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Subject[PATCH 1/2] MSR: Add support for safe variants
From: Rudolf Marek <r.marek@assembler.cz>

Add support for _safe (exception handled) variants of rdmsr_on_cpu
and wrmsr_on_cpu. This is needed for the upcoming coretemp hardware
monitoring driver, which might step into non-existing (poorly
documented) MSR.

Signed-off-by: Rudolf Marek <r.marek@assembler.cz>
Cc: Alexey Dobriyan <adobriyan@openvz.org>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
---
Andrew, can you please pick this patch? I don't want to keep it in my
hwmon tree, as it might useful for others as well.

arch/i386/lib/msr-on-cpu.c | 71 ++++++++++++++++++++++++++++++++++++++++----
include/asm-i386/msr.h | 12 +++++++
include/asm-x86_64/msr.h | 11 +++++++
3 files changed, 87 insertions(+), 7 deletions(-)

--- linux-2.6.21-rc4.orig/arch/i386/lib/msr-on-cpu.c 2007-02-28 09:48:18.000000000 +0100
+++ linux-2.6.21-rc4/arch/i386/lib/msr-on-cpu.c 2007-03-24 20:50:05.000000000 +0100
@@ -6,6 +6,7 @@
struct msr_info {
u32 msr_no;
u32 l, h;
+ int err;
};

static void __rdmsr_on_cpu(void *info)
@@ -15,20 +16,38 @@ static void __rdmsr_on_cpu(void *info)
rdmsr(rv->msr_no, rv->l, rv->h);
}

-void rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
+static void __rdmsr_safe_on_cpu(void *info)
{
+ struct msr_info *rv = info;
+
+ rv->err = rdmsr_safe(rv->msr_no, &rv->l, &rv->h);
+}
+
+static int _rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h, int safe)
+{
+ int err = 0;
preempt_disable();
if (smp_processor_id() == cpu)
- rdmsr(msr_no, *l, *h);
+ if (safe)
+ err = rdmsr_safe(msr_no, l, h);
+ else
+ 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);
+ if (safe) {
+ smp_call_function_single(cpu, __rdmsr_safe_on_cpu,
+ &rv, 0, 1);
+ err = rv.err;
+ } else {
+ smp_call_function_single(cpu, __rdmsr_on_cpu, &rv, 0, 1);
+ }
*l = rv.l;
*h = rv.h;
}
preempt_enable();
+ return err;
}

static void __wrmsr_on_cpu(void *info)
@@ -38,21 +57,61 @@ static void __wrmsr_on_cpu(void *info)
wrmsr(rv->msr_no, rv->l, rv->h);
}

-void wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
+static void __wrmsr_safe_on_cpu(void *info)
{
+ struct msr_info *rv = info;
+
+ rv->err = wrmsr_safe(rv->msr_no, rv->l, rv->h);
+}
+
+static int _wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h, int safe)
+{
+ int err = 0;
preempt_disable();
if (smp_processor_id() == cpu)
- wrmsr(msr_no, l, h);
+ if (safe)
+ err = wrmsr_safe(msr_no, l, h);
+ else
+ 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);
+ if (safe) {
+ smp_call_function_single(cpu, __wrmsr_safe_on_cpu,
+ &rv, 0, 1);
+ err = rv.err;
+ } else {
+ smp_call_function_single(cpu, __wrmsr_on_cpu, &rv, 0, 1);
+ }
}
preempt_enable();
+ return err;
+}
+
+void wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
+{
+ _wrmsr_on_cpu(cpu, msr_no, l, h, 0);
+}
+
+void rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
+{
+ _rdmsr_on_cpu(cpu, msr_no, l, h, 0);
+}
+
+int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
+{
+ return _wrmsr_on_cpu(cpu, msr_no, l, h, 1);
+}
+
+int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
+{
+ return _rdmsr_on_cpu(cpu, msr_no, l, h, 1);
}

EXPORT_SYMBOL(rdmsr_on_cpu);
EXPORT_SYMBOL(wrmsr_on_cpu);
+EXPORT_SYMBOL(rdmsr_safe_on_cpu);
+EXPORT_SYMBOL(wrmsr_safe_on_cpu);
--- linux-2.6.21-rc4.orig/include/asm-i386/msr.h 2007-02-28 09:48:21.000000000 +0100
+++ linux-2.6.21-rc4/include/asm-i386/msr.h 2007-03-24 20:50:05.000000000 +0100
@@ -4,7 +4,7 @@
#ifdef CONFIG_PARAVIRT
#include <asm/paravirt.h>
#else
-
+#include <linux/errno.h>
/*
* Access to machine-specific registers (available on 586 and better only)
* Note: the rd* operations modify the parameters directly (without using
@@ -86,6 +86,8 @@ static inline void wrmsrl (unsigned long
#ifdef CONFIG_SMP
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);
+int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h);
+int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h);
#else /* CONFIG_SMP */
static inline void rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
{
@@ -95,6 +97,14 @@ static inline void wrmsr_on_cpu(unsigned
{
wrmsr(msr_no, l, h);
}
+static inline int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
+{
+ return rdmsr_safe(msr_no, l, h);
+}
+static inline int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
+{
+ return wrmsr_safe(msr_no, l, h);
+}
#endif /* CONFIG_SMP */

/* symbolic names for some interesting MSRs */
--- linux-2.6.21-rc4.orig/include/asm-x86_64/msr.h 2007-02-28 09:48:21.000000000 +0100
+++ linux-2.6.21-rc4/include/asm-x86_64/msr.h 2007-03-24 20:50:05.000000000 +0100
@@ -2,6 +2,7 @@
#define X86_64_MSR_H 1

#ifndef __ASSEMBLY__
+#include <linux/errno.h>
/*
* Access to machine-specific registers (available on 586 and better only)
* Note: the rd* operations modify the parameters directly (without using
@@ -163,6 +164,8 @@ static inline unsigned int cpuid_edx(uns
#ifdef CONFIG_SMP
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);
+int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h);
+int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h);
#else /* CONFIG_SMP */
static inline void rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
{
@@ -172,6 +175,14 @@ static inline void wrmsr_on_cpu(unsigned
{
wrmsr(msr_no, l, h);
}
+static inline int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
+{
+ return rdmsr_safe(msr_no, l, h);
+}
+static inline int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
+{
+ return wrmsr_safe(msr_no, l, h);
+}
#endif /* CONFIG_SMP */

#endif

--
Jean Delvare
-
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