)
hash_init(file.insn_hash);
file.whitelist = find_section_by_name(file.elf, ".discard.func_stack_frame_non_standard");
file.rodata = find_section_by_name(file.elf, ".rodata");
- file.ignore_unreachables = false;
file.c_file = find_section_by_name(file.elf, ".comment");
+ file.ignore_unreachables = no_unreachable;
+ file.hints = false;
arch_initial_func_cfi_state(&initial_func_cfi);
@@ -1647,6 +1883,11 @@ int check(const char *_objname, bool _nofp)
goto out;
warnings += ret;
+ ret = validate_unwind_hints(&file);
+ if (ret < 0)
+ goto out;
+ warnings += ret;
+
if (!warnings) {
ret = validate_reachable_instructions(&file);
if (ret < 0)
@@ -1654,6 +1895,20 @@ int check(const char *_objname, bool _nofp)
warnings += ret;
}
+ if (orc) {
+ ret = create_orc(&file);
+ if (ret < 0)
+ goto out;
+
+ ret = create_orc_sections(&file);
+ if (ret < 0)
+ goto out;
+
+ ret = elf_write(file.elf);
+ if (ret < 0)
+ goto out;
+ }
+
out:
cleanup(&file);
diff --git a/tools/objtool/check.h b/tools/objtool/check.h
index da85f5b..c9af11f 100644
--- a/tools/objtool/check.h
+++ b/tools/objtool/check.h
@@ -22,12 +22,14 @@
#include "elf.h"
#include "cfi.h"
#include "arch.h"
+#include "orc.h"
#include <linux/hashtable.h>
struct insn_state {
struct cfi_reg cfa;
struct cfi_reg regs[CFI_NUM_REGS];
int stack_size;
+ unsigned char type;
bool bp_scratch;
bool drap;
int drap_reg;
@@ -41,13 +43,14 @@ struct instruction {
unsigned int len;
unsigned char type;
unsigned long immediate;
- bool alt_group, visited, dead_end, ignore;
+ bool alt_group, visited, dead_end, ignore, hint, save, restore;
struct symbol *call_dest;
struct instruction *jump_dest;
struct list_head alts;
struct symbol *func;
struct stack_op stack_op;
struct insn_state state;
+ struct orc_entry orc;
};
struct objtool_file {
@@ -55,12 +58,22 @@ struct objtool_file {
struct list_head insn_list;
DECLARE_HASHTABLE(insn_hash, 16);
struct section *rodata, *whitelist;
- bool ignore_unreachables, c_file;
+ bool ignore_unreachables, c_file, hints;
};
-int check(const char *objname, bool nofp);
+int check(const char *objname, bool no_fp, bool no_unreachable, bool orc);
+
+struct instruction *find_insn(struct objtool_file *file,
+ struct section *sec, unsigned long offset);
#define for_each_insn(file, insn) \
list_for_each_entry(insn, &file->insn_list, list)
+#define sec_for_each_insn(file, sec, insn) \
+ for (insn = find_insn(file, sec, 0); \
+ insn && &insn->list != &file->insn_list && \
+ insn->sec == sec; \
+ insn = list_next_entry(insn, list))
+
+
#endif /* _CHECK_H */
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 1a7e8aa..6e9f980 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -30,16 +30,6 @@
#include "elf.h"
#include "warn.h"
-/*
- * Fallback for systems without this "read, mmaping if possible" cmd.
