From 78b0b690f6558ed788dccafa45965325dd11ba89 Mon Sep 17 00:00:00 2001
From: James Morse <james.morse@arm.com>
Date: Tue, 29 Jan 2019 18:48:37 +0000
Subject: [PATCH] ACPI / APEI: Don't wait to serialise with oops messages when panic()ing
Git-commit: 78b0b690f6558ed788dccafa45965325dd11ba89
Patch-mainline: v5.1-rc1
References: bsc#1051510

oops_begin() exists to group printk() messages with the oops message
printed by die(). To reach this caller we know that platform firmware
took this error first, then notified the OS via NMI with a 'panic'
severity.

Don't wait for another CPU to release the die-lock before panic()ing,
our only goal is to print this fatal error and panic().

This code is always called in_nmi(), and since commit 42a0bb3f7138
("printk/nmi: generic solution for safe printk in NMI"), it has been
safe to call printk() from this context. Messages are batched in a
per-cpu buffer and printed via irq-work, or a call back from panic().

Link: https://patchwork.kernel.org/patch/10313555/
Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/acpi/apei/ghes.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index f008ba7c9ced..0c46b79e31b1 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -33,7 +33,6 @@
 #include <linux/interrupt.h>
 #include <linux/timer.h>
 #include <linux/cper.h>
-#include <linux/kdebug.h>
 #include <linux/platform_device.h>
 #include <linux/mutex.h>
 #include <linux/ratelimit.h>
@@ -949,7 +948,6 @@ static int ghes_notify_nmi(unsigned int cmd, struct pt_regs *regs)
 
 		sev = ghes_severity(ghes->estatus->error_severity);
 		if (sev >= GHES_SEV_PANIC) {
-			oops_begin();
 			ghes_print_queued_estatus();
 			__ghes_panic(ghes);
 		}
-- 
2.16.4