Add perf context support for ARMv7

[lttng-ust.git] / liblttng-ust / lttng-context-perf-counters.c

diff --git a/liblttng-ust/lttng-context-perf-counters.c b/liblttng-ust/lttng-context-perf-counters.c
index 383d020ce42e02be05c4c89dbd578294091aa6c9..c98e2ebdceeb2786862fcb95d8f331ae115aab0d 100644 (file)
--- a/liblttng-ust/lttng-context-perf-counters.c
+++ b/liblttng-ust/lttng-context-perf-counters.c
@@ -96,17 +96,13 @@ static bool arch_perf_use_read(void)
        return false;
 }
 
-#else /* defined(__x86_64__) || defined(__i386__) */
-
-#error "Perf event counters are only supported on x86 so far."
-
-#endif /* #else defined(__x86_64__) || defined(__i386__) */
-
 static
-uint64_t read_perf_counter(struct perf_event_mmap_page *pc)
+uint64_t read_perf_counter(
+               struct lttng_perf_counter_thread_field *thread_field)
 {
        uint32_t seq, idx;
        uint64_t count;
+       struct perf_event_mmap_page *pc = thread_field->pc;
 
        if (caa_unlikely(!pc))
                return 0;
@@ -127,6 +123,35 @@ uint64_t read_perf_counter(struct perf_event_mmap_page *pc)
        return count;
 }
 
+#elif defined (__ARM_ARCH_7A__)
+
+static bool arch_perf_use_read(void)
+{
+       return true;
+}
+
+static
+uint64_t read_perf_counter(
+               struct lttng_perf_counter_thread_field *thread_field)
+{
+       uint64_t count;
+
+       if (caa_unlikely(thread_field->fd < 0))
+               return 0;
+
+       if (caa_unlikely(read(thread_field->fd, &count, sizeof(count))
+                               < sizeof(count)))
+               return 0;
+
+       return count;
+}
+
+#else /* defined(__x86_64__) || defined(__i386__) || defined(__ARM_ARCH_7A__) */
+
+#error "Perf event counters are only supported on x86 and ARMv7 so far."
+
+#endif /* #else defined(__x86_64__) || defined(__i386__) || defined(__ARM_ARCH_7A__) */
+
 static
 int sys_perf_event_open(struct perf_event_attr *attr,
                pid_t pid, int cpu, int group_fd,
@@ -148,6 +173,20 @@ int open_perf_fd(struct perf_event_attr *attr)
        return fd;
 }
 
+static
+void close_perf_fd(int fd)
+{
+       int ret;
+
+       if (fd < 0)
+               return;
+
+       ret = close(fd);
+       if (ret) {
+               perror("Error closing LTTng-UST perf memory mapping FD");
+       }
+}
+
 static
 struct perf_event_mmap_page *setup_perf(
                struct lttng_perf_counter_thread_field *thread_field)
@@ -164,23 +203,9 @@ struct perf_event_mmap_page *setup_perf(
                thread_field->fd = -1;
        }
 
-end:
        return perf_addr;
 }
 
-static
-void close_perf_fd(int fd)
-{
-       int ret;
-
-       if (fd < 0)
-               return;
-
-       ret = close(fd);
-       if (ret)
-               perror("Error closing LTTng-UST perf memory mapping FD");
-}
-
 static
 void unmap_perf_page(struct perf_event_mmap_page *pc)
 {
@@ -298,7 +323,7 @@ uint64_t wrapper_perf_counter_read(struct lttng_ctx_field *field)
 
        perf_field = field->u.perf_counter;
        perf_thread_field = get_thread_field(perf_field);
-       return read_perf_counter(perf_thread_field->pc);
+       return read_perf_counter(perf_thread_field);
 }
 
 static
@@ -369,6 +394,24 @@ void lttng_destroy_perf_counter_field(struct lttng_ctx_field *field)
        free(perf_field);
 }
 
+#ifdef __ARM_ARCH_7A__
+
+static
+int perf_get_exclude_kernel(void)
+{
+       return 0;
+}
+
+#else /* __ARM_ARCH_7A__ */
+
+static
+int perf_get_exclude_kernel(void)
+{
+       return 1;
+}
+
+#endif /* __ARM_ARCH_7A__ */
+
 /* Called with UST lock held */
 int lttng_add_perf_counter_to_ctx(uint32_t type,
                                uint64_t config,
@@ -419,7 +462,7 @@ int lttng_add_perf_counter_to_ctx(uint32_t type,
 
        perf_field->attr.type = type;
        perf_field->attr.config = config;
-       perf_field->attr.exclude_kernel = 1;
+       perf_field->attr.exclude_kernel = perf_get_exclude_kernel();
        CDS_INIT_LIST_HEAD(&perf_field->thread_field_list);
        field->u.perf_counter = perf_field;