[PATCH v1 4/6] perf tools: Use dynamic register set for Dwarf unwind

From: James Clark
Date: Mon May 09 2022 - 10:43:59 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.

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 d38722560e80..a881784da966 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -875,7 +875,7 @@ 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