Fix: perf counters build against kernel headers < 3.12

[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 dbb1e6b1dcf368d339053ba1c199f90347007e79..7e87be94cfa5a5f7c19d63fe449b8c3ae70d5a76 100644 (file)
--- a/liblttng-ust/lttng-context-perf-counters.c
+++ b/liblttng-ust/lttng-context-perf-counters.c
@@ -28,7 +28,6 @@
 #include <stdbool.h>
 #include <sys/mman.h>
 #include <sys/syscall.h>
-#include <linux/perf_event.h>
 #include <lttng/ust-events.h>
 #include <lttng/ust-tracer.h>
 #include <lttng/ringbuffer-config.h>
@@ -39,6 +38,7 @@
 #include <urcu/ref.h>
 #include <usterr-signal-safe.h>
 #include <signal.h>
+#include "perf_event.h"
 #include "lttng-tracer-core.h"
 
 /*
@@ -108,6 +108,15 @@ uint64_t rdpmc(unsigned int counter)
        return low | ((uint64_t) high) << 32;
 }
 
+static
+bool has_rdpmc(struct perf_event_mmap_page *pc)
+{
+       if (caa_unlikely(!pc->cap_bit0_is_deprecated))
+               return false;
+       /* Since Linux kernel 3.12. */
+       return pc->cap_user_rdpmc;
+}
+
 static
 uint64_t arch_read_perf_counter(
                struct lttng_perf_counter_thread_field *thread_field)
@@ -124,7 +133,7 @@ uint64_t arch_read_perf_counter(
                cmm_barrier();
 
                idx = pc->index;
-               if (caa_likely(pc->cap_user_rdpmc && idx)) {
+               if (caa_likely(has_rdpmc(pc) && idx)) {
                        int64_t pmcval;
 
                        pmcval = rdpmc(idx - 1);
@@ -149,7 +158,7 @@ int arch_perf_keep_fd(struct lttng_perf_counter_thread_field *thread_field)
 
        if (!pc)
                return 0;
-       return !pc->cap_user_rdpmc;
+       return !has_rdpmc(pc);
 }
 
 #else
@@ -205,9 +214,7 @@ void close_perf_fd(int fd)
        }
 }
 
-static
-struct perf_event_mmap_page *setup_perf(
-               struct lttng_perf_counter_thread_field *thread_field)
+static void setup_perf(struct lttng_perf_counter_thread_field *thread_field)
 {
        void *perf_addr;
 
@@ -215,13 +222,12 @@ struct perf_event_mmap_page *setup_perf(
                        PROT_READ, MAP_SHARED, thread_field->fd, 0);
        if (perf_addr == MAP_FAILED)
                perf_addr = NULL;
+       thread_field->pc = perf_addr;
 
        if (!arch_perf_keep_fd(thread_field)) {
                close_perf_fd(thread_field->fd);
                thread_field->fd = -1;
        }
-
-       return perf_addr;
 }
 
 static
@@ -296,7 +302,7 @@ struct lttng_perf_counter_thread_field *
        thread_field->field = perf_field;
        thread_field->fd = open_perf_fd(&perf_field->attr);
        if (thread_field->fd >= 0)
-               thread_field->pc = setup_perf(thread_field);
+               setup_perf(thread_field);
        /*
         * Note: thread_field->pc can be NULL if setup_perf() fails.
         * Also, thread_field->fd can be -1 if open_perf_fd() fails.