Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/arch/x86_64/entry.S |
| 3 | * |
| 4 | * Copyright (C) 1991, 1992 Linus Torvalds |
| 5 | * Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs |
| 6 | * Copyright (C) 2000 Pavel Machek <pavel@suse.cz> |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 7 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 8 | * entry.S contains the system-call and fault low-level handling routines. |
| 9 | * |
Andy Lutomirski | 8b4777a | 2011-06-05 13:50:18 -0400 | [diff] [blame] | 10 | * Some of this is documented in Documentation/x86/entry_64.txt |
| 11 | * |
Alexander van Heukelum | 0bd7b79 | 2008-11-16 15:29:00 +0100 | [diff] [blame] | 12 | * A note on terminology: |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 13 | * - iret frame: Architecture defined interrupt frame from SS to RIP |
| 14 | * at the top of the kernel process stack. |
Andi Kleen | 2e91a17 | 2006-09-26 10:52:29 +0200 | [diff] [blame] | 15 | * |
| 16 | * Some macro usage: |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 17 | * - ENTRY/END: Define functions in the symbol table. |
| 18 | * - TRACE_IRQ_*: Trace hardirq state for lock debugging. |
| 19 | * - idtentry: Define exception entry points. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 20 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 21 | #include <linux/linkage.h> |
| 22 | #include <asm/segment.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 23 | #include <asm/cache.h> |
| 24 | #include <asm/errno.h> |
Ingo Molnar | d36f947 | 2015-06-03 18:29:26 +0200 | [diff] [blame] | 25 | #include "calling.h" |
Sam Ravnborg | e2d5df9 | 2005-09-09 21:28:48 +0200 | [diff] [blame] | 26 | #include <asm/asm-offsets.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 27 | #include <asm/msr.h> |
| 28 | #include <asm/unistd.h> |
| 29 | #include <asm/thread_info.h> |
| 30 | #include <asm/hw_irq.h> |
Jeremy Fitzhardinge | 0341c14 | 2009-02-13 11:14:01 -0800 | [diff] [blame] | 31 | #include <asm/page_types.h> |
Ingo Molnar | 2601e64 | 2006-07-03 00:24:45 -0700 | [diff] [blame] | 32 | #include <asm/irqflags.h> |
Glauber de Oliveira Costa | 72fe485 | 2008-01-30 13:32:08 +0100 | [diff] [blame] | 33 | #include <asm/paravirt.h> |
Tejun Heo | 9939dda | 2009-01-13 20:41:35 +0900 | [diff] [blame] | 34 | #include <asm/percpu.h> |
H. Peter Anvin | d7abc0f | 2012-04-20 12:19:50 -0700 | [diff] [blame] | 35 | #include <asm/asm.h> |
H. Peter Anvin | 63bcff2 | 2012-09-21 12:43:12 -0700 | [diff] [blame] | 36 | #include <asm/smap.h> |
H. Peter Anvin | 3891a04 | 2014-04-29 16:46:09 -0700 | [diff] [blame] | 37 | #include <asm/pgtable_types.h> |
Al Viro | 784d569 | 2016-01-11 11:04:34 -0500 | [diff] [blame] | 38 | #include <asm/export.h> |
Richard Fellner | 13be448 | 2017-05-04 14:26:50 +0200 | [diff] [blame] | 39 | #include <asm/kaiser.h> |
David Woodhouse | 8b1bacc | 2018-01-11 21:46:28 +0000 | [diff] [blame] | 40 | #include <asm/nospec-branch.h> |
Eric Paris | d7e7528 | 2012-01-03 14:23:06 -0500 | [diff] [blame] | 41 | #include <linux/err.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 42 | |
Roland McGrath | 86a1c34 | 2008-06-23 15:37:04 -0700 | [diff] [blame] | 43 | /* Avoid __ASSEMBLER__'ifying <linux/audit.h> just for this. */ |
| 44 | #include <linux/elf-em.h> |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 45 | #define AUDIT_ARCH_X86_64 (EM_X86_64|__AUDIT_ARCH_64BIT|__AUDIT_ARCH_LE) |
| 46 | #define __AUDIT_ARCH_64BIT 0x80000000 |
| 47 | #define __AUDIT_ARCH_LE 0x40000000 |
Roland McGrath | 86a1c34 | 2008-06-23 15:37:04 -0700 | [diff] [blame] | 48 | |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 49 | .code64 |
| 50 | .section .entry.text, "ax" |
Arnaldo Carvalho de Melo | 16444a8 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 51 | |
Glauber de Oliveira Costa | 72fe485 | 2008-01-30 13:32:08 +0100 | [diff] [blame] | 52 | #ifdef CONFIG_PARAVIRT |
Jeremy Fitzhardinge | 2be2998 | 2008-06-25 00:19:28 -0400 | [diff] [blame] | 53 | ENTRY(native_usergs_sysret64) |
Glauber de Oliveira Costa | 72fe485 | 2008-01-30 13:32:08 +0100 | [diff] [blame] | 54 | swapgs |
| 55 | sysretq |
Cyrill Gorcunov | b3baaa1 | 2009-02-23 22:57:00 +0300 | [diff] [blame] | 56 | ENDPROC(native_usergs_sysret64) |
Glauber de Oliveira Costa | 72fe485 | 2008-01-30 13:32:08 +0100 | [diff] [blame] | 57 | #endif /* CONFIG_PARAVIRT */ |
| 58 | |
Greg Kroah-Hartman | a11ca51 | 2017-12-04 12:59:57 +0100 | [diff] [blame] | 59 | .macro TRACE_IRQS_IRETQ |
Ingo Molnar | 2601e64 | 2006-07-03 00:24:45 -0700 | [diff] [blame] | 60 | #ifdef CONFIG_TRACE_IRQFLAGS |
Greg Kroah-Hartman | a11ca51 | 2017-12-04 12:59:57 +0100 | [diff] [blame] | 61 | bt $9, EFLAGS(%rsp) /* interrupts off? */ |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 62 | jnc 1f |
Ingo Molnar | 2601e64 | 2006-07-03 00:24:45 -0700 | [diff] [blame] | 63 | TRACE_IRQS_ON |
| 64 | 1: |
| 65 | #endif |
| 66 | .endm |
| 67 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 68 | /* |
Steven Rostedt | 5963e31 | 2012-05-30 11:54:53 -0400 | [diff] [blame] | 69 | * When dynamic function tracer is enabled it will add a breakpoint |
| 70 | * to all locations that it is about to modify, sync CPUs, update |
| 71 | * all the code, sync CPUs, then remove the breakpoints. In this time |
| 72 | * if lockdep is enabled, it might jump back into the debug handler |
| 73 | * outside the updating of the IST protection. (TRACE_IRQS_ON/OFF). |
| 74 | * |
| 75 | * We need to change the IDT table before calling TRACE_IRQS_ON/OFF to |
| 76 | * make sure the stack pointer does not get reset back to the top |
| 77 | * of the debug stack, and instead just reuses the current stack. |
| 78 | */ |
| 79 | #if defined(CONFIG_DYNAMIC_FTRACE) && defined(CONFIG_TRACE_IRQFLAGS) |
| 80 | |
| 81 | .macro TRACE_IRQS_OFF_DEBUG |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 82 | call debug_stack_set_zero |
Steven Rostedt | 5963e31 | 2012-05-30 11:54:53 -0400 | [diff] [blame] | 83 | TRACE_IRQS_OFF |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 84 | call debug_stack_reset |
Steven Rostedt | 5963e31 | 2012-05-30 11:54:53 -0400 | [diff] [blame] | 85 | .endm |
| 86 | |
| 87 | .macro TRACE_IRQS_ON_DEBUG |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 88 | call debug_stack_set_zero |
Steven Rostedt | 5963e31 | 2012-05-30 11:54:53 -0400 | [diff] [blame] | 89 | TRACE_IRQS_ON |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 90 | call debug_stack_reset |
Steven Rostedt | 5963e31 | 2012-05-30 11:54:53 -0400 | [diff] [blame] | 91 | .endm |
| 92 | |
Denys Vlasenko | f2db938 | 2015-02-26 14:40:30 -0800 | [diff] [blame] | 93 | .macro TRACE_IRQS_IRETQ_DEBUG |
Jan Beulich | 8a76e85 | 2018-07-02 04:47:57 -0600 | [diff] [blame] | 94 | btl $9, EFLAGS(%rsp) /* interrupts off? */ |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 95 | jnc 1f |
Steven Rostedt | 5963e31 | 2012-05-30 11:54:53 -0400 | [diff] [blame] | 96 | TRACE_IRQS_ON_DEBUG |
| 97 | 1: |
| 98 | .endm |
| 99 | |
| 100 | #else |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 101 | # define TRACE_IRQS_OFF_DEBUG TRACE_IRQS_OFF |
| 102 | # define TRACE_IRQS_ON_DEBUG TRACE_IRQS_ON |
| 103 | # define TRACE_IRQS_IRETQ_DEBUG TRACE_IRQS_IRETQ |
Steven Rostedt | 5963e31 | 2012-05-30 11:54:53 -0400 | [diff] [blame] | 104 | #endif |
| 105 | |
| 106 | /* |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 107 | * 64-bit SYSCALL instruction entry. Up to 6 arguments in registers. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 108 | * |
Andy Lutomirski | fda57b2 | 2016-03-09 19:00:35 -0800 | [diff] [blame] | 109 | * This is the only entry point used for 64-bit system calls. The |
| 110 | * hardware interface is reasonably well designed and the register to |
| 111 | * argument mapping Linux uses fits well with the registers that are |
| 112 | * available when SYSCALL is used. |
| 113 | * |
| 114 | * SYSCALL instructions can be found inlined in libc implementations as |
| 115 | * well as some other programs and libraries. There are also a handful |
| 116 | * of SYSCALL instructions in the vDSO used, for example, as a |
| 117 | * clock_gettimeofday fallback. |
| 118 | * |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 119 | * 64-bit SYSCALL saves rip to rcx, clears rflags.RF, then saves rflags to r11, |
Denys Vlasenko | b87cf63 | 2015-02-26 14:40:32 -0800 | [diff] [blame] | 120 | * then loads new ss, cs, and rip from previously programmed MSRs. |
| 121 | * rflags gets masked by a value from another MSR (so CLD and CLAC |
| 122 | * are not needed). SYSCALL does not save anything on the stack |
| 123 | * and does not change rsp. |
| 124 | * |
| 125 | * Registers on entry: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 126 | * rax system call number |
Denys Vlasenko | b87cf63 | 2015-02-26 14:40:32 -0800 | [diff] [blame] | 127 | * rcx return address |
| 128 | * r11 saved rflags (note: r11 is callee-clobbered register in C ABI) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 129 | * rdi arg0 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 130 | * rsi arg1 |
Alexander van Heukelum | 0bd7b79 | 2008-11-16 15:29:00 +0100 | [diff] [blame] | 131 | * rdx arg2 |
Denys Vlasenko | b87cf63 | 2015-02-26 14:40:32 -0800 | [diff] [blame] | 132 | * r10 arg3 (needs to be moved to rcx to conform to C ABI) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 133 | * r8 arg4 |
| 134 | * r9 arg5 |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 135 | * (note: r12-r15, rbp, rbx are callee-preserved in C ABI) |
Alexander van Heukelum | 0bd7b79 | 2008-11-16 15:29:00 +0100 | [diff] [blame] | 136 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 137 | * Only called from user space. |
| 138 | * |
Ingo Molnar | 7fcb3bc | 2015-03-17 14:42:59 +0100 | [diff] [blame] | 139 | * When user can change pt_regs->foo always force IRET. That is because |
Andi Kleen | 7bf36bb | 2006-04-07 19:50:00 +0200 | [diff] [blame] | 140 | * it deals with uncanonical addresses better. SYSRET has trouble |
| 141 | * with them due to bugs in both AMD and Intel CPUs. |
Alexander van Heukelum | 0bd7b79 | 2008-11-16 15:29:00 +0100 | [diff] [blame] | 142 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 143 | |
Ingo Molnar | b2502b4 | 2015-06-08 08:42:03 +0200 | [diff] [blame] | 144 | ENTRY(entry_SYSCALL_64) |
Denys Vlasenko | 9ed8e7d | 2015-03-19 18:17:47 +0100 | [diff] [blame] | 145 | /* |
| 146 | * Interrupts are off on entry. |
| 147 | * We do not frame this tiny irq-off block with TRACE_IRQS_OFF/ON, |
| 148 | * it is too small to ever cause noticeable irq latency. |
| 149 | */ |
Glauber de Oliveira Costa | 72fe485 | 2008-01-30 13:32:08 +0100 | [diff] [blame] | 150 | SWAPGS_UNSAFE_STACK |
Richard Fellner | 13be448 | 2017-05-04 14:26:50 +0200 | [diff] [blame] | 151 | SWITCH_KERNEL_CR3_NO_STACK |
Glauber de Oliveira Costa | 72fe485 | 2008-01-30 13:32:08 +0100 | [diff] [blame] | 152 | /* |
| 153 | * A hypervisor implementation might want to use a label |
| 154 | * after the swapgs, so that it can do the swapgs |
| 155 | * for the guest and jump here on syscall. |
| 156 | */ |
Ingo Molnar | b2502b4 | 2015-06-08 08:42:03 +0200 | [diff] [blame] | 157 | GLOBAL(entry_SYSCALL_64_after_swapgs) |
Glauber de Oliveira Costa | 72fe485 | 2008-01-30 13:32:08 +0100 | [diff] [blame] | 158 | |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 159 | movq %rsp, PER_CPU_VAR(rsp_scratch) |
| 160 | movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp |
Denys Vlasenko | 9ed8e7d | 2015-03-19 18:17:47 +0100 | [diff] [blame] | 161 | |
Andy Lutomirski | 1e423bf | 2016-01-28 15:11:28 -0800 | [diff] [blame] | 162 | TRACE_IRQS_OFF |
| 163 | |
Denys Vlasenko | 9ed8e7d | 2015-03-19 18:17:47 +0100 | [diff] [blame] | 164 | /* Construct struct pt_regs on stack */ |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 165 | pushq $__USER_DS /* pt_regs->ss */ |
| 166 | pushq PER_CPU_VAR(rsp_scratch) /* pt_regs->sp */ |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 167 | pushq %r11 /* pt_regs->flags */ |
| 168 | pushq $__USER_CS /* pt_regs->cs */ |
| 169 | pushq %rcx /* pt_regs->ip */ |
| 170 | pushq %rax /* pt_regs->orig_ax */ |
| 171 | pushq %rdi /* pt_regs->di */ |
| 172 | pushq %rsi /* pt_regs->si */ |
| 173 | pushq %rdx /* pt_regs->dx */ |
| 174 | pushq %rcx /* pt_regs->cx */ |
| 175 | pushq $-ENOSYS /* pt_regs->ax */ |
| 176 | pushq %r8 /* pt_regs->r8 */ |
| 177 | pushq %r9 /* pt_regs->r9 */ |
| 178 | pushq %r10 /* pt_regs->r10 */ |
Dan Williams | 22b5557 | 2018-02-23 14:06:21 -0800 | [diff] [blame] | 179 | /* |
| 180 | * Clear extra registers that a speculation attack might |
| 181 | * otherwise want to exploit. Interleave XOR with PUSH |
| 182 | * for better uop scheduling: |
| 183 | */ |
| 184 | xorq %r10, %r10 /* nospec r10 */ |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 185 | pushq %r11 /* pt_regs->r11 */ |
Dan Williams | 22b5557 | 2018-02-23 14:06:21 -0800 | [diff] [blame] | 186 | xorq %r11, %r11 /* nospec r11 */ |
Andy Lutomirski | 572e509 | 2018-01-28 10:38:49 -0800 | [diff] [blame] | 187 | pushq %rbx /* pt_regs->rbx */ |
Dan Williams | 22b5557 | 2018-02-23 14:06:21 -0800 | [diff] [blame] | 188 | xorl %ebx, %ebx /* nospec rbx */ |
Andy Lutomirski | 572e509 | 2018-01-28 10:38:49 -0800 | [diff] [blame] | 189 | pushq %rbp /* pt_regs->rbp */ |
