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Commit 3bd29515 authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Ingo Molnar
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x86/entry/32: Fix FS and GS restore in opportunistic SYSEXIT 



We either need to restore them before popping and thus changing
ESP, or we need to adjust the offsets.  The former is simpler.

Reported-and-tested-by: default avatarBorislav Petkov <bp@suse.de>
Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
Cc: Andy 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: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 5f310f73 x86/entry/32: ("Re-implement SYSENTER using the new C path")
Link: http://lkml.kernel.org/r/461e5c7d8fa3821529893a4893ac9c4bc37f9e17.1445035014.git.luto@kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 657c1eea

arch/x86/entry/entry_32.S

+2 −2
Original line number Diff line number Diff line
@@ -315,14 +315,14 @@ sysenter_past_esp: 
	TRACE_IRQS_ON			/* User mode traces as IRQs on. */

	movl	PT_EIP(%esp), %edx	/* pt_regs->ip */

	movl	PT_OLDESP(%esp), %ecx	/* pt_regs->sp */

1:	mov	PT_FS(%esp), %fs

	PTGS_TO_GS

	popl	%ebx			/* pt_regs->bx */

	addl	$2*4, %esp		/* skip pt_regs->cx and pt_regs->dx */

	popl	%esi			/* pt_regs->si */

	popl	%edi			/* pt_regs->di */

	popl	%ebp			/* pt_regs->bp */

	popl	%eax			/* pt_regs->ax */

1:	mov	PT_FS(%esp), %fs

	PTGS_TO_GS



	/*

	 * Return back to the vDSO, which will pop ecx and edx.