powerpc: Fix various issues with return to userspace

We have a few problems when returning to userspace. This is a
quick set of fixes for 3.3, I'll look into a more comprehensive
rework for 3.4. This fixes:

 - We kept interrupts soft-disabled when schedule'ing or calling
do_signal when returning to userspace as a result of a hardware
interrupt.

 - Rename do_signal to do_notify_resume like all other archs (and
do_signal_pending back to do_signal, which it was before Roland
changed it).

 - Add the missing call to key_replace_session_keyring() to
do_notify_resume().
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---

arch/powerpc/kernel/entry_32.S

@@ -1213,7 +1213,7 @@ do_user_signal:			/* r10 contains MSR_KERNEL here */
 	stw	r3,_TRAP(r1)
 2:	addi	r3,r1,STACK_FRAME_OVERHEAD
 	mr	r4,r9
-	bl	do_signal
+	bl	do_notify_resume
 	REST_NVGPRS(r1)
 	b	recheck
 

arch/powerpc/kernel/entry_64.S

@@ -751,12 +751,16 @@ user_work:
 
 	andi.	r0,r4,_TIF_NEED_RESCHED
 	beq	1f
+	li	r5,1
+	TRACE_AND_RESTORE_IRQ(r5);
 	bl	.schedule
 	b	.ret_from_except_lite
 
 1:	bl	.save_nvgprs
+	li	r5,1
+	TRACE_AND_RESTORE_IRQ(r5);
 	addi	r3,r1,STACK_FRAME_OVERHEAD
-	bl	.do_signal
+	bl	.do_notify_resume
 	b	.ret_from_except
 
 unrecov_restore:

arch/powerpc/kernel/signal.c

@@ -11,6 +11,7 @@
 
 #include <linux/tracehook.h>
 #include <linux/signal.h>
+#include <linux/key.h>
 #include <asm/hw_breakpoint.h>
 #include <asm/uaccess.h>
 #include <asm/unistd.h>
@@ -113,8 +114,9 @@ static void check_syscall_restart(struct pt_regs *regs, struct k_sigaction *ka,
 	}
 }
 
-static int do_signal_pending(sigset_t *oldset, struct pt_regs *regs)
+static int do_signal(struct pt_regs *regs)
 {
+	sigset_t *oldset;
 	siginfo_t info;
 	int signr;
 	struct k_sigaction ka;
@@ -123,7 +125,7 @@ static int do_signal_pending(sigset_t *oldset, struct pt_regs *regs)
 
 	if (current_thread_info()->local_flags & _TLF_RESTORE_SIGMASK)
 		oldset = &current->saved_sigmask;
-	else if (!oldset)
+	else
 		oldset = &current->blocked;
 
 	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
@@ -191,14 +193,16 @@ static int do_signal_pending(sigset_t *oldset, struct pt_regs *regs)
 	return ret;
 }
 
-void do_signal(struct pt_regs *regs, unsigned long thread_info_flags)
+void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags)
 {
 	if (thread_info_flags & _TIF_SIGPENDING)
-		do_signal_pending(NULL, regs);
+		do_signal(regs);
 
 	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 		clear_thread_flag(TIF_NOTIFY_RESUME);
 		tracehook_notify_resume(regs);
+		if (current->replacement_session_keyring)
+			key_replace_session_keyring();
 	}
 }
 

arch/powerpc/kernel/signal.h

@@ -12,7 +12,7 @@
 
 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
 
-extern void do_signal(struct pt_regs *regs, unsigned long thread_info_flags);
+extern void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags);
 
 extern void __user * get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
 				  size_t frame_size, int is_32);