Dan Williams | 22b5557 | 2018-02-23 14:06:21 -0800 | [diff] [blame] | 190 | xorl %ebp, %ebp /* nospec rbp */ |
Andy Lutomirski | 572e509 | 2018-01-28 10:38:49 -0800 | [diff] [blame] | 191 | pushq %r12 /* pt_regs->r12 */ |
Dan Williams | 22b5557 | 2018-02-23 14:06:21 -0800 | [diff] [blame] | 192 | xorq %r12, %r12 /* nospec r12 */ |
Andy Lutomirski | 572e509 | 2018-01-28 10:38:49 -0800 | [diff] [blame] | 193 | pushq %r13 /* pt_regs->r13 */ |
Dan Williams | 22b5557 | 2018-02-23 14:06:21 -0800 | [diff] [blame] | 194 | xorq %r13, %r13 /* nospec r13 */ |
Andy Lutomirski | 572e509 | 2018-01-28 10:38:49 -0800 | [diff] [blame] | 195 | pushq %r14 /* pt_regs->r14 */ |
Dan Williams | 22b5557 | 2018-02-23 14:06:21 -0800 | [diff] [blame] | 196 | xorq %r14, %r14 /* nospec r14 */ |
Andy Lutomirski | 572e509 | 2018-01-28 10:38:49 -0800 | [diff] [blame] | 197 | pushq %r15 /* pt_regs->r15 */ |
Dan Williams | 22b5557 | 2018-02-23 14:06:21 -0800 | [diff] [blame] | 198 | xorq %r15, %r15 /* nospec r15 */ |
Denys Vlasenko | 9ed8e7d | 2015-03-19 18:17:47 +0100 | [diff] [blame] | 199 | |
Andy Lutomirski | 1e423bf | 2016-01-28 15:11:28 -0800 | [diff] [blame] | 200 | /* IRQs are off. */ |
Andy Lutomirski | 1e423bf | 2016-01-28 15:11:28 -0800 | [diff] [blame] | 201 | movq %rsp, %rdi |
| 202 | call do_syscall_64 /* returns with IRQs disabled */ |
| 203 | |
Denys Vlasenko | 76f5df4 | 2015-02-26 14:40:27 -0800 | [diff] [blame] | 204 | RESTORE_EXTRA_REGS |
Andy Lutomirski | 29ea1b2 | 2015-07-03 12:44:28 -0700 | [diff] [blame] | 205 | TRACE_IRQS_IRETQ /* we're about to change IF */ |
Denys Vlasenko | fffbb5d | 2015-04-02 18:46:59 +0200 | [diff] [blame] | 206 | |
| 207 | /* |
| 208 | * Try to use SYSRET instead of IRET if we're returning to |
| 209 | * a completely clean 64-bit userspace context. |
| 210 | */ |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 211 | movq RCX(%rsp), %rcx |
| 212 | movq RIP(%rsp), %r11 |
| 213 | cmpq %rcx, %r11 /* RCX == RIP */ |
| 214 | jne opportunistic_sysret_failed |
Denys Vlasenko | fffbb5d | 2015-04-02 18:46:59 +0200 | [diff] [blame] | 215 | |
| 216 | /* |
| 217 | * On Intel CPUs, SYSRET with non-canonical RCX/RIP will #GP |
| 218 | * in kernel space. This essentially lets the user take over |
Denys Vlasenko | 17be0ae | 2015-04-21 18:27:29 +0200 | [diff] [blame] | 219 | * the kernel, since userspace controls RSP. |
Denys Vlasenko | fffbb5d | 2015-04-02 18:46:59 +0200 | [diff] [blame] | 220 | * |
Denys Vlasenko | 17be0ae | 2015-04-21 18:27:29 +0200 | [diff] [blame] | 221 | * If width of "canonical tail" ever becomes variable, this will need |
Denys Vlasenko | fffbb5d | 2015-04-02 18:46:59 +0200 | [diff] [blame] | 222 | * to be updated to remain correct on both old and new CPUs. |
| 223 | */ |
| 224 | .ifne __VIRTUAL_MASK_SHIFT - 47 |
| 225 | .error "virtual address width changed -- SYSRET checks need update" |
| 226 | .endif |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 227 | |
Denys Vlasenko | 17be0ae | 2015-04-21 18:27:29 +0200 | [diff] [blame] | 228 | /* Change top 16 bits to be the sign-extension of 47th bit */ |
| 229 | shl $(64 - (__VIRTUAL_MASK_SHIFT+1)), %rcx |
| 230 | sar $(64 - (__VIRTUAL_MASK_SHIFT+1)), %rcx |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 231 | |
Denys Vlasenko | 17be0ae | 2015-04-21 18:27:29 +0200 | [diff] [blame] | 232 | /* If this changed %rcx, it was not canonical */ |
| 233 | cmpq %rcx, %r11 |
| 234 | jne opportunistic_sysret_failed |
Denys Vlasenko | fffbb5d | 2015-04-02 18:46:59 +0200 | [diff] [blame] | 235 | |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 236 | cmpq $__USER_CS, CS(%rsp) /* CS must match SYSRET */ |
| 237 | jne opportunistic_sysret_failed |
Denys Vlasenko | fffbb5d | 2015-04-02 18:46:59 +0200 | [diff] [blame] | 238 | |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 239 | movq R11(%rsp), %r11 |
| 240 | cmpq %r11, EFLAGS(%rsp) /* R11 == RFLAGS */ |
| 241 | jne opportunistic_sysret_failed |
Denys Vlasenko | fffbb5d | 2015-04-02 18:46:59 +0200 | [diff] [blame] | 242 | |
| 243 | /* |
Borislav Petkov | 3e03530 | 2016-08-03 19:14:29 +0200 | [diff] [blame] | 244 | * SYSCALL clears RF when it saves RFLAGS in R11 and SYSRET cannot |
| 245 | * restore RF properly. If the slowpath sets it for whatever reason, we |
| 246 | * need to restore it correctly. |
| 247 | * |
| 248 | * SYSRET can restore TF, but unlike IRET, restoring TF results in a |
| 249 | * trap from userspace immediately after SYSRET. This would cause an |
| 250 | * infinite loop whenever #DB happens with register state that satisfies |
| 251 | * the opportunistic SYSRET conditions. For example, single-stepping |
| 252 | * this user code: |
Denys Vlasenko | fffbb5d | 2015-04-02 18:46:59 +0200 | [diff] [blame] | 253 | * |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 254 | * movq $stuck_here, %rcx |
Denys Vlasenko | fffbb5d | 2015-04-02 18:46:59 +0200 | [diff] [blame] | 255 | * pushfq |
| 256 | * popq %r11 |
| 257 | * stuck_here: |
| 258 | * |
| 259 | * would never get past 'stuck_here'. |
| 260 | */ |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 261 | testq $(X86_EFLAGS_RF|X86_EFLAGS_TF), %r11 |
| 262 | jnz opportunistic_sysret_failed |
Denys Vlasenko | fffbb5d | 2015-04-02 18:46:59 +0200 | [diff] [blame] | 263 | |
| 264 | /* nothing to check for RSP */ |
| 265 | |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 266 | cmpq $__USER_DS, SS(%rsp) /* SS must match SYSRET */ |
| 267 | jne opportunistic_sysret_failed |
Denys Vlasenko | fffbb5d | 2015-04-02 18:46:59 +0200 | [diff] [blame] | 268 | |
| 269 | /* |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 270 | * We win! This label is here just for ease of understanding |
| 271 | * perf profiles. Nothing jumps here. |
Denys Vlasenko | fffbb5d | 2015-04-02 18:46:59 +0200 | [diff] [blame] | 272 | */ |
| 273 | syscall_return_via_sysret: |
Denys Vlasenko | 17be0ae | 2015-04-21 18:27:29 +0200 | [diff] [blame] | 274 | /* rcx and r11 are already restored (see code above) */ |
| 275 | RESTORE_C_REGS_EXCEPT_RCX_R11 |
Andy Lutomirski | d7f8d17 | 2018-01-28 10:38:49 -0800 | [diff] [blame] | 276 | |
Dave Hansen | 8f0baad | 2017-08-30 16:23:00 -0700 | [diff] [blame] | 277 | /* |
| 278 | * This opens a window where we have a user CR3, but are |
| 279 | * running in the kernel. This makes using the CS |
| 280 | * register useless for telling whether or not we need to |
| 281 | * switch CR3 in NMIs. Normal interrupts are OK because |
| 282 | * they are off here. |
| 283 | */ |
Richard Fellner | 13be448 | 2017-05-04 14:26:50 +0200 | [diff] [blame] | 284 | SWITCH_USER_CR3 |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 285 | movq RSP(%rsp), %rsp |
Denys Vlasenko | fffbb5d | 2015-04-02 18:46:59 +0200 | [diff] [blame] | 286 | USERGS_SYSRET64 |
Denys Vlasenko | fffbb5d | 2015-04-02 18:46:59 +0200 | [diff] [blame] | 287 | |
| 288 | opportunistic_sysret_failed: |
Dave Hansen | 8f0baad | 2017-08-30 16:23:00 -0700 | [diff] [blame] | 289 | /* |
| 290 | * This opens a window where we have a user CR3, but are |
| 291 | * running in the kernel. This makes using the CS |
| 292 | * register useless for telling whether or not we need to |
| 293 | * switch CR3 in NMIs. Normal interrupts are OK because |
| 294 | * they are off here. |
| 295 | */ |
Richard Fellner | 13be448 | 2017-05-04 14:26:50 +0200 | [diff] [blame] | 296 | SWITCH_USER_CR3 |
Denys Vlasenko | fffbb5d | 2015-04-02 18:46:59 +0200 | [diff] [blame] | 297 | SWAPGS |
| 298 | jmp restore_c_regs_and_iret |
Ingo Molnar | b2502b4 | 2015-06-08 08:42:03 +0200 | [diff] [blame] | 299 | END(entry_SYSCALL_64) |
Alexander van Heukelum | 0bd7b79 | 2008-11-16 15:29:00 +0100 | [diff] [blame] | 300 | |
Jan Beulich | 7effaa8 | 2005-09-12 18:49:24 +0200 | [diff] [blame] | 301 | /* |
Brian Gerst | 0100301 | 2016-08-13 12:38:19 -0400 | [diff] [blame] | 302 | * %rdi: prev task |
| 303 | * %rsi: next task |
| 304 | */ |
| 305 | ENTRY(__switch_to_asm) |
| 306 | /* |
| 307 | * Save callee-saved registers |
| 308 | * This must match the order in inactive_task_frame |
| 309 | */ |
| 310 | pushq %rbp |
| 311 | pushq %rbx |
| 312 | pushq %r12 |
| 313 | pushq %r13 |
| 314 | pushq %r14 |
| 315 | pushq %r15 |
| 316 | |
| 317 | /* switch stack */ |
| 318 | movq %rsp, TASK_threadsp(%rdi) |
| 319 | movq TASK_threadsp(%rsi), %rsp |
| 320 | |
| 321 | #ifdef CONFIG_CC_STACKPROTECTOR |
| 322 | movq TASK_stack_canary(%rsi), %rbx |
| 323 | movq %rbx, PER_CPU_VAR(irq_stack_union)+stack_canary_offset |
| 324 | #endif |
| 325 | |
David Woodhouse | abf67b1 | 2018-01-12 17:49:25 +0000 | [diff] [blame] | 326 | #ifdef CONFIG_RETPOLINE |
| 327 | /* |
| 328 | * When switching from a shallower to a deeper call stack |
| 329 | * the RSB may either underflow or use entries populated |
| 330 | * with userspace addresses. On CPUs where those concerns |
| 331 | * exist, overwrite the RSB with entries which capture |
| 332 | * speculative execution to prevent attack. |
| 333 | */ |
David Woodhouse | afb9851 | 2018-02-19 10:50:56 +0000 | [diff] [blame] | 334 | FILL_RETURN_BUFFER %r12, RSB_CLEAR_LOOPS, X86_FEATURE_RSB_CTXSW |
David Woodhouse | abf67b1 | 2018-01-12 17:49:25 +0000 | [diff] [blame] | 335 | #endif |
| 336 | |
Brian Gerst | 0100301 | 2016-08-13 12:38:19 -0400 | [diff] [blame] | 337 | /* restore callee-saved registers */ |
| 338 | popq %r15 |
| 339 | popq %r14 |
| 340 | popq %r13 |
| 341 | popq %r12 |
| 342 | popq %rbx |
| 343 | popq %rbp |
| 344 | |
| 345 | jmp __switch_to |
| 346 | END(__switch_to_asm) |
| 347 | |
| 348 | /* |
Denys Vlasenko | 1eeb207 | 2015-02-26 14:40:33 -0800 | [diff] [blame] | 349 | * A newly forked process directly context switches into this address. |
| 350 | * |
Brian Gerst | 0100301 | 2016-08-13 12:38:19 -0400 | [diff] [blame] | 351 | * rax: prev task we switched from |
Brian Gerst | 616d248 | 2016-08-13 12:38:20 -0400 | [diff] [blame] | 352 | * rbx: kernel thread func (NULL for user thread) |
| 353 | * r12: kernel thread arg |
Denys Vlasenko | 1eeb207 | 2015-02-26 14:40:33 -0800 | [diff] [blame] | 354 | */ |
| 355 | ENTRY(ret_from_fork) |
Brian Gerst | 0100301 | 2016-08-13 12:38:19 -0400 | [diff] [blame] | 356 | movq %rax, %rdi |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 357 | call schedule_tail /* rdi: 'prev' task parameter */ |
Denys Vlasenko | 1eeb207 | 2015-02-26 14:40:33 -0800 | [diff] [blame] | 358 | |
Brian Gerst | 616d248 | 2016-08-13 12:38:20 -0400 | [diff] [blame] | 359 | testq %rbx, %rbx /* from kernel_thread? */ |
| 360 | jnz 1f /* kernel threads are uncommon */ |
Denys Vlasenko | 1eeb207 | 2015-02-26 14:40:33 -0800 | [diff] [blame] | 361 | |
Brian Gerst | 616d248 | 2016-08-13 12:38:20 -0400 | [diff] [blame] | 362 | 2: |
Andy Lutomirski | 24d978b | 2016-01-28 15:11:27 -0800 | [diff] [blame] | 363 | movq %rsp, %rdi |
| 364 | call syscall_return_slowpath /* returns with IRQs disabled */ |
| 365 | TRACE_IRQS_ON /* user mode is traced as IRQS on */ |
Richard Fellner | 13be448 | 2017-05-04 14:26:50 +0200 | [diff] [blame] | 366 | SWITCH_USER_CR3 |
Andy Lutomirski | 24d978b | 2016-01-28 15:11:27 -0800 | [diff] [blame] | 367 | SWAPGS |
| 368 | jmp restore_regs_and_iret |
Brian Gerst | 616d248 | 2016-08-13 12:38:20 -0400 | [diff] [blame] | 369 | |
| 370 | 1: |
| 371 | /* kernel thread */ |
| 372 | movq %r12, %rdi |
David Woodhouse | 8b1bacc | 2018-01-11 21:46:28 +0000 | [diff] [blame] | 373 | CALL_NOSPEC %rbx |
Brian Gerst | 616d248 | 2016-08-13 12:38:20 -0400 | [diff] [blame] | 374 | /* |
| 375 | * A kernel thread is allowed to return here after successfully |
| 376 | * calling do_execve(). Exit to userspace to complete the execve() |
| 377 | * syscall. |
| 378 | */ |
| 379 | movq $0, RAX(%rsp) |
| 380 | jmp 2b |
Denys Vlasenko | 1eeb207 | 2015-02-26 14:40:33 -0800 | [diff] [blame] | 381 | END(ret_from_fork) |
| 382 | |
| 383 | /* |
Denys Vlasenko | 3304c9c | 2015-04-03 21:49:13 +0200 | [diff] [blame] | 384 | * Build the entry stubs with some assembler magic. |
| 385 | * We pack 1 stub into every 8-byte block. |
H. Peter Anvin | 939b787 | 2008-11-11 13:51:52 -0800 | [diff] [blame] | 386 | */ |
Denys Vlasenko | 3304c9c | 2015-04-03 21:49:13 +0200 | [diff] [blame] | 387 | .align 8 |
H. Peter Anvin | 939b787 | 2008-11-11 13:51:52 -0800 | [diff] [blame] | 388 | ENTRY(irq_entries_start) |
Denys Vlasenko | 3304c9c | 2015-04-03 21:49:13 +0200 | [diff] [blame] | 389 | vector=FIRST_EXTERNAL_VECTOR |
| 390 | .rept (FIRST_SYSTEM_VECTOR - FIRST_EXTERNAL_VECTOR) |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 391 | pushq $(~vector+0x80) /* Note: always in signed byte range */ |
Denys Vlasenko | 3304c9c | 2015-04-03 21:49:13 +0200 | [diff] [blame] | 392 | vector=vector+1 |
| 393 | jmp common_interrupt |
Denys Vlasenko | 3304c9c | 2015-04-03 21:49:13 +0200 | [diff] [blame] | 394 | .align 8 |
| 395 | .endr |
H. Peter Anvin | 939b787 | 2008-11-11 13:51:52 -0800 | [diff] [blame] | 396 | END(irq_entries_start) |
| 397 | |
Alexander van Heukelum | d99015b | 2008-11-19 01:18:11 +0100 | [diff] [blame] | 398 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 399 | * Interrupt entry/exit. |
| 400 | * |
| 401 | * Interrupt entry points save only callee clobbered registers in fast path. |
Alexander van Heukelum | d99015b | 2008-11-19 01:18:11 +0100 | [diff] [blame] | 402 | * |
