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-rw-r--r--tools/lib/perf/mmap.c459
1 files changed, 459 insertions, 0 deletions
diff --git a/tools/lib/perf/mmap.c b/tools/lib/perf/mmap.c
new file mode 100644
index 000000000..0d1634ced
--- /dev/null
+++ b/tools/lib/perf/mmap.c
@@ -0,0 +1,459 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <sys/mman.h>
+#include <inttypes.h>
+#include <asm/bug.h>
+#include <errno.h>
+#include <string.h>
+#include <linux/ring_buffer.h>
+#include <linux/perf_event.h>
+#include <perf/mmap.h>
+#include <perf/event.h>
+#include <perf/evsel.h>
+#include <internal/mmap.h>
+#include <internal/lib.h>
+#include <linux/kernel.h>
+#include <linux/math64.h>
+#include <linux/stringify.h>
+#include "internal.h"
+
+void perf_mmap__init(struct perf_mmap *map, struct perf_mmap *prev,
+ bool overwrite, libperf_unmap_cb_t unmap_cb)
+{
+ map->fd = -1;
+ map->overwrite = overwrite;
+ map->unmap_cb = unmap_cb;
+ refcount_set(&map->refcnt, 0);
+ if (prev)
+ prev->next = map;
+}
+
+size_t perf_mmap__mmap_len(struct perf_mmap *map)
+{
+ return map->mask + 1 + page_size;
+}
+
+int perf_mmap__mmap(struct perf_mmap *map, struct perf_mmap_param *mp,
+ int fd, struct perf_cpu cpu)
+{
+ map->prev = 0;
+ map->mask = mp->mask;
+ map->base = mmap(NULL, perf_mmap__mmap_len(map), mp->prot,
+ MAP_SHARED, fd, 0);
+ if (map->base == MAP_FAILED) {
+ map->base = NULL;
+ return -1;
+ }
+
+ map->fd = fd;
+ map->cpu = cpu;
+ return 0;
+}
+
+void perf_mmap__munmap(struct perf_mmap *map)
+{
+ if (map && map->base != NULL) {
+ munmap(map->base, perf_mmap__mmap_len(map));
+ map->base = NULL;
+ map->fd = -1;
+ refcount_set(&map->refcnt, 0);
+ }
+ if (map && map->unmap_cb)
+ map->unmap_cb(map);
+}
+
+void perf_mmap__get(struct perf_mmap *map)
+{
+ refcount_inc(&map->refcnt);
+}
+
+void perf_mmap__put(struct perf_mmap *map)
+{
+ BUG_ON(map->base && refcount_read(&map->refcnt) == 0);
+
+ if (refcount_dec_and_test(&map->refcnt))
+ perf_mmap__munmap(map);
+}
+
+static inline void perf_mmap__write_tail(struct perf_mmap *md, u64 tail)
+{
+ ring_buffer_write_tail(md->base, tail);
+}
+
+u64 perf_mmap__read_head(struct perf_mmap *map)
+{
+ return ring_buffer_read_head(map->base);
+}
+
+static bool perf_mmap__empty(struct perf_mmap *map)
+{
+ struct perf_event_mmap_page *pc = map->base;
+
+ return perf_mmap__read_head(map) == map->prev && !pc->aux_size;
+}
+
+void perf_mmap__consume(struct perf_mmap *map)
+{
+ if (!map->overwrite) {
+ u64 old = map->prev;
+
+ perf_mmap__write_tail(map, old);
+ }
+
+ if (refcount_read(&map->refcnt) == 1 && perf_mmap__empty(map))
+ perf_mmap__put(map);
+}
+
+static int overwrite_rb_find_range(void *buf, int mask, u64 *start, u64 *end)
+{
+ struct perf_event_header *pheader;
+ u64 evt_head = *start;
+ int size = mask + 1;
+
+ pr_debug2("%s: buf=%p, start=%"PRIx64"\n", __func__, buf, *start);
+ pheader = (struct perf_event_header *)(buf + (*start & mask));
+ while (true) {
+ if (evt_head - *start >= (unsigned int)size) {
+ pr_debug("Finished reading overwrite ring buffer: rewind\n");
+ if (evt_head - *start > (unsigned int)size)
+ evt_head -= pheader->size;
+ *end = evt_head;
+ return 0;
+ }
+
+ pheader = (struct perf_event_header *)(buf + (evt_head & mask));
+
+ if (pheader->size == 0) {
+ pr_debug("Finished reading overwrite ring buffer: get start\n");
+ *end = evt_head;
+ return 0;
+ }
+
+ evt_head += pheader->size;
+ pr_debug3("move evt_head: %"PRIx64"\n", evt_head);
+ }
+ WARN_ONCE(1, "Shouldn't get here\n");
+ return -1;
+}
+
+/*
+ * Report the start and end of the available data in ringbuffer
+ */
+static int __perf_mmap__read_init(struct perf_mmap *md)
+{
+ u64 head = perf_mmap__read_head(md);
+ u64 old = md->prev;
+ unsigned char *data = md->base + page_size;
+ unsigned long size;
+
+ md->start = md->overwrite ? head : old;
+ md->end = md->overwrite ? old : head;
+
+ if ((md->end - md->start) < md->flush)
+ return -EAGAIN;
+
+ size = md->end - md->start;
+ if (size > (unsigned long)(md->mask) + 1) {
+ if (!md->overwrite) {
+ WARN_ONCE(1, "failed to keep up with mmap data. (warn only once)\n");
+
+ md->prev = head;
+ perf_mmap__consume(md);
+ return -EAGAIN;
+ }
+
+ /*
+ * Backward ring buffer is full. We still have a chance to read
+ * most of data from it.
