perf record: Allow mixing --user-regs with --call-graph=dwarf

[linux.git] / tools / perf / util / evsel.c

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index a6f572a40deb3bb1e3aaa64d03c53a7e0372c46f..cc6e7a0dda928c5d1628c06f33e39e48c18e19ef 100644 (file)
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -702,7 +702,14 @@ static void __perf_evsel__config_callchain(struct perf_evsel *evsel,
                if (!function) {
                        perf_evsel__set_sample_bit(evsel, REGS_USER);
                        perf_evsel__set_sample_bit(evsel, STACK_USER);
-                       attr->sample_regs_user |= PERF_REGS_MASK;
+                       if (opts->sample_user_regs && DWARF_MINIMAL_REGS != PERF_REGS_MASK) {
+                               attr->sample_regs_user |= DWARF_MINIMAL_REGS;
+                               pr_warning("WARNING: The use of --call-graph=dwarf may require all the user registers, "
+                                          "specifying a subset with --user-regs may render DWARF unwinding unreliable, "
+                                          "so the minimal registers set (IP, SP) is explicitly forced.\n");
+                       } else {
+                               attr->sample_regs_user |= PERF_REGS_MASK;
+                       }
                        attr->sample_stack_user = param->dump_size;
                        attr->exclude_callchain_user = 1;
                } else {