perf pmu: Remove duplication around EVENT_SOURCE_DEVICE_PATH

The pattern for accessing EVENT_SOURCE_DEVICE_PATH is duplicated in a
few places, so add two utility functions to cover it. Also just use
perf_pmu__scan_file() instead of pmu_type() which already does the same
thing.

No functional changes.

Reviewed-by: Leo Yan <leo.yan@linaro.org>
Signed-off-by: James Clark <james.clark@arm.com>
Acked-by: Suzuki Poulouse <suzuki.poulose@arm.com>
Tested-by: Tanmay Jagdale <tanmay@marvell.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Bharat Bhushan <bbhushan2@marvell.com>
Cc: George Cherian <gcherian@marvell.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Linu Cherian <lcherian@marvell.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sunil Kovvuri Goutham <sgoutham@marvell.com>
Cc: Will Deacon <will@kernel.org>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20230120143702.4035046-2-james.clark@arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/arch/arm/util/auxtrace.c b/tools/perf/arch/arm/util/auxtrace.c
index deeb163..adec6c9 100644 (file)
--- a/tools/perf/arch/arm/util/auxtrace.c
+++ b/tools/perf/arch/arm/util/auxtrace.c
@@ -55,17 +55,16 @@ static struct perf_pmu **find_all_arm_spe_pmus(int *nr_spes, int *err)
 
 static struct perf_pmu **find_all_hisi_ptt_pmus(int *nr_ptts, int *err)
 {
-       const char *sysfs = sysfs__mountpoint();
        struct perf_pmu **hisi_ptt_pmus = NULL;
        struct dirent *dent;
        char path[PATH_MAX];
        DIR *dir = NULL;
        int idx = 0;
 
-       snprintf(path, PATH_MAX, "%s" EVENT_SOURCE_DEVICE_PATH, sysfs);
+       perf_pmu__event_source_devices_scnprintf(path, sizeof(path));
        dir = opendir(path);
        if (!dir) {
-               pr_err("can't read directory '%s'\n", EVENT_SOURCE_DEVICE_PATH);
+               pr_err("can't read directory '%s'\n", path);
                *err = -EINVAL;
                return NULL;
        }

diff --git a/tools/perf/arch/arm64/util/pmu.c b/tools/perf/arch/arm64/util/pmu.c
index 9e674ca..801bf52 100644 (file)
--- a/tools/perf/arch/arm64/util/pmu.c
+++ b/tools/perf/arch/arm64/util/pmu.c
@@ -44,8 +44,8 @@ double perf_pmu__cpu_slots_per_cycle(void)
        struct perf_pmu *pmu = pmu__find_core_pmu();
 
        if (pmu) {
-               scnprintf(path, PATH_MAX,
-                       EVENT_SOURCE_DEVICE_PATH "%s/caps/slots", pmu->name);
+               perf_pmu__pathname_scnprintf(path, sizeof(path),
+                                            pmu->name, "caps/slots");
                /*
                 * The value of slots is not greater than 32 bits, but sysfs__read_int
                 * can't read value with 0x prefix, so use sysfs__read_ull instead.

diff --git a/tools/perf/arch/x86/util/pmu.c b/tools/perf/arch/x86/util/pmu.c
index 74d69db..358340b 100644 (file)
--- a/tools/perf/arch/x86/util/pmu.c
+++ b/tools/perf/arch/x86/util/pmu.c
@@ -15,8 +15,6 @@
 #include "../../../util/pmu.h"
 #include "../../../util/fncache.h"
 
-#define TEMPLATE_ALIAS "%s/bus/event_source/devices/%s/alias"
-
 struct pmu_alias {
        char *name;
        char *alias;
@@ -72,18 +70,14 @@ static int setup_pmu_alias_list(void)
        char path[PATH_MAX];
        DIR *dir;
        struct dirent *dent;
-       const char *sysfs = sysfs__mountpoint();
        struct pmu_alias *pmu_alias;
        char buf[MAX_PMU_NAME_LEN];
        FILE *file;
        int ret = -ENOMEM;
 
-       if (!sysfs)
+       if (!perf_pmu__event_source_devices_scnprintf(path, sizeof(path)))
                return -1;
 
-       snprintf(path, PATH_MAX,
-                "%s" EVENT_SOURCE_DEVICE_PATH, sysfs);
-
        dir = opendir(path);
        if (!dir)
                return -errno;
@@ -93,9 +87,7 @@ static int setup_pmu_alias_list(void)
                    !strcmp(dent->d_name, ".."))
                        continue;
 
