The patch titled
rdmsr_on_cpu, wrmsr_on_cpu
has been removed from the -mm tree. Its filename was
rdmsr_on_cpu-wrmsr_on_cpu.patch
This patch was dropped because it is obsolete
------------------------------------------------------
Subject: rdmsr_on_cpu, wrmsr_on_cpu
From: Alexey Dobriyan <adobriyan@xxxxxxxxxx>
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@xxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxx>
Acked-by: Dave Jones <davej@xxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/i386/lib/Makefile | 2
arch/i386/lib/msr-on-cpu.c | 70 +++++++++++++++++++++++++++++++++
arch/x86_64/lib/Makefile | 2
arch/x86_64/lib/msr-on-cpu.c | 1
include/asm-i386/msr.h | 3 +
include/asm-x86_64/msr.h | 2
6 files changed, 79 insertions(+), 1 deletion(-)
diff -puN arch/i386/lib/Makefile~rdmsr_on_cpu-wrmsr_on_cpu arch/i386/lib/Makefile
--- a/arch/i386/lib/Makefile~rdmsr_on_cpu-wrmsr_on_cpu
+++ a/arch/i386/lib/Makefile
@@ -7,3 +7,5 @@ lib-y = checksum.o delay.o usercopy.o ge
bitops.o semaphore.o
lib-$(CONFIG_X86_USE_3DNOW) += mmx.o
+
+obj-y = msr-on-cpu.o
diff -puN /dev/null arch/i386/lib/msr-on-cpu.c
--- /dev/null
+++ a/arch/i386/lib/msr-on-cpu.c
@@ -0,0 +1,70 @@
+#include <linux/module.h>
+#include <linux/preempt.h>
+#include <linux/smp.h>
+#include <asm/msr.h>
+
+#ifdef CONFIG_SMP
+struct msr_info {
+ u32 msr_no;
+ u32 l, h;
+};
+
+static void __rdmsr_on_cpu(void *info)
+{
+ struct msr_info *rv = info;
+
+ rdmsr(rv->msr_no, rv->l, rv->h);
+}
+
+void rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
+{
+ preempt_disable();
+ if (smp_processor_id() == cpu)
+ rdmsr(msr_no, *l, *h);
+ else {
+ struct msr_info rv;
+
+ rv.msr_no = msr_no;
+ smp_call_function_single(cpu, __rdmsr_on_cpu, &rv, 0, 1);
+ *l = rv.l;
+ *h = rv.h;
+ }
+ preempt_enable();
+}
+
+static void __wrmsr_on_cpu(void *info)
+{
+ struct msr_info *rv = info;
+
+ wrmsr(rv->msr_no, rv->l, rv->h);
+}
+
+void wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
+{
+ preempt_disable();
+ if (smp_processor_id() == cpu)
+ wrmsr(msr_no, l, h);
+ else {
+ struct msr_info rv;
+
+ rv.msr_no = msr_no;
+ rv.l = l;
+ rv.h = h;
+ smp_call_function_single(cpu, __wrmsr_on_cpu, &rv, 0, 1);
+ }
+ preempt_enable();
+}
+#else
+void rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
+{
+ rdmsr(msr_no, *l, *h);
+}
+
+void wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
+{
+ wrmsr(msr_no, l, h);
+}
+#endif
+
+EXPORT_SYMBOL(rdmsr_on_cpu);
+EXPORT_SYMBOL(wrmsr_on_cpu);
diff -puN arch/x86_64/lib/Makefile~rdmsr_on_cpu-wrmsr_on_cpu arch/x86_64/lib/Makefile
--- a/arch/x86_64/lib/Makefile~rdmsr_on_cpu-wrmsr_on_cpu
+++ a/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 -puN /dev/null arch/x86_64/lib/msr-on-cpu.c
--- /dev/null
+++ a/arch/x86_64/lib/msr-on-cpu.c
@@ -0,0 +1 @@
+#include "../../i386/lib/msr-on-cpu.c"
diff -puN include/asm-i386/msr.h~rdmsr_on_cpu-wrmsr_on_cpu include/asm-i386/msr.h
--- a/include/asm-i386/msr.h~rdmsr_on_cpu-wrmsr_on_cpu
+++ a/include/asm-i386/msr.h
@@ -83,6 +83,9 @@ static inline void wrmsrl (unsigned long
: "c" (counter))
#endif /* !CONFIG_PARAVIRT */
+void rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h);
+void wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h);
+
/* symbolic names for some interesting MSRs */
/* Intel defined MSRs. */
#define MSR_IA32_P5_MC_ADDR 0
diff -puN include/asm-x86_64/msr.h~rdmsr_on_cpu-wrmsr_on_cpu include/asm-x86_64/msr.h
--- a/include/asm-x86_64/msr.h~rdmsr_on_cpu-wrmsr_on_cpu
+++ a/include/asm-x86_64/msr.h
@@ -160,6 +160,8 @@ static inline unsigned int cpuid_edx(uns
#define MSR_IA32_UCODE_WRITE 0x79
#define MSR_IA32_UCODE_REV 0x8b
+void rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h);
+void wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h);
#endif
_
Patches currently in -mm which might be from adobriyan@xxxxxxxxxx are
git-parisc.patch
rdmsr_on_cpu-wrmsr_on_cpu.patch
allow-access-to-proc-pid-fd-after-setuid.patch
fix-race-between-proc_get_inode-and-remove_proc_entry.patch
utimensat-implementation.patch
utimensat-implementation-fix.patch
-
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