[PATCH v2 2/2] x86/entry/32: Fix FS and GS restore in opportunistic SYSEXIT
From: Andy Lutomirski
Date: Fri Oct 16 2015 - 18:43:41 EST
We either need to restore them before popping and thus changing ESP,
or we need to adjust the offsets. The former is simpler.
Fixes: 5f310f739b4c x86/entry/32: ("Re-implement SYSENTER using the new C path")
Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>
---
arch/x86/entry/entry_32.S | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index ba0dad937be9..e3ede42d30e2 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -315,6 +315,8 @@ 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 */
popl %eax /* skip pt_regs->cx */
popl %eax /* skip pt_regs->dx */
@@ -322,8 +324,6 @@ sysenter_past_esp:
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.
--
2.4.3
--
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