+ */
+ if (overwrite_rb_find_range(data, md->mask, &md->start, &md->end))
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+int perf_mmap__read_init(struct perf_mmap *map)
+{
+ /*
+ * Check if event was unmapped due to a POLLHUP/POLLERR.
+ */
+ if (!refcount_read(&map->refcnt))
+ return -ENOENT;
+
+ return __perf_mmap__read_init(map);
+}
+
+/*
+ * Mandatory for overwrite mode
+ * The direction of overwrite mode is backward.
+ * The last perf_mmap__read() will set tail to map->core.prev.
+ * Need to correct the map->core.prev to head which is the end of next read.
+ */
+void perf_mmap__read_done(struct perf_mmap *map)
+{
+ /*
+ * Check if event was unmapped due to a POLLHUP/POLLERR.
+ */
+ if (!refcount_read(&map->refcnt))
+ return;
+
+ map->prev = perf_mmap__read_head(map);
+}
+
+/* When check_messup is true, 'end' must points to a good entry */
+static union perf_event *perf_mmap__read(struct perf_mmap *map,
+ u64 *startp, u64 end)
+{
+ unsigned char *data = map->base + page_size;
+ union perf_event *event = NULL;
+ int diff = end - *startp;
+
+ if (diff >= (int)sizeof(event->header)) {
+ size_t size;
+
+ event = (union perf_event *)&data[*startp & map->mask];
+ size = event->header.size;
+
+ if (size < sizeof(event->header) || diff < (int)size)
+ return NULL;
+
+ /*
+ * Event straddles the mmap boundary -- header should always
+ * be inside due to u64 alignment of output.
+ */
+ if ((*startp & map->mask) + size != ((*startp + size) & map->mask)) {
+ unsigned int offset = *startp;
+ unsigned int len = min(sizeof(*event), size), cpy;
+ void *dst = map->event_copy;
+
+ do {
+ cpy = min(map->mask + 1 - (offset & map->mask), len);
+ memcpy(dst, &data[offset & map->mask], cpy);
+ offset += cpy;
+ dst += cpy;
+ len -= cpy;
+ } while (len);
+
+ event = (union perf_event *)map->event_copy;
+ }
+
+ *startp += size;
+ }
+
+ return event;
+}
+
+/*
+ * Read event from ring buffer one by one.
+ * Return one event for each call.
+ *
+ * Usage:
+ * perf_mmap__read_init()
+ * while(event = perf_mmap__read_event()) {
+ * //process the event
+ * perf_mmap__consume()
+ * }
+ * perf_mmap__read_done()
+ */
+union perf_event *perf_mmap__read_event(struct perf_mmap *map)
+{
+ union perf_event *event;
+
+ /*
+ * Check if event was unmapped due to a POLLHUP/POLLERR.
+ */
+ if (!refcount_read(&map->refcnt))
+ return NULL;
+
+ /* non-overwirte doesn't pause the ringbuffer */
+ if (!map->overwrite)
+ map->end = perf_mmap__read_head(map);
+
+ event = perf_mmap__read(map, &map->start, map->end);
+
+ if (!map->overwrite)
+ map->prev = map->start;
+
+ return event;
+}
+
+#if defined(__i386__) || defined(__x86_64__)
+static u64 read_perf_counter(unsigned int counter)
+{
+ unsigned int low, high;
+
+ asm volatile("rdpmc" : "=a" (low), "=d" (high) : "c" (counter));
+
+ return low | ((u64)high) << 32;
+}
+
+static u64 read_timestamp(void)
+{
+ unsigned int low, high;
+
+ asm volatile("rdtsc" : "=a" (low), "=d" (high));
+
+ return low | ((u64)high) << 32;
+}
+#elif defined(__aarch64__)
+#define read_sysreg(r) ({ \
+ u64 __val; \
+ asm volatile("mrs %0, " __stringify(r) : "=r" (__val)); \
+ __val; \
+})
+
+static u64 read_pmccntr(void)
+{
+ return read_sysreg(pmccntr_el0);
+}
+
+#define PMEVCNTR_READ(idx) \
