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| author | Andy Lutomirski <luto@amacapital.net> | 2015-03-10 21:05:58 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-03-17 11:25:26 +0300 |
| commit | 3ee4298f440c81638cbb5ec06f2497fb7a9a9eb4 (patch) | |
| tree | cfbe101b43f5d5b7557cbb90e3bc7b0ff04c5e5e /arch/x86/include/asm/processor.h | |
| parent | 9a036b93a344235b7899401d04e97c34f3a2554c (diff) | |
| download | linux-3ee4298f440c81638cbb5ec06f2497fb7a9a9eb4.tar.xz | |
x86/asm/entry: Create and use a 'TOP_OF_KERNEL_STACK_PADDING' macro
x86_32, unlike x86_64, pads the top of the kernel stack, because the
hardware stack frame formats are variable in size.
Document this padding and give it a name.
This should make no change whatsoever to the compiled kernel
image. It also doesn't fix any of the current bugs in this area.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Acked-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/02bf2f54b8dcb76a62a142b6dfe07d4ef7fc582e.1426009661.git.luto@amacapital.net
[ Fixed small details, such as a missed magic constant in entry_32.S pointed out by Denys Vlasenko. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/include/asm/processor.h')
| -rw-r--r-- | arch/x86/include/asm/processor.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 48a61c1c626e..88d9aa745898 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -849,7 +849,8 @@ extern unsigned long thread_saved_pc(struct task_struct *tsk); #define task_pt_regs(task) \ ({ \ struct pt_regs *__regs__; \ - __regs__ = (struct pt_regs *)(KSTK_TOP(task_stack_page(task))-8); \ + __regs__ = (struct pt_regs *)(KSTK_TOP(task_stack_page(task)) - \ + TOP_OF_KERNEL_STACK_PADDING); \ __regs__ - 1; \ }) |