@@ -1,5 +1,6 @@
// SPDX-License-Identifier: GPL-2.0
#include <errno.h>
+#include <linux/kconfig.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <inttypes.h>
@@ -8,6 +9,7 @@
#include <stdio.h>
#include <string.h>
#include <sys/param.h>
+#include <sys/utsname.h>
#include <perf/cpumap.h>
#include <perf/evlist.h>
#include <perf/mmap.h>
@@ -176,16 +178,104 @@ static int read_objdump_output(FILE *f, void *buf, size_t *len, u64 start_addr)
return err;
}
+/*
+ * Only gets GNU objdump version. Returns 0 for llvm-objdump.
+ */
+static int objdump_version(void)
+{
+ size_t line_len;
+ char cmd[PATH_MAX * 2];
+ char *line = NULL;
+ const char *fmt;
+ FILE *f;
+ int ret;
+
+ int version_tmp, version_num = 0;
+ char *version = 0, *token;
+
+ fmt = "%s --version";
+ ret = snprintf(cmd, sizeof(cmd), fmt, test_objdump_path);
+ if (ret <= 0 || (size_t)ret >= sizeof(cmd))
+ return -1;
+ /* Ignore objdump errors */
+ strcat(cmd, " 2>/dev/null");
+ f = popen(cmd, "r");
+ if (!f) {
+ pr_debug("popen failed\n");
+ return -1;
+ }
+ /* Get first line of objdump --version output */
+ ret = getline(&line, &line_len, f);
+ pclose(f);
+ if (ret < 0) {
+ pr_debug("getline failed\n");
+ return -1;
+ }
+
+ token = strsep(&line, " ");
+ if (token != NULL && !strcmp(token, "GNU")) {
+ // version is last part of first line of objdump --version output.
+ while ((token = strsep(&line, " ")))
+ version = token;
+
+ // Convert version into a format we can compare with
+ token = strsep(&version, ".");
+ version_num = atoi(token);
+ if (version_num)
+ version_num *= 10000;
+
+ token = strsep(&version, ".");
+ version_tmp = atoi(token);
+ if (token)
+ version_num += version_tmp * 100;
+
+ token = strsep(&version, ".");
+ version_tmp = atoi(token);
+ if (token)
+ version_num += version_tmp;
+ }
+
+ return version_num;
+}
+
static int read_via_objdump(const char *filename, u64 addr, void *buf,
size_t len)
{
+ u64 stop_address = addr + len;
+ struct utsname uname_buf;
char cmd[PATH_MAX * 2];
const char *fmt;
FILE *f;
int ret;
+ ret = uname(&uname_buf);
+ if (ret) {
+ pr_debug("uname failed\n");
+ return -1;
+ }
+
+ if (!strncmp(uname_buf.machine, "riscv", 5)) {
+ int version = objdump_version();
+
+ /* Default to this workaround if version parsing fails */
+ if (version < 0 || version > 24100) {
+ /*
+ * Starting at riscv objdump version 2.41, dumping in
+ * the middle of an instruction is not supported. riscv
+ * instructions are aligned along 2-byte intervals and
+ * can be either 2-bytes or 4-bytes. This makes it
+ * possible that the stop-address lands in the middle of
+ * a 4-byte instruction. Increase the stop_address by
+ * two to ensure an instruction is not cut in half, but
+ * leave the len as-is so only the expected number of
+ * bytes are collected.
+ */
+ stop_address += 2;
+ }
+ }
+
fmt = "%s -z -d --start-address=0x%"PRIx64" --stop-address=0x%"PRIx64" %s";
- ret = snprintf(cmd, sizeof(cmd), fmt, test_objdump_path, addr, addr + len,
+ ret = snprintf(cmd, sizeof(cmd), fmt, test_objdump_path, addr, stop_address,
filename);
if (ret <= 0 || (size_t)ret >= sizeof(cmd))
return -1;
After binutils commit e43d876 which was first included in binutils 2.41, riscv no longer supports dumping in the middle of instructions. Increase the objdump window by 2-bytes to ensure that any instruction that sits on the boundary of the specified stop-address is not cut in half. Signed-off-by: Charlie Jenkins <charlie@rivosinc.com> --- A binutils patch has been sent as well to fix this in objdump [1]. Link: https://sourceware.org/pipermail/binutils/2024-December/138139.html [1] --- Changes in v3: - Dynamically detect riscv for objdump change (Arnaldo) - Link to v2: https://lore.kernel.org/r/20241217-perf_fix_riscv_obj_reading-v2-1-58f81b7b4c7d@rivosinc.com Changes in v2: - Do objdump version detection at runtime (Ian) - Link to v1: https://lore.kernel.org/r/20241216-perf_fix_riscv_obj_reading-v1-0-b75962660a9b@rivosinc.com --- tools/perf/tests/code-reading.c | 92 ++++++++++++++++++++++++++++++++++++++++- 1 file changed, 91 insertions(+), 1 deletion(-) --- base-commit: 233157785a34612e5899be6edcc6a53ea682d379 change-id: 20241213-perf_fix_riscv_obj_reading-cabf02be3c85