1 files changed, 165 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/trace_helpers.c b/tools/testing/selftests/bpf/trace_helpers.c
new file mode 100644
index 000000000000..3868dcb63420
--- /dev/null
+++ b/tools/testing/selftests/bpf/trace_helpers.c
@@ -0,0 +1,165 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+#include <errno.h>
+#include <poll.h>
+#include <unistd.h>
+#include <linux/perf_event.h>
+#include <sys/mman.h>
+#include "trace_helpers.h"
+
+#define MAX_SYMS 300000
+static struct ksym syms[MAX_SYMS];
+static int sym_cnt;
+
+static int ksym_cmp(const void *p1, const void *p2)
+{
+	return ((struct ksym *)p1)->addr - ((struct ksym *)p2)->addr;
+}
+
+int load_kallsyms(void)
+{
+	FILE *f = fopen("/proc/kallsyms", "r");
+	char func[256], buf[256];
+	char symbol;
+	void *addr;
+	int i = 0;
+
+	if (!f)
+		return -ENOENT;
+
+	while (!feof(f)) {
+		if (!fgets(buf, sizeof(buf), f))
+			break;
+		if (sscanf(buf, "%p %c %s", &addr, &symbol, func) != 3)
+			break;
+		if (!addr)
+			continue;
+		syms[i].addr = (long) addr;
+		syms[i].name = strdup(func);
+		i++;
+	}
+	sym_cnt = i;
+	qsort(syms, sym_cnt, sizeof(struct ksym), ksym_cmp);
+	return 0;
+}
+
+struct ksym *ksym_search(long key)
+{
+	int start = 0, end = sym_cnt;
+	int result;
+
+	while (start < end) {
+		size_t mid = start + (end - start) / 2;
+
+		result = key - syms[mid].addr;
+		if (result < 0)
+			end = mid;
+		else if (result > 0)
+			start = mid + 1;
+		else
+			return &syms[mid];
+	}
+
+	if (start >= 1 && syms[start - 1].addr < key &&
+	    key < syms[start].addr)
+		/* valid ksym */
+		return &syms[start - 1];
+
+	/* out of range. return _stext */
+	return &syms[0];
+}
+
+long ksym_get_addr(const char *name)
+{
+	int i;
+
+	for (i = 0; i < sym_cnt; i++) {
+		if (strcmp(syms[i].name, name) == 0)
+			return syms[i].addr;
+	}
+
+	return 0;
+}
+
+static int page_size;
+static int page_cnt = 8;
+static struct perf_event_mmap_page *header;
+
+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 enum bpf_perf_event_ret bpf_perf_event_print(void *event, void *priv)
+{
+	struct perf_event_sample *e = event;
+	perf_event_print_fn fn = priv;
+	int ret;
+
+	if (e->header.type == PERF_RECORD_SAMPLE) {
+		ret = fn(e->data, e->size);
+		if (ret != LIBBPF_PERF_EVENT_CONT)
+			return ret;
+	} 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);
+	}
+
+	return LIBBPF_PERF_EVENT_CONT;
+}
+
+int perf_event_poller(int fd, perf_event_print_fn output_fn)
+{
+	enum bpf_perf_event_ret ret;
+	void *buf = NULL;
+	size_t len = 0;
+
+	for (;;) {
+		perf_event_poll(fd);
+		ret = bpf_perf_event_read_simple(header, page_cnt * page_size,
+						 page_size, &buf, &len,
+						 bpf_perf_event_print,
+						 output_fn);
+		if (ret != LIBBPF_PERF_EVENT_CONT)
+			break;
+	}
+	free(buf);
+
+	return ret;
+}