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Diffstat (limited to 'arch/x86/include/asm/system.h')
-rw-r--r--arch/x86/include/asm/system.h29
1 files changed, 23 insertions, 6 deletions
diff --git a/arch/x86/include/asm/system.h b/arch/x86/include/asm/system.h
index 8e626ea33a1..c22383743f3 100644
--- a/arch/x86/include/asm/system.h
+++ b/arch/x86/include/asm/system.h
@@ -86,27 +86,44 @@ do { \
, "rcx", "rbx", "rdx", "r8", "r9", "r10", "r11", \
"r12", "r13", "r14", "r15"
+#ifdef CONFIG_CC_STACKPROTECTOR
+#define __switch_canary \
+ "movq %P[task_canary](%%rsi),%%r8\n\t" \
+ "movq %%r8,"__percpu_arg([gs_canary])"\n\t"
+#define __switch_canary_oparam \
+ , [gs_canary] "=m" (per_cpu_var(irq_stack_union.stack_canary))
+#define __switch_canary_iparam \
+ , [task_canary] "i" (offsetof(struct task_struct, stack_canary))
+#else /* CC_STACKPROTECTOR */
+#define __switch_canary
+#define __switch_canary_oparam
+#define __switch_canary_iparam
+#endif /* CC_STACKPROTECTOR */
+
/* Save restore flags to clear handle leaking NT */
#define switch_to(prev, next, last) \
- asm volatile(SAVE_CONTEXT \
+ asm volatile(SAVE_CONTEXT \
"movq %%rsp,%P[threadrsp](%[prev])\n\t" /* save RSP */ \
"movq %P[threadrsp](%[next]),%%rsp\n\t" /* restore RSP */ \
"call __switch_to\n\t" \
".globl thread_return\n" \
"thread_return:\n\t" \
- "movq %%gs:%P[pda_pcurrent],%%rsi\n\t" \
+ "movq "__percpu_arg([current_task])",%%rsi\n\t" \
+ __switch_canary \
"movq %P[thread_info](%%rsi),%%r8\n\t" \
- LOCK_PREFIX "btr %[tif_fork],%P[ti_flags](%%r8)\n\t" \
"movq %%rax,%%rdi\n\t" \
- "jc ret_from_fork\n\t" \
+ "testl %[_tif_fork],%P[ti_flags](%%r8)\n\t" \
+ "jnz ret_from_fork\n\t" \
RESTORE_CONTEXT \
: "=a" (last) \
+ __switch_canary_oparam \
: [next] "S" (next), [prev] "D" (prev), \
[threadrsp] "i" (offsetof(struct task_struct, thread.sp)), \
[ti_flags] "i" (offsetof(struct thread_info, flags)), \
- [tif_fork] "i" (TIF_FORK), \
+ [_tif_fork] "i" (_TIF_FORK), \
[thread_info] "i" (offsetof(struct task_struct, stack)), \
- [pda_pcurrent] "i" (offsetof(struct x8664_pda, pcurrent)) \
+ [current_task] "m" (per_cpu_var(current_task)) \
+ __switch_canary_iparam \
: "memory", "cc" __EXTRA_CLOBBER)
#endif