samples/bpf: move common-purpose trace functions to selftests

There is no functionality change in this patch. The common-purpose
trace functions, including perf_event polling and ksym lookup,
are moved from trace_output_user.c and bpf_load.c to
selftests/bpf/trace_helpers.c so that these function can
be reused later in selftests.

Acked-by: Alexei Starovoitov <ast@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 10 insertions, 100 deletions

diff --git a/samples/bpf/trace_output_user.c b/samples/bpf/trace_output_user.c
index ccca1e348017..5e78c2ecd08d 100644
--- a/samples/bpf/trace_output_user.c
+++ b/samples/bpf/trace_output_user.c
@@ -21,100 +21,10 @@
 #include "libbpf.h"
 #include "bpf_load.h"
 #include "perf-sys.h"
+#include "trace_helpers.h"
 
 static int pmu_fd;
 
-int page_size;
-int page_cnt = 8;
-volatile struct perf_event_mmap_page *header;
-
-typedef void (*print_fn)(void *data, int size);
-
-static int perf_event_mmap(int fd)
-{
-	void *base;
-	int mmap_size;
-
-	page_size = getpagesize();
-	mmap_size = page_size * (page_cnt + 1);
-
-	base = mmap(NULL, mmap_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
-	if (base == MAP_FAILED) {
-		printf("mmap err\n");
-		return -1;
-	}
-
-	header = base;
-	return 0;
-}
-
-static int perf_event_poll(int fd)
-{
-	struct pollfd pfd = { .fd = fd, .events = POLLIN };
-
-	return poll(&pfd, 1, 1000);
-}
-
-struct perf_event_sample {
-	struct perf_event_header header;
-	__u32 size;
-	char data[];
-};
-
-static void perf_event_read(print_fn fn)
-{
-	__u64 data_tail = header->data_tail;
-	__u64 data_head = header->data_head;
-	__u64 buffer_size = page_cnt * page_size;
-	void *base, *begin, *end;
-	char buf[256];
-
-	asm volatile("" ::: "memory"); /* in real code it should be smp_rmb() */
-	if (data_head == data_tail)
-		return;
-
-	base = ((char *)header) + page_size;
-
-	begin = base + data_tail % buffer_size;
-	end = base + data_head % buffer_size;
-
-	while (begin != end) {
-		struct perf_event_sample *e;
-
-		e = begin;
-		if (begin + e->header.size > base + buffer_size) {
-			long len = base + buffer_size - begin;
-
-			assert(len < e->header.size);
-			memcpy(buf, begin, len);
-			memcpy(buf + len, base, e->header.size - len);
-			e = (void *) buf;
-			begin = base + e->header.size - len;
-		} else if (begin + e->header.size == base + buffer_size) {
-			begin = base;
-		} else {
-			begin += e->header.size;
-		}
-
-		if (e->header.type == PERF_RECORD_SAMPLE) {
-			fn(e->data, e->size);
-		} else if (e->header.type == PERF_RECORD_LOST) {
-			struct {
-				struct perf_event_header header;
-				__u64 id;
-				__u64 lost;
-			} *lost = (void *) e;
-			printf("lost %lld events\n", lost->lost);
-		} else {
-			printf("unknown event type=%d size=%d\n",
-			       e->header.type, e->header.size);
-		}
-	}
-
-	__sync_synchronize(); /* smp_mb() */
-	header->data_tail = data_head;
-}
-
 static __u64 time_get_ns(void)
 {
 	struct timespec ts;
@@ -127,7 +37,7 @@ static __u64 start_time;
 
 #define MAX_CNT 100000ll
 
-static void print_bpf_output(void *data, int size)
+static int print_bpf_output(void *data, int size)
 {
 	static __u64 cnt;
 	struct {
@@ -138,7 +48,7 @@ static void print_bpf_output(void *data, int size)
 	if (e->cookie != 0x12345678) {
 		printf("BUG pid %llx cookie %llx sized %d\n",
 		       e->pid, e->cookie, size);
-		kill(0, SIGINT);
+		return PERF_EVENT_ERROR;
 	}
 
 	cnt++;
@@ -146,8 +56,10 @@ static void print_bpf_output(void *data, int size)
 	if (cnt == MAX_CNT) {
 		printf("recv %lld events per sec\n",
 		       MAX_CNT * 1000000000ll / (time_get_ns() - start_time));
-		kill(0, SIGINT);
+		return PERF_EVENT_DONE;
 	}
+
+	return PERF_EVENT_CONT;
 }
 
 static void test_bpf_perf_event(void)
@@ -170,6 +82,7 @@ int main(int argc, char **argv)
 {
 	char filename[256];
 	FILE *f;
+	int ret;
 
 	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
 
@@ -187,10 +100,7 @@ int main(int argc, char **argv)
 	(void) f;
 
 	start_time = time_get_ns();
-	for (;;) {
-		perf_event_poll(pmu_fd);
-		perf_event_read(print_bpf_output);
-	}
-
-	return 0;
+	ret = perf_event_poller(pmu_fd, print_bpf_output);
+	kill(0, SIGINT);
+	return ret;
 }