[v2 05/12] powerpc/mce: Allow notifier callback to handle MCE

[Santosh Sivaraj]

From: Reza Arbab <arbab at linux.ibm.com>

If a notifier returns NOTIFY_STOP, consider the MCE handled, just as we
do when machine_check_early() returns 1.

Signed-off-by: Reza Arbab <arbab at linux.ibm.com>
---
 arch/powerpc/include/asm/asm-prototypes.h |  2 +-
 arch/powerpc/include/asm/mce.h            |  3 +-
 arch/powerpc/kernel/exceptions-64s.S      |  3 ++
 arch/powerpc/kernel/mce.c                 | 37 ++++++++++++++++++-----
 4 files changed, 35 insertions(+), 10 deletions(-)

diff --git a/arch/powerpc/include/asm/asm-prototypes.h b/arch/powerpc/include/asm/asm-prototypes.h
index f66f26ef3ce0..49ee8f08de2a 100644
--- a/arch/powerpc/include/asm/asm-prototypes.h
+++ b/arch/powerpc/include/asm/asm-prototypes.h
@@ -72,7 +72,7 @@ void machine_check_exception(struct pt_regs *regs);
 void emulation_assist_interrupt(struct pt_regs *regs);
 long do_slb_fault(struct pt_regs *regs, unsigned long ea);
 void do_bad_slb_fault(struct pt_regs *regs, unsigned long ea, long err);
-void machine_check_notify(struct pt_regs *regs);
+long machine_check_notify(struct pt_regs *regs);
 
 /* signals, syscalls and interrupts */
 long sys_swapcontext(struct ucontext __user *old_ctx,
diff --git a/arch/powerpc/include/asm/mce.h b/arch/powerpc/include/asm/mce.h
index 948bef579086..240dd1fdfe35 100644
--- a/arch/powerpc/include/asm/mce.h
+++ b/arch/powerpc/include/asm/mce.h
@@ -122,7 +122,8 @@ struct machine_check_event {
 			enum MCE_UeErrorType ue_error_type:8;
 			u8		effective_address_provided;
 			u8		physical_address_provided;
-			u8		reserved_1[5];
+			u8		process_event;
+			u8		reserved_1[4];
 			u64		effective_address;
 			u64		physical_address;
 			u8		reserved_2[8];
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 2e56014fca21..c83e38a403fd 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -460,6 +460,9 @@ EXC_COMMON_BEGIN(machine_check_handle_early)
 
 	addi	r3,r1,STACK_FRAME_OVERHEAD
 	bl	machine_check_notify
+	ld	r11,RESULT(r1)
+	or	r3,r3,r11
+	std	r3,RESULT(r1)
 
 	ld	r12,_MSR(r1)
 BEGIN_FTR_SECTION
diff --git a/arch/powerpc/kernel/mce.c b/arch/powerpc/kernel/mce.c
index 0ab171b41ede..4a37928ab30e 100644
--- a/arch/powerpc/kernel/mce.c
+++ b/arch/powerpc/kernel/mce.c
@@ -157,6 +157,8 @@ void save_mce_event(struct pt_regs *regs, long handled,
 			mce->u.ue_error.physical_address_provided = true;
 			mce->u.ue_error.physical_address = phys_addr;
 		}
+
+		mce->u.ue_error.process_event = true;
 	}
 	return;
 }
@@ -241,6 +243,10 @@ void machine_check_queue_event(void)
 	if (!get_mce_event(&evt, MCE_EVENT_RELEASE))
 		return;
 
+	if (evt.error_type == MCE_ERROR_TYPE_UE &&
+	    !evt.u.ue_error.process_event)
+		return;
+
 	index = __this_cpu_inc_return(mce_queue_count) - 1;
 	/* If queue is full, just return for now. */
 	if (index >= MAX_MC_EVT) {
@@ -647,16 +653,31 @@ long hmi_exception_realmode(struct pt_regs *regs)
 	return 1;
 }
 
-void machine_check_notify(struct pt_regs *regs)
+long machine_check_notify(struct pt_regs *regs)
 {
-	struct machine_check_event evt;
+	int index = __this_cpu_read(mce_nest_count) - 1;
+	struct machine_check_event *evt;
+	int rc;
 
-	if (!get_mce_event(&evt, MCE_EVENT_DONTRELEASE))
-		return;
+	if (index < 0 || index >= MAX_MC_EVT)
+		return 0;
 
-	blocking_notifier_call_chain(&mce_notifier_list, 0, &evt);
+	evt = this_cpu_ptr(&mce_event[index]);
 
-	if (evt.error_type == MCE_ERROR_TYPE_UE &&
-	    evt.u.ue_error.physical_address_provided)
-		machine_check_ue_event(&evt);
+	rc = blocking_notifier_call_chain(&mce_notifier_list, 0, evt);
+	if (rc & NOTIFY_STOP_MASK) {
+		if (evt->error_type == MCE_ERROR_TYPE_UE)
+			evt->u.ue_error.process_event = false;
+
+		if ((rc & NOTIFY_STOP_MASK) && (regs->msr & MSR_RI))
+			evt->disposition = MCE_DISPOSITION_RECOVERED;
+
+		return 1;
+	}
+
+	if (evt->error_type == MCE_ERROR_TYPE_UE &&
+	    evt->u.ue_error.physical_address_provided)
+		machine_check_ue_event(evt);
+
+	return 0;
 }
-- 
2.20.1