- */
-#ifndef ELF_C_READ_MMAP
-#define ELF_C_READ_MMAP ELF_C_READ
-#endif
-
-#define WARN_ELF(format, ...) \
- WARN(format ": %s", ##__VA_ARGS__, elf_errmsg(-1))
-
struct section *find_section_by_name(struct elf *elf, const char *name)
{
struct section *sec;
@@ -349,9 +339,10 @@ static int read_relas(struct elf *elf)
return 0;
}
-struct elf *elf_open(const char *name)
+struct elf *elf_open(const char *name, int flags)
{
struct elf *elf;
+ Elf_Cmd cmd;
elf_version(EV_CURRENT);
@@ -364,13 +355,20 @@ struct elf *elf_open(const char *name)
INIT_LIST_HEAD(&elf->sections);
- elf->fd = open(name, O_RDONLY);
+ elf->fd = open(name, flags);
if (elf->fd == -1) {
perror("open");
goto err;
}
- elf->elf = elf_begin(elf->fd, ELF_C_READ_MMAP, NULL);
+ if ((flags & O_ACCMODE) == O_RDONLY)
+ cmd = ELF_C_READ_MMAP;
+ else if ((flags & O_ACCMODE) == O_RDWR)
+ cmd = ELF_C_RDWR;
+ else /* O_WRONLY */
+ cmd = ELF_C_WRITE;
+
+ elf->elf = elf_begin(elf->fd, cmd, NULL);
if (!elf->elf) {
WARN_ELF("elf_begin");
goto err;
@@ -397,6 +395,194 @@ struct elf *elf_open(const char *name)
return NULL;
}
+struct section *elf_create_section(struct elf *elf, const char *name,
+ size_t entsize, int nr)
+{
+ struct section *sec, *shstrtab;
+ size_t size = entsize * nr;
+ struct Elf_Scn *s;
+ Elf_Data *data;
+
+ sec = malloc(sizeof(*sec));
+ if (!sec) {
+ perror("malloc");
+ return NULL;
+ }
+ memset(sec, 0, sizeof(*sec));
+
+ INIT_LIST_HEAD(&sec->symbol_list);
+ INIT_LIST_HEAD(&sec->rela_list);
+ hash_init(sec->rela_hash);
+ hash_init(sec->symbol_hash);
+
+ list_add_tail(&sec->list, &elf->sections);
+
+ s = elf_newscn(elf->elf);
+ if (!s) {
+ WARN_ELF("elf_newscn");
+ return NULL;
+ }
+
+ sec->name = strdup(name);
+ if (!sec->name) {
+ perror("strdup");
+ return NULL;
+ }
+
+ sec->idx = elf_ndxscn(s);
+ sec->len = size;
+ sec->changed = true;
+
+ sec->data = elf_newdata(s);
+ if (!sec->data) {
+ WARN_ELF("elf_newdata");
+ return NULL;
+ }
+
+ sec->data->d_size = size;
+ sec->data->d_align = 1;
+
+ if (size) {
+ sec->data->d_buf = malloc(size);
+ if (!sec->data->d_buf) {
+ perror("malloc");
+ return NULL;
+ }
+ memset(sec->data->d_buf, 0, size);
+ }
+
+ if (!gelf_getshdr(s, &sec->sh)) {
+ WARN_ELF("gelf_getshdr");
+ return NULL;
+ }
+
+ sec->sh.sh_size = size;
+ sec->sh.sh_entsize = entsize;
+ sec->sh.sh_type = SHT_PROGBITS;
+ sec->sh.sh_addralign = 1;
+ sec->sh.sh_flags = SHF_ALLOC;
+
+
+ /* Add section name to .shstrtab */
+ shstrtab = find_section_by_name(elf, ".shstrtab");
+ if (!shstrtab) {
+ WARN("can't find .shstrtab section");
+ return NULL;
+ }
+
+ s = elf_getscn(elf->elf, shstrtab->idx);
+ if (!s) {
+ WARN_ELF("elf_getscn");
+ return NULL;
+ }
+
+ data = elf_newdata(s);
+ if (!data) {
+ WARN_ELF("elf_newdata");
+ return NULL;
+ }
+
+ data->d_buf = sec->name;
+ data->d_size = strlen(name) + 1;
+ data->d_align = 1;
+
+ sec->sh.sh_name = shstrtab->len;
+
+ shstrtab->len += strlen(name) + 1;
+ shstrtab->changed = true;
+
+ return sec;
+}
+
+struct section *elf_create_rela_section(struct elf *elf, struct section *base)
+{
+ char *relaname;
+ struct section *sec;
+
+ relaname = malloc(strlen(base->name) + strlen(".rela") + 1);
