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authorAndy Lutomirski <luto@amacapital.net>2015-03-10 19:05:58 +0100
committerIngo Molnar <mingo@kernel.org>2015-03-17 09:25:26 +0100
commit3ee4298f440c81638cbb5ec06f2497fb7a9a9eb4 (patch)
treecfbe101b43f5d5b7557cbb90e3bc7b0ff04c5e5e /arch/x86/kernel/entry_32.S
parentx86/signal/64: Remove 'fs' and 'gs' from sigcontext (diff)
downloadlinux-3ee4298f440c81638cbb5ec06f2497fb7a9a9eb4.tar.xz
linux-3ee4298f440c81638cbb5ec06f2497fb7a9a9eb4.zip
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.S2
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