| 403 | * Entry runs with interrupts off. |
| 404 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 405 | |
Alexander van Heukelum | 722024d | 2008-11-13 13:50:20 +0100 | [diff] [blame] | 406 | /* 0(%rsp): ~(interrupt number) */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 407 | .macro interrupt func |
Denys Vlasenko | f6f6468 | 2015-01-08 17:25:15 +0100 | [diff] [blame] | 408 | cld |
Andy Lutomirski | ff46759 | 2015-07-03 12:44:29 -0700 | [diff] [blame] | 409 | ALLOC_PT_GPREGS_ON_STACK |
| 410 | SAVE_C_REGS |
| 411 | SAVE_EXTRA_REGS |
Denys Vlasenko | f6f6468 | 2015-01-08 17:25:15 +0100 | [diff] [blame] | 412 | |
Andy Lutomirski | ff46759 | 2015-07-03 12:44:29 -0700 | [diff] [blame] | 413 | testb $3, CS(%rsp) |
Denys Vlasenko | dde74f2 | 2015-04-27 15:21:51 +0200 | [diff] [blame] | 414 | jz 1f |
Andy Lutomirski | 02bc776 | 2015-07-03 12:44:31 -0700 | [diff] [blame] | 415 | |
| 416 | /* |
| 417 | * IRQ from user mode. Switch to kernel gsbase and inform context |
| 418 | * tracking that we're in kernel mode. |
| 419 | */ |
Denys Vlasenko | f6f6468 | 2015-01-08 17:25:15 +0100 | [diff] [blame] | 420 | SWAPGS |
Richard Fellner | 13be448 | 2017-05-04 14:26:50 +0200 | [diff] [blame] | 421 | SWITCH_KERNEL_CR3 |
Andy Lutomirski | f107505 | 2015-11-12 12:59:00 -0800 | [diff] [blame] | 422 | |
| 423 | /* |
| 424 | * We need to tell lockdep that IRQs are off. We can't do this until |
| 425 | * we fix gsbase, and we should do it before enter_from_user_mode |
| 426 | * (which can take locks). Since TRACE_IRQS_OFF idempotent, |
| 427 | * the simplest way to handle it is to just call it twice if |
| 428 | * we enter from user mode. There's no reason to optimize this since |
| 429 | * TRACE_IRQS_OFF is a no-op if lockdep is off. |
| 430 | */ |
| 431 | TRACE_IRQS_OFF |
| 432 | |
Andy Lutomirski | 478dc89 | 2015-11-12 12:59:04 -0800 | [diff] [blame] | 433 | CALL_enter_from_user_mode |
Andy Lutomirski | 02bc776 | 2015-07-03 12:44:31 -0700 | [diff] [blame] | 434 | |
Denys Vlasenko | 76f5df4 | 2015-02-26 14:40:27 -0800 | [diff] [blame] | 435 | 1: |
Denys Vlasenko | f6f6468 | 2015-01-08 17:25:15 +0100 | [diff] [blame] | 436 | /* |
Denys Vlasenko | e90e147 | 2015-02-26 14:40:28 -0800 | [diff] [blame] | 437 | * Save previous stack pointer, optionally switch to interrupt stack. |
Denys Vlasenko | f6f6468 | 2015-01-08 17:25:15 +0100 | [diff] [blame] | 438 | * irq_count is used to check if a CPU is already on an interrupt stack |
| 439 | * or not. While this is essentially redundant with preempt_count it is |
| 440 | * a little cheaper to use a separate counter in the PDA (short of |
| 441 | * moving irq_enter into assembly, which would be too much work) |
| 442 | */ |
Andy Lutomirski | a586f98 | 2015-07-03 12:44:30 -0700 | [diff] [blame] | 443 | movq %rsp, %rdi |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 444 | incl PER_CPU_VAR(irq_count) |
| 445 | cmovzq PER_CPU_VAR(irq_stack_ptr), %rsp |
Andy Lutomirski | a586f98 | 2015-07-03 12:44:30 -0700 | [diff] [blame] | 446 | pushq %rdi |
Denys Vlasenko | f6f6468 | 2015-01-08 17:25:15 +0100 | [diff] [blame] | 447 | /* We entered an interrupt context - irqs are off: */ |
| 448 | TRACE_IRQS_OFF |
| 449 | |
Andy Lutomirski | a586f98 | 2015-07-03 12:44:30 -0700 | [diff] [blame] | 450 | call \func /* rdi points to pt_regs */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 451 | .endm |
| 452 | |
Alexander van Heukelum | 722024d | 2008-11-13 13:50:20 +0100 | [diff] [blame] | 453 | /* |
| 454 | * The interrupt stubs push (~vector+0x80) onto the stack and |
| 455 | * then jump to common_interrupt. |
| 456 | */ |
H. Peter Anvin | 939b787 | 2008-11-11 13:51:52 -0800 | [diff] [blame] | 457 | .p2align CONFIG_X86_L1_CACHE_SHIFT |
| 458 | common_interrupt: |
Jan Beulich | ee4eb87 | 2012-11-02 11:18:39 +0000 | [diff] [blame] | 459 | ASM_CLAC |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 460 | addq $-0x80, (%rsp) /* Adjust vector to [-256, -1] range */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 461 | interrupt do_IRQ |
Denys Vlasenko | 34061f1 | 2015-03-23 14:03:59 +0100 | [diff] [blame] | 462 | /* 0(%rsp): old RSP */ |
Jan Beulich | 7effaa8 | 2005-09-12 18:49:24 +0200 | [diff] [blame] | 463 | ret_from_intr: |
Glauber de Oliveira Costa | 72fe485 | 2008-01-30 13:32:08 +0100 | [diff] [blame] | 464 | DISABLE_INTERRUPTS(CLBR_NONE) |
Ingo Molnar | 2601e64 | 2006-07-03 00:24:45 -0700 | [diff] [blame] | 465 | TRACE_IRQS_OFF |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 466 | decl PER_CPU_VAR(irq_count) |
Frederic Weisbecker | 625dbc3 | 2011-01-06 15:22:47 +0100 | [diff] [blame] | 467 | |
Frederic Weisbecker | a2bbe75 | 2011-07-02 16:52:45 +0200 | [diff] [blame] | 468 | /* Restore saved previous stack */ |
Andy Lutomirski | ff46759 | 2015-07-03 12:44:29 -0700 | [diff] [blame] | 469 | popq %rsp |
Frederic Weisbecker | 625dbc3 | 2011-01-06 15:22:47 +0100 | [diff] [blame] | 470 | |
Denys Vlasenko | 03335e9 | 2015-04-27 15:21:52 +0200 | [diff] [blame] | 471 | testb $3, CS(%rsp) |
Denys Vlasenko | dde74f2 | 2015-04-27 15:21:51 +0200 | [diff] [blame] | 472 | jz retint_kernel |
Andy Lutomirski | 02bc776 | 2015-07-03 12:44:31 -0700 | [diff] [blame] | 473 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 474 | /* Interrupt came from user space */ |
Andy Lutomirski | 02bc776 | 2015-07-03 12:44:31 -0700 | [diff] [blame] | 475 | GLOBAL(retint_user) |
| 476 | mov %rsp,%rdi |
| 477 | call prepare_exit_to_usermode |
Ingo Molnar | 2601e64 | 2006-07-03 00:24:45 -0700 | [diff] [blame] | 478 | TRACE_IRQS_IRETQ |
Richard Fellner | 13be448 | 2017-05-04 14:26:50 +0200 | [diff] [blame] | 479 | SWITCH_USER_CR3 |
Glauber de Oliveira Costa | 72fe485 | 2008-01-30 13:32:08 +0100 | [diff] [blame] | 480 | SWAPGS |
Andy Lutomirski | ff46759 | 2015-07-03 12:44:29 -0700 | [diff] [blame] | 481 | jmp restore_regs_and_iret |
Ingo Molnar | 2601e64 | 2006-07-03 00:24:45 -0700 | [diff] [blame] | 482 | |
Denys Vlasenko | 627276c | 2015-03-30 20:09:31 +0200 | [diff] [blame] | 483 | /* Returning to kernel space */ |
Denys Vlasenko | 6ba71b7 | 2015-03-31 19:00:05 +0200 | [diff] [blame] | 484 | retint_kernel: |
Denys Vlasenko | 627276c | 2015-03-30 20:09:31 +0200 | [diff] [blame] | 485 | #ifdef CONFIG_PREEMPT |
| 486 | /* Interrupts are off */ |
| 487 | /* Check if we need preemption */ |
Jan Beulich | 8a76e85 | 2018-07-02 04:47:57 -0600 | [diff] [blame] | 488 | btl $9, EFLAGS(%rsp) /* were interrupts off? */ |
Denys Vlasenko | 6ba71b7 | 2015-03-31 19:00:05 +0200 | [diff] [blame] | 489 | jnc 1f |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 490 | 0: cmpl $0, PER_CPU_VAR(__preempt_count) |
Denys Vlasenko | 36acef2 | 2015-03-31 19:00:07 +0200 | [diff] [blame] | 491 | jnz 1f |
Denys Vlasenko | 627276c | 2015-03-30 20:09:31 +0200 | [diff] [blame] | 492 | call preempt_schedule_irq |
Denys Vlasenko | 36acef2 | 2015-03-31 19:00:07 +0200 | [diff] [blame] | 493 | jmp 0b |
Denys Vlasenko | 6ba71b7 | 2015-03-31 19:00:05 +0200 | [diff] [blame] | 494 | 1: |
Denys Vlasenko | 627276c | 2015-03-30 20:09:31 +0200 | [diff] [blame] | 495 | #endif |
Ingo Molnar | 2601e64 | 2006-07-03 00:24:45 -0700 | [diff] [blame] | 496 | /* |
| 497 | * The iretq could re-enable interrupts: |
| 498 | */ |
| 499 | TRACE_IRQS_IRETQ |
Denys Vlasenko | fffbb5d | 2015-04-02 18:46:59 +0200 | [diff] [blame] | 500 | |
| 501 | /* |
| 502 | * At this label, code paths which return to kernel and to user, |
| 503 | * which come from interrupts/exception and from syscalls, merge. |
| 504 | */ |
Andy Lutomirski | ee08c6b | 2015-10-05 17:48:09 -0700 | [diff] [blame] | 505 | GLOBAL(restore_regs_and_iret) |
Andy Lutomirski | ff46759 | 2015-07-03 12:44:29 -0700 | [diff] [blame] | 506 | RESTORE_EXTRA_REGS |
Denys Vlasenko | fffbb5d | 2015-04-02 18:46:59 +0200 | [diff] [blame] | 507 | restore_c_regs_and_iret: |
Denys Vlasenko | 76f5df4 | 2015-02-26 14:40:27 -0800 | [diff] [blame] | 508 | RESTORE_C_REGS |
| 509 | REMOVE_PT_GPREGS_FROM_STACK 8 |
Andy Lutomirski | 7209a75 | 2014-07-23 08:34:11 -0700 | [diff] [blame] | 510 | INTERRUPT_RETURN |
| 511 | |
| 512 | ENTRY(native_iret) |
H. Peter Anvin | 3891a04 | 2014-04-29 16:46:09 -0700 | [diff] [blame] | 513 | /* |
| 514 | * Are we returning to a stack segment from the LDT? Note: in |
| 515 | * 64-bit mode SS:RSP on the exception stack is always valid. |
| 516 | */ |
H. Peter Anvin | 34273f4 | 2014-05-04 10:36:22 -0700 | [diff] [blame] | 517 | #ifdef CONFIG_X86_ESPFIX64 |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 518 | testb $4, (SS-RIP)(%rsp) |
| 519 | jnz native_irq_return_ldt |
H. Peter Anvin | 34273f4 | 2014-05-04 10:36:22 -0700 | [diff] [blame] | 520 | #endif |
H. Peter Anvin | 3891a04 | 2014-04-29 16:46:09 -0700 | [diff] [blame] | 521 | |
Andy Lutomirski | af726f2 | 2014-11-22 18:00:31 -0800 | [diff] [blame] | 522 | .global native_irq_return_iret |
Andy Lutomirski | 7209a75 | 2014-07-23 08:34:11 -0700 | [diff] [blame] | 523 | native_irq_return_iret: |
Andy Lutomirski | b645af2 | 2014-11-22 18:00:33 -0800 | [diff] [blame] | 524 | /* |
| 525 | * This may fault. Non-paranoid faults on return to userspace are |
| 526 | * handled by fixup_bad_iret. These include #SS, #GP, and #NP. |
| 527 | * Double-faults due to espfix64 are handled in do_double_fault. |
| 528 | * Other faults here are fatal. |
| 529 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 530 | iretq |
Ingo Molnar | 3701d863 | 2008-02-09 23:24:08 +0100 | [diff] [blame] | 531 | |
H. Peter Anvin | 34273f4 | 2014-05-04 10:36:22 -0700 | [diff] [blame] | 532 | #ifdef CONFIG_X86_ESPFIX64 |
Andy Lutomirski | 7209a75 | 2014-07-23 08:34:11 -0700 | [diff] [blame] | 533 | native_irq_return_ldt: |
Andy Lutomirski | 85063fa | 2016-09-12 15:05:51 -0700 | [diff] [blame] | 534 | /* |
| 535 | * We are running with user GSBASE. All GPRs contain their user |
| 536 | * values. We have a percpu ESPFIX stack that is eight slots |
| 537 | * long (see ESPFIX_STACK_SIZE). espfix_waddr points to the bottom |
| 538 | * of the ESPFIX stack. |
| 539 | * |
| 540 | * We clobber RAX and RDI in this code. We stash RDI on the |
| 541 | * normal stack and RAX on the ESPFIX stack. |
| 542 | * |
| 543 | * The ESPFIX stack layout we set up looks like this: |
| 544 | * |
| 545 | * --- top of ESPFIX stack --- |
| 546 | * SS |
| 547 | * RSP |
| 548 | * RFLAGS |
| 549 | * CS |
| 550 | * RIP <-- RSP points here when we're done |
| 551 | * RAX <-- espfix_waddr points here |
| 552 | * --- bottom of ESPFIX stack --- |
| 553 | */ |
| 554 | |
| 555 | pushq %rdi /* Stash user RDI */ |
H. Peter Anvin | 3891a04 | 2014-04-29 16:46:09 -0700 | [diff] [blame] | 556 | SWAPGS |
Richard Fellner | 13be448 | 2017-05-04 14:26:50 +0200 | [diff] [blame] | 557 | SWITCH_KERNEL_CR3 |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 558 | movq PER_CPU_VAR(espfix_waddr), %rdi |
Andy Lutomirski | 85063fa | 2016-09-12 15:05:51 -0700 | [diff] [blame] | 559 | movq %rax, (0*8)(%rdi) /* user RAX */ |
| 560 | movq (1*8)(%rsp), %rax /* user RIP */ |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 561 | movq %rax, (1*8)(%rdi) |
Andy Lutomirski | 85063fa | 2016-09-12 15:05:51 -0700 | [diff] [blame] | 562 | movq (2*8)(%rsp), %rax /* user CS */ |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 563 | movq %rax, (2*8)(%rdi) |
Andy Lutomirski | 85063fa | 2016-09-12 15:05:51 -0700 | [diff] [blame] | 564 | movq (3*8)(%rsp), %rax /* user RFLAGS */ |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 565 | movq %rax, (3*8)(%rdi) |
Andy Lutomirski | 85063fa | 2016-09-12 15:05:51 -0700 | [diff] [blame] | 566 | movq (5*8)(%rsp), %rax /* user SS */ |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 567 | movq %rax, (5*8)(%rdi) |
Andy Lutomirski | 85063fa | 2016-09-12 15:05:51 -0700 | [diff] [blame] | 568 | movq (4*8)(%rsp), %rax /* user RSP */ |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 569 | movq %rax, (4*8)(%rdi) |
Andy Lutomirski | 85063fa | 2016-09-12 15:05:51 -0700 | [diff] [blame] | 570 | /* Now RAX == RSP. */ |
| 571 | |
| 572 | andl $0xffff0000, %eax /* RAX = (RSP & 0xffff0000) */ |
| 573 | popq %rdi /* Restore user RDI */ |
| 574 | |
| 575 | /* |
| 576 | * espfix_stack[31:16] == 0. The page tables are set up such that |
| 577 | * (espfix_stack | (X & 0xffff0000)) points to a read-only alias of |
| 578 | * espfix_waddr for any X. That is, there are 65536 RO aliases of |
| 579 | * the same page. Set up RSP so that RSP[31:16] contains the |
| 580 | * respective 16 bits of the /userspace/ RSP and RSP nonetheless |
| 581 | * still points to an RO alias of the ESPFIX stack. |
| 582 | */ |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 583 | orq PER_CPU_VAR(espfix_stack), %rax |
Richard Fellner | 13be448 | 2017-05-04 14:26:50 +0200 | [diff] [blame] | 584 | SWITCH_USER_CR3 |
H. Peter Anvin | 3891a04 | 2014-04-29 16:46:09 -0700 | [diff] [blame] | 585 | SWAPGS |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 586 | movq %rax, %rsp |
Andy Lutomirski | 85063fa | 2016-09-12 15:05:51 -0700 | [diff] [blame] | 587 | |
| 588 | /* |
| 589 | * At this point, we cannot write to the stack any more, but we can |
| 590 | * still read. |
| 591 | */ |
| 592 | popq %rax /* Restore user RAX */ |
| 593 | |
| 594 | /* |
| 595 | * RSP now points to an ordinary IRET frame, except that the page |
