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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 e16321709c ("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>
This commit is contained in:
George Beshers 2015-09-12 21:51:05 -05:00 committed by Ingo Molnar
parent 6ff33f3902
commit 7c52198b9c
1 changed files with 1 additions and 1 deletions
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2
arch/x86/include/asm/uv/uv_hub.h
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@ -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)