x86/platform/uv: Insert per_cpu accessor function on uv_hub_nmi

George Beshers · Ingo Molnar · commit 7c52198b9c36 · 2015-09-13T09:27:53.000+02:00
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 e163217 ("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>
diff --git 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)
 
