Re: [PATCH 1/4] tools/power/cpupower: Read energy_perf_bias from sysfs
From: Shuah Khan
Date: Thu Oct 15 2020 - 13:49:35 EST
On 10/15/20 8:46 AM, Borislav Petkov wrote:
From: Borislav Petkov <bp@xxxxxxx>
... instead of poking at the MSR. For that, move the accessor functions
to misc.c and add a sysfs-writing function too.
> There should be no functional changes resulting from this.
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Cc: Thomas Renninger <trenn@xxxxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
---
tools/power/cpupower/lib/cpupower.c | 23 +++++++++-
tools/power/cpupower/lib/cpupower_intern.h | 5 ++
tools/power/cpupower/utils/cpupower-info.c | 2 +-
tools/power/cpupower/utils/cpupower-set.c | 2 +-
tools/power/cpupower/utils/helpers/helpers.h | 8 ++--
tools/power/cpupower/utils/helpers/misc.c | 48 ++++++++++++++++++++
tools/power/cpupower/utils/helpers/msr.c | 28 ------------
7 files changed, 81 insertions(+), 35 deletions(-)
diff --git a/tools/power/cpupower/lib/cpupower.c b/tools/power/cpupower/lib/cpupower.c
index 3656e697537e..d2fa4bbecf74 100644
--- a/tools/power/cpupower/lib/cpupower.c
+++ b/tools/power/cpupower/lib/cpupower.c
@@ -16,8 +16,8 @@
unsigned int cpupower_read_sysfs(const char *path, char *buf, size_t buflen)
{
- int fd;
ssize_t numread;
+ int fd;
Is there a reason to move "int fd"?
fd = open(path, O_RDONLY);
if (fd == -1)
@@ -35,6 +35,27 @@ unsigned int cpupower_read_sysfs(const char *path, char *buf, size_t buflen)
return (unsigned int) numread;
}
+unsigned int cpupower_write_sysfs(const char *path, char *buf, size_t buflen)
+{
+ ssize_t numwritten;
+ int fd;
+
+ fd = open(path, O_WRONLY);
+ if (fd == -1)
+ return 0;
+
+ numwritten = write(fd, buf, buflen - 1);
+ if (numwritten < 1) {
+ perror("write failed");
Please add filename to the error message
+ close(fd);
+ return -1;
+ }
+
+ close(fd);
+
+ return (unsigned int) numwritten;
+}
+
/*
* Detect whether a CPU is online
*
diff --git a/tools/power/cpupower/lib/cpupower_intern.h b/tools/power/cpupower/lib/cpupower_intern.h
index 4887c76d23f8..ac1112b956ec 100644
--- a/tools/power/cpupower/lib/cpupower_intern.h
+++ b/tools/power/cpupower/lib/cpupower_intern.h
@@ -1,6 +1,11 @@
/* SPDX-License-Identifier: GPL-2.0 */
#define PATH_TO_CPU "/sys/devices/system/cpu/"
+
+#ifndef MAX_LINE_LEN
#define MAX_LINE_LEN 4096
+#endif
+
#define SYSFS_PATH_MAX 255
unsigned int cpupower_read_sysfs(const char *path, char *buf, size_t buflen);
+unsigned int cpupower_write_sysfs(const char *path, char *buf, size_t buflen);
diff --git a/tools/power/cpupower/utils/cpupower-info.c b/tools/power/cpupower/utils/cpupower-info.c
index 0ba61a2c4d81..06345b543786 100644
--- a/tools/power/cpupower/utils/cpupower-info.c
+++ b/tools/power/cpupower/utils/cpupower-info.c
@@ -101,7 +101,7 @@ int cmd_info(int argc, char **argv)
}
if (params.perf_bias) {
- ret = msr_intel_get_perf_bias(cpu);
+ ret = cpupower_intel_get_perf_bias(cpu);
if (ret < 0) {
fprintf(stderr,
_("Could not read perf-bias value[%d]\n"), ret);
diff --git a/tools/power/cpupower/utils/cpupower-set.c b/tools/power/cpupower/utils/cpupower-set.c
index 052044d7e012..180d5ba877e6 100644
--- a/tools/power/cpupower/utils/cpupower-set.c
+++ b/tools/power/cpupower/utils/cpupower-set.c
@@ -95,7 +95,7 @@ int cmd_set(int argc, char **argv)
}
if (params.perf_bias) {
- ret = msr_intel_set_perf_bias(cpu, perf_bias);
+ ret = cpupower_intel_set_perf_bias(cpu, perf_bias);
if (ret) {
fprintf(stderr, _("Error setting perf-bias "
"value on CPU %d\n"), cpu);
diff --git a/tools/power/cpupower/utils/helpers/helpers.h b/tools/power/cpupower/utils/helpers/helpers.h
index c258eeccd05f..37dac161f3fe 100644
--- a/tools/power/cpupower/utils/helpers/helpers.h
+++ b/tools/power/cpupower/utils/helpers/helpers.h
@@ -105,8 +105,8 @@ extern struct cpupower_cpu_info cpupower_cpu_info;
extern int read_msr(int cpu, unsigned int idx, unsigned long long *val);
extern int write_msr(int cpu, unsigned int idx, unsigned long long val);
-extern int msr_intel_set_perf_bias(unsigned int cpu, unsigned int val);
