[PATCH] Fix CONFIG_COMPAT_VDSO
I wouldn't mind if CONFIG_COMPAT_VDSO went away entirely. But if it's there,
it should work properly. Currently it's quite haphazard: both real vma and
fixmap are mapped, both are put in the two different AT_* slots, sysenter
returns to the vma address rather than the fixmap address, and core dumps yet
are another story.
This patch makes CONFIG_COMPAT_VDSO disable the real vma and use the fixmap
area consistently. This makes it actually compatible with what the old vdso
implementation did.
Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/i386/kernel/entry.S b/arch/i386/kernel/entry.S
index 06461b8..5e47683 100644
--- a/arch/i386/kernel/entry.S
+++ b/arch/i386/kernel/entry.S
@@ -302,12 +302,16 @@
pushl $(__USER_CS)
CFI_ADJUST_CFA_OFFSET 4
/*CFI_REL_OFFSET cs, 0*/
+#ifndef CONFIG_COMPAT_VDSO
/*
* Push current_thread_info()->sysenter_return to the stack.
* A tiny bit of offset fixup is necessary - 4*4 means the 4 words
* pushed above; +8 corresponds to copy_thread's esp0 setting.
*/
pushl (TI_sysenter_return-THREAD_SIZE+8+4*4)(%esp)
+#else
+ pushl $SYSENTER_RETURN
+#endif
CFI_ADJUST_CFA_OFFSET 4
CFI_REL_OFFSET eip, 0
diff --git a/arch/i386/kernel/sysenter.c b/arch/i386/kernel/sysenter.c
index 7de9117..454d12d 100644
--- a/arch/i386/kernel/sysenter.c
+++ b/arch/i386/kernel/sysenter.c
@@ -100,6 +100,7 @@
return 0;
}
+#ifndef CONFIG_COMPAT_VDSO
static struct page *syscall_nopage(struct vm_area_struct *vma,
unsigned long adr, int *type)
{
@@ -187,3 +188,4 @@
{
return 0;
}
+#endif