+ if (!relaname) {
+ perror("malloc");
+ return NULL;
+ }
+ strcpy(relaname, ".rela");
+ strcat(relaname, base->name);
+
+ sec = elf_create_section(elf, relaname, sizeof(GElf_Rela), 0);
+ if (!sec)
+ return NULL;
+
+ base->rela = sec;
+ sec->base = base;
+
+ sec->sh.sh_type = SHT_RELA;
+ sec->sh.sh_addralign = 8;
+ sec->sh.sh_link = find_section_by_name(elf, ".symtab")->idx;
+ sec->sh.sh_info = base->idx;
+ sec->sh.sh_flags = SHF_INFO_LINK;
+
+ return sec;
+}
+
+int elf_rebuild_rela_section(struct section *sec)
+{
+ struct rela *rela;
+ int nr, idx = 0, size;
+ GElf_Rela *relas;
+
+ nr = 0;
+ list_for_each_entry(rela, &sec->rela_list, list)
+ nr++;
+
+ size = nr * sizeof(*relas);
+ relas = malloc(size);
+ if (!relas) {
+ perror("malloc");
+ return -1;
+ }
+
+ sec->data->d_buf = relas;
+ sec->data->d_size = size;
+
+ sec->sh.sh_size = size;
+
+ idx = 0;
+ list_for_each_entry(rela, &sec->rela_list, list) {
+ relas[idx].r_offset = rela->offset;
+ relas[idx].r_addend = rela->addend;
+ relas[idx].r_info = GELF_R_INFO(rela->sym->idx, rela->type);
+ idx++;
+ }
+
+ return 0;
+}
+
+int elf_write(struct elf *elf)
+{
+ struct section *sec;
+ Elf_Scn *s;
+
+ list_for_each_entry(sec, &elf->sections, list) {
+ if (sec->changed) {
+ s = elf_getscn(elf->elf, sec->idx);
+ if (!s) {
+ WARN_ELF("elf_getscn");
+ return -1;
+ }
+ if (!gelf_update_shdr (s, &sec->sh)) {
+ WARN_ELF("gelf_update_shdr");
+ return -1;
+ }
+ }
+ }
+
+ if (elf_update(elf->elf, ELF_C_WRITE) < 0) {
+ WARN_ELF("elf_update");
+ return -1;
+ }
+
+ return 0;
+}
+
void elf_close(struct elf *elf)
{
struct section *sec, *tmpsec;
diff --git a/tools/objtool/elf.h b/tools/objtool/elf.h
index 343968b..d86e2ff1 100644
--- a/tools/objtool/elf.h
+++ b/tools/objtool/elf.h
@@ -28,6 +28,13 @@
# define elf_getshdrstrndx elf_getshstrndx
#endif
+/*
+ * Fallback for systems without this "read, mmaping if possible" cmd.
+ */
+#ifndef ELF_C_READ_MMAP
+#define ELF_C_READ_MMAP ELF_C_READ
+#endif
+
struct section {
struct list_head list;
GElf_Shdr sh;
@@ -41,6 +48,7 @@ struct section {
char *name;
int idx;
unsigned int len;
+ bool changed, text;
};
struct symbol {
@@ -75,7 +83,7 @@ struct elf {
};
-struct elf *elf_open(const char *name);
+struct elf *elf_open(const char *name, int flags);
struct section *find_section_by_name(struct elf *elf, const char *name);
struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset);
struct symbol *find_symbol_containing(struct section *sec, unsigned long offset);
@@ -83,6 +91,11 @@ struct rela *find_rela_by_dest(struct section *sec, unsigned long offset);
struct rela *find_rela_by_dest_range(struct section *sec, unsigned long offset,
unsigned int len);
struct symbol *find_containing_func(struct section *sec, unsigned long offset);
+struct section *elf_create_section(struct elf *elf, const char *name, size_t
+ entsize, int nr);
+struct section *elf_create_rela_section(struct elf *elf, struct section *base);
+int elf_rebuild_rela_section(struct section *sec);
+int elf_write(struct elf *elf);
void elf_close(struct elf *elf);
#define for_each_sec(file, sec) \
diff --git a/tools/objtool/objtool.c b/tools/objtool/objtool.c
