4 files changed, 60 insertions, 35 deletions

diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index f8a7a1a1a9f4..ef2074c3e906 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -588,23 +588,19 @@ _GLOBAL(ret_from_except_lite)
 fast_exc_return_irq:
 restore:
 	/*
-	 * This is the main kernel exit path, we first check if we
-	 * have to change our interrupt state.
+	 * This is the main kernel exit path. First we check if we
+	 * are about to re-enable interrupts
 	 */
 	ld	r5,SOFTE(r1)
 	lbz	r6,PACASOFTIRQEN(r13)
-	cmpwi	cr1,r5,0
-	cmpw	cr0,r5,r6
-	beq	cr0,4f
+	cmpwi	cr0,r5,0
+	beq	restore_irq_off
 
-	/* We do, handle disable first, which is easy */
-	bne	cr1,3f;
- 	li	r0,0
-	stb	r0,PACASOFTIRQEN(r13);
-	TRACE_DISABLE_INTS
-	b	4f
+	/* We are enabling, were we already enabled ? Yes, just return */
+	cmpwi	cr0,r6,1
+	beq	cr0,do_restore
 
-3:	/*
+	/*
 	 * We are about to soft-enable interrupts (we are hard disabled
 	 * at this point). We check if there's anything that needs to
 	 * be replayed first.
@@ -626,7 +622,7 @@ restore_no_replay:
 	/*
 	 * Final return path. BookE is handled in a different file
 	 */
-4:
+do_restore:
 #ifdef CONFIG_PPC_BOOK3E
 	b	.exception_return_book3e
 #else
@@ -700,6 +696,25 @@ fast_exception_return:
 #endif /* CONFIG_PPC_BOOK3E */
 
 	/*
+	 * We are returning to a context with interrupts soft disabled.
+	 *
+	 * However, we may also about to hard enable, so we need to
+	 * make sure that in this case, we also clear PACA_IRQ_HARD_DIS
+	 * or that bit can get out of sync and bad things will happen
+	 */
+restore_irq_off:
+	ld	r3,_MSR(r1)
+	lbz	r7,PACAIRQHAPPENED(r13)
+	andi.	r0,r3,MSR_EE
+	beq	1f
+	rlwinm	r7,r7,0,~PACA_IRQ_HARD_DIS
+	stb	r7,PACAIRQHAPPENED(r13)
+1:	li	r0,0
+	stb	r0,PACASOFTIRQEN(r13);
+	TRACE_DISABLE_INTS
+	b	do_restore
+
+	/*
 	 * Something did happen, check if a re-emit is needed
 	 * (this also clears paca->irq_happened)
 	 */
@@ -748,6 +763,9 @@ restore_check_irq_replay:
 #endif /* CONFIG_PPC_BOOK3E */
 1:	b	.ret_from_except /* What else to do here ? */
  
+
+
+3:
 do_work:
 #ifdef CONFIG_PREEMPT
 	andi.	r0,r3,MSR_PR	/* Returning to user mode? */
@@ -767,16 +785,6 @@ do_work:
 	SOFT_DISABLE_INTS(r3,r4)
 1:	bl	.preempt_schedule_irq
 
-	/* Hard-disable interrupts again (and update PACA) */
-#ifdef CONFIG_PPC_BOOK3E
-	wrteei	0
-#else
-	ld	r10,PACAKMSR(r13) /* Get kernel MSR without EE */
-	mtmsrd	r10,1
-#endif /* CONFIG_PPC_BOOK3E */
-	li	r0,PACA_IRQ_HARD_DIS
-	stb	r0,PACAIRQHAPPENED(r13)
-
 	/* Re-test flags and eventually loop */
 	clrrdi	r9,r1,THREAD_SHIFT
 	ld	r4,TI_FLAGS(r9)
@@ -787,14 +795,6 @@ do_work:
 user_work:
 #endif /* CONFIG_PREEMPT */
 
-	/* Enable interrupts */
-#ifdef CONFIG_PPC_BOOK3E
-	wrteei	1
-#else
-	ori	r10,r10,MSR_EE
-	mtmsrd	r10,1
-#endif /* CONFIG_PPC_BOOK3E */
-
 	andi.	r0,r4,_TIF_NEED_RESCHED
 	beq	1f
 	bl	.restore_interrupts
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index cb705fdbb458..8f880bc77c56 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -768,8 +768,8 @@ alignment_common:
 	std	r3,_DAR(r1)
 	std	r4,_DSISR(r1)
 	bl	.save_nvgprs
+	DISABLE_INTS
 	addi	r3,r1,STACK_FRAME_OVERHEAD
-	ENABLE_INTS
 	bl	.alignment_exception
 	b	.ret_from_except
 
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 43eb74fcedde..641da9e868ce 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -229,6 +229,19 @@ notrace void arch_local_irq_restore(unsigned long en)
 	 */
 	if (unlikely(irq_happened != PACA_IRQ_HARD_DIS))
 		__hard_irq_disable();
+#ifdef CONFIG_TRACE_IRQFLAG
+	else {
+		/*
+		 * We should already be hard disabled here. We had bugs
+		 * where that wasn't the case so let's dbl check it and
+		 * warn if we are wrong. Only do that when IRQ tracing
+		 * is enabled as mfmsr() can be costly.
+		 */
+		if (WARN_ON(mfmsr() & MSR_EE))
+			__hard_irq_disable();
+	}
+#endif /* CONFIG_TRACE_IRQFLAG */
+
 	set_soft_enabled(0);
 
 	/*
@@ -260,11 +273,17 @@ EXPORT_SYMBOL(arch_local_irq_restore);
  * if they are currently disabled. This is typically called before
  * schedule() or do_signal() when returning to userspace. We do it
  * in C to avoid the burden of dealing with lockdep etc...
+ *
+ * NOTE: This is called with interrupts hard disabled but not marked
+ * as such in paca->irq_happened, so we need to resync this.
  */
 void restore_interrupts(void)
 {
-	if (irqs_disabled())
+	if (irqs_disabled()) {
+		local_paca->irq_happened |= PACA_IRQ_HARD_DIS;
 		local_irq_enable();
+	} else
+		__hard_irq_enable();
 }
 
 #endif /* CONFIG_PPC64 */
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 6aa0c663e247..158972341a2d 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -248,7 +248,7 @@ void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr)
 				   addr, regs->nip, regs->link, code);
 	}
 
-	if (!arch_irq_disabled_regs(regs))
+	if (arch_irqs_disabled() && !arch_irq_disabled_regs(regs))
 		local_irq_enable();
 
 	memset(&info, 0, sizeof(info));
@@ -1019,7 +1019,9 @@ void __kprobes program_check_exception(struct pt_regs *regs)
 		return;
 	}
 
-	local_irq_enable();
+	/* We restore the interrupt state now */
+	if (!arch_irq_disabled_regs(regs))
+		local_irq_enable();
 
 #ifdef CONFIG_MATH_EMULATION
 	/* (reason & REASON_ILLEGAL) would be the obvious thing here,
@@ -1069,6 +1071,10 @@ void alignment_exception(struct pt_regs *regs)
 {
 	int sig, code, fixed = 0;
 
+	/* We restore the interrupt state now */
+	if (!arch_irq_disabled_regs(regs))
+		local_irq_enable();
+
 	/* we don't implement logging of alignment exceptions */
 	if (!(current->thread.align_ctl & PR_UNALIGN_SIGBUS))
 		fixed = fix_alignment(regs);