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x86: move stack_canary into irq_stack

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Impact: x86_64 percpu area layout change, irq_stack now at the beginning

Now that the PDA is empty except for the stack canary, it can be removed.
The irqstack is moved to the start of the per-cpu section.  If the stack
protector is enabled, the canary overlaps the bottom 48 bytes of the irqstack.

tj: * updated subject
    * dropped asm relocation of irq_stack_ptr
    * updated comments a bit
    * rebased on top of stack canary changes

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Brian Gerst
2009-01-19 12:21:28 +09:00
committed by Tejun Heo
parent 8c7e58e690
commit 947e76cdc3
10 changed files with 46 additions and 62 deletions
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4
arch/x86/include/asm/system.h
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@@ -89,10 +89,10 @@ do { \
#ifdef CONFIG_CC_STACKPROTECTOR
#define __switch_canary \
"movq %P[task_canary](%%rsi),%%r8\n\t" \
"movq %%r8,%%gs:%P[pda_canary]\n\t"
"movq %%r8,%%gs:%P[gs_canary]\n\t"
#define __switch_canary_param \
, [task_canary] "i" (offsetof(struct task_struct, stack_canary)) \
, [pda_canary] "i" (offsetof(struct x8664_pda, stack_canary))
, [gs_canary] "i" (offsetof(union irq_stack_union, stack_canary))
#else /* CC_STACKPROTECTOR */
#define __switch_canary
#define __switch_canary_param