On Sat, Oct 05, 2019 at 05:16:09PM +0800, Leo Yan wrote:
If the u64 variable 'offset' is a negative integer, comparison it with bigger than zero is always going to be true because it is unsigned. Fix this by using s64 type for variable 'offset'.
Signed-off-by: Leo Yan leo.yan@linaro.org
tools/perf/util/cs-etm.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c index 4ba0f871f086..4bc2d9709d4f 100644 --- a/tools/perf/util/cs-etm.c +++ b/tools/perf/util/cs-etm.c @@ -940,7 +940,7 @@ u64 cs_etm__last_executed_instr(const struct cs_etm_packet *packet) static inline u64 cs_etm__instr_addr(struct cs_etm_queue *etmq, u64 trace_chan_id, const struct cs_etm_packet *packet,
u64 offset)
s64 offset)
In Suzuki's reply there was two choices, 1) move the while(offset > 0) to while (offset) or change the type of @offset to an s64. Here we know offset can't be negative because of the tidq->period_instructions >= etm->instructions_sample_period
in function cs_etm__sample(). As such I think option #1 is the right way to deal with this rather than changing the type of the variable.
Mathieu
{ if (packet->isa == CS_ETM_ISA_T32) { u64 addr = packet->start_addr; @@ -1372,7 +1372,7 @@ static int cs_etm__sample(struct cs_etm_queue *etmq, * sample is reported as though instruction has just been * executed, but PC has not advanced to next instruction) */
u64 offset = (instrs_executed - instrs_over - 1);
s64 offset = (instrs_executed - instrs_over - 1);2.17.1