[PATCH v3 3/5] perf tools: Use dynamic register set for Dwarf unwind

From: James Clark
Date: Wed May 25 2022 - 11:42:10 EST


Architectures can detect availability of extra registers at
runtime so use this more complete set for unwinding. This
will include the VG register on arm64 in a later commit.

If the function isn't implemented then PERF_REGS_MASK is
returned and there is no change.

Reviewed-by: Leo Yan <leo.yan@xxxxxxxxxx>
Signed-off-by: James Clark <james.clark@xxxxxxx>
---
tools/perf/util/evsel.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index ef169ad15236..020836a4c4bc 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -896,7 +896,7 @@ static void __evsel__config_callchain(struct evsel *evsel, struct record_opts *o
"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_regs_user |= arch__user_reg_mask();
}
attr->sample_stack_user = param->dump_size;
attr->exclude_callchain_user = 1;
--
2.28.0