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authorAndy Lutomirski <luto@kernel.org>2015-10-16 15:42:55 -0700
committerIngo Molnar <mingo@kernel.org>2015-10-18 12:11:16 +0200
commit3bd29515d1cad26fa85a1a9b442de8816c1f5c54 (patch)
tree89bc78824c420dafce56d7056571fa11384b03b8 /arch/x86/entry
parent657c1eea0019e80685a84cbb1919794243a187c9 (diff)
downloadop-kernel-dev-3bd29515d1cad26fa85a1a9b442de8816c1f5c54.zip
op-kernel-dev-3bd29515d1cad26fa85a1a9b442de8816c1f5c54.tar.gz
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: Borislav Petkov <bp@suse.de> Signed-off-by: Andy 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: 5f310f739b4c 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: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/entry')
-rw-r--r--arch/x86/entry/entry_32.S4
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index 4f97f49..3eb572e 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -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.
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