| 596 | * is read-only and RSP[31:16] are preloaded with the userspace |
| 597 | * values. We can now IRET back to userspace. |
| 598 | */ |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 599 | jmp native_irq_return_iret |
H. Peter Anvin | 34273f4 | 2014-05-04 10:36:22 -0700 | [diff] [blame] | 600 | #endif |
Jan Beulich | 4b787e0 | 2006-06-26 13:56:55 +0200 | [diff] [blame] | 601 | END(common_interrupt) |
H. Peter Anvin | 3891a04 | 2014-04-29 16:46:09 -0700 | [diff] [blame] | 602 | |
Masami Hiramatsu | 8222d71 | 2009-08-27 13:23:25 -0400 | [diff] [blame] | 603 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 604 | * APIC interrupts. |
Alexander van Heukelum | 0bd7b79 | 2008-11-16 15:29:00 +0100 | [diff] [blame] | 605 | */ |
Seiji Aguchi | cf910e8 | 2013-06-20 11:46:53 -0400 | [diff] [blame] | 606 | .macro apicinterrupt3 num sym do_sym |
Alexander van Heukelum | 322648d | 2008-11-23 10:08:28 +0100 | [diff] [blame] | 607 | ENTRY(\sym) |
Jan Beulich | ee4eb87 | 2012-11-02 11:18:39 +0000 | [diff] [blame] | 608 | ASM_CLAC |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 609 | pushq $~(\num) |
Jan Beulich | 39e9543 | 2011-11-29 11:03:46 +0000 | [diff] [blame] | 610 | .Lcommon_\sym: |
Alexander van Heukelum | 322648d | 2008-11-23 10:08:28 +0100 | [diff] [blame] | 611 | interrupt \do_sym |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 612 | jmp ret_from_intr |
Alexander van Heukelum | 322648d | 2008-11-23 10:08:28 +0100 | [diff] [blame] | 613 | END(\sym) |
| 614 | .endm |
Jacob Shin | 89b831e | 2005-11-05 17:25:53 +0100 | [diff] [blame] | 615 | |
Seiji Aguchi | cf910e8 | 2013-06-20 11:46:53 -0400 | [diff] [blame] | 616 | #ifdef CONFIG_TRACING |
| 617 | #define trace(sym) trace_##sym |
| 618 | #define smp_trace(sym) smp_trace_##sym |
| 619 | |
| 620 | .macro trace_apicinterrupt num sym |
| 621 | apicinterrupt3 \num trace(\sym) smp_trace(\sym) |
| 622 | .endm |
| 623 | #else |
| 624 | .macro trace_apicinterrupt num sym do_sym |
| 625 | .endm |
| 626 | #endif |
| 627 | |
Alexander Potapenko | 469f002 | 2016-07-15 11:42:43 +0200 | [diff] [blame] | 628 | /* Make sure APIC interrupt handlers end up in the irqentry section: */ |
| 629 | #if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN) |
| 630 | # define PUSH_SECTION_IRQENTRY .pushsection .irqentry.text, "ax" |
| 631 | # define POP_SECTION_IRQENTRY .popsection |
| 632 | #else |
| 633 | # define PUSH_SECTION_IRQENTRY |
| 634 | # define POP_SECTION_IRQENTRY |
| 635 | #endif |
| 636 | |
Seiji Aguchi | cf910e8 | 2013-06-20 11:46:53 -0400 | [diff] [blame] | 637 | .macro apicinterrupt num sym do_sym |
Alexander Potapenko | 469f002 | 2016-07-15 11:42:43 +0200 | [diff] [blame] | 638 | PUSH_SECTION_IRQENTRY |
Seiji Aguchi | cf910e8 | 2013-06-20 11:46:53 -0400 | [diff] [blame] | 639 | apicinterrupt3 \num \sym \do_sym |
| 640 | trace_apicinterrupt \num \sym |
Alexander Potapenko | 469f002 | 2016-07-15 11:42:43 +0200 | [diff] [blame] | 641 | POP_SECTION_IRQENTRY |
Seiji Aguchi | cf910e8 | 2013-06-20 11:46:53 -0400 | [diff] [blame] | 642 | .endm |
| 643 | |
Alexander van Heukelum | 0bd7b79 | 2008-11-16 15:29:00 +0100 | [diff] [blame] | 644 | #ifdef CONFIG_SMP |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 645 | apicinterrupt3 IRQ_MOVE_CLEANUP_VECTOR irq_move_cleanup_interrupt smp_irq_move_cleanup_interrupt |
| 646 | apicinterrupt3 REBOOT_VECTOR reboot_interrupt smp_reboot_interrupt |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 647 | #endif |
| 648 | |
Nick Piggin | 03b4863 | 2009-01-20 04:36:04 +0100 | [diff] [blame] | 649 | #ifdef CONFIG_X86_UV |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 650 | apicinterrupt3 UV_BAU_MESSAGE uv_bau_message_intr1 uv_bau_message_interrupt |
Nick Piggin | 03b4863 | 2009-01-20 04:36:04 +0100 | [diff] [blame] | 651 | #endif |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 652 | |
| 653 | apicinterrupt LOCAL_TIMER_VECTOR apic_timer_interrupt smp_apic_timer_interrupt |
| 654 | apicinterrupt X86_PLATFORM_IPI_VECTOR x86_platform_ipi smp_x86_platform_ipi |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 655 | |
Yang Zhang | d78f266 | 2013-04-11 19:25:11 +0800 | [diff] [blame] | 656 | #ifdef CONFIG_HAVE_KVM |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 657 | apicinterrupt3 POSTED_INTR_VECTOR kvm_posted_intr_ipi smp_kvm_posted_intr_ipi |
| 658 | apicinterrupt3 POSTED_INTR_WAKEUP_VECTOR kvm_posted_intr_wakeup_ipi smp_kvm_posted_intr_wakeup_ipi |
Yang Zhang | d78f266 | 2013-04-11 19:25:11 +0800 | [diff] [blame] | 659 | #endif |
| 660 | |
Seiji Aguchi | 33e5ff6 | 2013-06-22 07:33:30 -0400 | [diff] [blame] | 661 | #ifdef CONFIG_X86_MCE_THRESHOLD |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 662 | apicinterrupt THRESHOLD_APIC_VECTOR threshold_interrupt smp_threshold_interrupt |
Seiji Aguchi | 33e5ff6 | 2013-06-22 07:33:30 -0400 | [diff] [blame] | 663 | #endif |
| 664 | |
Aravind Gopalakrishnan | 24fd78a | 2015-05-06 06:58:56 -0500 | [diff] [blame] | 665 | #ifdef CONFIG_X86_MCE_AMD |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 666 | apicinterrupt DEFERRED_ERROR_VECTOR deferred_error_interrupt smp_deferred_error_interrupt |
Aravind Gopalakrishnan | 24fd78a | 2015-05-06 06:58:56 -0500 | [diff] [blame] | 667 | #endif |
| 668 | |
Seiji Aguchi | 33e5ff6 | 2013-06-22 07:33:30 -0400 | [diff] [blame] | 669 | #ifdef CONFIG_X86_THERMAL_VECTOR |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 670 | apicinterrupt THERMAL_APIC_VECTOR thermal_interrupt smp_thermal_interrupt |
Seiji Aguchi | 33e5ff6 | 2013-06-22 07:33:30 -0400 | [diff] [blame] | 671 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 672 | |
Alexander van Heukelum | 322648d | 2008-11-23 10:08:28 +0100 | [diff] [blame] | 673 | #ifdef CONFIG_SMP |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 674 | apicinterrupt CALL_FUNCTION_SINGLE_VECTOR call_function_single_interrupt smp_call_function_single_interrupt |
| 675 | apicinterrupt CALL_FUNCTION_VECTOR call_function_interrupt smp_call_function_interrupt |
| 676 | apicinterrupt RESCHEDULE_VECTOR reschedule_interrupt smp_reschedule_interrupt |
Alexander van Heukelum | 322648d | 2008-11-23 10:08:28 +0100 | [diff] [blame] | 677 | #endif |
| 678 | |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 679 | apicinterrupt ERROR_APIC_VECTOR error_interrupt smp_error_interrupt |
| 680 | apicinterrupt SPURIOUS_APIC_VECTOR spurious_interrupt smp_spurious_interrupt |
Alexander van Heukelum | 0bd7b79 | 2008-11-16 15:29:00 +0100 | [diff] [blame] | 681 | |
Peter Zijlstra | e360adb | 2010-10-14 14:01:34 +0800 | [diff] [blame] | 682 | #ifdef CONFIG_IRQ_WORK |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 683 | apicinterrupt IRQ_WORK_VECTOR irq_work_interrupt smp_irq_work_interrupt |
Ingo Molnar | 241771e | 2008-12-03 10:39:53 +0100 | [diff] [blame] | 684 | #endif |
| 685 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 686 | /* |
| 687 | * Exception entry points. |
Alexander van Heukelum | 0bd7b79 | 2008-11-16 15:29:00 +0100 | [diff] [blame] | 688 | */ |
Andy Lutomirski | 9b47668 | 2015-03-05 19:19:07 -0800 | [diff] [blame] | 689 | #define CPU_TSS_IST(x) PER_CPU_VAR(cpu_tss) + (TSS_ist + ((x) - 1) * 8) |
Andy Lutomirski | 577ed45 | 2014-05-21 15:07:09 -0700 | [diff] [blame] | 690 | |
| 691 | .macro idtentry sym do_sym has_error_code:req paranoid=0 shift_ist=-1 |
Alexander van Heukelum | 322648d | 2008-11-23 10:08:28 +0100 | [diff] [blame] | 692 | ENTRY(\sym) |
Andy Lutomirski | 577ed45 | 2014-05-21 15:07:09 -0700 | [diff] [blame] | 693 | /* Sanity check */ |
| 694 | .if \shift_ist != -1 && \paranoid == 0 |
| 695 | .error "using shift_ist requires paranoid=1" |
| 696 | .endif |
| 697 | |
Jan Beulich | ee4eb87 | 2012-11-02 11:18:39 +0000 | [diff] [blame] | 698 | ASM_CLAC |
Alexander van Heukelum | b8b1d08 | 2008-11-21 16:44:28 +0100 | [diff] [blame] | 699 | PARAVIRT_ADJUST_EXCEPTION_FRAME |
Andy Lutomirski | cb5dd2c | 2014-05-21 15:07:08 -0700 | [diff] [blame] | 700 | |
| 701 | .ifeq \has_error_code |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 702 | pushq $-1 /* ORIG_RAX: no syscall to restart */ |
Andy Lutomirski | cb5dd2c | 2014-05-21 15:07:08 -0700 | [diff] [blame] | 703 | .endif |
| 704 | |
Denys Vlasenko | 76f5df4 | 2015-02-26 14:40:27 -0800 | [diff] [blame] | 705 | ALLOC_PT_GPREGS_ON_STACK |
Andy Lutomirski | cb5dd2c | 2014-05-21 15:07:08 -0700 | [diff] [blame] | 706 | |
| 707 | .if \paranoid |
Andy Lutomirski | 48e08d0 | 2014-11-11 12:49:41 -0800 | [diff] [blame] | 708 | .if \paranoid == 1 |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 709 | testb $3, CS(%rsp) /* If coming from userspace, switch stacks */ |
| 710 | jnz 1f |
Andy Lutomirski | 48e08d0 | 2014-11-11 12:49:41 -0800 | [diff] [blame] | 711 | .endif |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 712 | call paranoid_entry |
Andy Lutomirski | cb5dd2c | 2014-05-21 15:07:08 -0700 | [diff] [blame] | 713 | .else |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 714 | call error_entry |
Andy Lutomirski | cb5dd2c | 2014-05-21 15:07:08 -0700 | [diff] [blame] | 715 | .endif |
Denys Vlasenko | ebfc453 | 2015-02-26 14:40:34 -0800 | [diff] [blame] | 716 | /* returned flag: ebx=0: need swapgs on exit, ebx=1: don't need it */ |
Andy Lutomirski | cb5dd2c | 2014-05-21 15:07:08 -0700 | [diff] [blame] | 717 | |
Andy Lutomirski | cb5dd2c | 2014-05-21 15:07:08 -0700 | [diff] [blame] | 718 | .if \paranoid |
Andy Lutomirski | 577ed45 | 2014-05-21 15:07:09 -0700 | [diff] [blame] | 719 | .if \shift_ist != -1 |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 720 | TRACE_IRQS_OFF_DEBUG /* reload IDT in case of recursion */ |
Andy Lutomirski | 577ed45 | 2014-05-21 15:07:09 -0700 | [diff] [blame] | 721 | .else |
Alexander van Heukelum | b8b1d08 | 2008-11-21 16:44:28 +0100 | [diff] [blame] | 722 | TRACE_IRQS_OFF |
Andy Lutomirski | cb5dd2c | 2014-05-21 15:07:08 -0700 | [diff] [blame] | 723 | .endif |
Andy Lutomirski | 577ed45 | 2014-05-21 15:07:09 -0700 | [diff] [blame] | 724 | .endif |
Andy Lutomirski | cb5dd2c | 2014-05-21 15:07:08 -0700 | [diff] [blame] | 725 | |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 726 | movq %rsp, %rdi /* pt_regs pointer */ |
Andy Lutomirski | cb5dd2c | 2014-05-21 15:07:08 -0700 | [diff] [blame] | 727 | |
| 728 | .if \has_error_code |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 729 | movq ORIG_RAX(%rsp), %rsi /* get error code */ |
| 730 | movq $-1, ORIG_RAX(%rsp) /* no syscall to restart */ |
Andy Lutomirski | cb5dd2c | 2014-05-21 15:07:08 -0700 | [diff] [blame] | 731 | .else |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 732 | xorl %esi, %esi /* no error code */ |
Andy Lutomirski | cb5dd2c | 2014-05-21 15:07:08 -0700 | [diff] [blame] | 733 | .endif |
| 734 | |
Andy Lutomirski | 577ed45 | 2014-05-21 15:07:09 -0700 | [diff] [blame] | 735 | .if \shift_ist != -1 |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 736 | subq $EXCEPTION_STKSZ, CPU_TSS_IST(\shift_ist) |
Andy Lutomirski | 577ed45 | 2014-05-21 15:07:09 -0700 | [diff] [blame] | 737 | .endif |
| 738 | |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 739 | call \do_sym |
Andy Lutomirski | cb5dd2c | 2014-05-21 15:07:08 -0700 | [diff] [blame] | 740 | |
Andy Lutomirski | 577ed45 | 2014-05-21 15:07:09 -0700 | [diff] [blame] | 741 | .if \shift_ist != -1 |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 742 | addq $EXCEPTION_STKSZ, CPU_TSS_IST(\shift_ist) |
Andy Lutomirski | 577ed45 | 2014-05-21 15:07:09 -0700 | [diff] [blame] | 743 | .endif |
| 744 | |
Denys Vlasenko | ebfc453 | 2015-02-26 14:40:34 -0800 | [diff] [blame] | 745 | /* these procedures expect "no swapgs" flag in ebx */ |
Andy Lutomirski | cb5dd2c | 2014-05-21 15:07:08 -0700 | [diff] [blame] | 746 | .if \paranoid |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 747 | jmp paranoid_exit |
Andy Lutomirski | cb5dd2c | 2014-05-21 15:07:08 -0700 | [diff] [blame] | 748 | .else |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 749 | jmp error_exit |
Andy Lutomirski | cb5dd2c | 2014-05-21 15:07:08 -0700 | [diff] [blame] | 750 | .endif |
| 751 | |
Andy Lutomirski | 48e08d0 | 2014-11-11 12:49:41 -0800 | [diff] [blame] | 752 | .if \paranoid == 1 |
Andy Lutomirski | 48e08d0 | 2014-11-11 12:49:41 -0800 | [diff] [blame] | 753 | /* |
| 754 | * Paranoid entry from userspace. Switch stacks and treat it |
| 755 | * as a normal entry. This means that paranoid handlers |
| 756 | * run in real process context if user_mode(regs). |
| 757 | */ |
| 758 | 1: |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 759 | call error_entry |
Andy Lutomirski | 48e08d0 | 2014-11-11 12:49:41 -0800 | [diff] [blame] | 760 | |
Andy Lutomirski | 48e08d0 | 2014-11-11 12:49:41 -0800 | [diff] [blame] | 761 | |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 762 | movq %rsp, %rdi /* pt_regs pointer */ |
| 763 | call sync_regs |
| 764 | movq %rax, %rsp /* switch stack */ |
Andy Lutomirski | 48e08d0 | 2014-11-11 12:49:41 -0800 | [diff] [blame] | 765 | |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 766 | movq %rsp, %rdi /* pt_regs pointer */ |
Andy Lutomirski | 48e08d0 | 2014-11-11 12:49:41 -0800 | [diff] [blame] | 767 | |
| 768 | .if \has_error_code |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 769 | movq ORIG_RAX(%rsp), %rsi /* get error code */ |