index ecc5b1b..31e0f91 100644
--- a/tools/objtool/objtool.c
+++ b/tools/objtool/objtool.c
@@ -42,10 +42,11 @@ struct cmd_struct {
};
static const char objtool_usage_string[] =
- "objtool [OPTIONS] COMMAND [ARGS]";
+ "objtool COMMAND [ARGS]";
static struct cmd_struct objtool_cmds[] = {
{"check", cmd_check, "Perform stack metadata validation on an object file" },
+ {"orc", cmd_orc, "Generate in-place ORC unwind tables for an object file" },
};
bool help;
diff --git a/tools/objtool/orc.h b/tools/objtool/orc.h
new file mode 100644
index 0000000..a4139e3
--- /dev/null
+++ b/tools/objtool/orc.h
@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _ORC_H
+#define _ORC_H
+
+#include "orc_types.h"
+
+struct objtool_file;
+
+int create_orc(struct objtool_file *file);
+int create_orc_sections(struct objtool_file *file);
+
+int orc_dump(const char *objname);
+
+#endif /* _ORC_H */
diff --git a/tools/objtool/orc_dump.c b/tools/objtool/orc_dump.c
new file mode 100644
index 0000000..36c5bf6
--- /dev/null
+++ b/tools/objtool/orc_dump.c
@@ -0,0 +1,212 @@
+/*
+ * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <unistd.h>
+#include "orc.h"
+#include "warn.h"
+
+static const char *reg_name(unsigned int reg)
+{
+ switch (reg) {
+ case ORC_REG_PREV_SP:
+ return "prevsp";
+ case ORC_REG_DX:
+ return "dx";
+ case ORC_REG_DI:
+ return "di";
+ case ORC_REG_BP:
+ return "bp";
+ case ORC_REG_SP:
+ return "sp";
+ case ORC_REG_R10:
+ return "r10";
+ case ORC_REG_R13:
+ return "r13";
+ case ORC_REG_BP_INDIRECT:
+ return "bp(ind)";
+ case ORC_REG_SP_INDIRECT:
+ return "sp(ind)";
+ default:
+ return "?";
+ }
+}
+
+static const char *orc_type_name(unsigned int type)
+{
+ switch (type) {
+ case ORC_TYPE_CALL:
+ return "call";
+ case ORC_TYPE_REGS:
+ return "regs";
+ case ORC_TYPE_REGS_IRET:
+ return "iret";
+ default:
+ return "?";
+ }
+}
+
+static void print_reg(unsigned int reg, int offset)
+{
+ if (reg == ORC_REG_BP_INDIRECT)
+ printf("(bp%+d)", offset);
+ else if (reg == ORC_REG_SP_INDIRECT)
+ printf("(sp%+d)", offset);
+ else if (reg == ORC_REG_UNDEFINED)
+ printf("(und)");
+ else
+ printf("%s%+d", reg_name(reg), offset);
+}
+
+int orc_dump(const char *_objname)
+{
+ int fd, nr_entries, i, *orc_ip = NULL, orc_size = 0;
+ struct orc_entry *orc = NULL;
+ char *name;
+ unsigned long nr_sections, orc_ip_addr = 0;
+ size_t shstrtab_idx;
+ Elf *elf;
+ Elf_Scn *scn;
+ GElf_Shdr sh;
+ GElf_Rela rela;
+ GElf_Sym sym;
+ Elf_Data *data, *symtab = NULL, *rela_orc_ip = NULL;
+
+
+ objname = _objname;
+
+ elf_version(EV_CURRENT);
+
+ fd = open(objname, O_RDONLY);
+ if (fd == -1) {
+ perror("open");
+ return -1;
+ }
+
+ elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
+ if (!elf) {
+ WARN_ELF("elf_begin");
+ return -1;
+ }
+
+ if (elf_getshdrnum(elf, &nr_sections)) {
+ WARN_ELF("elf_getshdrnum");
+ return -1;
+ }
+
+ if (elf_getshdrstrndx(elf, &shstrtab_idx)) {
+ WARN_ELF("elf_getshdrstrndx");
+ return -1;
+ }
+
+ for (i = 0; i < nr_sections; i++) {
+ scn = elf_getscn(elf, i);
+ if (!scn) {
+ WARN_ELF("elf_getscn");
+ return -1;
+ }
+
+ if (!gelf_getshdr(scn, &sh)) {
+ WARN_ELF("gelf_getshdr");
+ return -1;
