From 6778948f9de86c3cfaf36725a7c87dcff9ba247f Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Mon, 11 Dec 2023 08:20:59 +0000
Subject: [PATCH] kernel_5.10 no rt
---
kernel/tools/testing/selftests/bpf/trace_helpers.c | 162 ++++++++++++++---------------------------------------
1 files changed, 43 insertions(+), 119 deletions(-)
diff --git a/kernel/tools/testing/selftests/bpf/trace_helpers.c b/kernel/tools/testing/selftests/bpf/trace_helpers.c
index 82922f1..1bbd1d9 100644
--- a/kernel/tools/testing/selftests/bpf/trace_helpers.c
+++ b/kernel/tools/testing/selftests/bpf/trace_helpers.c
@@ -4,11 +4,14 @@
#include <string.h>
#include <assert.h>
#include <errno.h>
+#include <fcntl.h>
#include <poll.h>
#include <unistd.h>
#include <linux/perf_event.h>
#include <sys/mman.h>
#include "trace_helpers.h"
+
+#define DEBUGFS "/sys/kernel/debug/tracing/"
#define MAX_SYMS 300000
static struct ksym syms[MAX_SYMS];
@@ -30,9 +33,7 @@
if (!f)
return -ENOENT;
- while (!feof(f)) {
- if (!fgets(buf, sizeof(buf), f))
- break;
+ while (fgets(buf, sizeof(buf), f)) {
if (sscanf(buf, "%p %c %s", &addr, &symbol, func) != 3)
break;
if (!addr)
@@ -89,126 +90,49 @@
return 0;
}
-static int page_size;
-static int page_cnt = 8;
-static struct perf_event_mmap_page *header;
-
-int perf_event_mmap_header(int fd, struct perf_event_mmap_page **header)
+/* open kallsyms and read symbol addresses on the fly. Without caching all symbols,
+ * this is faster than load + find.
+ */
+int kallsyms_find(const char *sym, unsigned long long *addr)
{
- void *base;
- int mmap_size;
+ char type, name[500];
+ unsigned long long value;
+ int err = 0;
+ FILE *f;
- page_size = getpagesize();
- mmap_size = page_size * (page_cnt + 1);
+ f = fopen("/proc/kallsyms", "r");
+ if (!f)
+ return -EINVAL;
- 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;
-}
-
-int perf_event_mmap(int fd)
-{
- return perf_event_mmap_header(fd, &header);
-}
-
-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;
-}
-
-int perf_event_poller_multi(int *fds, struct perf_event_mmap_page **headers,
- int num_fds, perf_event_print_fn output_fn)
-{
- enum bpf_perf_event_ret ret;
- struct pollfd *pfds;
- void *buf = NULL;
- size_t len = 0;
- int i;
-
- pfds = calloc(num_fds, sizeof(*pfds));
- if (!pfds)
- return LIBBPF_PERF_EVENT_ERROR;
-
- for (i = 0; i < num_fds; i++) {
- pfds[i].fd = fds[i];
- pfds[i].events = POLLIN;
- }
-
- for (;;) {
- poll(pfds, num_fds, 1000);
- for (i = 0; i < num_fds; i++) {
- if (!pfds[i].revents)
- continue;
-
- ret = bpf_perf_event_read_simple(headers[i],
- page_cnt * page_size,
- page_size, &buf, &len,
- bpf_perf_event_print,
- output_fn);
- if (ret != LIBBPF_PERF_EVENT_CONT)
- break;
+ while (fscanf(f, "%llx %c %499s%*[^\n]\n", &value, &type, name) > 0) {
+ if (strcmp(name, sym) == 0) {
+ *addr = value;
+ goto out;
}
}
- free(buf);
- free(pfds);
+ err = -ENOENT;
- return ret;
+out:
+ fclose(f);
+ return err;
+}
+
+void read_trace_pipe(void)
+{
+ int trace_fd;
+
+ trace_fd = open(DEBUGFS "trace_pipe", O_RDONLY, 0);
+ if (trace_fd < 0)
+ return;
+
+ while (1) {
+ static char buf[4096];
+ ssize_t sz;
+
+ sz = read(trace_fd, buf, sizeof(buf) - 1);
+ if (sz > 0) {
+ buf[sz] = 0;
+ puts(buf);
+ }
+ }
}
--
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