diff options
| author | Andy Lutomirski <luto@amacapital.net> | 2015-03-10 11:05:58 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-03-17 09:25:26 +0100 |
| commit | 3ee4298f440c81638cbb5ec06f2497fb7a9a9eb4 (patch) | |
| tree | cfbe101b43f5d5b7557cbb90e3bc7b0ff04c5e5e /arch/x86/kernel/entry_32.S | |
| parent | 9a036b93a344235b7899401d04e97c34f3a2554c (diff) | |
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/kernel/entry_32.S')
| -rw-r--r-- | arch/x86/kernel/entry_32.S | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S index e33ba51b1069..4c8cc34e6d68 100644 --- a/arch/x86/kernel/entry_32.S +++ b/arch/x86/kernel/entry_32.S @@ -398,7 +398,7 @@ sysenter_past_esp: * A tiny bit of offset fixup is necessary - 4*4 means the 4 words * pushed above; +8 corresponds to copy_thread's esp0 setting. */ - pushl_cfi ((TI_sysenter_return)-THREAD_SIZE+8+4*4)(%esp) + pushl_cfi ((TI_sysenter_return)-THREAD_SIZE+TOP_OF_KERNEL_STACK_PADDING+4*4)(%esp) CFI_REL_OFFSET eip, 0 pushl_cfi %eax |