[PATCH v4 2/5] perf tools riscv: Add support for get_cpuid_str function

From: Nikita Shubin
Date: Fri Jun 24 2022 - 12:01:43 EST


From: Nikita Shubin <n.shubin@xxxxxxxxx>

The get_cpuid_str function returns the string that
contains values of MVENDORID, MARCHID and MIMPID in
hex format separated by coma.

The values themselves are taken from first cpu entry
in "/proc/cpuid" that contains "mvendorid", "marchid"
and "mimpid".

Signed-off-by: Nikita Shubin <n.shubin@xxxxxxxxx>
---
tools/perf/arch/riscv/util/Build | 1 +
tools/perf/arch/riscv/util/header.c | 109 ++++++++++++++++++++++++++++
2 files changed, 110 insertions(+)
create mode 100644 tools/perf/arch/riscv/util/header.c

diff --git a/tools/perf/arch/riscv/util/Build b/tools/perf/arch/riscv/util/Build
index 7d3050134ae0..603dbb5ae4dc 100644
--- a/tools/perf/arch/riscv/util/Build
+++ b/tools/perf/arch/riscv/util/Build
@@ -1,4 +1,5 @@
perf-y += perf_regs.o
+perf-y += header.o

perf-$(CONFIG_DWARF) += dwarf-regs.o
perf-$(CONFIG_LIBDW_DWARF_UNWIND) += unwind-libdw.o
diff --git a/tools/perf/arch/riscv/util/header.c b/tools/perf/arch/riscv/util/header.c
new file mode 100644
index 000000000000..53e8ddf7990b
--- /dev/null
+++ b/tools/perf/arch/riscv/util/header.c
@@ -0,0 +1,109 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Implementation of get_cpuid().
+ *
+ * Author: Nikita Shubin <n.shubin@xxxxxxxxx>
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <api/fs/fs.h>
+#include <errno.h>
+#include "../../util/debug.h"
+#include "../../util/header.h"
+
+#define CPUINFO_MVEN "mvendorid"
+#define CPUINFO_MARCH "marchid"
+#define CPUINFO_MIMP "mimpid"
+#define CPUINFO "/proc/cpuinfo"
+
+static char *_get_field(const char *line)
+{
+ char *line2, *nl;
+
+ line2 = strrchr(line, ' ');
+ if (!line2)
+ return NULL;
+
+ line2++;
+ nl = strrchr(line, '\n');
+ if (!nl)
+ return NULL;
+
+ return strndup(line2, nl - line2);
+}
+
+static char *_get_cpuid(void)
+{
+ char *line = NULL;
+ char *mvendorid = NULL;
+ char *marchid = NULL;
+ char *mimpid = NULL;
+ char *cpuid = NULL;
+ int read;
+ unsigned long line_sz;
+ FILE *cpuinfo;
+
+ cpuinfo = fopen(CPUINFO, "r");
+ if (cpuinfo == NULL)
+ return cpuid;
+
+ while ((read = getline(&line, &line_sz, cpuinfo)) != -1) {
+ if (!strncmp(line, CPUINFO_MVEN, strlen(CPUINFO_MVEN))) {
+ mvendorid = _get_field(line);
+ if (!mvendorid)
+ goto free;
+ } else if (!strncmp(line, CPUINFO_MARCH, strlen(CPUINFO_MARCH))) {
+ marchid = _get_field(line);
+ if (!marchid)
+ goto free;
+ } else if (!strncmp(line, CPUINFO_MIMP, strlen(CPUINFO_MIMP))) {
+ mimpid = _get_field(line);
+ if (!mimpid)
+ goto free;
+
+ break;
+ }
+ }
+
+ if (!mvendorid || !marchid || !mimpid) {
+ cpuid = NULL;
+ goto free;
+ }
+
+ if (asprintf(&cpuid, "%s-%s-%s", mvendorid, marchid, mimpid) < 0)
+ cpuid = NULL;
+
+free:
+ fclose(cpuinfo);
+
+ if (mvendorid)
+ free(mvendorid);
+
+ if (marchid)
+ free(marchid);
+
+ if (mimpid)
+ free(mimpid);
+
+ return cpuid;
+}
+
+int get_cpuid(char *buffer, size_t sz)
+{
+ char *cpuid = _get_cpuid();
+
+ if (sz < strlen(cpuid)) {
+ free(cpuid);
+ return -EINVAL;
+ }
+
+ scnprintf(buffer, sz, "%s", cpuid);
+ return 0;
+}
+
+char *
+get_cpuid_str(struct perf_pmu *pmu __maybe_unused)
+{
+ return _get_cpuid();
+}
--
2.35.1