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authorRoland McGrath <roland@redhat.com>2008-01-30 13:30:43 +0100
committerIngo Molnar <mingo@elte.hu>2008-01-30 13:30:43 +0100
commit36197c92a20c142fc2a068e0366053d770fa0096 (patch)
tree796f377cadc86bb9cad36090698f6bbaec0ca0f1 /arch/x86/ia32
parent0aa97fb22624f18e5925d702ab0364d3838cfd91 (diff)
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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>
Diffstat (limited to 'arch/x86/ia32')
-rw-r--r--arch/x86/ia32/ia32entry.S7
-rw-r--r--arch/x86/ia32/syscall32.c4
2 files changed, 7 insertions, 4 deletions
diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index df588f0f76e1..2499a324feaa 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 @@ ENTRY(ia32_sysenter_target)
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 @@ sysenter_do_call:
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 @@ sysenter_do_call:
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 */
diff --git a/arch/x86/ia32/syscall32.c b/arch/x86/ia32/syscall32.c
index d751d96c2ef2..98ff99f5b59a 100644
--- a/arch/x86/ia32/syscall32.c
+++ b/arch/x86/ia32/syscall32.c
@@ -46,6 +46,10 @@ int syscall32_setup_pages(struct linux_binprm *bprm, int exstack)
VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC|
VM_ALWAYSDUMP,
syscall32_pages);
+ if (ret == 0) {
+ current->mm->context.vdso = (void __user *)VSYSCALL32_BASE;
+ current_thread_info()->sysenter_return = VSYSCALL32_SYSEXIT;
+ }
up_write(&mm->mmap_sem);
return ret;
}