-               snprintf(path, PATH_MAX,
-                        TEMPLATE_ALIAS, sysfs, dent->d_name);
-
+               perf_pmu__pathname_scnprintf(path, sizeof(path), dent->d_name, "alias");
                if (!file_available(path))
                        continue;
 

diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index cbb4fbf..1edbb71 100644 (file)
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -108,14 +108,10 @@ int perf_pmu__format_parse(char *dir, struct list_head *head)
 static int pmu_format(const char *name, struct list_head *format)
 {
        char path[PATH_MAX];
-       const char *sysfs = sysfs__mountpoint();
 
-       if (!sysfs)
+       if (!perf_pmu__pathname_scnprintf(path, sizeof(path), name, "format"))
                return -1;
 
-       snprintf(path, PATH_MAX,
-                "%s" EVENT_SOURCE_DEVICE_PATH "%s/format", sysfs, name);
-
        if (!file_available(path))
                return 0;
 
@@ -514,14 +510,10 @@ static int pmu_aliases_parse(char *dir, struct list_head *head)
 static int pmu_aliases(const char *name, struct list_head *head)
 {
        char path[PATH_MAX];
-       const char *sysfs = sysfs__mountpoint();
 
-       if (!sysfs)
+       if (!perf_pmu__pathname_scnprintf(path, sizeof(path), name, "events"))
                return -1;
 
-       snprintf(path, PATH_MAX,
-                "%s/bus/event_source/devices/%s/events", sysfs, name);
-
        if (!file_available(path))
                return 0;
 
@@ -555,52 +547,16 @@ static int pmu_alias_terms(struct perf_pmu_alias *alias,
        return 0;
 }
 
-/*
- * Reading/parsing the default pmu type value, which should be
- * located at:
- * /sys/bus/event_source/devices/<dev>/type as sysfs attribute.
- */
-static int pmu_type(const char *name, __u32 *type)
-{
-       char path[PATH_MAX];
-       FILE *file;
-       int ret = 0;
-       const char *sysfs = sysfs__mountpoint();
-
-       if (!sysfs)
-               return -1;
-
-       snprintf(path, PATH_MAX,
-                "%s" EVENT_SOURCE_DEVICE_PATH "%s/type", sysfs, name);
-
-       if (access(path, R_OK) < 0)
-               return -1;
-
-       file = fopen(path, "r");
-       if (!file)
-               return -EINVAL;
-
-       if (1 != fscanf(file, "%u", type))
-               ret = -1;
-
-       fclose(file);
-       return ret;
-}
-
 /* Add all pmus in sysfs to pmu list: */
 static void pmu_read_sysfs(void)
 {
        char path[PATH_MAX];
        DIR *dir;
        struct dirent *dent;
-       const char *sysfs = sysfs__mountpoint();
 
-       if (!sysfs)
+       if (!perf_pmu__event_source_devices_scnprintf(path, sizeof(path)))
                return;
 
-       snprintf(path, PATH_MAX,
-                "%s" EVENT_SOURCE_DEVICE_PATH, sysfs);
-
        dir = opendir(path);
        if (!dir)
                return;
@@ -697,14 +653,9 @@ static char *pmu_id(const char *name)
 static int is_arm_pmu_core(const char *name)
 {
        char path[PATH_MAX];
-       const char *sysfs = sysfs__mountpoint();
 
-       if (!sysfs)
+       if (!perf_pmu__pathname_scnprintf(path, sizeof(path), name, "cpus"))
                return 0;
-
-       /* Look for cpu sysfs (specific to arm) */
-       scnprintf(path, PATH_MAX, "%s/bus/event_source/devices/%s/cpus",
-                               sysfs, name);
        return file_available(path);
 }
 
@@ -970,11 +921,8 @@ static struct perf_pmu *pmu_lookup(const char *lookup_name)
                return NULL;
 
        /*
-        * Check the type first to avoid unnecessary work.
+        * Check the aliases first to avoid unnecessary work.
         */
-       if (pmu_type(name, &type))
-               return NULL;
-
        if (pmu_aliases(name, &aliases))
                return NULL;
 
@@ -984,9 +932,14 @@ static struct perf_pmu *pmu_lookup(const char *lookup_name)
 
        pmu->cpus = pmu_cpumask(name);
        pmu->name = strdup(name);
+
        if (!pmu->name)
                goto err;
 
