x86 vDSO: consolidate vdso32

This makes x86_64's ia32 emulation support share the sources used in the
32-bit kernel for the 32-bit vDSO and much of its setup code.

The 32-bit vDSO mapping now behaves the same on x86_64 as on native 32-bit.
The abi.syscall32 sysctl on x86_64 now takes the same values that
vm.vdso_enabled takes on the 32-bit kernel.  That is, 1 means a randomized
vDSO location, 2 means the fixed old address.  The CONFIG_COMPAT_VDSO
option is now available to make this the default setting, the same meaning
it has for the 32-bit kernel.  (This does not affect the 64-bit vDSO.)

The argument vdso32=[012] can be used on both 32-bit and 64-bit kernels to
set this paramter at boot time.  The vdso=[012] argument still does this
same thing on the 32-bit kernel.

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>

1 files changed, 10 insertions, 6 deletions

diff --git a/arch/x86/vdso/vdso32.S b/arch/x86/vdso/vdso32.S
index cab020c99c3d..1e36f72cab86 100644
--- a/arch/x86/vdso/vdso32.S
+++ b/arch/x86/vdso/vdso32.S
@@ -2,14 +2,18 @@
 
 __INITDATA
 
-        .globl vsyscall_int80_start, vsyscall_int80_end
-vsyscall_int80_start:
+        .globl vdso32_default_start, vdso32_default_end
+vdso32_default_start:
+#ifdef CONFIG_X86_32
         .incbin "arch/x86/vdso/vdso32-int80.so"
-vsyscall_int80_end:
+#else
+        .incbin "arch/x86/vdso/vdso32-syscall.so"
+#endif
+vdso32_default_end:
 
-        .globl vsyscall_sysenter_start, vsyscall_sysenter_end
-vsyscall_sysenter_start:
+        .globl vdso32_sysenter_start, vdso32_sysenter_end
+vdso32_sysenter_start:
         .incbin "arch/x86/vdso/vdso32-sysenter.so"
-vsyscall_sysenter_end:
+vdso32_sysenter_end:
 
 __FINIT