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, 14 insertions, 8 deletions

diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c
index 0fc5d8563e19..39356a756b28 100644
--- a/arch/x86/ia32/ia32_signal.c
+++ b/arch/x86/ia32/ia32_signal.c
@@ -31,7 +31,7 @@
 #include <asm/sigcontext32.h>
 #include <asm/fpu32.h>
 #include <asm/proto.h>
-#include <asm/vsyscall32.h>
+#include <asm/vdso.h>
 
 #define DEBUG_SIG 0
 
@@ -465,13 +465,16 @@ int ia32_setup_frame(int sig, struct k_sigaction *ka,
                         goto give_sigsegv;
         }
 
-        /* Return stub is in 32bit vsyscall page */
-        if (current->binfmt->hasvdso)
-                restorer = VSYSCALL32_SIGRETURN;
-        else
-                restorer = (void *)&frame->retcode;
-        if (ka->sa.sa_flags & SA_RESTORER)
+        if (ka->sa.sa_flags & SA_RESTORER) {
                 restorer = ka->sa.sa_restorer;
+        } else {
+                /* Return stub is in 32bit vsyscall page */
+                if (current->binfmt->hasvdso)
+                        restorer = VDSO32_SYMBOL(current->mm->context.vdso,
+                                                 sigreturn);
+                else
+                        restorer = (void *)&frame->retcode;
+        }
         err |= __put_user(ptr_to_compat(restorer), &frame->pretcode);
 
         /*
@@ -519,7 +522,7 @@ int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 {
         struct rt_sigframe __user *frame;
         struct exec_domain *ed = current_thread_info()->exec_domain;
-        void __user *restorer = VSYSCALL32_RTSIGRETURN;
+        void __user *restorer;
         int err = 0;
 
         /* __copy_to_user optimizes that into a single 8 byte store */
@@ -564,6 +567,9 @@ int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 
         if (ka->sa.sa_flags & SA_RESTORER)
                 restorer = ka->sa.sa_restorer;
+        else
+                restorer = VDSO32_SYMBOL(current->mm->context.vdso,
+                                         rt_sigreturn);
         err |= __put_user(ptr_to_compat(restorer), &frame->pretcode);
 
         /*