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| author | Brian Gerst <brgerst@gmail.com> | 2009-01-19 12:21:28 +0900 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2009-01-20 12:29:20 +0900 |
| commit | 947e76cdc34c782fc947313d4331380686eebbad (patch) | |
| tree | de5d424c4760269fd7800bc745e48b060c725300 /arch/x86/kernel/head_64.S | |
| parent | 8c7e58e690ae60ab4215b025f433ed4af261e103 (diff) | |
| download | linux-947e76cdc34c782fc947313d4331380686eebbad.tar.gz linux-947e76cdc34c782fc947313d4331380686eebbad.tar.bz2 linux-947e76cdc34c782fc947313d4331380686eebbad.zip | |
x86: move stack_canary into irq_stack
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>
Diffstat (limited to 'arch/x86/kernel/head_64.S')
| -rw-r--r-- | arch/x86/kernel/head_64.S | 13 |
1 files changed, 5 insertions, 8 deletions
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index 98ea26a2fca1..a0a2b5ca9b7d 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -242,13 +242,10 @@ ENTRY(secondary_startup_64) /* Set up %gs. * - * On SMP, %gs should point to the per-cpu area. For initial - * boot, make %gs point to the init data section. For a - * secondary CPU,initial_gs should be set to its pda address - * before the CPU runs this code. - * - * On UP, initial_gs points to PER_CPU_VAR(__pda) and doesn't - * change. + * The base of %gs always points to the bottom of the irqstack + * union. If the stack protector canary is enabled, it is + * located at %gs:40. Note that, on SMP, the boot cpu uses + * init data section till per cpu areas are set up. */ movl $MSR_GS_BASE,%ecx movq initial_gs(%rip),%rax @@ -281,7 +278,7 @@ ENTRY(secondary_startup_64) #ifdef CONFIG_SMP .quad __per_cpu_load #else - .quad PER_CPU_VAR(__pda) + .quad PER_CPU_VAR(irq_stack_union) #endif __FINITDATA |