x86 vDSO: ia32 sysenter_return
This changes the 64-bit kernel's support for the 32-bit sysenter
instruction to use stored fields rather than constants for the
user-mode return address, as the 32-bit kernel does. This adds a
sysenter_return field to struct thread_info, as 32-bit has. There
is no observable effect from this yet. It makes the assembly code
independent of the 32-bit vDSO mapping address, paving the way for
making the vDSO address vary as it does on the 32-bit kernel.
[ akpm@linux-foundation.org: build fix on !CONFIG_IA32_EMULATION ]
Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index df588f0..2499a32 100644
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -12,7 +12,6 @@
#include <asm/ia32_unistd.h>
#include <asm/thread_info.h>
#include <asm/segment.h>
-#include <asm/vsyscall32.h>
#include <asm/irqflags.h>
#include <linux/linkage.h>
@@ -104,7 +103,7 @@
pushfq
CFI_ADJUST_CFA_OFFSET 8
/*CFI_REL_OFFSET rflags,0*/
- movl $VSYSCALL32_SYSEXIT, %r10d
+ movl 8*3-THREAD_SIZE+threadinfo_sysenter_return(%rsp), %r10d
CFI_REGISTER rip,r10
pushq $__USER32_CS
CFI_ADJUST_CFA_OFFSET 8
@@ -142,6 +141,8 @@
andl $~TS_COMPAT,threadinfo_status(%r10)
/* clear IF, that popfq doesn't enable interrupts early */
andl $~0x200,EFLAGS-R11(%rsp)
+ movl RIP-R11(%rsp),%edx /* User %eip */
+ CFI_REGISTER rip,rdx
RESTORE_ARGS 1,24,1,1,1,1
popfq
CFI_ADJUST_CFA_OFFSET -8
@@ -149,8 +150,6 @@
popq %rcx /* User %esp */
CFI_ADJUST_CFA_OFFSET -8
CFI_REGISTER rsp,rcx
- movl $VSYSCALL32_SYSEXIT,%edx /* User %eip */
- CFI_REGISTER rip,rdx
TRACE_IRQS_ON
swapgs
sti /* sti only takes effect after the next instruction */