| 770 | movq $-1, ORIG_RAX(%rsp) /* no syscall to restart */ |
Andy Lutomirski | 48e08d0 | 2014-11-11 12:49:41 -0800 | [diff] [blame] | 771 | .else |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 772 | xorl %esi, %esi /* no error code */ |
Andy Lutomirski | 48e08d0 | 2014-11-11 12:49:41 -0800 | [diff] [blame] | 773 | .endif |
| 774 | |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 775 | call \do_sym |
Andy Lutomirski | 48e08d0 | 2014-11-11 12:49:41 -0800 | [diff] [blame] | 776 | |
Andy Lutomirski | 9871563 | 2018-07-22 11:05:09 -0700 | [diff] [blame] | 777 | jmp error_exit |
Andy Lutomirski | 48e08d0 | 2014-11-11 12:49:41 -0800 | [diff] [blame] | 778 | .endif |
Alexander van Heukelum | ddeb8f2 | 2008-11-24 13:24:28 +0100 | [diff] [blame] | 779 | END(\sym) |
Alexander van Heukelum | 322648d | 2008-11-23 10:08:28 +0100 | [diff] [blame] | 780 | .endm |
Alexander van Heukelum | b8b1d08 | 2008-11-21 16:44:28 +0100 | [diff] [blame] | 781 | |
Seiji Aguchi | 25c74b1 | 2013-10-30 16:37:00 -0400 | [diff] [blame] | 782 | #ifdef CONFIG_TRACING |
Andy Lutomirski | cb5dd2c | 2014-05-21 15:07:08 -0700 | [diff] [blame] | 783 | .macro trace_idtentry sym do_sym has_error_code:req |
| 784 | idtentry trace(\sym) trace(\do_sym) has_error_code=\has_error_code |
| 785 | idtentry \sym \do_sym has_error_code=\has_error_code |
Seiji Aguchi | 25c74b1 | 2013-10-30 16:37:00 -0400 | [diff] [blame] | 786 | .endm |
| 787 | #else |
Andy Lutomirski | cb5dd2c | 2014-05-21 15:07:08 -0700 | [diff] [blame] | 788 | .macro trace_idtentry sym do_sym has_error_code:req |
| 789 | idtentry \sym \do_sym has_error_code=\has_error_code |
Seiji Aguchi | 25c74b1 | 2013-10-30 16:37:00 -0400 | [diff] [blame] | 790 | .endm |
| 791 | #endif |
| 792 | |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 793 | idtentry divide_error do_divide_error has_error_code=0 |
| 794 | idtentry overflow do_overflow has_error_code=0 |
| 795 | idtentry bounds do_bounds has_error_code=0 |
| 796 | idtentry invalid_op do_invalid_op has_error_code=0 |
| 797 | idtentry device_not_available do_device_not_available has_error_code=0 |
| 798 | idtentry double_fault do_double_fault has_error_code=1 paranoid=2 |
| 799 | idtentry coprocessor_segment_overrun do_coprocessor_segment_overrun has_error_code=0 |
| 800 | idtentry invalid_TSS do_invalid_TSS has_error_code=1 |
| 801 | idtentry segment_not_present do_segment_not_present has_error_code=1 |
| 802 | idtentry spurious_interrupt_bug do_spurious_interrupt_bug has_error_code=0 |
| 803 | idtentry coprocessor_error do_coprocessor_error has_error_code=0 |
| 804 | idtentry alignment_check do_alignment_check has_error_code=1 |
| 805 | idtentry simd_coprocessor_error do_simd_coprocessor_error has_error_code=0 |
Andy Lutomirski | 5cec93c | 2011-06-05 13:50:24 -0400 | [diff] [blame] | 806 | |
Ingo Molnar | 2601e64 | 2006-07-03 00:24:45 -0700 | [diff] [blame] | 807 | |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 808 | /* |
| 809 | * Reload gs selector with exception handling |
| 810 | * edi: new selector |
| 811 | */ |
Jeremy Fitzhardinge | 9f9d489 | 2008-06-25 00:19:32 -0400 | [diff] [blame] | 812 | ENTRY(native_load_gs_index) |
Ingo Molnar | 131484c | 2015-05-28 12:21:47 +0200 | [diff] [blame] | 813 | pushfq |
Jeremy Fitzhardinge | b8aa287 | 2009-01-28 14:35:03 -0800 | [diff] [blame] | 814 | DISABLE_INTERRUPTS(CLBR_ANY & ~CLBR_RDI) |
Cyrill Gorcunov | 9f1e87e | 2008-11-27 21:10:08 +0300 | [diff] [blame] | 815 | SWAPGS |
Borislav Petkov | 42c748bb | 2016-04-07 17:31:50 -0700 | [diff] [blame] | 816 | .Lgs_change: |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 817 | movl %edi, %gs |
Borislav Petkov | 96e5d28 | 2016-04-07 17:31:49 -0700 | [diff] [blame] | 818 | 2: ALTERNATIVE "", "mfence", X86_BUG_SWAPGS_FENCE |
Glauber de Oliveira Costa | 72fe485 | 2008-01-30 13:32:08 +0100 | [diff] [blame] | 819 | SWAPGS |
Ingo Molnar | 131484c | 2015-05-28 12:21:47 +0200 | [diff] [blame] | 820 | popfq |
Cyrill Gorcunov | 9f1e87e | 2008-11-27 21:10:08 +0300 | [diff] [blame] | 821 | ret |
Alexander van Heukelum | 6efdcfa | 2008-11-23 10:15:32 +0100 | [diff] [blame] | 822 | END(native_load_gs_index) |
Al Viro | 784d569 | 2016-01-11 11:04:34 -0500 | [diff] [blame] | 823 | EXPORT_SYMBOL(native_load_gs_index) |
Alexander van Heukelum | 0bd7b79 | 2008-11-16 15:29:00 +0100 | [diff] [blame] | 824 | |
Borislav Petkov | 42c748bb | 2016-04-07 17:31:50 -0700 | [diff] [blame] | 825 | _ASM_EXTABLE(.Lgs_change, bad_gs) |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 826 | .section .fixup, "ax" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 827 | /* running with kernelgs */ |
Alexander van Heukelum | 0bd7b79 | 2008-11-16 15:29:00 +0100 | [diff] [blame] | 828 | bad_gs: |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 829 | SWAPGS /* switch back to user gs */ |
Andy Lutomirski | b038c84 | 2016-04-26 12:23:27 -0700 | [diff] [blame] | 830 | .macro ZAP_GS |
| 831 | /* This can't be a string because the preprocessor needs to see it. */ |
| 832 | movl $__USER_DS, %eax |
| 833 | movl %eax, %gs |
| 834 | .endm |
| 835 | ALTERNATIVE "", "ZAP_GS", X86_BUG_NULL_SEG |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 836 | xorl %eax, %eax |
| 837 | movl %eax, %gs |
| 838 | jmp 2b |
Cyrill Gorcunov | 9f1e87e | 2008-11-27 21:10:08 +0300 | [diff] [blame] | 839 | .previous |
Alexander van Heukelum | 0bd7b79 | 2008-11-16 15:29:00 +0100 | [diff] [blame] | 840 | |
Andi Kleen | 2699500 | 2006-08-02 22:37:28 +0200 | [diff] [blame] | 841 | /* Call softirq on interrupt stack. Interrupts are off. */ |
Frederic Weisbecker | 7d65f4a | 2013-09-05 15:49:45 +0200 | [diff] [blame] | 842 | ENTRY(do_softirq_own_stack) |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 843 | pushq %rbp |
| 844 | mov %rsp, %rbp |
| 845 | incl PER_CPU_VAR(irq_count) |
| 846 | cmove PER_CPU_VAR(irq_stack_ptr), %rsp |
| 847 | push %rbp /* frame pointer backlink */ |
| 848 | call __do_softirq |
Andi Kleen | 2699500 | 2006-08-02 22:37:28 +0200 | [diff] [blame] | 849 | leaveq |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 850 | decl PER_CPU_VAR(irq_count) |
Andi Kleen | ed6b676 | 2005-07-28 21:15:49 -0700 | [diff] [blame] | 851 | ret |
Frederic Weisbecker | 7d65f4a | 2013-09-05 15:49:45 +0200 | [diff] [blame] | 852 | END(do_softirq_own_stack) |
Andi Kleen | 75154f4 | 2007-06-23 02:29:25 +0200 | [diff] [blame] | 853 | |
Jeremy Fitzhardinge | 3d75e1b | 2008-07-08 15:06:49 -0700 | [diff] [blame] | 854 | #ifdef CONFIG_XEN |
Andy Lutomirski | cb5dd2c | 2014-05-21 15:07:08 -0700 | [diff] [blame] | 855 | idtentry xen_hypervisor_callback xen_do_hypervisor_callback has_error_code=0 |
Jeremy Fitzhardinge | 3d75e1b | 2008-07-08 15:06:49 -0700 | [diff] [blame] | 856 | |
| 857 | /* |
Cyrill Gorcunov | 9f1e87e | 2008-11-27 21:10:08 +0300 | [diff] [blame] | 858 | * A note on the "critical region" in our callback handler. |
| 859 | * We want to avoid stacking callback handlers due to events occurring |
| 860 | * during handling of the last event. To do this, we keep events disabled |
| 861 | * until we've done all processing. HOWEVER, we must enable events before |
| 862 | * popping the stack frame (can't be done atomically) and so it would still |
| 863 | * be possible to get enough handler activations to overflow the stack. |
| 864 | * Although unlikely, bugs of that kind are hard to track down, so we'd |
| 865 | * like to avoid the possibility. |
| 866 | * So, on entry to the handler we detect whether we interrupted an |
| 867 | * existing activation in its critical region -- if so, we pop the current |
| 868 | * activation and restart the handler using the previous one. |
| 869 | */ |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 870 | ENTRY(xen_do_hypervisor_callback) /* do_hypervisor_callback(struct *pt_regs) */ |
| 871 | |
Cyrill Gorcunov | 9f1e87e | 2008-11-27 21:10:08 +0300 | [diff] [blame] | 872 | /* |
| 873 | * Since we don't modify %rdi, evtchn_do_upall(struct *pt_regs) will |
| 874 | * see the correct pointer to the pt_regs |
| 875 | */ |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 876 | movq %rdi, %rsp /* we don't return, adjust the stack frame */ |
| 877 | 11: incl PER_CPU_VAR(irq_count) |
| 878 | movq %rsp, %rbp |
| 879 | cmovzq PER_CPU_VAR(irq_stack_ptr), %rsp |
| 880 | pushq %rbp /* frame pointer backlink */ |
| 881 | call xen_evtchn_do_upcall |
| 882 | popq %rsp |
| 883 | decl PER_CPU_VAR(irq_count) |
David Vrabel | fdfd811 | 2015-02-19 15:23:17 +0000 | [diff] [blame] | 884 | #ifndef CONFIG_PREEMPT |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 885 | call xen_maybe_preempt_hcall |
David Vrabel | fdfd811 | 2015-02-19 15:23:17 +0000 | [diff] [blame] | 886 | #endif |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 887 | jmp error_exit |
Alexander van Heukelum | 371c394 | 2011-03-11 21:59:38 +0100 | [diff] [blame] | 888 | END(xen_do_hypervisor_callback) |
Jeremy Fitzhardinge | 3d75e1b | 2008-07-08 15:06:49 -0700 | [diff] [blame] | 889 | |
| 890 | /* |
Cyrill Gorcunov | 9f1e87e | 2008-11-27 21:10:08 +0300 | [diff] [blame] | 891 | * Hypervisor uses this for application faults while it executes. |
| 892 | * We get here for two reasons: |
| 893 | * 1. Fault while reloading DS, ES, FS or GS |
| 894 | * 2. Fault while executing IRET |
| 895 | * Category 1 we do not need to fix up as Xen has already reloaded all segment |
| 896 | * registers that could be reloaded and zeroed the others. |
| 897 | * Category 2 we fix up by killing the current process. We cannot use the |
| 898 | * normal Linux return path in this case because if we use the IRET hypercall |
| 899 | * to pop the stack frame we end up in an infinite loop of failsafe callbacks. |
| 900 | * We distinguish between categories by comparing each saved segment register |
| 901 | * with its current contents: any discrepancy means we in category 1. |
| 902 | */ |
Jeremy Fitzhardinge | 3d75e1b | 2008-07-08 15:06:49 -0700 | [diff] [blame] | 903 | ENTRY(xen_failsafe_callback) |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 904 | movl %ds, %ecx |
| 905 | cmpw %cx, 0x10(%rsp) |
| 906 | jne 1f |
| 907 | movl %es, %ecx |
| 908 | cmpw %cx, 0x18(%rsp) |
| 909 | jne 1f |
| 910 | movl %fs, %ecx |
| 911 | cmpw %cx, 0x20(%rsp) |
| 912 | jne 1f |
| 913 | movl %gs, %ecx |
| 914 | cmpw %cx, 0x28(%rsp) |
| 915 | jne 1f |
Jeremy Fitzhardinge | 3d75e1b | 2008-07-08 15:06:49 -0700 | [diff] [blame] | 916 | /* All segments match their saved values => Category 2 (Bad IRET). */ |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 917 | movq (%rsp), %rcx |
| 918 | movq 8(%rsp), %r11 |
| 919 | addq $0x30, %rsp |
| 920 | pushq $0 /* RIP */ |
| 921 | pushq %r11 |
| 922 | pushq %rcx |
| 923 | jmp general_protection |
Jeremy Fitzhardinge | 3d75e1b | 2008-07-08 15:06:49 -0700 | [diff] [blame] | 924 | 1: /* Segment mismatch => Category 1 (Bad segment). Retry the IRET. */ |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 925 | movq (%rsp), %rcx |
| 926 | movq 8(%rsp), %r11 |
| 927 | addq $0x30, %rsp |
| 928 | pushq $-1 /* orig_ax = -1 => not a system call */ |
Denys Vlasenko | 76f5df4 | 2015-02-26 14:40:27 -0800 | [diff] [blame] | 929 | ALLOC_PT_GPREGS_ON_STACK |
| 930 | SAVE_C_REGS |
| 931 | SAVE_EXTRA_REGS |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 932 | jmp error_exit |
Jeremy Fitzhardinge | 3d75e1b | 2008-07-08 15:06:49 -0700 | [diff] [blame] | 933 | END(xen_failsafe_callback) |
| 934 | |
Seiji Aguchi | cf910e8 | 2013-06-20 11:46:53 -0400 | [diff] [blame] | 935 | apicinterrupt3 HYPERVISOR_CALLBACK_VECTOR \ |
Sheng Yang | 38e20b0 | 2010-05-14 12:40:51 +0100 | [diff] [blame] | 936 | xen_hvm_callback_vector xen_evtchn_do_upcall |
| 937 | |
Jeremy Fitzhardinge | 3d75e1b | 2008-07-08 15:06:49 -0700 | [diff] [blame] | 938 | #endif /* CONFIG_XEN */ |
Alexander van Heukelum | ddeb8f2 | 2008-11-24 13:24:28 +0100 | [diff] [blame] | 939 | |
K. Y. Srinivasan | bc2b033 | 2013-02-03 17:22:39 -0800 | [diff] [blame] | 940 | #if IS_ENABLED(CONFIG_HYPERV) |
Seiji Aguchi | cf910e8 | 2013-06-20 11:46:53 -0400 | [diff] [blame] | 941 | apicinterrupt3 HYPERVISOR_CALLBACK_VECTOR \ |
K. Y. Srinivasan | bc2b033 | 2013-02-03 17:22:39 -0800 | [diff] [blame] | 942 | hyperv_callback_vector hyperv_vector_handler |
| 943 | #endif /* CONFIG_HYPERV */ |
| 944 | |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 945 | idtentry debug do_debug has_error_code=0 paranoid=1 shift_ist=DEBUG_STACK |
Andy Lutomirski | 3681c24 | 2015-07-23 15:37:48 -0700 | [diff] [blame] | 946 | idtentry int3 do_int3 has_error_code=0 |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 947 | idtentry stack_segment do_stack_segment has_error_code=1 |
| 948 | |
Jeremy Fitzhardinge | 6cac5a9 | 2009-03-29 19:56:29 -0700 | [diff] [blame] | 949 | #ifdef CONFIG_XEN |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 950 | idtentry xen_debug do_debug has_error_code=0 |
| 951 | idtentry xen_int3 do_int3 has_error_code=0 |
| 952 | idtentry xen_stack_segment do_stack_segment has_error_code=1 |
Jeremy Fitzhardinge | 6cac5a9 | 2009-03-29 19:56:29 -0700 | [diff] [blame] | 953 | #endif |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 954 | |
| 955 | idtentry general_protection do_general_protection has_error_code=1 |
