From b077ffb3b767c3efb44d00b998385a9cb127255c Mon Sep 17 00:00:00 2001
From: Alexey Dobriyan <adobriyan@openvz.org>
Date: Fri, 16 Feb 2007 01:48:11 -0800
Subject: rdmsr_on_cpu, wrmsr_on_cpu

There was OpenVZ specific bug rendering some cpufreq drivers unusable on SMP.
In short, when cpufreq code thinks it confined itself to needed cpu by means
of set_cpus_allowed() to execute rdmsr, some "virtual cpu" feature can migrate
process to anywhere.  This triggers bugons and does wrong things in general.

This got fixed by introducing rdmsr_on_cpu and wrmsr_on_cpu executing rdmsr
and wrmsr on given physical cpu by means of smp_call_function_single().

Dave Jones mentioned cpufreq might be not only user of rdmsr_on_cpu() and
wrmsr_on_cpu(), so I'm putting them into arch/{i386,x86_64}/lib/ .

Signed-off-by: Alexey Dobriyan <adobriyan@openvz.org>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dave Jones <davej@redhat.com>
---
 arch/x86_64/lib/Makefile     | 2 +-
 arch/x86_64/lib/msr-on-cpu.c | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)
 create mode 100644 arch/x86_64/lib/msr-on-cpu.c

(limited to 'arch/x86_64/lib')

diff --git a/arch/x86_64/lib/Makefile b/arch/x86_64/lib/Makefile
index b78d417..0a43f07 100644
--- a/arch/x86_64/lib/Makefile
+++ b/arch/x86_64/lib/Makefile
@@ -4,7 +4,7 @@
 
 CFLAGS_csum-partial.o := -funroll-loops
 
-obj-y := io.o iomap_copy.o
+obj-y := io.o iomap_copy.o msr-on-cpu.o
 
 lib-y := csum-partial.o csum-copy.o csum-wrappers.o delay.o \
 	usercopy.o getuser.o putuser.o  \
diff --git a/arch/x86_64/lib/msr-on-cpu.c b/arch/x86_64/lib/msr-on-cpu.c
new file mode 100644
index 0000000..47e0ec4
--- /dev/null
+++ b/arch/x86_64/lib/msr-on-cpu.c
@@ -0,0 +1 @@
+#include "../../i386/lib/msr-on-cpu.c"
-- 
cgit v1.1


From b44755cfaa72e7ed3d831a946bb4e7dfe7548966 Mon Sep 17 00:00:00 2001
From: Adrian Bunk <bunk@stusta.de>
Date: Tue, 20 Feb 2007 01:07:13 +0100
Subject: {rd,wr}msr_on_cpu SMP=n optimization

Let's save a few bytes in the CONFIG_SMP=n case.

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Dave Jones <davej@redhat.com>
---
 arch/x86_64/lib/Makefile | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

(limited to 'arch/x86_64/lib')

diff --git a/arch/x86_64/lib/Makefile b/arch/x86_64/lib/Makefile
index 0a43f07..43d051f 100644
--- a/arch/x86_64/lib/Makefile
+++ b/arch/x86_64/lib/Makefile
@@ -4,7 +4,8 @@
 
 CFLAGS_csum-partial.o := -funroll-loops
 
-obj-y := io.o iomap_copy.o msr-on-cpu.o
+obj-y := io.o iomap_copy.o
+obj-$(CONFIG_SMP)	+= msr-on-cpu.o
 
 lib-y := csum-partial.o csum-copy.o csum-wrappers.o delay.o \
 	usercopy.o getuser.o putuser.o  \
-- 
cgit v1.1