From: kan.liang@intel.com
To: peterz@infradead.org, tglx@linutronix.de, mingo@redhat.com,
linux-kernel@vger.kernel.org
Cc: bp@alien8.de, acme@kernel.org, eranian@google.com,
jolsa@kernel.org, ak@linux.intel.com,
Kan Liang <Kan.liang@intel.com>
Subject: [PATCH V3 1/2] x86/msr: add msr_set/clear_bit_on_cpu/cpus access functions
Date: Mon, 27 Mar 2017 11:30:47 -0700 [thread overview]
Message-ID: <1490639448-4147-2-git-send-email-kan.liang@intel.com> (raw)
In-Reply-To: <1490639448-4147-1-git-send-email-kan.liang@intel.com>
From: Kan Liang <Kan.liang@intel.com>
To flip a MSR bit on many CPUs or specific CPU, currently it has to do
read-modify-write operation on the MSR through rd/wrmsr_on_cpu(s).
It actually sends two IPIs to the given CPU.
It is necessory to extend the single operation - msr_set/clear_bit - on
many CPUs or given CPU. It only sends one IPI to the given CPU, and
simplify MSR content manipulation.
The new functions wrap the smp_call_function* boilerplate code.
Signed-off-by: Kan Liang <Kan.liang@intel.com>
---
arch/x86/include/asm/msr.h | 25 +++++++++++++++
arch/x86/lib/msr-smp.c | 76 ++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 101 insertions(+)
diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h
index 898dba2..bfd83ab 100644
--- a/arch/x86/include/asm/msr.h
+++ b/arch/x86/include/asm/msr.h
@@ -25,6 +25,7 @@ struct msr_info {
struct msr reg;
struct msr *msrs;
int err;
+ u8 bit;
};
struct msr_regs_info {
@@ -314,6 +315,10 @@ int msr_set_bit(u32 msr, u8 bit);
int msr_clear_bit(u32 msr, u8 bit);
#ifdef CONFIG_SMP
+int msr_set_bit_on_cpu(unsigned int cpu, u32 msr, u8 bit);
+int msr_clear_bit_on_cpu(unsigned int cpu, u32 msr, u8 bit);
+void msr_set_bit_on_cpus(const struct cpumask *mask, u32 msr, u8 bit);
+void msr_clear_bit_on_cpus(const struct cpumask *mask, u32 msr, u8 bit);
int rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h);
int wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h);
int rdmsrl_on_cpu(unsigned int cpu, u32 msr_no, u64 *q);
@@ -327,6 +332,26 @@ int wrmsrl_safe_on_cpu(unsigned int cpu, u32 msr_no, u64 q);
int rdmsr_safe_regs_on_cpu(unsigned int cpu, u32 regs[8]);
int wrmsr_safe_regs_on_cpu(unsigned int cpu, u32 regs[8]);
#else /* CONFIG_SMP */
+static inline int msr_set_bit_on_cpu(unsigned int cpu, u32 msr, u8 bit)
+{
+ return msr_set_bit(msr, bit);
+}
+
+static inline int msr_clear_bit_on_cpu(unsigned int cpu, u32 msr, u8 bit)
+{
+ return msr_clear_bit(msr, bit);
+}
+
+static inline void msr_set_bit_on_cpus(const struct cpumask *mask, u32 msr, u8 bit)
+{
+ msr_set_bit(msr, bit);
+}
+
+static inline void msr_clear_bit_on_cpus(const struct cpumask *mask, u32 msr, u8 bit)
+{
+ msr_clear_bit(msr, bit);
+}
+
static inline int rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
{
rdmsr(msr_no, *l, *h);
diff --git a/arch/x86/lib/msr-smp.c b/arch/x86/lib/msr-smp.c
index ce68b6a..8e704d9 100644
--- a/arch/x86/lib/msr-smp.c
+++ b/arch/x86/lib/msr-smp.c
@@ -3,6 +3,82 @@
#include <linux/smp.h>
#include <asm/msr.h>
+static void __msr_set_bit_on_cpu(void *info)
+{
+ struct msr_info *bit_info = info;
+
+ msr_set_bit(bit_info->msr_no, bit_info->bit);
+}
+
+static void __msr_clear_bit_on_cpu(void *info)
+{
+ struct msr_info *bit_info = info;
+
+ msr_clear_bit(bit_info->msr_no, bit_info->bit);
+}
+
+int msr_set_bit_on_cpu(unsigned int cpu, u32 msr, u8 bit)
+{
+ struct msr_info info;
+ int err;
+
+ info.msr_no = msr;
+ info.bit = bit;
+
+ err = smp_call_function_single(cpu, __msr_set_bit_on_cpu, &info, 1);
+
+ return err;
+}
+EXPORT_SYMBOL(msr_set_bit_on_cpu);
+
+int msr_clear_bit_on_cpu(unsigned int cpu, u32 msr, u8 bit)
+{
+ struct msr_info info;
+ int err;
+
+ info.msr_no = msr;
+ info.bit = bit;
+
+ err = smp_call_function_single(cpu, __msr_clear_bit_on_cpu, &info, 1);
+
+ return err;
+}
+EXPORT_SYMBOL(msr_clear_bit_on_cpu);
+
+void msr_set_bit_on_cpus(const struct cpumask *mask, u32 msr, u8 bit)
+{
+ struct msr_info info;
+ int this_cpu;
+
+ info.msr_no = msr;
+ info.bit = bit;
+
+ this_cpu = get_cpu();
+ if (cpumask_test_cpu(this_cpu, mask))
+ __msr_set_bit_on_cpu(&info);
+
+ smp_call_function_many(mask, __msr_set_bit_on_cpu, &info, 1);
+ put_cpu();
+}
+EXPORT_SYMBOL(msr_set_bit_on_cpus);
+
+void msr_clear_bit_on_cpus(const struct cpumask *mask, u32 msr, u8 bit)
+{
+ struct msr_info info;
+ int this_cpu;
+
+ info.msr_no = msr;
+ info.bit = bit;
+
+ this_cpu = get_cpu();
+ if (cpumask_test_cpu(this_cpu, mask))
+ __msr_clear_bit_on_cpu(&info);
+
+ smp_call_function_many(mask, __msr_clear_bit_on_cpu, &info, 1);
+ put_cpu();
+}
+EXPORT_SYMBOL(msr_clear_bit_on_cpus);
+
static void __rdmsr_on_cpu(void *info)
{
struct msr_info *rv = info;
--
2.7.4
next prev parent reply other threads:[~2017-03-27 18:46 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-27 18:30 [PATCH V3 0/2] measure SMI cost (kernel) kan.liang
2017-03-27 18:30 ` kan.liang [this message]
2017-03-28 8:36 ` [PATCH V3 1/2] x86/msr: add msr_set/clear_bit_on_cpu/cpus access functions Thomas Gleixner
2017-03-28 17:23 ` Thomas Gleixner
2017-03-28 17:38 ` Liang, Kan
2017-03-28 18:34 ` Thomas Gleixner
2017-03-27 18:30 ` [PATCH V3 2/2] perf/x86: add sysfs entry to freeze counter on SMI kan.liang
2017-03-28 8:42 ` Thomas Gleixner
2017-03-28 13:23 ` Liang, Kan
2017-03-28 17:03 ` Thomas Gleixner
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