| 956 | trace_idtentry page_fault do_page_fault has_error_code=1 |
| 957 | |
Gleb Natapov | 631bc48 | 2010-10-14 11:22:52 +0200 | [diff] [blame] | 958 | #ifdef CONFIG_KVM_GUEST |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 959 | idtentry async_page_fault do_async_page_fault has_error_code=1 |
Gleb Natapov | 631bc48 | 2010-10-14 11:22:52 +0200 | [diff] [blame] | 960 | #endif |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 961 | |
Alexander van Heukelum | ddeb8f2 | 2008-11-24 13:24:28 +0100 | [diff] [blame] | 962 | #ifdef CONFIG_X86_MCE |
Thomas Gleixner | c5aa687 | 2018-01-18 16:28:26 +0100 | [diff] [blame] | 963 | idtentry machine_check do_mce has_error_code=0 paranoid=1 |
Alexander van Heukelum | ddeb8f2 | 2008-11-24 13:24:28 +0100 | [diff] [blame] | 964 | #endif |
| 965 | |
Denys Vlasenko | ebfc453 | 2015-02-26 14:40:34 -0800 | [diff] [blame] | 966 | /* |
| 967 | * Save all registers in pt_regs, and switch gs if needed. |
| 968 | * Use slow, but surefire "are we in kernel?" check. |
Hugh Dickins | 05ddad1 | 2017-09-26 18:43:07 -0700 | [diff] [blame] | 969 | * |
| 970 | * Return: ebx=0: needs swapgs but not SWITCH_USER_CR3 in paranoid_exit |
| 971 | * ebx=1: needs neither swapgs nor SWITCH_USER_CR3 in paranoid_exit |
| 972 | * ebx=2: needs both swapgs and SWITCH_USER_CR3 in paranoid_exit |
| 973 | * ebx=3: needs SWITCH_USER_CR3 but not swapgs in paranoid_exit |
Denys Vlasenko | ebfc453 | 2015-02-26 14:40:34 -0800 | [diff] [blame] | 974 | */ |
| 975 | ENTRY(paranoid_entry) |
Denys Vlasenko | 1eeb207 | 2015-02-26 14:40:33 -0800 | [diff] [blame] | 976 | cld |
| 977 | SAVE_C_REGS 8 |
| 978 | SAVE_EXTRA_REGS 8 |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 979 | movl $1, %ebx |
| 980 | movl $MSR_GS_BASE, %ecx |
Denys Vlasenko | 1eeb207 | 2015-02-26 14:40:33 -0800 | [diff] [blame] | 981 | rdmsr |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 982 | testl %edx, %edx |
| 983 | js 1f /* negative -> in kernel */ |
Denys Vlasenko | 1eeb207 | 2015-02-26 14:40:33 -0800 | [diff] [blame] | 984 | SWAPGS |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 985 | xorl %ebx, %ebx |
Hugh Dickins | 05ddad1 | 2017-09-26 18:43:07 -0700 | [diff] [blame] | 986 | 1: |
Kees Cook | e71fac0 | 2018-01-03 10:17:35 -0800 | [diff] [blame] | 987 | #ifdef CONFIG_PAGE_TABLE_ISOLATION |
Hugh Dickins | 05ddad1 | 2017-09-26 18:43:07 -0700 | [diff] [blame] | 988 | /* |
| 989 | * We might have come in between a swapgs and a SWITCH_KERNEL_CR3 |
| 990 | * on entry, or between a SWITCH_USER_CR3 and a swapgs on exit. |
| 991 | * Do a conditional SWITCH_KERNEL_CR3: this could safely be done |
| 992 | * unconditionally, but we need to find out whether the reverse |
| 993 | * should be done on return (conveyed to paranoid_exit in %ebx). |
| 994 | */ |
Hugh Dickins | 23e0943 | 2017-09-24 16:59:49 -0700 | [diff] [blame] | 995 | ALTERNATIVE "jmp 2f", "movq %cr3, %rax", X86_FEATURE_KAISER |
Hugh Dickins | 05ddad1 | 2017-09-26 18:43:07 -0700 | [diff] [blame] | 996 | testl $KAISER_SHADOW_PGD_OFFSET, %eax |
| 997 | jz 2f |
| 998 | orl $2, %ebx |
| 999 | andq $(~(X86_CR3_PCID_ASID_MASK | KAISER_SHADOW_PGD_OFFSET)), %rax |
Hugh Dickins | 169b369 | 2017-10-03 20:49:04 -0700 | [diff] [blame] | 1000 | /* If PCID enabled, set X86_CR3_PCID_NOFLUSH_BIT */ |
| 1001 | ALTERNATIVE "", "bts $63, %rax", X86_FEATURE_PCID |
Hugh Dickins | 05ddad1 | 2017-09-26 18:43:07 -0700 | [diff] [blame] | 1002 | movq %rax, %cr3 |
| 1003 | 2: |
| 1004 | #endif |
| 1005 | ret |
Denys Vlasenko | ebfc453 | 2015-02-26 14:40:34 -0800 | [diff] [blame] | 1006 | END(paranoid_entry) |
Denys Vlasenko | 1eeb207 | 2015-02-26 14:40:33 -0800 | [diff] [blame] | 1007 | |
Denys Vlasenko | ebfc453 | 2015-02-26 14:40:34 -0800 | [diff] [blame] | 1008 | /* |
| 1009 | * "Paranoid" exit path from exception stack. This is invoked |
| 1010 | * only on return from non-NMI IST interrupts that came |
| 1011 | * from kernel space. |
| 1012 | * |
| 1013 | * We may be returning to very strange contexts (e.g. very early |
| 1014 | * in syscall entry), so checking for preemption here would |
| 1015 | * be complicated. Fortunately, we there's no good reason |
| 1016 | * to try to handle preemption here. |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 1017 | * |
Hugh Dickins | 05ddad1 | 2017-09-26 18:43:07 -0700 | [diff] [blame] | 1018 | * On entry: ebx=0: needs swapgs but not SWITCH_USER_CR3 |
| 1019 | * ebx=1: needs neither swapgs nor SWITCH_USER_CR3 |
| 1020 | * ebx=2: needs both swapgs and SWITCH_USER_CR3 |
| 1021 | * ebx=3: needs SWITCH_USER_CR3 but not swapgs |
Denys Vlasenko | ebfc453 | 2015-02-26 14:40:34 -0800 | [diff] [blame] | 1022 | */ |
Alexander van Heukelum | ddeb8f2 | 2008-11-24 13:24:28 +0100 | [diff] [blame] | 1023 | ENTRY(paranoid_exit) |
Alexander van Heukelum | ddeb8f2 | 2008-11-24 13:24:28 +0100 | [diff] [blame] | 1024 | DISABLE_INTERRUPTS(CLBR_NONE) |
Steven Rostedt | 5963e31 | 2012-05-30 11:54:53 -0400 | [diff] [blame] | 1025 | TRACE_IRQS_OFF_DEBUG |
Denys Vlasenko | f2db938 | 2015-02-26 14:40:30 -0800 | [diff] [blame] | 1026 | TRACE_IRQS_IRETQ_DEBUG |
Kees Cook | e71fac0 | 2018-01-03 10:17:35 -0800 | [diff] [blame] | 1027 | #ifdef CONFIG_PAGE_TABLE_ISOLATION |
Hugh Dickins | 23e0943 | 2017-09-24 16:59:49 -0700 | [diff] [blame] | 1028 | /* No ALTERNATIVE for X86_FEATURE_KAISER: paranoid_entry sets %ebx */ |
Hugh Dickins | 05ddad1 | 2017-09-26 18:43:07 -0700 | [diff] [blame] | 1029 | testl $2, %ebx /* SWITCH_USER_CR3 needed? */ |
| 1030 | jz paranoid_exit_no_switch |
| 1031 | SWITCH_USER_CR3 |
| 1032 | paranoid_exit_no_switch: |
| 1033 | #endif |
| 1034 | testl $1, %ebx /* swapgs needed? */ |
| 1035 | jnz paranoid_exit_no_swapgs |
| 1036 | SWAPGS_UNSAFE_STACK |
| 1037 | paranoid_exit_no_swapgs: |
Denys Vlasenko | 76f5df4 | 2015-02-26 14:40:27 -0800 | [diff] [blame] | 1038 | RESTORE_EXTRA_REGS |
| 1039 | RESTORE_C_REGS |
| 1040 | REMOVE_PT_GPREGS_FROM_STACK 8 |
Andy Lutomirski | 48e08d0 | 2014-11-11 12:49:41 -0800 | [diff] [blame] | 1041 | INTERRUPT_RETURN |
Alexander van Heukelum | ddeb8f2 | 2008-11-24 13:24:28 +0100 | [diff] [blame] | 1042 | END(paranoid_exit) |
| 1043 | |
| 1044 | /* |
Denys Vlasenko | ebfc453 | 2015-02-26 14:40:34 -0800 | [diff] [blame] | 1045 | * Save all registers in pt_regs, and switch gs if needed. |
Alexander van Heukelum | ddeb8f2 | 2008-11-24 13:24:28 +0100 | [diff] [blame] | 1046 | */ |
| 1047 | ENTRY(error_entry) |
Alexander van Heukelum | ddeb8f2 | 2008-11-24 13:24:28 +0100 | [diff] [blame] | 1048 | cld |
Denys Vlasenko | 76f5df4 | 2015-02-26 14:40:27 -0800 | [diff] [blame] | 1049 | SAVE_C_REGS 8 |
| 1050 | SAVE_EXTRA_REGS 8 |
Dave Hansen | 8f0baad | 2017-08-30 16:23:00 -0700 | [diff] [blame] | 1051 | /* |
| 1052 | * error_entry() always returns with a kernel gsbase and |
| 1053 | * CR3. We must also have a kernel CR3/gsbase before |
| 1054 | * calling TRACE_IRQS_*. Just unconditionally switch to |
| 1055 | * the kernel CR3 here. |
| 1056 | */ |
| 1057 | SWITCH_KERNEL_CR3 |
Denys Vlasenko | 03335e9 | 2015-04-27 15:21:52 +0200 | [diff] [blame] | 1058 | testb $3, CS+8(%rsp) |
Andy Lutomirski | cb6f64e | 2015-07-03 12:44:27 -0700 | [diff] [blame] | 1059 | jz .Lerror_kernelspace |
Andy Lutomirski | 539f511 | 2015-06-09 12:36:01 -0700 | [diff] [blame] | 1060 | |
Andy Lutomirski | cb6f64e | 2015-07-03 12:44:27 -0700 | [diff] [blame] | 1061 | /* |
| 1062 | * We entered from user mode or we're pretending to have entered |
| 1063 | * from user mode due to an IRET fault. |
| 1064 | */ |
Alexander van Heukelum | ddeb8f2 | 2008-11-24 13:24:28 +0100 | [diff] [blame] | 1065 | SWAPGS |
Andy Lutomirski | 539f511 | 2015-06-09 12:36:01 -0700 | [diff] [blame] | 1066 | |
Andy Lutomirski | cb6f64e | 2015-07-03 12:44:27 -0700 | [diff] [blame] | 1067 | .Lerror_entry_from_usermode_after_swapgs: |
Andy Lutomirski | f107505 | 2015-11-12 12:59:00 -0800 | [diff] [blame] | 1068 | /* |
| 1069 | * We need to tell lockdep that IRQs are off. We can't do this until |
| 1070 | * we fix gsbase, and we should do it before enter_from_user_mode |
| 1071 | * (which can take locks). |
| 1072 | */ |
| 1073 | TRACE_IRQS_OFF |
Andy Lutomirski | 478dc89 | 2015-11-12 12:59:04 -0800 | [diff] [blame] | 1074 | CALL_enter_from_user_mode |
Andy Lutomirski | f107505 | 2015-11-12 12:59:00 -0800 | [diff] [blame] | 1075 | ret |
Andy Lutomirski | 02bc776 | 2015-07-03 12:44:31 -0700 | [diff] [blame] | 1076 | |
Andy Lutomirski | cb6f64e | 2015-07-03 12:44:27 -0700 | [diff] [blame] | 1077 | .Lerror_entry_done: |
Alexander van Heukelum | ddeb8f2 | 2008-11-24 13:24:28 +0100 | [diff] [blame] | 1078 | TRACE_IRQS_OFF |
| 1079 | ret |
Alexander van Heukelum | ddeb8f2 | 2008-11-24 13:24:28 +0100 | [diff] [blame] | 1080 | |
Denys Vlasenko | ebfc453 | 2015-02-26 14:40:34 -0800 | [diff] [blame] | 1081 | /* |
| 1082 | * There are two places in the kernel that can potentially fault with |
| 1083 | * usergs. Handle them here. B stepping K8s sometimes report a |
| 1084 | * truncated RIP for IRET exceptions returning to compat mode. Check |
| 1085 | * for these here too. |
| 1086 | */ |
Andy Lutomirski | cb6f64e | 2015-07-03 12:44:27 -0700 | [diff] [blame] | 1087 | .Lerror_kernelspace: |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 1088 | leaq native_irq_return_iret(%rip), %rcx |
| 1089 | cmpq %rcx, RIP+8(%rsp) |
Andy Lutomirski | cb6f64e | 2015-07-03 12:44:27 -0700 | [diff] [blame] | 1090 | je .Lerror_bad_iret |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 1091 | movl %ecx, %eax /* zero extend */ |
| 1092 | cmpq %rax, RIP+8(%rsp) |
Andy Lutomirski | cb6f64e | 2015-07-03 12:44:27 -0700 | [diff] [blame] | 1093 | je .Lbstep_iret |
Borislav Petkov | 42c748bb | 2016-04-07 17:31:50 -0700 | [diff] [blame] | 1094 | cmpq $.Lgs_change, RIP+8(%rsp) |
Andy Lutomirski | cb6f64e | 2015-07-03 12:44:27 -0700 | [diff] [blame] | 1095 | jne .Lerror_entry_done |
Andy Lutomirski | 539f511 | 2015-06-09 12:36:01 -0700 | [diff] [blame] | 1096 | |
| 1097 | /* |
Borislav Petkov | 42c748bb | 2016-04-07 17:31:50 -0700 | [diff] [blame] | 1098 | * hack: .Lgs_change can fail with user gsbase. If this happens, fix up |
Andy Lutomirski | 539f511 | 2015-06-09 12:36:01 -0700 | [diff] [blame] | 1099 | * gsbase and proceed. We'll fix up the exception and land in |
Borislav Petkov | 42c748bb | 2016-04-07 17:31:50 -0700 | [diff] [blame] | 1100 | * .Lgs_change's error handler with kernel gsbase. |
Andy Lutomirski | 539f511 | 2015-06-09 12:36:01 -0700 | [diff] [blame] | 1101 | */ |
Wanpeng Li | 2fa5f04 | 2016-09-30 09:01:06 +0800 | [diff] [blame] | 1102 | SWAPGS |
| 1103 | jmp .Lerror_entry_done |
Brian Gerst | ae24ffe | 2009-10-12 10:18:23 -0400 | [diff] [blame] | 1104 | |
Andy Lutomirski | cb6f64e | 2015-07-03 12:44:27 -0700 | [diff] [blame] | 1105 | .Lbstep_iret: |
Brian Gerst | ae24ffe | 2009-10-12 10:18:23 -0400 | [diff] [blame] | 1106 | /* Fix truncated RIP */ |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 1107 | movq %rcx, RIP+8(%rsp) |
Andy Lutomirski | b645af2 | 2014-11-22 18:00:33 -0800 | [diff] [blame] | 1108 | /* fall through */ |
| 1109 | |
Andy Lutomirski | cb6f64e | 2015-07-03 12:44:27 -0700 | [diff] [blame] | 1110 | .Lerror_bad_iret: |
Andy Lutomirski | 539f511 | 2015-06-09 12:36:01 -0700 | [diff] [blame] | 1111 | /* |
| 1112 | * We came from an IRET to user mode, so we have user gsbase. |
| 1113 | * Switch to kernel gsbase: |
| 1114 | */ |
Andy Lutomirski | b645af2 | 2014-11-22 18:00:33 -0800 | [diff] [blame] | 1115 | SWAPGS |
Andy Lutomirski | 539f511 | 2015-06-09 12:36:01 -0700 | [diff] [blame] | 1116 | |
| 1117 | /* |
| 1118 | * Pretend that the exception came from user mode: set up pt_regs |
Andy Lutomirski | 9871563 | 2018-07-22 11:05:09 -0700 | [diff] [blame] | 1119 | * as if we faulted immediately after IRET. |
Andy Lutomirski | 539f511 | 2015-06-09 12:36:01 -0700 | [diff] [blame] | 1120 | */ |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 1121 | mov %rsp, %rdi |
| 1122 | call fixup_bad_iret |
| 1123 | mov %rax, %rsp |
Andy Lutomirski | cb6f64e | 2015-07-03 12:44:27 -0700 | [diff] [blame] | 1124 | jmp .Lerror_entry_from_usermode_after_swapgs |
Alexander van Heukelum | ddeb8f2 | 2008-11-24 13:24:28 +0100 | [diff] [blame] | 1125 | END(error_entry) |
| 1126 | |
Alexander van Heukelum | ddeb8f2 | 2008-11-24 13:24:28 +0100 | [diff] [blame] | 1127 | ENTRY(error_exit) |
Alexander van Heukelum | ddeb8f2 | 2008-11-24 13:24:28 +0100 | [diff] [blame] | 1128 | DISABLE_INTERRUPTS(CLBR_NONE) |
| 1129 | TRACE_IRQS_OFF |
Andy Lutomirski | 9871563 | 2018-07-22 11:05:09 -0700 | [diff] [blame] | 1130 | testb $3, CS(%rsp) |
| 1131 | jz retint_kernel |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 1132 | jmp retint_user |
Alexander van Heukelum | ddeb8f2 | 2008-11-24 13:24:28 +0100 | [diff] [blame] | 1133 | END(error_exit) |
| 1134 | |
Denys Vlasenko | 0784b36 | 2015-04-01 16:50:57 +0200 | [diff] [blame] | 1135 | /* Runs on exception stack */ |
Alexander van Heukelum | ddeb8f2 | 2008-11-24 13:24:28 +0100 | [diff] [blame] | 1136 | ENTRY(nmi) |
Andy Lutomirski | fc57a7c | 2015-09-20 16:32:04 -0700 | [diff] [blame] | 1137 | /* |
| 1138 | * Fix up the exception frame if we're on Xen. |
| 1139 | * PARAVIRT_ADJUST_EXCEPTION_FRAME is guaranteed to push at most |
| 1140 | * one value to the stack on native, so it may clobber the rdx |
