From 7c52198b9c36001d47e11d50f7f1556805c5c3e3 Mon Sep 17 00:00:00 2001
From: George Beshers <gbeshers@sgi.com>
Date: Sat, 12 Sep 2015 21:51:05 -0500
Subject: [PATCH] x86/platform/uv: Insert per_cpu accessor function on
uv_hub_nmi
UV: NMI: insert this_cpu_read accessor function on uv_hub_nmi.
On SGI UV systems a 'power nmi' command from the CMC causes
all processors to drop into uv_handle_nmi(). With the 4.0
kernel this results in
BUG: unable to handle kernel paging request
The bug is caused by the current code trying to use the PER_CPU
variable uv_cpu_nmi.hub without an appropriate accessor
function. That oversight occurred in
commit e16321709c82 ("uv: Replace __get_cpu_var")
Author: Christoph Lameter <cl@linux.com>
Date: Sun Aug 17 12:30:41 2014 -0500
This patch inserts this_cpu_read() in the uv_hub_nmi macro
restoring the intended functionality.
Signed-off-by: George Beshers <gbeshers@sgi.com>
Acked-by: Mike Travis <travis@sgi.com>
Cc: Alex Thorlton <athorlton@sgi.com>
Cc: Dimitri Sivanich <sivanich@sgi.com>
Cc: Hedi Berriche <hedi@sgi.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russ Anderson <rja@sgi.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/include/asm/uv/uv_hub.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/uv/uv_hub.h b/arch/x86/include/asm/uv/uv_hub.h
index a00ad8f2a6578f..ea7074784cc471 100644
--- a/arch/x86/include/asm/uv/uv_hub.h
+++ b/arch/x86/include/asm/uv/uv_hub.h
@@ -609,7 +609,7 @@ struct uv_cpu_nmi_s {
DECLARE_PER_CPU(struct uv_cpu_nmi_s, uv_cpu_nmi);
-#define uv_hub_nmi (uv_cpu_nmi.hub)
+#define uv_hub_nmi this_cpu_read(uv_cpu_nmi.hub)
#define uv_cpu_nmi_per(cpu) (per_cpu(uv_cpu_nmi, cpu))
#define uv_hub_nmi_per(cpu) (uv_cpu_nmi_per(cpu).hub)
--
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