On Thu, Jul 20, 2017 at 11:26:06AM +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 <[email protected]> > --- > tools/perf/arch/arm64/util/Build | 1 + > tools/perf/arch/arm64/util/header.c | 59 > +++++++++++++++++++++++++++++++++++++ > 2 files changed, 60 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..4e25498 > --- /dev/null > +++ b/tools/perf/arch/arm64/util/header.c > @@ -0,0 +1,59 @@ > +#include <stdio.h> > +#include <stdlib.h> > +#include <api/fs/fs.h> > +#include "header.h" > + > +#define MIDR "/regs/identification/midr_el1" > +#define MIDR_SIZE 128 > + > +char *get_cpuid_str(struct perf_pmu *pmu) > +{ > + char *buf = malloc(MIDR_SIZE); > + char *temp = NULL; > + char path[PATH_MAX]; > + const char *sysfs = sysfs__mountpoint(); > + int cpu, ret; > + unsigned long long midr; > + struct cpu_map *cpus; > + FILE *file; > + > + if (!pmu->cpus) > + return NULL; > + > + if (!sysfs) > + 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++) { > + ret = snprintf(path, PATH_MAX, > + "%s/devices/system/cpu/cpu%d"MIDR, > + sysfs, cpus->map[cpu]); > + if (ret == PATH_MAX) { > + pr_err("sysfs path crossed PATH_MAX(%d) size\n", > PATH_MAX); > + goto err; > + } > + > + file = fopen(path, "r"); > + if (!file) > + continue; > + > + temp = fgets(buf, MIDR_SIZE, file); > + fclose(file); > + if (!temp) > + continue; > + > + /* Ignore/clear Variant[23:20] and > + * Revision[3:0] of MIDR > + */ > + midr = strtoll(buf, NULL, 16); > + midr &= (~(0xf << 20 | 0xf)); > + snprintf(buf, MIDR_SIZE, "0x%016llx", midr); > + cpu_map__put(cpus); > + return buf; > + } > + > +err: cpu_map__put(cpus); > + free(buf); > + return NULL; > +}
Might just be me, but I found this really difficult to read. I think it works, but having the return at the end of loop is really counter-intuitive. I'll leave it up to Arnaldo, since I can't find any functional problems with this series from the arm64 side. Cheers, Will
