[PATCH] i386: Abstract sensitive instructions
Abstract sensitive instructions in assembler code, replacing them with macros
(which currently are #defined to the native versions). We use long names:
assembler is case-insensitive, so if something goes wrong and macros do not
expand, it would assemble anyway.
Resulting object files are exactly the same as before.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Andi Kleen <ak@suse.de>
diff --git a/arch/i386/kernel/entry.S b/arch/i386/kernel/entry.S
index 4b08452..3872fca 100644
--- a/arch/i386/kernel/entry.S
+++ b/arch/i386/kernel/entry.S
@@ -76,8 +76,15 @@
NT_MASK = 0x00004000
VM_MASK = 0x00020000
+/* These are replaces for paravirtualization */
+#define DISABLE_INTERRUPTS cli
+#define ENABLE_INTERRUPTS sti
+#define ENABLE_INTERRUPTS_SYSEXIT sti; sysexit
+#define INTERRUPT_RETURN iret
+#define GET_CR0_INTO_EAX movl %cr0, %eax
+
#ifdef CONFIG_PREEMPT
-#define preempt_stop cli; TRACE_IRQS_OFF
+#define preempt_stop DISABLE_INTERRUPTS; TRACE_IRQS_OFF
#else
#define preempt_stop
#define resume_kernel restore_nocheck
@@ -236,7 +243,7 @@
testl $(VM_MASK | 3), %eax
jz resume_kernel
ENTRY(resume_userspace)
- cli # make sure we don't miss an interrupt
+ DISABLE_INTERRUPTS # make sure we don't miss an interrupt
# setting need_resched or sigpending
# between sampling and the iret
movl TI_flags(%ebp), %ecx
@@ -247,7 +254,7 @@
#ifdef CONFIG_PREEMPT
ENTRY(resume_kernel)
- cli
+ DISABLE_INTERRUPTS
cmpl $0,TI_preempt_count(%ebp) # non-zero preempt_count ?
jnz restore_nocheck
need_resched:
@@ -275,7 +282,7 @@
* No need to follow this irqs on/off section: the syscall
* disabled irqs and here we enable it straight after entry:
*/
- sti
+ ENABLE_INTERRUPTS
pushl $(__USER_DS)
CFI_ADJUST_CFA_OFFSET 4
/*CFI_REL_OFFSET ss, 0*/
@@ -320,7 +327,7 @@
jae syscall_badsys
call *sys_call_table(,%eax,4)
movl %eax,EAX(%esp)
- cli
+ DISABLE_INTERRUPTS
TRACE_IRQS_OFF
movl TI_flags(%ebp), %ecx
testw $_TIF_ALLWORK_MASK, %cx
@@ -330,8 +337,7 @@
movl OLDESP(%esp), %ecx
xorl %ebp,%ebp
TRACE_IRQS_ON
- sti
- sysexit
+ ENABLE_INTERRUPTS_SYSEXIT
CFI_ENDPROC
@@ -356,7 +362,7 @@
call *sys_call_table(,%eax,4)
movl %eax,EAX(%esp) # store the return value
syscall_exit:
- cli # make sure we don't miss an interrupt
+ DISABLE_INTERRUPTS # make sure we don't miss an interrupt
# setting need_resched or sigpending
# between sampling and the iret
TRACE_IRQS_OFF
@@ -381,11 +387,11 @@
RESTORE_REGS
addl $4, %esp
CFI_ADJUST_CFA_OFFSET -4
-1: iret
+1: INTERRUPT_RETURN
.section .fixup,"ax"
iret_exc:
TRACE_IRQS_ON
- sti
+ ENABLE_INTERRUPTS
pushl $0 # no error code
pushl $do_iret_error
jmp error_code
@@ -409,7 +415,7 @@
* dosemu and wine happy. */
subl $8, %esp # reserve space for switch16 pointer
CFI_ADJUST_CFA_OFFSET 8
- cli
+ DISABLE_INTERRUPTS
TRACE_IRQS_OFF
movl %esp, %eax
/* Set up the 16bit stack frame with switch32 pointer on top,
@@ -419,7 +425,7 @@
TRACE_IRQS_IRET
RESTORE_REGS
lss 20+4(%esp), %esp # switch to 16bit stack
-1: iret
+1: INTERRUPT_RETURN
.section __ex_table,"a"
.align 4
.long 1b,iret_exc
@@ -434,7 +440,7 @@
jz work_notifysig
work_resched:
call schedule
- cli # make sure we don't miss an interrupt
+ DISABLE_INTERRUPTS # make sure we don't miss an interrupt
# setting need_resched or sigpending
# between sampling and the iret
TRACE_IRQS_OFF
@@ -490,7 +496,7 @@
testb $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP), %cl
jz work_pending
TRACE_IRQS_ON
- sti # could let do_syscall_trace() call
+ ENABLE_INTERRUPTS # could let do_syscall_trace() call
# schedule() instead
movl %esp, %eax
movl $1, %edx
@@ -668,7 +674,7 @@
pushl $-1 # mark this as an int
CFI_ADJUST_CFA_OFFSET 4
SAVE_ALL
- movl %cr0, %eax
+ GET_CR0_INTO_EAX
testl $0x4, %eax # EM (math emulation bit)
jne device_not_available_emulate
preempt_stop
@@ -811,7 +817,7 @@
call do_nmi
RESTORE_REGS
lss 12+4(%esp), %esp # back to 16bit stack
-1: iret
+1: INTERRUPT_RETURN
CFI_ENDPROC
.section __ex_table,"a"
.align 4
diff --git a/include/asm-i386/spinlock.h b/include/asm-i386/spinlock.h
index 3243293..b0b3043 100644
--- a/include/asm-i386/spinlock.h
+++ b/include/asm-i386/spinlock.h
@@ -7,6 +7,9 @@
#include <asm/processor.h>
#include <linux/compiler.h>
+#define CLI_STRING "cli"
+#define STI_STRING "sti"
+
/*
* Your basic SMP spinlocks, allowing only a single CPU anywhere
*
@@ -55,12 +58,12 @@
"2:\t"
"testl $0x200, %1\n\t"
"jz 4f\n\t"
- "sti\n"
+ STI_STRING "\n"
"3:\t"
"rep;nop\n\t"
"cmpb $0, %0\n\t"
"jle 3b\n\t"
- "cli\n\t"
+ CLI_STRING "\n\t"
"jmp 1b\n"
"4:\t"
"rep;nop\n\t"