1 files changed, 175 insertions, 0 deletions

diff --git a/tools/perf/tests/rdpmc.c b/tools/perf/tests/rdpmc.c
new file mode 100644
index 000000000000..ff94886aad99
--- /dev/null
+++ b/tools/perf/tests/rdpmc.c
@@ -0,0 +1,175 @@
+#include <unistd.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <sys/mman.h>
+#include "types.h"
+#include "perf.h"
+#include "debug.h"
+#include "tests.h"
+
+#if defined(__x86_64__) || defined(__i386__)
+
+#define barrier() asm volatile("" ::: "memory")
+
+static u64 rdpmc(unsigned int counter)
+{
+        unsigned int low, high;
+
+        asm volatile("rdpmc" : "=a" (low), "=d" (high) : "c" (counter));
+
+        return low | ((u64)high) << 32;
+}
+
+static u64 rdtsc(void)
+{
+        unsigned int low, high;
+
+        asm volatile("rdtsc" : "=a" (low), "=d" (high));
+
+        return low | ((u64)high) << 32;
+}
+
+static u64 mmap_read_self(void *addr)
+{
+        struct perf_event_mmap_page *pc = addr;
+        u32 seq, idx, time_mult = 0, time_shift = 0;
+        u64 count, cyc = 0, time_offset = 0, enabled, running, delta;
+
+        do {
+                seq = pc->lock;
+                barrier();
+
+                enabled = pc->time_enabled;
+                running = pc->time_running;
+
+                if (enabled != running) {
+                        cyc = rdtsc();
+                        time_mult = pc->time_mult;
+                        time_shift = pc->time_shift;
+                        time_offset = pc->time_offset;
+                }
+
+                idx = pc->index;
+                count = pc->offset;
+                if (idx)
+                        count += rdpmc(idx - 1);
+
+                barrier();
+        } while (pc->lock != seq);
+
+        if (enabled != running) {
+                u64 quot, rem;
+
+                quot = (cyc >> time_shift);
+                rem = cyc & ((1 << time_shift) - 1);
+                delta = time_offset + quot * time_mult +
+                        ((rem * time_mult) >> time_shift);
+
+                enabled += delta;
+                if (idx)
+                        running += delta;
+
+                quot = count / running;
+                rem = count % running;
+                count = quot * enabled + (rem * enabled) / running;
+        }
+
+        return count;
+}
+
+/*
+ * If the RDPMC instruction faults then signal this back to the test parent task:
+ */
+static void segfault_handler(int sig __maybe_unused,
+                             siginfo_t *info __maybe_unused,
+                             void *uc __maybe_unused)
+{
+        exit(-1);
+}
+
+static int __test__rdpmc(void)
+{
+        volatile int tmp = 0;
+        u64 i, loops = 1000;
+        int n;
+        int fd;
+        void *addr;
+        struct perf_event_attr attr = {
+                .type = PERF_TYPE_HARDWARE,
+                .config = PERF_COUNT_HW_INSTRUCTIONS,
+                .exclude_kernel = 1,
+        };
+        u64 delta_sum = 0;
+        struct sigaction sa;
+
+        sigfillset(&sa.sa_mask);
+        sa.sa_sigaction = segfault_handler;
+        sigaction(SIGSEGV, &sa, NULL);
+
+        fd = sys_perf_event_open(&attr, 0, -1, -1, 0);
+        if (fd < 0) {
+                pr_err("Error: sys_perf_event_open() syscall returned "
+                       "with %d (%s)\n", fd, strerror(errno));
+                return -1;
+        }
+
+        addr = mmap(NULL, page_size, PROT_READ, MAP_SHARED, fd, 0);
+        if (addr == (void *)(-1)) {
+                pr_err("Error: mmap() syscall returned with (%s)\n",
+                       strerror(errno));
+                goto out_close;
+        }
+
+        for (n = 0; n < 6; n++) {
+                u64 stamp, now, delta;
+
+                stamp = mmap_read_self(addr);
+
+                for (i = 0; i < loops; i++)
+                        tmp++;
+
+                now = mmap_read_self(addr);
+                loops *= 10;
+
+                delta = now - stamp;
+                pr_debug("%14d: %14Lu\n", n, (long long)delta);
+
+                delta_sum += delta;
+        }
+
+        munmap(addr, page_size);
+        pr_debug("   ");
+out_close:
+        close(fd);
+
+        if (!delta_sum)
+                return -1;
+
+        return 0;
+}
+
+int test__rdpmc(void)
+{
+        int status = 0;
+        int wret = 0;
+        int ret;
+        int pid;
+
+        pid = fork();
+        if (pid < 0)
+                return -1;
+
+        if (!pid) {
+                ret = __test__rdpmc();
+
+                exit(ret);
+        }
+
+        wret = waitpid(pid, &status, 0);
+        if (wret < 0 || status)
+                return -1;
+
+        return 0;
+}
+
+#endif