perf probe: Fixup Arm64 SDT arguments

Arm64 ELF section '.note.stapsdt' uses string format "-4@[sp, NUM]" if
the probe is to access data in stack, e.g. below is an example for
dumping Arm64 ELF file and shows the argument format:

  Arguments: -4@[sp, 12] -4@[sp, 8] -4@[sp, 4]

Comparing against other archs' argument format, Arm64's argument
introduces an extra space character in the middle of square brackets,
due to argv_split() uses space as splitter, the argument is wrongly
divided into two items.

To support Arm64 SDT, this patch fixes up for this case, if any item
contains sub string "[sp", concatenates the two continuous items.  And
adds the detailed explaination in comment.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexandre Truong <alexandre.truong@arm.com>
Cc: Alexis Berlemont <alexis.berlemont@gmail.com>
Cc: He Zhe <zhe.he@windriver.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lore.kernel.org/lkml/20201225052751.24513-3-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/probe-file.c b/tools/perf/util/probe-file.c
index bbecb449ea9443954a8bd5e71e3977cfb80104e1..52273542e6ef48e1c957752c152ca196a79d7587 100644 (file)
--- a/tools/perf/util/probe-file.c
+++ b/tools/perf/util/probe-file.c
@@ -794,6 +794,8 @@ static char *synthesize_sdt_probe_command(struct sdt_note *note,
        char *ret = NULL;
        int i, args_count, err;
        unsigned long long ref_ctr_offset;
+       char *arg;
+       int arg_idx = 0;
 
        if (strbuf_init(&buf, 32) < 0)
                return NULL;
@@ -818,11 +820,43 @@ static char *synthesize_sdt_probe_command(struct sdt_note *note,
                if (args == NULL)
                        goto error;
 
-               for (i = 0; i < args_count; ++i) {
-                       if (synthesize_sdt_probe_arg(&buf, i, args[i]) < 0) {
+               for (i = 0; i < args_count; ) {
+                       /*
+                        * FIXUP: Arm64 ELF section '.note.stapsdt' uses string
+                        * format "-4@[sp, NUM]" if a probe is to access data in
+                        * the stack, e.g. below is an example for the SDT
+                        * Arguments:
+                        *
+                        *   Arguments: -4@[sp, 12] -4@[sp, 8] -4@[sp, 4]
+                        *
+                        * Since the string introduces an extra space character
+                        * in the middle of square brackets, the argument is
+                        * divided into two items.  Fixup for this case, if an
+                        * item contains sub string "[sp,", need to concatenate
+                        * the two items.
+                        */
+                       if (strstr(args[i], "[sp,") && (i+1) < args_count) {
+                               err = asprintf(&arg, "%s %s", args[i], args[i+1]);
+                               i += 2;
+                       } else {
+                               err = asprintf(&arg, "%s", args[i]);
+                               i += 1;
+                       }
+
+                       /* Failed to allocate memory */
+                       if (err < 0) {
                                argv_free(args);
                                goto error;
                        }
+
+                       if (synthesize_sdt_probe_arg(&buf, arg_idx, arg) < 0) {
+                               free(arg);
+                               argv_free(args);
+                               goto error;
+                       }
+
+                       free(arg);
+                       arg_idx++;
                }
 
                argv_free(args);