| 1141 | * scratch slot, but it won't clobber any of the important |
| 1142 | * slots past it. |
| 1143 | * |
| 1144 | * Xen is a different story, because the Xen frame itself overlaps |
| 1145 | * the "NMI executing" variable. |
| 1146 | */ |
Alexander van Heukelum | ddeb8f2 | 2008-11-24 13:24:28 +0100 | [diff] [blame] | 1147 | PARAVIRT_ADJUST_EXCEPTION_FRAME |
Andy Lutomirski | fc57a7c | 2015-09-20 16:32:04 -0700 | [diff] [blame] | 1148 | |
Steven Rostedt | 3f3c8b8 | 2011-12-08 12:36:23 -0500 | [diff] [blame] | 1149 | /* |
| 1150 | * We allow breakpoints in NMIs. If a breakpoint occurs, then |
| 1151 | * the iretq it performs will take us out of NMI context. |
| 1152 | * This means that we can have nested NMIs where the next |
| 1153 | * NMI is using the top of the stack of the previous NMI. We |
| 1154 | * can't let it execute because the nested NMI will corrupt the |
| 1155 | * stack of the previous NMI. NMI handlers are not re-entrant |
| 1156 | * anyway. |
| 1157 | * |
| 1158 | * To handle this case we do the following: |
| 1159 | * Check the a special location on the stack that contains |
| 1160 | * a variable that is set when NMIs are executing. |
| 1161 | * The interrupted task's stack is also checked to see if it |
| 1162 | * is an NMI stack. |
| 1163 | * If the variable is not set and the stack is not the NMI |
| 1164 | * stack then: |
| 1165 | * o Set the special variable on the stack |
Andy Lutomirski | 0b22930 | 2015-07-15 10:29:36 -0700 | [diff] [blame] | 1166 | * o Copy the interrupt frame into an "outermost" location on the |
| 1167 | * stack |
| 1168 | * o Copy the interrupt frame into an "iret" location on the stack |
Steven Rostedt | 3f3c8b8 | 2011-12-08 12:36:23 -0500 | [diff] [blame] | 1169 | * o Continue processing the NMI |
| 1170 | * If the variable is set or the previous stack is the NMI stack: |
Andy Lutomirski | 0b22930 | 2015-07-15 10:29:36 -0700 | [diff] [blame] | 1171 | * o Modify the "iret" location to jump to the repeat_nmi |
Steven Rostedt | 3f3c8b8 | 2011-12-08 12:36:23 -0500 | [diff] [blame] | 1172 | * o return back to the first NMI |
| 1173 | * |
| 1174 | * Now on exit of the first NMI, we first clear the stack variable |
| 1175 | * The NMI stack will tell any nested NMIs at that point that it is |
| 1176 | * nested. Then we pop the stack normally with iret, and if there was |
| 1177 | * a nested NMI that updated the copy interrupt stack frame, a |
| 1178 | * jump will be made to the repeat_nmi code that will handle the second |
| 1179 | * NMI. |
Andy Lutomirski | 9b6e6a8 | 2015-07-15 10:29:35 -0700 | [diff] [blame] | 1180 | * |
| 1181 | * However, espfix prevents us from directly returning to userspace |
| 1182 | * with a single IRET instruction. Similarly, IRET to user mode |
| 1183 | * can fault. We therefore handle NMIs from user space like |
| 1184 | * other IST entries. |
Steven Rostedt | 3f3c8b8 | 2011-12-08 12:36:23 -0500 | [diff] [blame] | 1185 | */ |
| 1186 | |
Andy Lutomirski | 10d5bf2 | 2017-08-07 19:43:13 -0700 | [diff] [blame] | 1187 | ASM_CLAC |
| 1188 | |
Denys Vlasenko | 146b2b0 | 2015-03-25 18:18:13 +0100 | [diff] [blame] | 1189 | /* Use %rdx as our temp variable throughout */ |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 1190 | pushq %rdx |
Steven Rostedt | 3f3c8b8 | 2011-12-08 12:36:23 -0500 | [diff] [blame] | 1191 | |
Andy Lutomirski | 9b6e6a8 | 2015-07-15 10:29:35 -0700 | [diff] [blame] | 1192 | testb $3, CS-RIP+8(%rsp) |
| 1193 | jz .Lnmi_from_kernel |
Steven Rostedt | 45d5a16 | 2012-02-19 16:43:37 -0500 | [diff] [blame] | 1194 | |
| 1195 | /* |
Andy Lutomirski | 9b6e6a8 | 2015-07-15 10:29:35 -0700 | [diff] [blame] | 1196 | * NMI from user mode. We need to run on the thread stack, but we |
| 1197 | * can't go through the normal entry paths: NMIs are masked, and |
| 1198 | * we don't want to enable interrupts, because then we'll end |
| 1199 | * up in an awkward situation in which IRQs are on but NMIs |
| 1200 | * are off. |
Andy Lutomirski | 83c133c | 2015-09-20 16:32:05 -0700 | [diff] [blame] | 1201 | * |
| 1202 | * We also must not push anything to the stack before switching |
| 1203 | * stacks lest we corrupt the "NMI executing" variable. |
Andy Lutomirski | 9b6e6a8 | 2015-07-15 10:29:35 -0700 | [diff] [blame] | 1204 | */ |
| 1205 | |
Andy Lutomirski | 83c133c | 2015-09-20 16:32:05 -0700 | [diff] [blame] | 1206 | SWAPGS_UNSAFE_STACK |
Dave Hansen | 8f0baad | 2017-08-30 16:23:00 -0700 | [diff] [blame] | 1207 | /* |
| 1208 | * percpu variables are mapped with user CR3, so no need |
| 1209 | * to switch CR3 here. |
| 1210 | */ |
Andy Lutomirski | 9b6e6a8 | 2015-07-15 10:29:35 -0700 | [diff] [blame] | 1211 | cld |
| 1212 | movq %rsp, %rdx |
| 1213 | movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp |
| 1214 | pushq 5*8(%rdx) /* pt_regs->ss */ |
| 1215 | pushq 4*8(%rdx) /* pt_regs->rsp */ |
| 1216 | pushq 3*8(%rdx) /* pt_regs->flags */ |
| 1217 | pushq 2*8(%rdx) /* pt_regs->cs */ |
| 1218 | pushq 1*8(%rdx) /* pt_regs->rip */ |
| 1219 | pushq $-1 /* pt_regs->orig_ax */ |
| 1220 | pushq %rdi /* pt_regs->di */ |
| 1221 | pushq %rsi /* pt_regs->si */ |
| 1222 | pushq (%rdx) /* pt_regs->dx */ |
| 1223 | pushq %rcx /* pt_regs->cx */ |
| 1224 | pushq %rax /* pt_regs->ax */ |
| 1225 | pushq %r8 /* pt_regs->r8 */ |
| 1226 | pushq %r9 /* pt_regs->r9 */ |
| 1227 | pushq %r10 /* pt_regs->r10 */ |
| 1228 | pushq %r11 /* pt_regs->r11 */ |
| 1229 | pushq %rbx /* pt_regs->rbx */ |
| 1230 | pushq %rbp /* pt_regs->rbp */ |
| 1231 | pushq %r12 /* pt_regs->r12 */ |
| 1232 | pushq %r13 /* pt_regs->r13 */ |
| 1233 | pushq %r14 /* pt_regs->r14 */ |
| 1234 | pushq %r15 /* pt_regs->r15 */ |
| 1235 | |
| 1236 | /* |
| 1237 | * At this point we no longer need to worry about stack damage |
| 1238 | * due to nesting -- we're on the normal thread stack and we're |
| 1239 | * done with the NMI stack. |
| 1240 | */ |
| 1241 | |
| 1242 | movq %rsp, %rdi |
| 1243 | movq $-1, %rsi |
Kees Cook | e71fac0 | 2018-01-03 10:17:35 -0800 | [diff] [blame] | 1244 | #ifdef CONFIG_PAGE_TABLE_ISOLATION |
Dave Hansen | 8f0baad | 2017-08-30 16:23:00 -0700 | [diff] [blame] | 1245 | /* Unconditionally use kernel CR3 for do_nmi() */ |
| 1246 | /* %rax is saved above, so OK to clobber here */ |
Hugh Dickins | 23e0943 | 2017-09-24 16:59:49 -0700 | [diff] [blame] | 1247 | ALTERNATIVE "jmp 2f", "movq %cr3, %rax", X86_FEATURE_KAISER |
Hugh Dickins | d0142ce | 2017-08-27 16:24:27 -0700 | [diff] [blame] | 1248 | /* If PCID enabled, NOFLUSH now and NOFLUSH on return */ |
Hugh Dickins | 169b369 | 2017-10-03 20:49:04 -0700 | [diff] [blame] | 1249 | ALTERNATIVE "", "bts $63, %rax", X86_FEATURE_PCID |
Dave Hansen | 8f0baad | 2017-08-30 16:23:00 -0700 | [diff] [blame] | 1250 | pushq %rax |
Hugh Dickins | 2684b12 | 2017-08-30 16:23:00 -0700 | [diff] [blame] | 1251 | /* mask off "user" bit of pgd address and 12 PCID bits: */ |
| 1252 | andq $(~(X86_CR3_PCID_ASID_MASK | KAISER_SHADOW_PGD_OFFSET)), %rax |
Dave Hansen | 8f0baad | 2017-08-30 16:23:00 -0700 | [diff] [blame] | 1253 | movq %rax, %cr3 |
Hugh Dickins | 23e0943 | 2017-09-24 16:59:49 -0700 | [diff] [blame] | 1254 | 2: |
Dave Hansen | 8f0baad | 2017-08-30 16:23:00 -0700 | [diff] [blame] | 1255 | #endif |
Andy Lutomirski | 9b6e6a8 | 2015-07-15 10:29:35 -0700 | [diff] [blame] | 1256 | call do_nmi |
Hugh Dickins | 1937794 | 2017-09-21 20:39:56 -0700 | [diff] [blame] | 1257 | |
Kees Cook | e71fac0 | 2018-01-03 10:17:35 -0800 | [diff] [blame] | 1258 | #ifdef CONFIG_PAGE_TABLE_ISOLATION |
Dave Hansen | 8f0baad | 2017-08-30 16:23:00 -0700 | [diff] [blame] | 1259 | /* |
| 1260 | * Unconditionally restore CR3. I know we return to |
| 1261 | * kernel code that needs user CR3, but do we ever return |
| 1262 | * to "user mode" where we need the kernel CR3? |
| 1263 | */ |
Hugh Dickins | 23e0943 | 2017-09-24 16:59:49 -0700 | [diff] [blame] | 1264 | ALTERNATIVE "", "popq %rax; movq %rax, %cr3", X86_FEATURE_KAISER |
Dave Hansen | 8f0baad | 2017-08-30 16:23:00 -0700 | [diff] [blame] | 1265 | #endif |
Andy Lutomirski | 9b6e6a8 | 2015-07-15 10:29:35 -0700 | [diff] [blame] | 1266 | |
| 1267 | /* |
| 1268 | * Return back to user mode. We must *not* do the normal exit |
Dave Hansen | 8f0baad | 2017-08-30 16:23:00 -0700 | [diff] [blame] | 1269 | * work, because we don't want to enable interrupts. Do not |
| 1270 | * switch to user CR3: we might be going back to kernel code |
| 1271 | * that had a user CR3 set. |
Andy Lutomirski | 9b6e6a8 | 2015-07-15 10:29:35 -0700 | [diff] [blame] | 1272 | */ |
| 1273 | SWAPGS |
| 1274 | jmp restore_c_regs_and_iret |
| 1275 | |
| 1276 | .Lnmi_from_kernel: |
| 1277 | /* |
Andy Lutomirski | 0b22930 | 2015-07-15 10:29:36 -0700 | [diff] [blame] | 1278 | * Here's what our stack frame will look like: |
| 1279 | * +---------------------------------------------------------+ |
| 1280 | * | original SS | |
| 1281 | * | original Return RSP | |
| 1282 | * | original RFLAGS | |
| 1283 | * | original CS | |
| 1284 | * | original RIP | |
| 1285 | * +---------------------------------------------------------+ |
| 1286 | * | temp storage for rdx | |
| 1287 | * +---------------------------------------------------------+ |
| 1288 | * | "NMI executing" variable | |
| 1289 | * +---------------------------------------------------------+ |
| 1290 | * | iret SS } Copied from "outermost" frame | |
| 1291 | * | iret Return RSP } on each loop iteration; overwritten | |
| 1292 | * | iret RFLAGS } by a nested NMI to force another | |
| 1293 | * | iret CS } iteration if needed. | |
| 1294 | * | iret RIP } | |
| 1295 | * +---------------------------------------------------------+ |
| 1296 | * | outermost SS } initialized in first_nmi; | |
| 1297 | * | outermost Return RSP } will not be changed before | |
| 1298 | * | outermost RFLAGS } NMI processing is done. | |
| 1299 | * | outermost CS } Copied to "iret" frame on each | |
| 1300 | * | outermost RIP } iteration. | |
| 1301 | * +---------------------------------------------------------+ |
| 1302 | * | pt_regs | |
| 1303 | * +---------------------------------------------------------+ |
| 1304 | * |
| 1305 | * The "original" frame is used by hardware. Before re-enabling |
| 1306 | * NMIs, we need to be done with it, and we need to leave enough |
| 1307 | * space for the asm code here. |
| 1308 | * |
| 1309 | * We return by executing IRET while RSP points to the "iret" frame. |
| 1310 | * That will either return for real or it will loop back into NMI |
| 1311 | * processing. |
| 1312 | * |
| 1313 | * The "outermost" frame is copied to the "iret" frame on each |
| 1314 | * iteration of the loop, so each iteration starts with the "iret" |
| 1315 | * frame pointing to the final return target. |
| 1316 | */ |
| 1317 | |
| 1318 | /* |
| 1319 | * Determine whether we're a nested NMI. |
| 1320 | * |
Andy Lutomirski | a27507c | 2015-07-15 10:29:37 -0700 | [diff] [blame] | 1321 | * If we interrupted kernel code between repeat_nmi and |
| 1322 | * end_repeat_nmi, then we are a nested NMI. We must not |
| 1323 | * modify the "iret" frame because it's being written by |
| 1324 | * the outer NMI. That's okay; the outer NMI handler is |
| 1325 | * about to about to call do_nmi anyway, so we can just |
| 1326 | * resume the outer NMI. |
| 1327 | */ |
| 1328 | |
| 1329 | movq $repeat_nmi, %rdx |
| 1330 | cmpq 8(%rsp), %rdx |
| 1331 | ja 1f |
| 1332 | movq $end_repeat_nmi, %rdx |
| 1333 | cmpq 8(%rsp), %rdx |
| 1334 | ja nested_nmi_out |
| 1335 | 1: |
| 1336 | |
| 1337 | /* |
| 1338 | * Now check "NMI executing". If it's set, then we're nested. |
Andy Lutomirski | 0b22930 | 2015-07-15 10:29:36 -0700 | [diff] [blame] | 1339 | * This will not detect if we interrupted an outer NMI just |
| 1340 | * before IRET. |
Steven Rostedt | 3f3c8b8 | 2011-12-08 12:36:23 -0500 | [diff] [blame] | 1341 | */ |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 1342 | cmpl $1, -8(%rsp) |
| 1343 | je nested_nmi |
Steven Rostedt | 3f3c8b8 | 2011-12-08 12:36:23 -0500 | [diff] [blame] | 1344 | |
| 1345 | /* |
Andy Lutomirski | 0b22930 | 2015-07-15 10:29:36 -0700 | [diff] [blame] | 1346 | * Now test if the previous stack was an NMI stack. This covers |
| 1347 | * the case where we interrupt an outer NMI after it clears |
Andy Lutomirski | 810bc07 | 2015-07-15 10:29:38 -0700 | [diff] [blame] | 1348 | * "NMI executing" but before IRET. We need to be careful, though: |
| 1349 | * there is one case in which RSP could point to the NMI stack |
| 1350 | * despite there being no NMI active: naughty userspace controls |
| 1351 | * RSP at the very beginning of the SYSCALL targets. We can |
| 1352 | * pull a fast one on naughty userspace, though: we program |
| 1353 | * SYSCALL to mask DF, so userspace cannot cause DF to be set |
| 1354 | * if it controls the kernel's RSP. We set DF before we clear |
| 1355 | * "NMI executing". |
Steven Rostedt | 3f3c8b8 | 2011-12-08 12:36:23 -0500 | [diff] [blame] | 1356 | */ |
Denys Vlasenko | 0784b36 | 2015-04-01 16:50:57 +0200 | [diff] [blame] | 1357 | lea 6*8(%rsp), %rdx |
| 1358 | /* Compare the NMI stack (rdx) with the stack we came from (4*8(%rsp)) */ |
| 1359 | cmpq %rdx, 4*8(%rsp) |
| 1360 | /* If the stack pointer is above the NMI stack, this is a normal NMI */ |
| 1361 | ja first_nmi |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 1362 | |
