When decoding the perf_regs mask in regs_dump__printf(), we loop through the mask using find_first_bit and find_next_bit functions. "mask" is of type "u64", but sent as a "unsigned long *" to lib functions along with sizeof(). While the exisitng code works fine in most of the case, the logic is broken when using a 32bit perf on a 64bit kernel (Big Endian). We end up reading the wrong word of the u64 first in the lib functions. Proposed fix is to swap the words of the u64 to handle this case. This is not endianess swap.
Suggested-by: Yury Norov <[email protected]> Cc: Yury Norov <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Arnaldo Carvalho de Melo <[email protected]> Cc: Alexander Shishkin <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: Adrian Hunter <[email protected]> Cc: Kan Liang <[email protected]> Cc: Wang Nan <[email protected]> Cc: Michael Ellerman <[email protected]> Signed-off-by: Madhavan Srinivasan <[email protected]> --- Changelog v1: 1)updated commit message and patch subject 2)Add the fix to print_sample_iregs() in builtin-script.c tools/perf/builtin-script.c | 7 ++++++- tools/perf/util/session.c | 7 ++++++- 2 files changed, 12 insertions(+), 2 deletions(-) diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c index e3ce2f34d3ad..76d5006ebcc3 100644 --- a/tools/perf/builtin-script.c +++ b/tools/perf/builtin-script.c @@ -412,11 +412,16 @@ static void print_sample_iregs(struct perf_sample *sample, struct regs_dump *regs = &sample->intr_regs; uint64_t mask = attr->sample_regs_intr; unsigned i = 0, r; + unsigned long _mask[sizeof(mask)/sizeof(unsigned long)]; if (!regs) return; - for_each_set_bit(r, (unsigned long *) &mask, sizeof(mask) * 8) { + _mask[0] = mask & ULONG_MAX; + if (sizeof(mask) > sizeof(unsigned long)) + _mask[1] = mask >> 32; + + for_each_set_bit(r, _mask, sizeof(mask) * 8) { u64 val = regs->regs[i++]; printf("%5s:0x%"PRIx64" ", perf_reg_name(r), val); } diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c index 5214974e841a..2eaa42a4832a 100644 --- a/tools/perf/util/session.c +++ b/tools/perf/util/session.c @@ -940,8 +940,13 @@ static void branch_stack__printf(struct perf_sample *sample) static void regs_dump__printf(u64 mask, u64 *regs) { unsigned rid, i = 0; + unsigned long _mask[sizeof(mask)/sizeof(unsigned long)]; - for_each_set_bit(rid, (unsigned long *) &mask, sizeof(mask) * 8) { + _mask[0] = mask & ULONG_MAX; + if (sizeof(mask) > sizeof(unsigned long)) + _mask[1] = mask >> 32; + + for_each_set_bit(rid, _mask, sizeof(mask) * 8) { u64 val = regs[i++]; printf(".... %-5s 0x%" PRIx64 "\n", -- 1.9.1