-extern int msr_intel_get_perf_bias(unsigned int cpu);
+extern int cpupower_intel_set_perf_bias(unsigned int cpu, unsigned int val);
+extern int cpupower_intel_get_perf_bias(unsigned int cpu);
extern unsigned long long msr_intel_get_turbo_ratio(unsigned int cpu);
/* Read/Write msr ****************************/
@@ -150,9 +150,9 @@ static inline int read_msr(int cpu, unsigned int idx, unsigned long long *val)
{ return -1; };
static inline int write_msr(int cpu, unsigned int idx, unsigned long long val)
{ return -1; };
-static inline int msr_intel_set_perf_bias(unsigned int cpu, unsigned int val)
+static inline int cpupower_intel_set_perf_bias(unsigned int cpu, unsigned int val)
{ return -1; };
-static inline int msr_intel_get_perf_bias(unsigned int cpu)
+static inline int cpupower_intel_get_perf_bias(unsigned int cpu)
{ return -1; };
static inline unsigned long long msr_intel_get_turbo_ratio(unsigned int cpu)
{ return 0; };
diff --git a/tools/power/cpupower/utils/helpers/misc.c b/tools/power/cpupower/utils/helpers/misc.c
index f406adc40bad..e8f8f643a627 100644
--- a/tools/power/cpupower/utils/helpers/misc.c
+++ b/tools/power/cpupower/utils/helpers/misc.c
@@ -1,7 +1,15 @@
// SPDX-License-Identifier: GPL-2.0
+
+#include <stdio.h>
+#include <errno.h>
+#include <stdlib.h>
+
#if defined(__i386__) || defined(__x86_64__)
#include "helpers/helpers.h"
+#include "helpers/sysfs.h"
+
+#include "cpupower_intern.h"
#define MSR_AMD_HWCR 0xc0010015
@@ -40,4 +48,44 @@ int cpufreq_has_boost_support(unsigned int cpu, int *support, int *active,
*support = *active = 1;
return 0;
}
+
+int cpupower_intel_get_perf_bias(unsigned int cpu)
+{
+ char linebuf[MAX_LINE_LEN];
+ char path[SYSFS_PATH_MAX];
+ unsigned long val;
+ char *endp;
+
+ if (!(cpupower_cpu_info.caps & CPUPOWER_CAP_PERF_BIAS))
+ return -1;
+
+ snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/power/energy_perf_bias", cpu);
Please add return check for snprintf, please add a define for
"cpu%u/power/energy_perf_bias" since it is hardcoded in
read/write functions.
+
+ if (cpupower_read_sysfs(path, linebuf, MAX_LINE_LEN) == 0)
+ return -1;
+
+ val = strtol(linebuf, &endp, 0);
+ if (endp == linebuf || errno == ERANGE)
+ return -1;
+
+ return val;
+}
+
+int cpupower_intel_set_perf_bias(unsigned int cpu, unsigned int val)
+{
+ char path[SYSFS_PATH_MAX];
+ char linebuf[3] = {};
+
+ if (!(cpupower_cpu_info.caps & CPUPOWER_CAP_PERF_BIAS))
+ return -1;
+
+ snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/power/energy_perf_bias", cpu);
Please add return check for snprintf, please add a define for
"cpu%u/power/energy_perf_bias" since it is hardcoded in
read/write functions.
+ snprintf(linebuf, sizeof(linebuf), "%d", val);
return value check?
+
+ if (cpupower_write_sysfs(path, linebuf, 3) <= 0)
+ return -1;
+
+ return 0;
+}
+
#endif /* #if defined(__i386__) || defined(__x86_64__) */
diff --git a/tools/power/cpupower/utils/helpers/msr.c b/tools/power/cpupower/utils/helpers/msr.c
index ab9950748838..8b0b6be74bb8 100644
--- a/tools/power/cpupower/utils/helpers/msr.c
+++ b/tools/power/cpupower/utils/helpers/msr.c
@@ -11,7 +11,6 @@
/* Intel specific MSRs */
#define MSR_IA32_PERF_STATUS 0x198
#define MSR_IA32_MISC_ENABLES 0x1a0
-#define MSR_IA32_ENERGY_PERF_BIAS 0x1b0
#define MSR_NEHALEM_TURBO_RATIO_LIMIT 0x1ad
/*
@@ -73,33 +72,6 @@ int write_msr(int cpu, unsigned int idx, unsigned long long val)
return -1;
}
-int msr_intel_get_perf_bias(unsigned int cpu)
-{
- unsigned long long val;
- int ret;
-
- if (!(cpupower_cpu_info.caps & CPUPOWER_CAP_PERF_BIAS))
- return -1;
-
- ret = read_msr(cpu, MSR_IA32_ENERGY_PERF_BIAS, &val);
- if (ret)
- return ret;
- return val;
-}
-
-int msr_intel_set_perf_bias(unsigned int cpu, unsigned int val)
-{
- int ret;
-
- if (!(cpupower_cpu_info.caps & CPUPOWER_CAP_PERF_BIAS))
- return -1;
-
- ret = write_msr(cpu, MSR_IA32_ENERGY_PERF_BIAS, val);
- if (ret)
- return ret;
- return 0;
-}
-
unsigned long long msr_intel_get_turbo_ratio(unsigned int cpu)
{
unsigned long long val;
thnaks,
-- Shuah