+ }
+
+ name = elf_strptr(elf, shstrtab_idx, sh.sh_name);
+ if (!name) {
+ WARN_ELF("elf_strptr");
+ return -1;
+ }
+
+ data = elf_getdata(scn, NULL);
+ if (!data) {
+ WARN_ELF("elf_getdata");
+ return -1;
+ }
+
+ if (!strcmp(name, ".symtab")) {
+ symtab = data;
+ } else if (!strcmp(name, ".orc_unwind")) {
+ orc = data->d_buf;
+ orc_size = sh.sh_size;
+ } else if (!strcmp(name, ".orc_unwind_ip")) {
+ orc_ip = data->d_buf;
+ orc_ip_addr = sh.sh_addr;
+ } else if (!strcmp(name, ".rela.orc_unwind_ip")) {
+ rela_orc_ip = data;
+ }
+ }
+
+ if (!symtab || !orc || !orc_ip)
+ return 0;
+
+ if (orc_size % sizeof(*orc) != 0) {
+ WARN("bad .orc_unwind section size");
+ return -1;
+ }
+
+ nr_entries = orc_size / sizeof(*orc);
+ for (i = 0; i < nr_entries; i++) {
+ if (rela_orc_ip) {
+ if (!gelf_getrela(rela_orc_ip, i, &rela)) {
+ WARN_ELF("gelf_getrela");
+ return -1;
+ }
+
+ if (!gelf_getsym(symtab, GELF_R_SYM(rela.r_info), &sym)) {
+ WARN_ELF("gelf_getsym");
+ return -1;
+ }
+
+ scn = elf_getscn(elf, sym.st_shndx);
+ if (!scn) {
+ WARN_ELF("elf_getscn");
+ return -1;
+ }
+
+ if (!gelf_getshdr(scn, &sh)) {
+ WARN_ELF("gelf_getshdr");
+ return -1;
+ }
+
+ name = elf_strptr(elf, shstrtab_idx, sh.sh_name);
+ if (!name || !*name) {
+ WARN_ELF("elf_strptr");
+ return -1;
+ }
+
+ printf("%s+%lx:", name, rela.r_addend);
+
+ } else {
+ printf("%lx:", orc_ip_addr + (i * sizeof(int)) + orc_ip[i]);
+ }
+
+
+ printf(" sp:");
+
+ print_reg(orc[i].sp_reg, orc[i].sp_offset);
+
+ printf(" bp:");
+
+ print_reg(orc[i].bp_reg, orc[i].bp_offset);
+
+ printf(" type:%s\n", orc_type_name(orc[i].type));
+ }
+
+ elf_end(elf);
+ close(fd);
+
+ return 0;
+}
diff --git a/tools/objtool/orc_gen.c b/tools/objtool/orc_gen.c
new file mode 100644
index 0000000..e5ca314
--- /dev/null
+++ b/tools/objtool/orc_gen.c
@@ -0,0 +1,214 @@
+/*
+ * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "orc.h"
+#include "check.h"
+#include "warn.h"
+
+int create_orc(struct objtool_file *file)
+{
+ struct instruction *insn;
+
+ for_each_insn(file, insn) {
+ struct orc_entry *orc = &insn->orc;
+ struct cfi_reg *cfa = &insn->state.cfa;
+ struct cfi_reg *bp = &insn->state.regs[CFI_BP];
+
+ if (cfa->base == CFI_UNDEFINED) {
+ orc->sp_reg = ORC_REG_UNDEFINED;
+ continue;
+ }
+
+ switch (cfa->base) {
+ case CFI_SP:
+ orc->sp_reg = ORC_REG_SP;
+ break;
+ case CFI_SP_INDIRECT:
+ orc->sp_reg = ORC_REG_SP_INDIRECT;
+ break;
+ case CFI_BP:
+ orc->sp_reg = ORC_REG_BP;
+ break;
+ case CFI_BP_INDIRECT:
+ orc->sp_reg = ORC_REG_BP_INDIRECT;
+ break;
+ case CFI_R10:
+ orc->sp_reg = ORC_REG_R10;
+ break;
+ case CFI_R13:
+ orc->sp_reg = ORC_REG_R13;
+ break;
+ case CFI_DI:
+ orc->sp_reg = ORC_REG_DI;
+ break;
+ case CFI_DX:
+ orc->sp_reg = ORC_REG_DX;
+ break;
+ default:
+ WARN_FUNC("unknown CFA base reg %d",
+ insn->sec, insn->offset, cfa->base);
+ return -1;
+ }
+
+ switch(bp->base) {
+ case CFI_UNDEFINED:
+ orc->bp_reg = ORC_REG_UNDEFINED;
+ break;
+ case CFI_CFA:
+ orc->bp_reg = ORC_REG_PREV_SP;
+ break;
+ case CFI_BP:
+ orc->bp_reg = ORC_REG_BP;
+ break;
+ default:
+ WARN_FUNC("unknown BP base reg %d",
+ insn->sec, insn->offset, bp->base);
+ return -1;