+       /* Read type, and ensure that type value is successfully assigned (return 1) */
+       if (perf_pmu__scan_file(pmu, "type", "%u", &type) != 1)
+               goto err;
+
        alias_name = pmu_find_alias_name(name);
        if (alias_name) {
                pmu->alias_name = strdup(alias_name);
@@ -1787,16 +1740,11 @@ bool pmu_have_event(const char *pname, const char *name)
 static FILE *perf_pmu__open_file(struct perf_pmu *pmu, const char *name)
 {
        char path[PATH_MAX];
-       const char *sysfs;
 
-       sysfs = sysfs__mountpoint();
-       if (!sysfs)
+       if (!perf_pmu__pathname_scnprintf(path, sizeof(path), pmu->name, name) ||
+           !file_available(path))
                return NULL;
 
-       snprintf(path, PATH_MAX,
-                "%s" EVENT_SOURCE_DEVICE_PATH "%s/%s", sysfs, pmu->name, name);
-       if (!file_available(path))
-               return NULL;
        return fopen(path, "r");
 }
 
@@ -1850,7 +1798,6 @@ int perf_pmu__caps_parse(struct perf_pmu *pmu)
 {
        struct stat st;
        char caps_path[PATH_MAX];
-       const char *sysfs = sysfs__mountpoint();
        DIR *caps_dir;
        struct dirent *evt_ent;
 
@@ -1859,12 +1806,9 @@ int perf_pmu__caps_parse(struct perf_pmu *pmu)
 
        pmu->nr_caps = 0;
 
-       if (!sysfs)
+       if (!perf_pmu__pathname_scnprintf(caps_path, sizeof(caps_path), pmu->name, "caps"))
                return -1;
 
-       snprintf(caps_path, PATH_MAX,
-                "%s" EVENT_SOURCE_DEVICE_PATH "%s/caps", sysfs, pmu->name);
-
        if (stat(caps_path, &st) < 0) {
                pmu->caps_initialized = true;
                return 0;       /* no error if caps does not exist */
@@ -1999,3 +1943,31 @@ double __weak perf_pmu__cpu_slots_per_cycle(void)
 {
        return NAN;
 }
+
+int perf_pmu__event_source_devices_scnprintf(char *pathname, size_t size)
+{
+       const char *sysfs = sysfs__mountpoint();
+
+       if (!sysfs)
+               return 0;
+       return scnprintf(pathname, size, "%s/bus/event_source/devices/", sysfs);
+}
+
+/*
+ * Fill 'buf' with the path to a file or folder in 'pmu_name' in
+ * sysfs. For example if pmu_name = "cs_etm" and 'filename' = "format"
+ * then pathname will be filled with
+ * "/sys/bus/event_source/devices/cs_etm/format"
+ *
+ * Return 0 if the sysfs mountpoint couldn't be found or if no
+ * characters were written.
+ */
+int perf_pmu__pathname_scnprintf(char *buf, size_t size,
+                                const char *pmu_name, const char *filename)
+{
+       char base_path[PATH_MAX];
+
+       if (!perf_pmu__event_source_devices_scnprintf(base_path, sizeof(base_path)))
+               return 0;
+       return scnprintf(buf, size, "%s%s/%s", base_path, pmu_name, filename);
+}

diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h
index fd414ba..96d030c 100644 (file)
--- a/tools/perf/util/pmu.h
+++ b/tools/perf/util/pmu.h
@@ -22,7 +22,6 @@ enum {
 };
 
 #define PERF_PMU_FORMAT_BITS 64
-#define EVENT_SOURCE_DEVICE_PATH "/bus/event_source/devices/"
 #define CPUS_TEMPLATE_CPU      "%s/bus/event_source/devices/%s/cpus"
 #define MAX_PMU_NAME_LEN 128
 
@@ -260,4 +259,8 @@ int perf_pmu__cpus_match(struct perf_pmu *pmu, struct perf_cpu_map *cpus,
 char *pmu_find_real_name(const char *name);
 char *pmu_find_alias_name(const char *name);
 double perf_pmu__cpu_slots_per_cycle(void);
+int perf_pmu__event_source_devices_scnprintf(char *pathname, size_t size);
+int perf_pmu__pathname_scnprintf(char *buf, size_t size,
+                                const char *pmu_name, const char *filename);
+
 #endif /* __PMU_H */