/* * sampleip: sample instruction pointer and frequency count in a BPF map. * * Copyright 2016 Netflix, Inc. * * This program is free software; you can redistribute it and/or * modify it under the terms of version 2 of the GNU General Public * License as published by the Free Software Foundation. */ #include #include #include #include #include #include #include #include #include #include #include #include #include "libbpf.h" #include "bpf_load.h" #include "perf-sys.h" #define DEFAULT_FREQ 99 #define DEFAULT_SECS 5 #define MAX_IPS 8192 #define PAGE_OFFSET 0xffff880000000000 static int nr_cpus; static void usage(void) { printf("USAGE: sampleip [-F freq] [duration]\n"); printf(" -F freq # sample frequency (Hertz), default 99\n"); printf(" duration # sampling duration (seconds), default 5\n"); } static int sampling_start(int *pmu_fd, int freq) { int i; struct perf_event_attr pe_sample_attr = { .type = PERF_TYPE_SOFTWARE, .freq = 1, .sample_period = freq, .config = PERF_COUNT_SW_CPU_CLOCK, .inherit = 1, }; for (i = 0; i < nr_cpus; i++) { pmu_fd[i] = sys_perf_event_open(&pe_sample_attr, -1 /* pid */, i, -1 /* group_fd */, 0 /* flags */); if (pmu_fd[i] < 0) { fprintf(stderr, "ERROR: Initializing perf sampling\n"); return 1; } assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0); assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE, 0) == 0); } return 0; } static void sampling_end(int *pmu_fd) { int i; for (i = 0; i < nr_cpus; i++) close(pmu_fd[i]); } struct ipcount { __u64 ip; __u32 count; }; /* used for sorting */ struct ipcount counts[MAX_IPS]; static int count_cmp(const void *p1, const void *p2) { return ((struct ipcount *)p1)->count - ((struct ipcount *)p2)->count; } static void print_ip_map(int fd) { struct ksym *sym; __u64 key, next_key; __u32 value; int i, max; printf("%-19s %-32s %s\n", "ADDR", "KSYM", "COUNT"); /* fetch IPs and counts */ key = 0, i = 0; while (bpf_map_get_next_key(fd, &key, &next_key) == 0) { bpf_map_lookup_elem(fd, &next_key, &value); counts[i].ip = next_key; counts[i++].count = value; key = next_key; } max = i; /* sort and print */ qsort(counts, max, sizeof(struct ipcount), count_cmp); for (i = 0; i < max; i++) { if (counts[i].ip > PAGE_OFFSET) { sym = ksym_search(counts[i].ip); printf("0x%-17llx %-32s %u\n", counts[i].ip, sym->name, counts[i].count); } else { printf("0x%-17llx %-32s %u\n", counts[i].ip, "(user)", counts[i].count); } } if (max == MAX_IPS) { printf("WARNING: IP hash was full (max %d entries); ", max); printf("may have dropped samples\n"); } } static void int_exit(int sig) { printf("\n"); print_ip_map(map_fd[0]); exit(0); } int main(int argc, char **argv) { char filename[256]; int *pmu_fd, opt, freq = DEFAULT_FREQ, secs = DEFAULT_SECS; /* process arguments */ while ((opt = getopt(argc, argv, "F:h")) != -1) { switch (opt) { case 'F': freq = atoi(optarg); break; case 'h': default: usage(); return 0; } } if (argc - optind == 1) secs = atoi(argv[optind]); if (freq == 0 || secs == 0) { usage(); return 1; } /* initialize kernel symbol translation */ if (load_kallsyms()) { fprintf(stderr, "ERROR: loading /proc/kallsyms\n"); return 2; } /* create perf FDs for each CPU */ nr_cpus = sysconf(_SC_NPROCESSORS_CONF); pmu_fd = malloc(nr_cpus * sizeof(int)); if (pmu_fd == NULL) { fprintf(stderr, "ERROR: malloc of pmu_fd\n"); return 1; } /* load BPF program */ snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); if (load_bpf_file(filename)) { fprintf(stderr, "ERROR: loading BPF program (errno %d):\n", errno); if (strcmp(bpf_log_buf, "") == 0) fprintf(stderr, "Try: ulimit -l unlimited\n"); else fprintf(stderr, "%s", bpf_log_buf); return 1; } signal(SIGINT, int_exit); /* do sampling */ printf("Sampling at %d Hertz for %d seconds. Ctrl-C also ends.\n", freq, secs); if (sampling_start(pmu_fd, freq) != 0) return 1; sleep(secs); sampling_end(pmu_fd); free(pmu_fd); /* output sample counts */ print_ip_map(map_fd[0]); return 0; } 9'>9space:mode:
authorBenjamin Herrenschmidt <benh@kernel.crashing.org>2017-02-03 17:10:28 +1100
committerMichael Ellerman <mpe@ellerman.id.au>2017-02-08 23:36:29 +1100
commitd7df2443cd5f67fc6ee7c05a88e4996e8177f91b (patch)
tree098a7c0ca4fceb8a65cb1f693c9d71990388933d /tools/usb/ffs-aio-example/multibuff
parenta0615a16f7d0ceb5804d295203c302d496d8ee91 (diff)
powerpc/mm: Fix spurrious segfaults on radix with autonuma
When autonuma (Automatic NUMA balancing) marks a PTE inaccessible it clears all the protection bits but leave the PTE valid. With the Radix MMU, an attempt at executing from such a PTE will take a fault with bit 35 of SRR1 set "SRR1_ISI_N_OR_G". It is thus incorrect to treat all such faults as errors. We should pass them to handle_mm_fault() for autonuma to deal with. The case of pages that are really not executable is handled by the existing test for VM_EXEC further down. That leaves us with catching the kernel attempts at executing user pages. We can catch that earlier, even before we do find_vma. It is never valid on powerpc for the kernel to take an exec fault to begin with. So fold that test with the existing test for the kernel faulting on kernel addresses to bail out early. Fixes: 1d18ad026844 ("powerpc/mm: Detect instruction fetch denied and report") Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by: Balbir Singh <bsingharora@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'tools/usb/ffs-aio-example/multibuff')