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Commit ff8287f3 authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Ingo Molnar
Browse files

x86/asm/entry/32: Improve a TOP_OF_KERNEL_STACK_PADDING comment 



At Denys' request, clean up the comment describing stack padding
in the 32-bit sysenter path.

No code changes.

Signed-off-by: default avatarAndy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/41fee7bb8490ae840fe7ef2699f9c2feb932e729.1428002830.git.luto@kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent d9dc64f3

arch/x86/kernel/entry_32.S

+6 −3
Original line number Diff line number Diff line
@@ -395,8 +395,11 @@ sysenter_past_esp: 
	/*CFI_REL_OFFSET cs, 0*/

	/*

	 * Push current_thread_info()->sysenter_return to the stack.

	 * A tiny bit of offset fixup is necessary - 4*4 means the 4 words

	 * pushed above; +8 corresponds to copy_thread's esp0 setting.

	 * A tiny bit of offset fixup is necessary: TI_sysenter_return

	 * is relative to thread_info, which is at the bottom of the

	 * kernel stack page.  4*4 means the 4 words pushed above;

	 * TOP_OF_KERNEL_STACK_PADDING takes us to the top of the stack;

	 * and THREAD_SIZE takes us to the bottom.

	 */

	pushl_cfi ((TI_sysenter_return) - THREAD_SIZE + TOP_OF_KERNEL_STACK_PADDING + 4*4)(%esp)

	CFI_REL_OFFSET eip, 0