+ }
+
+ orc->sp_offset = cfa->offset;
+ orc->bp_offset = bp->offset;
+ orc->type = insn->state.type;
+ }
+
+ return 0;
+}
+
+static int create_orc_entry(struct section *u_sec, struct section *ip_relasec,
+ unsigned int idx, struct section *insn_sec,
+ unsigned long insn_off, struct orc_entry *o)
+{
+ struct orc_entry *orc;
+ struct rela *rela;
+
+ /* populate ORC data */
+ orc = (struct orc_entry *)u_sec->data->d_buf + idx;
+ memcpy(orc, o, sizeof(*orc));
+
+ /* populate rela for ip */
+ rela = malloc(sizeof(*rela));
+ if (!rela) {
+ perror("malloc");
+ return -1;
+ }
+ memset(rela, 0, sizeof(*rela));
+
+ rela->sym = insn_sec->sym;
+ rela->addend = insn_off;
+ rela->type = R_X86_64_PC32;
+ rela->offset = idx * sizeof(int);
+
+ list_add_tail(&rela->list, &ip_relasec->rela_list);
+ hash_add(ip_relasec->rela_hash, &rela->hash, rela->offset);
+
+ return 0;
+}
+
+int create_orc_sections(struct objtool_file *file)
+{
+ struct instruction *insn, *prev_insn;
+ struct section *sec, *u_sec, *ip_relasec;
+ unsigned int idx;
+
+ struct orc_entry empty = {
+ .sp_reg = ORC_REG_UNDEFINED,
+ .bp_reg = ORC_REG_UNDEFINED,
+ .type = ORC_TYPE_CALL,
+ };
+
+ sec = find_section_by_name(file->elf, ".orc_unwind");
+ if (sec) {
+ WARN("file already has .orc_unwind section, skipping");
+ return -1;
+ }
+
+ /* count the number of needed orcs */
+ idx = 0;
+ for_each_sec(file, sec) {
+ if (!sec->text)
+ continue;
+
+ prev_insn = NULL;
+ sec_for_each_insn(file, sec, insn) {
+ if (!prev_insn ||
+ memcmp(&insn->orc, &prev_insn->orc,
+ sizeof(struct orc_entry))) {
+ idx++;
+ }
+ prev_insn = insn;
+ }
+
+ /* section terminator */
+ if (prev_insn)
+ idx++;
+ }
+ if (!idx)
+ return -1;
+
+
+ /* create .orc_unwind_ip and .rela.orc_unwind_ip sections */
+ sec = elf_create_section(file->elf, ".orc_unwind_ip", sizeof(int), idx);
+
+ ip_relasec = elf_create_rela_section(file->elf, sec);
+ if (!ip_relasec)
+ return -1;
+
+ /* create .orc_unwind section */
+ u_sec = elf_create_section(file->elf, ".orc_unwind",
+ sizeof(struct orc_entry), idx);
+
+ /* populate sections */
+ idx = 0;
+ for_each_sec(file, sec) {
+ if (!sec->text)
+ continue;
+
+ prev_insn = NULL;
+ sec_for_each_insn(file, sec, insn) {
+ if (!prev_insn || memcmp(&insn->orc, &prev_insn->orc,
+ sizeof(struct orc_entry))) {
+
+ if (create_orc_entry(u_sec, ip_relasec, idx,
+ insn->sec, insn->offset,
+ &insn->orc))
+ return -1;
+
+ idx++;
+ }
+ prev_insn = insn;
+ }
+
+ /* section terminator */
+ if (prev_insn) {
+ if (create_orc_entry(u_sec, ip_relasec, idx,
+ prev_insn->sec,
+ prev_insn->offset + prev_insn->len,
+ &empty))
+ return -1;
+
+ idx++;
+ }
+ }
+
+ if (elf_rebuild_rela_section(ip_relasec))
+ return -1;
+
+ return 0;
+}
diff --git a/tools/objtool/orc_types.h b/tools/objtool/orc_types.h
new file mode 100644
index 0000000..9c9dc57
--- /dev/null
+++ b/tools/objtool/orc_types.h
@@ -0,0 +1,107 @@
+/*
+ * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _ORC_TYPES_H
+#define _ORC_TYPES_H
+
+#include <linux/types.h>
+#include <linux/compiler.h>
+
+/*
+ * The ORC_REG_* registers are base registers which are used to find other
+ * registers on the stack.
