[PATCH v3 1/3] perf: use hweight64 instead of hweight_long

Mao Han
2019-04-10T08:25:06Z

On 32-bits platform with more than 32 registers, the 64 bits mask is
truncate to the lower 32 bits and the return value of hweight_long will
always smaller than 32. When kernel outputs more than 32 registers, but
the user perf program only counts 32, there will be a data mismatch
result to overflow check fail.

CC: Peter Zijlstra <peterz@infradead.org>
CC: Ingo Molnar <mingo@redhat.com>
CC: Arnaldo Carvalho de Melo <acme@kernel.org>
CC: Alexander Shishkin <alexander.shishkin@linux.intel.com>
CC: Jiri Olsa <jolsa@redhat.com>
CC: Namhyung Kim <namhyung@kernel.org>

Signed-off-by: Mao Han <han_mao@c-sky.com>
---
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 7835e05..73c78be 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -2322,7 +2322,7 @@ int perf_evsel__parse_sample(struct perf_evsel *evsel, union perf_event *event,
if (data->user_regs.abi) {
u64 mask = evsel->attr.sample_regs_user;

- sz = hweight_long(mask) * sizeof(u64);
+ sz = hweight64(mask) * sizeof(u64);
OVERFLOW_CHECK(array, sz, max_size);
data->user_regs.mask = mask;
data->user_regs.regs = (u64 *)array;
--
2.7.4