1 files changed, 112 insertions, 0 deletions
diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index 282e3af85d5a..344e689567ee 100644
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -1798,3 +1798,115 @@ bool is_perf_pid_map_name(const char *dso_name)
 
 	return perf_pid_map_tid(dso_name, &tid);
 }
+
+struct find_file_offset_data {
+	u64 ip;
+	u64 offset;
+};
+
+/* This will be called for each PHDR in an ELF binary */
+static int find_file_offset(u64 start, u64 len, u64 pgoff, void *arg)
+{
+	struct find_file_offset_data *data = arg;
+
+	if (start <= data->ip && data->ip < start + len) {
+		data->offset = pgoff + data->ip - start;
+		return 1;
+	}
+	return 0;
+}
+
+static const u8 *__dso__read_symbol(struct dso *dso, const char *symfs_filename,
+				    u64 start, size_t len,
+				    u8 **out_buf, u64 *out_buf_len, bool *is_64bit)
+{
+	struct nscookie nsc;
+	int fd;
+	ssize_t count;
+	struct find_file_offset_data data = {
+		.ip = start,
+	};
+	u8 *code_buf = NULL;
+	int saved_errno;
+
+	nsinfo__mountns_enter(dso__nsinfo(dso), &nsc);
+	fd = open(symfs_filename, O_RDONLY);
+	saved_errno = errno;
+	nsinfo__mountns_exit(&nsc);
+	if (fd < 0) {
+		errno = saved_errno;
+		return NULL;
+	}
+	if (file__read_maps(fd, /*exe=*/true, find_file_offset, &data, is_64bit) <= 0) {
+		close(fd);
+		errno = ENOENT;
+		return NULL;
+	}
+	code_buf = malloc(len);
+	if (code_buf == NULL) {
+		close(fd);
+		errno = ENOMEM;
+		return NULL;
+	}
+	count = pread(fd, code_buf, len, data.offset);
+	saved_errno = errno;
+	close(fd);
+	if ((u64)count != len) {
+		free(code_buf);
+		errno = saved_errno;
+		return NULL;
+	}
+	*out_buf = code_buf;
+	*out_buf_len = len;
+	return code_buf;
+}
+
+/*
+ * Read a symbol into memory for disassembly by a library like capstone of
+ * libLLVM. If memory is allocated out_buf holds it.
+ */
+const u8 *dso__read_symbol(struct dso *dso, const char *symfs_filename,
+			   const struct map *map, const struct symbol *sym,
+			   u8 **out_buf, u64 *out_buf_len, bool *is_64bit)
+{
+	u64 start = map__rip_2objdump(map, sym->start);
+	u64 end = map__rip_2objdump(map, sym->end);
+	size_t len = end - start;
+
+	*out_buf = NULL;
+	*out_buf_len = 0;
+	*is_64bit = false;
+
+	if (dso__binary_type(dso) == DSO_BINARY_TYPE__BPF_IMAGE) {
+		/*
+		 * Note, there is fallback BPF image disassembly in the objdump
+		 * version but it currently does nothing.
+		 */
+		errno = EOPNOTSUPP;
+		return NULL;
+	}
+	if (dso__binary_type(dso) == DSO_BINARY_TYPE__BPF_PROG_INFO) {
+#ifdef HAVE_LIBBPF_SUPPORT
+		struct bpf_prog_info_node *info_node;
+		struct perf_bpil *info_linear;
+
+		*is_64bit = sizeof(void *) == sizeof(u64);
+		info_node = perf_env__find_bpf_prog_info(dso__bpf_prog(dso)->env,
+							 dso__bpf_prog(dso)->id);
+		if (!info_node) {
+			errno = SYMBOL_ANNOTATE_ERRNO__BPF_MISSING_BTF;
+			return NULL;
+		}
+		info_linear = info_node->info_linear;
+		assert(len <= info_linear->info.jited_prog_len);
+		*out_buf_len = len;
+		return (const u8 *)(uintptr_t)(info_linear->info.jited_prog_insns);
+#else
+		pr_debug("No BPF program disassembly support\n");
+		errno = EOPNOTSUPP;
+		return NULL;
+#endif
+	}
+	return __dso__read_symbol(dso, symfs_filename, start, len,
+				  out_buf, out_buf_len, is_64bit);
+}