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-rw-r--r--tools/perf/util/evsel.c9
-rw-r--r--tools/perf/util/perf_regs.h4
2 files changed, 12 insertions, 1 deletions
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index a6f572a40deb..cc6e7a0dda92 100644
--- 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 {
diff --git a/tools/perf/util/perf_regs.h b/tools/perf/util/perf_regs.h
index cb9c246c8962..47fe34e5f7d5 100644
--- a/tools/perf/util/perf_regs.h
+++ b/tools/perf/util/perf_regs.h
@@ -29,12 +29,16 @@ uint64_t arch__user_reg_mask(void);
#ifdef HAVE_PERF_REGS_SUPPORT
#include <perf_regs.h>
+#define DWARF_MINIMAL_REGS ((1ULL << PERF_REG_IP) | (1ULL << PERF_REG_SP))
+
int perf_reg_value(u64 *valp, struct regs_dump *regs, int id);
#else
#define PERF_REGS_MASK 0
#define PERF_REGS_MAX 0
+#define DWARF_MINIMAL_REGS PERF_REGS_MASK
+
static inline const char *perf_reg_name(int id __maybe_unused)
{
return NULL;