+ *
+ * ORC_REG_PREV_SP, also known as DWARF Call Frame Address (CFA), is the
+ * address of the previous frame: the caller's SP before it called the current
+ * function.
+ *
+ * ORC_REG_UNDEFINED means the corresponding register's value didn't change in
+ * the current frame.
+ *
+ * The most commonly used base registers are SP and BP -- which the previous SP
+ * is usually based on -- and PREV_SP and UNDEFINED -- which the previous BP is
+ * usually based on.
+ *
+ * The rest of the base registers are needed for special cases like entry code
+ * and GCC realigned stacks.
+ */
+#define ORC_REG_UNDEFINED 0
+#define ORC_REG_PREV_SP 1
+#define ORC_REG_DX 2
+#define ORC_REG_DI 3
+#define ORC_REG_BP 4
+#define ORC_REG_SP 5
+#define ORC_REG_R10 6
+#define ORC_REG_R13 7
+#define ORC_REG_BP_INDIRECT 8
+#define ORC_REG_SP_INDIRECT 9
+#define ORC_REG_MAX 15
+
+/*
+ * ORC_TYPE_CALL: Indicates that sp_reg+sp_offset resolves to PREV_SP (the
+ * caller's SP right before it made the call). Used for all callable
+ * functions, i.e. all C code and all callable asm functions.
+ *
+ * ORC_TYPE_REGS: Used in entry code to indicate that sp_reg+sp_offset points
+ * to a fully populated pt_regs from a syscall, interrupt, or exception.
+ *
+ * ORC_TYPE_REGS_IRET: Used in entry code to indicate that sp_reg+sp_offset
+ * points to the iret return frame.
+ *
+ * The UNWIND_HINT macros are used only for the unwind_hint struct. They
+ * aren't used in struct orc_entry due to size and complexity constraints.
+ * Objtool converts them to real types when it converts the hints to orc
+ * entries.
+ */
+#define ORC_TYPE_CALL 0
+#define ORC_TYPE_REGS 1
+#define ORC_TYPE_REGS_IRET 2
+#define UNWIND_HINT_TYPE_SAVE 3
+#define UNWIND_HINT_TYPE_RESTORE 4
+
+#ifndef __ASSEMBLY__
+/*
+ * This struct is more or less a vastly simplified version of the DWARF Call
+ * Frame Information standard. It contains only the necessary parts of DWARF
+ * CFI, simplified for ease of access by the in-kernel unwinder. It tells the
+ * unwinder how to find the previous SP and BP (and sometimes entry regs) on
+ * the stack for a given code address. Each instance of the struct corresponds
+ * to one or more code locations.
+ */
+struct orc_entry {
+ s16 sp_offset;
+ s16 bp_offset;
+ unsigned sp_reg:4;
+ unsigned bp_reg:4;
+ unsigned type:2;
+} __packed;
+
+/*
+ * This struct is used by asm and inline asm code to manually annotate the
+ * location of registers on the stack for the ORC unwinder.
+ *
+ * Type can be either ORC_TYPE_* or UNWIND_HINT_TYPE_*.
+ */
+struct unwind_hint {
+ u32 ip;
+ s16 sp_offset;
+ u8 sp_reg;
+ u8 type;
+};
+#endif /* __ASSEMBLY__ */
+
+#endif /* _ORC_TYPES_H */