Denys Vlasenko | 0784b36 | 2015-04-01 16:50:57 +0200 | [diff] [blame] | 1363 | subq $EXCEPTION_STKSZ, %rdx |
| 1364 | cmpq %rdx, 4*8(%rsp) |
| 1365 | /* If it is below the NMI stack, it is a normal NMI */ |
| 1366 | jb first_nmi |
Andy Lutomirski | 810bc07 | 2015-07-15 10:29:38 -0700 | [diff] [blame] | 1367 | |
| 1368 | /* Ah, it is within the NMI stack. */ |
| 1369 | |
| 1370 | testb $(X86_EFLAGS_DF >> 8), (3*8 + 1)(%rsp) |
| 1371 | jz first_nmi /* RSP was user controlled. */ |
| 1372 | |
| 1373 | /* This is a nested NMI. */ |
Denys Vlasenko | 0784b36 | 2015-04-01 16:50:57 +0200 | [diff] [blame] | 1374 | |
Steven Rostedt | 3f3c8b8 | 2011-12-08 12:36:23 -0500 | [diff] [blame] | 1375 | nested_nmi: |
| 1376 | /* |
Andy Lutomirski | 0b22930 | 2015-07-15 10:29:36 -0700 | [diff] [blame] | 1377 | * Modify the "iret" frame to point to repeat_nmi, forcing another |
| 1378 | * iteration of NMI handling. |
Steven Rostedt | 3f3c8b8 | 2011-12-08 12:36:23 -0500 | [diff] [blame] | 1379 | */ |
Andy Lutomirski | 23a781e | 2015-07-15 10:29:39 -0700 | [diff] [blame] | 1380 | subq $8, %rsp |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 1381 | leaq -10*8(%rsp), %rdx |
| 1382 | pushq $__KERNEL_DS |
| 1383 | pushq %rdx |
Ingo Molnar | 131484c | 2015-05-28 12:21:47 +0200 | [diff] [blame] | 1384 | pushfq |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 1385 | pushq $__KERNEL_CS |
| 1386 | pushq $repeat_nmi |
Steven Rostedt | 3f3c8b8 | 2011-12-08 12:36:23 -0500 | [diff] [blame] | 1387 | |
| 1388 | /* Put stack back */ |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 1389 | addq $(6*8), %rsp |
Steven Rostedt | 3f3c8b8 | 2011-12-08 12:36:23 -0500 | [diff] [blame] | 1390 | |
| 1391 | nested_nmi_out: |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 1392 | popq %rdx |
Steven Rostedt | 3f3c8b8 | 2011-12-08 12:36:23 -0500 | [diff] [blame] | 1393 | |
Andy Lutomirski | 0b22930 | 2015-07-15 10:29:36 -0700 | [diff] [blame] | 1394 | /* We are returning to kernel mode, so this cannot result in a fault. */ |
Steven Rostedt | 3f3c8b8 | 2011-12-08 12:36:23 -0500 | [diff] [blame] | 1395 | INTERRUPT_RETURN |
| 1396 | |
| 1397 | first_nmi: |
Andy Lutomirski | 0b22930 | 2015-07-15 10:29:36 -0700 | [diff] [blame] | 1398 | /* Restore rdx. */ |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 1399 | movq (%rsp), %rdx |
Jan Beulich | 6261091 | 2012-02-24 14:54:37 +0000 | [diff] [blame] | 1400 | |
Andy Lutomirski | 36f1a77 | 2015-07-15 10:29:40 -0700 | [diff] [blame] | 1401 | /* Make room for "NMI executing". */ |
| 1402 | pushq $0 |
Steven Rostedt | 3f3c8b8 | 2011-12-08 12:36:23 -0500 | [diff] [blame] | 1403 | |
Andy Lutomirski | 0b22930 | 2015-07-15 10:29:36 -0700 | [diff] [blame] | 1404 | /* Leave room for the "iret" frame */ |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 1405 | subq $(5*8), %rsp |
Salman Qazi | 28696f4 | 2012-10-01 17:29:25 -0700 | [diff] [blame] | 1406 | |
Andy Lutomirski | 0b22930 | 2015-07-15 10:29:36 -0700 | [diff] [blame] | 1407 | /* Copy the "original" frame to the "outermost" frame */ |
Steven Rostedt | 3f3c8b8 | 2011-12-08 12:36:23 -0500 | [diff] [blame] | 1408 | .rept 5 |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 1409 | pushq 11*8(%rsp) |
Steven Rostedt | 3f3c8b8 | 2011-12-08 12:36:23 -0500 | [diff] [blame] | 1410 | .endr |
Jan Beulich | 6261091 | 2012-02-24 14:54:37 +0000 | [diff] [blame] | 1411 | |
Steven Rostedt | 79fb4ad | 2012-02-24 15:55:13 -0500 | [diff] [blame] | 1412 | /* Everything up to here is safe from nested NMIs */ |
| 1413 | |
Andy Lutomirski | a97439a | 2015-07-15 10:29:41 -0700 | [diff] [blame] | 1414 | #ifdef CONFIG_DEBUG_ENTRY |
| 1415 | /* |
| 1416 | * For ease of testing, unmask NMIs right away. Disabled by |
| 1417 | * default because IRET is very expensive. |
| 1418 | */ |
| 1419 | pushq $0 /* SS */ |
| 1420 | pushq %rsp /* RSP (minus 8 because of the previous push) */ |
| 1421 | addq $8, (%rsp) /* Fix up RSP */ |
| 1422 | pushfq /* RFLAGS */ |
| 1423 | pushq $__KERNEL_CS /* CS */ |
| 1424 | pushq $1f /* RIP */ |
| 1425 | INTERRUPT_RETURN /* continues at repeat_nmi below */ |
| 1426 | 1: |
| 1427 | #endif |
| 1428 | |
Andy Lutomirski | 0b22930 | 2015-07-15 10:29:36 -0700 | [diff] [blame] | 1429 | repeat_nmi: |
Jan Beulich | 6261091 | 2012-02-24 14:54:37 +0000 | [diff] [blame] | 1430 | /* |
| 1431 | * If there was a nested NMI, the first NMI's iret will return |
| 1432 | * here. But NMIs are still enabled and we can take another |
| 1433 | * nested NMI. The nested NMI checks the interrupted RIP to see |
| 1434 | * if it is between repeat_nmi and end_repeat_nmi, and if so |
| 1435 | * it will just return, as we are about to repeat an NMI anyway. |
| 1436 | * This makes it safe to copy to the stack frame that a nested |
| 1437 | * NMI will update. |
Andy Lutomirski | 0b22930 | 2015-07-15 10:29:36 -0700 | [diff] [blame] | 1438 | * |
| 1439 | * RSP is pointing to "outermost RIP". gsbase is unknown, but, if |
| 1440 | * we're repeating an NMI, gsbase has the same value that it had on |
| 1441 | * the first iteration. paranoid_entry will load the kernel |
Andy Lutomirski | 36f1a77 | 2015-07-15 10:29:40 -0700 | [diff] [blame] | 1442 | * gsbase if needed before we call do_nmi. "NMI executing" |
| 1443 | * is zero. |
Jan Beulich | 6261091 | 2012-02-24 14:54:37 +0000 | [diff] [blame] | 1444 | */ |
Andy Lutomirski | 36f1a77 | 2015-07-15 10:29:40 -0700 | [diff] [blame] | 1445 | movq $1, 10*8(%rsp) /* Set "NMI executing". */ |
Steven Rostedt | 3f3c8b8 | 2011-12-08 12:36:23 -0500 | [diff] [blame] | 1446 | |
Andy Lutomirski | 0b22930 | 2015-07-15 10:29:36 -0700 | [diff] [blame] | 1447 | /* |
| 1448 | * Copy the "outermost" frame to the "iret" frame. NMIs that nest |
| 1449 | * here must not modify the "iret" frame while we're writing to |
| 1450 | * it or it will end up containing garbage. |
| 1451 | */ |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 1452 | addq $(10*8), %rsp |
Steven Rostedt | 3f3c8b8 | 2011-12-08 12:36:23 -0500 | [diff] [blame] | 1453 | .rept 5 |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 1454 | pushq -6*8(%rsp) |
Steven Rostedt | 3f3c8b8 | 2011-12-08 12:36:23 -0500 | [diff] [blame] | 1455 | .endr |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 1456 | subq $(5*8), %rsp |
Jan Beulich | 6261091 | 2012-02-24 14:54:37 +0000 | [diff] [blame] | 1457 | end_repeat_nmi: |
Steven Rostedt | 3f3c8b8 | 2011-12-08 12:36:23 -0500 | [diff] [blame] | 1458 | |
| 1459 | /* |
Andy Lutomirski | 0b22930 | 2015-07-15 10:29:36 -0700 | [diff] [blame] | 1460 | * Everything below this point can be preempted by a nested NMI. |
| 1461 | * If this happens, then the inner NMI will change the "iret" |
| 1462 | * frame to point back to repeat_nmi. |
Steven Rostedt | 3f3c8b8 | 2011-12-08 12:36:23 -0500 | [diff] [blame] | 1463 | */ |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 1464 | pushq $-1 /* ORIG_RAX: no syscall to restart */ |
Denys Vlasenko | 76f5df4 | 2015-02-26 14:40:27 -0800 | [diff] [blame] | 1465 | ALLOC_PT_GPREGS_ON_STACK |
| 1466 | |
Steven Rostedt | 1fd466e | 2011-12-08 12:32:27 -0500 | [diff] [blame] | 1467 | /* |
Dave Hansen | 8f0baad | 2017-08-30 16:23:00 -0700 | [diff] [blame] | 1468 | * Use the same approach as paranoid_entry to handle SWAPGS, but |
| 1469 | * without CR3 handling since we do that differently in NMIs. No |
| 1470 | * need to use paranoid_exit as we should not be calling schedule |
| 1471 | * in NMI context. Even with normal interrupts enabled. An NMI |
| 1472 | * should not be setting NEED_RESCHED or anything that normal |
| 1473 | * interrupts and exceptions might do. |
Steven Rostedt | 1fd466e | 2011-12-08 12:32:27 -0500 | [diff] [blame] | 1474 | */ |
Dave Hansen | 8f0baad | 2017-08-30 16:23:00 -0700 | [diff] [blame] | 1475 | cld |
| 1476 | SAVE_C_REGS |
| 1477 | SAVE_EXTRA_REGS |
| 1478 | movl $1, %ebx |
| 1479 | movl $MSR_GS_BASE, %ecx |
| 1480 | rdmsr |
| 1481 | testl %edx, %edx |
| 1482 | js 1f /* negative -> in kernel */ |
| 1483 | SWAPGS |
| 1484 | xorl %ebx, %ebx |
| 1485 | 1: |
Hugh Dickins | 1937794 | 2017-09-21 20:39:56 -0700 | [diff] [blame] | 1486 | movq %rsp, %rdi |
| 1487 | movq $-1, %rsi |
Kees Cook | e71fac0 | 2018-01-03 10:17:35 -0800 | [diff] [blame] | 1488 | #ifdef CONFIG_PAGE_TABLE_ISOLATION |
Dave Hansen | 8f0baad | 2017-08-30 16:23:00 -0700 | [diff] [blame] | 1489 | /* Unconditionally use kernel CR3 for do_nmi() */ |
| 1490 | /* %rax is saved above, so OK to clobber here */ |
Hugh Dickins | 23e0943 | 2017-09-24 16:59:49 -0700 | [diff] [blame] | 1491 | ALTERNATIVE "jmp 2f", "movq %cr3, %rax", X86_FEATURE_KAISER |
Hugh Dickins | d0142ce | 2017-08-27 16:24:27 -0700 | [diff] [blame] | 1492 | /* If PCID enabled, NOFLUSH now and NOFLUSH on return */ |
Hugh Dickins | 169b369 | 2017-10-03 20:49:04 -0700 | [diff] [blame] | 1493 | ALTERNATIVE "", "bts $63, %rax", X86_FEATURE_PCID |
Dave Hansen | 8f0baad | 2017-08-30 16:23:00 -0700 | [diff] [blame] | 1494 | pushq %rax |
Hugh Dickins | 2684b12 | 2017-08-30 16:23:00 -0700 | [diff] [blame] | 1495 | /* mask off "user" bit of pgd address and 12 PCID bits: */ |
| 1496 | andq $(~(X86_CR3_PCID_ASID_MASK | KAISER_SHADOW_PGD_OFFSET)), %rax |
Dave Hansen | 8f0baad | 2017-08-30 16:23:00 -0700 | [diff] [blame] | 1497 | movq %rax, %cr3 |
Hugh Dickins | 23e0943 | 2017-09-24 16:59:49 -0700 | [diff] [blame] | 1498 | 2: |
Dave Hansen | 8f0baad | 2017-08-30 16:23:00 -0700 | [diff] [blame] | 1499 | #endif |
Steven Rostedt | 7fbb98c | 2012-06-07 10:21:21 -0400 | [diff] [blame] | 1500 | |
Alexander van Heukelum | ddeb8f2 | 2008-11-24 13:24:28 +0100 | [diff] [blame] | 1501 | /* paranoidentry do_nmi, 0; without TRACE_IRQS_OFF */ |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 1502 | call do_nmi |
Hugh Dickins | 1937794 | 2017-09-21 20:39:56 -0700 | [diff] [blame] | 1503 | |
Kees Cook | e71fac0 | 2018-01-03 10:17:35 -0800 | [diff] [blame] | 1504 | #ifdef CONFIG_PAGE_TABLE_ISOLATION |
Dave Hansen | 8f0baad | 2017-08-30 16:23:00 -0700 | [diff] [blame] | 1505 | /* |
| 1506 | * Unconditionally restore CR3. We might be returning to |
| 1507 | * kernel code that needs user CR3, like just just before |
| 1508 | * a sysret. |
| 1509 | */ |
Hugh Dickins | 23e0943 | 2017-09-24 16:59:49 -0700 | [diff] [blame] | 1510 | ALTERNATIVE "", "popq %rax; movq %rax, %cr3", X86_FEATURE_KAISER |
Dave Hansen | 8f0baad | 2017-08-30 16:23:00 -0700 | [diff] [blame] | 1511 | #endif |
Steven Rostedt | 7fbb98c | 2012-06-07 10:21:21 -0400 | [diff] [blame] | 1512 | |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 1513 | testl %ebx, %ebx /* swapgs needed? */ |
| 1514 | jnz nmi_restore |
Alexander van Heukelum | ddeb8f2 | 2008-11-24 13:24:28 +0100 | [diff] [blame] | 1515 | nmi_swapgs: |
Dave Hansen | 8f0baad | 2017-08-30 16:23:00 -0700 | [diff] [blame] | 1516 | /* We fixed up CR3 above, so no need to switch it here */ |
Alexander van Heukelum | ddeb8f2 | 2008-11-24 13:24:28 +0100 | [diff] [blame] | 1517 | SWAPGS_UNSAFE_STACK |
| 1518 | nmi_restore: |
Denys Vlasenko | 76f5df4 | 2015-02-26 14:40:27 -0800 | [diff] [blame] | 1519 | RESTORE_EXTRA_REGS |
| 1520 | RESTORE_C_REGS |
Andy Lutomirski | 0b22930 | 2015-07-15 10:29:36 -0700 | [diff] [blame] | 1521 | |
| 1522 | /* Point RSP at the "iret" frame. */ |
Denys Vlasenko | 76f5df4 | 2015-02-26 14:40:27 -0800 | [diff] [blame] | 1523 | REMOVE_PT_GPREGS_FROM_STACK 6*8 |
Salman Qazi | 28696f4 | 2012-10-01 17:29:25 -0700 | [diff] [blame] | 1524 | |
Andy Lutomirski | 810bc07 | 2015-07-15 10:29:38 -0700 | [diff] [blame] | 1525 | /* |
| 1526 | * Clear "NMI executing". Set DF first so that we can easily |
| 1527 | * distinguish the remaining code between here and IRET from |
| 1528 | * the SYSCALL entry and exit paths. On a native kernel, we |
| 1529 | * could just inspect RIP, but, on paravirt kernels, |
| 1530 | * INTERRUPT_RETURN can translate into a jump into a |
| 1531 | * hypercall page. |
| 1532 | */ |
| 1533 | std |
| 1534 | movq $0, 5*8(%rsp) /* clear "NMI executing" */ |
Andy Lutomirski | 0b22930 | 2015-07-15 10:29:36 -0700 | [diff] [blame] | 1535 | |
| 1536 | /* |
| 1537 | * INTERRUPT_RETURN reads the "iret" frame and exits the NMI |
| 1538 | * stack in a single instruction. We are returning to kernel |
| 1539 | * mode, so this cannot result in a fault. |
| 1540 | */ |
Andy Lutomirski | 5ca6f70 | 2015-06-04 13:24:29 -0700 | [diff] [blame] | 1541 | INTERRUPT_RETURN |
Alexander van Heukelum | ddeb8f2 | 2008-11-24 13:24:28 +0100 | [diff] [blame] | 1542 | END(nmi) |
| 1543 | |
| 1544 | ENTRY(ignore_sysret) |
Ingo Molnar | 4d73213 | 2015-06-08 20:43:07 +0200 | [diff] [blame] | 1545 | mov $-ENOSYS, %eax |
Alexander van Heukelum | ddeb8f2 | 2008-11-24 13:24:28 +0100 | [diff] [blame] | 1546 | sysret |
Alexander van Heukelum | ddeb8f2 | 2008-11-24 13:24:28 +0100 | [diff] [blame] | 1547 | END(ignore_sysret) |
Andy Lutomirski | 2deb4be | 2016-07-14 13:22:55 -0700 | [diff] [blame] | 1548 | |
| 1549 | ENTRY(rewind_stack_do_exit) |
| 1550 | /* Prevent any naive code from trying to unwind to our caller. */ |
| 1551 | xorl %ebp, %ebp |
| 1552 | |
| 1553 | movq PER_CPU_VAR(cpu_current_top_of_stack), %rax |
| 1554 | leaq -TOP_OF_KERNEL_STACK_PADDING-PTREGS_SIZE(%rax), %rsp |
| 1555 | |
| 1556 | call do_exit |
| 1557 | 1: jmp 1b |
| 1558 | END(rewind_stack_do_exit) |