Messages in this thread | | | Date | Wed, 11 Oct 2017 13:13:32 +0100 | From | Will Deacon <> | Subject | Re: [PATCH v6 2/4] perf tools arm64: Add support for get_cpuid_str function. |
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On Thu, Aug 24, 2017 at 05:33:47PM +0530, Ganapatrao Kulkarni wrote: > function get_cpuid_str returns MIDR string of the first online > cpu from the range of cpus associated with the pmu core device. > > Signed-off-by: Ganapatrao Kulkarni <ganapatrao.kulkarni@cavium.com> > --- > tools/perf/arch/arm64/util/Build | 1 + > tools/perf/arch/arm64/util/header.c | 60 +++++++++++++++++++++++++++++++++++++ > 2 files changed, 61 insertions(+) > create mode 100644 tools/perf/arch/arm64/util/header.c > > diff --git a/tools/perf/arch/arm64/util/Build b/tools/perf/arch/arm64/util/Build > index cef6fb3..b1ab72d 100644 > --- a/tools/perf/arch/arm64/util/Build > +++ b/tools/perf/arch/arm64/util/Build > @@ -1,3 +1,4 @@ > +libperf-y += header.o > libperf-$(CONFIG_DWARF) += dwarf-regs.o > libperf-$(CONFIG_LOCAL_LIBUNWIND) += unwind-libunwind.o > > diff --git a/tools/perf/arch/arm64/util/header.c b/tools/perf/arch/arm64/util/header.c > new file mode 100644 > index 0000000..f02a32e > --- /dev/null > +++ b/tools/perf/arch/arm64/util/header.c > @@ -0,0 +1,60 @@ > +#include <stdio.h> > +#include <stdlib.h> > +#include <api/fs/fs.h> > +#include "header.h" > + > +#define MIDR "/regs/identification/midr_el1" > +#define MIDR_SIZE 19 > + > +char *get_cpuid_str(struct perf_pmu *pmu) > +{ > + char *buf = NULL; > + char path[PATH_MAX]; > + const char *sysfs = sysfs__mountpoint(); > + int cpu; > + u64 midr = 0; > + struct cpu_map *cpus; > + FILE *file; > + > + if (!sysfs || !pmu->cpus) > + return NULL; > + > + buf = malloc(MIDR_SIZE); > + if (!buf) > + return NULL; > + > + /* read midr from list of cpus mapped to this pmu */ > + cpus = cpu_map__get(pmu->cpus); > + for (cpu = 0; cpu < cpus->nr; cpu++) { > + scnprintf(path, PATH_MAX, "%s/devices/system/cpu/cpu%d"MIDR, > + sysfs, cpus->map[cpu]); > + > + file = fopen(path, "r"); > + if (!file) { > + pr_debug("fopen failed for file %s\n", path); > + continue; > + } > + > + if (!fgets(buf, MIDR_SIZE, file)) > + continue; > + fclose(file);
Don't you want to fclose the file if the fgets fails?
> + > + /* Ignore/clear Variant[23:20] and > + * Revision[3:0] of MIDR > + */ > + midr = strtoul(buf, NULL, 16); > + midr &= (~(0xf << 20 | 0xf));
It would be cleaner if you had #defines for the MIDR fields that you're masking.
> + scnprintf(buf, MIDR_SIZE, "0x%016lx", midr); > + /* got midr break loop */ > + break; > + } > + > + if (!midr) { > + pr_err("failed to get cpuid string\n");
Might be helpful to print the PMU name and the CPU map if there's a way to do that.
Will
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