[PATCH] perf/core: Reset remaining bits in perf_clear_branch_entry_bitfields()

From: Anshuman Khandual
Date: Thu Dec 01 2022 - 00:51:22 EST


perf_clear_branch_entry_bitfields() resets all struct perf_branch_entry bit
fields before capturing branch records. This resets remaining bit fields
except 'new_type', which is valid only when 'type' is PERF_BR_EXTEND_ABI.

Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: linux-perf-users@xxxxxxxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
---
This applies on v6.1-rc6

'perf_branch_entry.new_type' can remain uninitialized as explained earlier.
Also there is no PERF_BR_NEW_UNKNOWN to spare, because 'perf_branch_entry.
new_type' enumeration starts at PERF_BR_NEW_FAULT_ALGN, to save a position
for the extended branch types instead.

include/linux/perf_event.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 0031f7b4d9ab..c97b5f6f77a4 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -1110,8 +1110,9 @@ static inline void perf_clear_branch_entry_bitfields(struct perf_branch_entry *b
br->in_tx = 0;
br->abort = 0;
br->cycles = 0;
- br->type = 0;
+ br->type = PERF_BR_UNKNOWN;
br->spec = PERF_BR_SPEC_NA;
+ br->priv = PERF_BR_PRIV_UNKNOWN;
br->reserved = 0;
}

--
2.25.1