There are two checks, one is for size when running without admin, but this one is covered by the driver and reported on in more detail here (builtin-record.c):
pr_err("Permission error mapping pages.\n" "Consider increasing " "/proc/sys/kernel/perf_event_mlock_kb,\n" "or try again with a smaller value of -m/--mmap_pages.\n" "(current value: %u,%u)\n",
This had the effect of artificially limiting the aux buffer size to a value smaller than what was allowed because perf_event_mlock_kb wasn't taken into account.
The second is to check for a power of two, but this is covered here (evlist.c):
pr_info("rounding mmap pages size to %s (%lu pages)\n", buf, pages);
Signed-off-by: James Clark james.clark@arm.com --- tools/perf/arch/arm/util/cs-etm.c | 19 ------------------- 1 file changed, 19 deletions(-)
diff --git a/tools/perf/arch/arm/util/cs-etm.c b/tools/perf/arch/arm/util/cs-etm.c index 293a23bf8be3..8a3d54a86c9c 100644 --- a/tools/perf/arch/arm/util/cs-etm.c +++ b/tools/perf/arch/arm/util/cs-etm.c @@ -407,25 +407,6 @@ static int cs_etm_recording_options(struct auxtrace_record *itr,
}
- /* Validate auxtrace_mmap_pages provided by user */ - if (opts->auxtrace_mmap_pages) { - unsigned int max_page = (KiB(128) / page_size); - size_t sz = opts->auxtrace_mmap_pages * (size_t)page_size; - - if (!privileged && - opts->auxtrace_mmap_pages > max_page) { - opts->auxtrace_mmap_pages = max_page; - pr_err("auxtrace too big, truncating to %d\n", - max_page); - } - - if (!is_power_of_2(sz)) { - pr_err("Invalid mmap size for %s: must be a power of 2\n", - CORESIGHT_ETM_PMU_NAME); - return -EINVAL; - } - } - if (opts->auxtrace_snapshot_mode) pr_debug2("%s snapshot size: %zu\n", CORESIGHT_ETM_PMU_NAME, opts->auxtrace_snapshot_size);