+ static u64 read_pmevcntr_##idx(void) { \
+ return read_sysreg(pmevcntr##idx##_el0); \
+ }
+
+PMEVCNTR_READ(0);
+PMEVCNTR_READ(1);
+PMEVCNTR_READ(2);
+PMEVCNTR_READ(3);
+PMEVCNTR_READ(4);
+PMEVCNTR_READ(5);
+PMEVCNTR_READ(6);
+PMEVCNTR_READ(7);
+PMEVCNTR_READ(8);
+PMEVCNTR_READ(9);
+PMEVCNTR_READ(10);
+PMEVCNTR_READ(11);
+PMEVCNTR_READ(12);
+PMEVCNTR_READ(13);
+PMEVCNTR_READ(14);
+PMEVCNTR_READ(15);
+PMEVCNTR_READ(16);
+PMEVCNTR_READ(17);
+PMEVCNTR_READ(18);
+PMEVCNTR_READ(19);
+PMEVCNTR_READ(20);
+PMEVCNTR_READ(21);
+PMEVCNTR_READ(22);
+PMEVCNTR_READ(23);
+PMEVCNTR_READ(24);
+PMEVCNTR_READ(25);
+PMEVCNTR_READ(26);
+PMEVCNTR_READ(27);
+PMEVCNTR_READ(28);
+PMEVCNTR_READ(29);
+PMEVCNTR_READ(30);
+
+/*
+ * Read a value direct from PMEVCNTR<idx>
+ */
+static u64 read_perf_counter(unsigned int counter)
+{
+ static u64 (* const read_f[])(void) = {
+ read_pmevcntr_0,
+ read_pmevcntr_1,
+ read_pmevcntr_2,
+ read_pmevcntr_3,
+ read_pmevcntr_4,
+ read_pmevcntr_5,
+ read_pmevcntr_6,
+ read_pmevcntr_7,
+ read_pmevcntr_8,
+ read_pmevcntr_9,
+ read_pmevcntr_10,
+ read_pmevcntr_11,
+ read_pmevcntr_13,
+ read_pmevcntr_12,
+ read_pmevcntr_14,
+ read_pmevcntr_15,
+ read_pmevcntr_16,
+ read_pmevcntr_17,
+ read_pmevcntr_18,
+ read_pmevcntr_19,
+ read_pmevcntr_20,
+ read_pmevcntr_21,
+ read_pmevcntr_22,
+ read_pmevcntr_23,
+ read_pmevcntr_24,
+ read_pmevcntr_25,
+ read_pmevcntr_26,
+ read_pmevcntr_27,
+ read_pmevcntr_28,
+ read_pmevcntr_29,
+ read_pmevcntr_30,
+ read_pmccntr
+ };
+
+ if (counter < ARRAY_SIZE(read_f))
+ return (read_f[counter])();
+
+ return 0;
+}
+
+static u64 read_timestamp(void) { return read_sysreg(cntvct_el0); }
+
+#else
+static u64 read_perf_counter(unsigned int counter __maybe_unused) { return 0; }
+static u64 read_timestamp(void) { return 0; }
+#endif
+
+int perf_mmap__read_self(struct perf_mmap *map, struct perf_counts_values *count)
+{
+ struct perf_event_mmap_page *pc = map->base;
+ u32 seq, idx, time_mult = 0, time_shift = 0;
+ u64 cnt, cyc = 0, time_offset = 0, time_cycles = 0, time_mask = ~0ULL;
+
+ if (!pc || !pc->cap_user_rdpmc)
+ return -1;
+
+ do {
+ seq = READ_ONCE(pc->lock);
+ barrier();
+
+ count->ena = READ_ONCE(pc->time_enabled);
+ count->run = READ_ONCE(pc->time_running);
+
+ if (pc->cap_user_time && count->ena != count->run) {
+ cyc = read_timestamp();
+ time_mult = READ_ONCE(pc->time_mult);
+ time_shift = READ_ONCE(pc->time_shift);
+ time_offset = READ_ONCE(pc->time_offset);
+
+ if (pc->cap_user_time_short) {
+ time_cycles = READ_ONCE(pc->time_cycles);
+ time_mask = READ_ONCE(pc->time_mask);
+ }
+ }
+
+ idx = READ_ONCE(pc->index);
+ cnt = READ_ONCE(pc->offset);
+ if (pc->cap_user_rdpmc && idx) {
+ s64 evcnt = read_perf_counter(idx - 1);
+ u16 width = READ_ONCE(pc->pmc_width);
+
+ evcnt <<= 64 - width;
+ evcnt >>= 64 - width;
+ cnt += evcnt;
+ } else
+ return -1;
+
+ barrier();
+ } while (READ_ONCE(pc->lock) != seq);
+
+ if (count->ena != count->run) {
+ u64 delta;
+
+ /* Adjust for cap_usr_time_short, a nop if not */
+ cyc = time_cycles + ((cyc - time_cycles) & time_mask);
+
+ delta = time_offset + mul_u64_u32_shr(cyc, time_mult, time_shift);
+
+ count->ena += delta;
+ if (idx)
+ count->run += delta;
+ }
+
+ count->val = cnt;
+
+ return 0;
+}
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