[PATCH] powerpc vdso updates

This patch cleans up some locking & error handling in the ppc vdso and
moves the vdso base pointer from the thread struct to the mm context
where it more logically belongs. It brings the powerpc implementation
closer to Ingo's new x86 one and also adds an arch_vma_name() function
allowing to print [vsdo] in /proc/<pid>/maps if Ingo's x86 vdso patch is
also applied.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
index 27f65b9..23ba69c 100644
--- a/arch/powerpc/kernel/signal_64.c
+++ b/arch/powerpc/kernel/signal_64.c
@@ -394,8 +394,8 @@
 	current->thread.fpscr.val = 0;
 
 	/* Set up to return from userspace. */
-	if (vdso64_rt_sigtramp && current->thread.vdso_base) {
-		regs->link = current->thread.vdso_base + vdso64_rt_sigtramp;
+	if (vdso64_rt_sigtramp && current->mm->context.vdso_base) {
+		regs->link = current->mm->context.vdso_base + vdso64_rt_sigtramp;
 	} else {
 		err |= setup_trampoline(__NR_rt_sigreturn, &frame->tramp[0]);
 		if (err)