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libcpumf: Function to return PMU name

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Return the PMU name as found in the sysfs tree given a PMU type number.

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Reviewed-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
This commit is contained in:
Thomas Richter
2022-04-28 15:53:15 +02:00
committed by Jan Höppner
parent acdce2a7a9
commit a58460b5c7
4 changed files with 63 additions and 1 deletions
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14
include/lib/libcpumf.h
View File

@@ -30,6 +30,20 @@
*/
int libcpumf_pmutype(const char *dirname);
/**
* Read out the PMU name from a given type.
*
* Return the PMU name this PMU was registered in kernel. If the PMU was
* registered without a name, it is not listed in the directory.
* The caller must free the memory returned by name.
*
* @param[in] wanted_type Type number of the PMU
* @param[out] name Name of the PMU (when retval is 0)
* @retval 0 PMU wanted_type detected and PMU name valid
* @retval -1 No PMU with wanted_type
*/
int libcpumf_pmuname(unsigned int wanted_type, char **name);
/**
* Read out the CPU list from a given file name, for example from files
* /sys/devices/system/cpu/online or /sys/devices/system/cpu/possible.

2
libcpumf/Makefile
View File

@@ -13,7 +13,7 @@ $(lib): $(objects)
install: all
libcpumf_example: libcpumf_example.o $(lib)
libcpumf_example: libcpumf_example.o $(lib) $(rootdir)/libutil/libutil.a
clean:
rm -f *.o $(lib) $(examples)

9
libcpumf/libcpumf_example.c
View File

@@ -14,6 +14,7 @@ int main(void)
{
unsigned long min, max, speed, sfb_min, sfb_max;
int rc, pmu, cfvn, csvn, auth;
char *pmuname;
cpu_set_t set;
pmu = libcpumf_pmutype(S390_CPUMF_CF);
@@ -74,5 +75,13 @@ int main(void)
putchar('\n');
printf("PAI crypto support %d\n", libcpumf_have_pai_crypto());
rc = libcpumf_pmuname(10, &pmuname);
if (rc) {
printf("PMU type 10 PMU name lookup error %d\n", rc);
} else {
printf("PMU type 10 PMU name %s\n", pmuname);
free(pmuname);
}
return EXIT_SUCCESS;
}

39
libcpumf/libcpumf_pmutype.c
View File

@@ -4,10 +4,16 @@
* it under the terms of the MIT license. See LICENSE for details.
*/
#include <err.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "lib/util_file.h"
#include "lib/util_libc.h"
#include "lib/util_path.h"
#include "lib/util_scandir.h"
#include "lib/libcpumf.h"
int libcpumf_pmutype(const char *dirname)
@@ -31,3 +37,36 @@ int libcpumf_pmutype(const char *dirname)
}
return ret;
}
int libcpumf_pmuname(unsigned int wanted_type, char **name)
{
struct dirent **de_vec;
unsigned int type;
char *dirname;
char *path;
int count;
int rc;
path = util_path_sysfs("devices");
count = util_scandir(&de_vec, alphasort, path, "(pai|cpum_).*");
free(path);
*name = NULL;
for (int i = 0; i < count; i++) {
if (de_vec[i]->d_type == DT_DIR) {
dirname = de_vec[i]->d_name;
path = util_path_sysfs("devices/%s/type", dirname);
rc = util_file_read_ui(&type, 10, path);
if (rc)
warn("Failed to open %s", path);
free(path);
if (!rc && type == wanted_type) {
*name = util_strdup(dirname);
goto out;
}
}
}
out:
util_scandir_free(de_vec, count);
return *name ? 0 : -1;
}