From 80c0120a3cca30166c0ab8b24e44be67e97b79af Mon Sep 17 00:00:00 2001 From: David Ahern Date: Fri, 8 Jun 2012 11:47:51 -0300 Subject: [PATCH] perf tools: Fix endianity swapping for adds_features bitmask Based on Jiri's latest attempt: https://lkml.org/lkml/2012/5/16/61 Basically, adds_features should be byte swapped assuming unsigned longs are either 8-bytes (u64) or 4-bytes (u32). Fixes 32-bit ppc dumping 64-bit x86 feature data: ======== captured on: Sun May 20 19:23:23 2012 hostname : nxos-vdc-dev3 os release : 3.4.0-rc7+ perf version : 3.4.rc4.137.g978da3 arch : x86_64 nrcpus online : 16 nrcpus avail : 16 cpudesc : Intel(R) Xeon(R) CPU E5540 @ 2.53GHz cpuid : GenuineIntel,6,26,5 total memory : 24680324 kB ... Verified 64-bit x86 can still dump feature data for 32-bit ppc. Signed-off-by: David Ahern Reviewed-by: Jiri Olsa Cc: Corey Ashford Cc: Frederic Weisbecker Cc: Paul Mackerras Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/4FBBB539.5010805@gmail.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/header.c | 16 +++++++++------- tools/perf/util/include/linux/bitops.h | 2 ++ tools/perf/util/session.c | 10 ++++++++++ tools/perf/util/session.h | 1 + 4 files changed, 22 insertions(+), 7 deletions(-) diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c index 2dd5edf161b7..4f9b247fb312 100644 --- a/tools/perf/util/header.c +++ b/tools/perf/util/header.c @@ -1942,7 +1942,6 @@ int perf_file_header__read(struct perf_file_header *header, else return -1; } else if (ph->needs_swap) { - unsigned int i; /* * feature bitmap is declared as an array of unsigned longs -- * not good since its size can differ between the host that @@ -1958,14 +1957,17 @@ int perf_file_header__read(struct perf_file_header *header, * file), punt and fallback to the original behavior -- * clearing all feature bits and setting buildid. */ - for (i = 0; i < BITS_TO_LONGS(HEADER_FEAT_BITS); ++i) - header->adds_features[i] = bswap_64(header->adds_features[i]); + mem_bswap_64(&header->adds_features, + BITS_TO_U64(HEADER_FEAT_BITS)); if (!test_bit(HEADER_HOSTNAME, header->adds_features)) { - for (i = 0; i < BITS_TO_LONGS(HEADER_FEAT_BITS); ++i) { - header->adds_features[i] = bswap_64(header->adds_features[i]); - header->adds_features[i] = bswap_32(header->adds_features[i]); - } + /* unswap as u64 */ + mem_bswap_64(&header->adds_features, + BITS_TO_U64(HEADER_FEAT_BITS)); + + /* unswap as u32 */ + mem_bswap_32(&header->adds_features, + BITS_TO_U32(HEADER_FEAT_BITS)); } if (!test_bit(HEADER_HOSTNAME, header->adds_features)) { diff --git a/tools/perf/util/include/linux/bitops.h b/tools/perf/util/include/linux/bitops.h index f1584833bd22..587a230d2075 100644 --- a/tools/perf/util/include/linux/bitops.h +++ b/tools/perf/util/include/linux/bitops.h @@ -8,6 +8,8 @@ #define BITS_PER_LONG __WORDSIZE #define BITS_PER_BYTE 8 #define BITS_TO_LONGS(nr) DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long)) +#define BITS_TO_U64(nr) DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(u64)) +#define BITS_TO_U32(nr) DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(u32)) #define for_each_set_bit(bit, addr, size) \ for ((bit) = find_first_bit((addr), (size)); \ diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c index 2600916efa83..c3e399bcf18d 100644 --- a/tools/perf/util/session.c +++ b/tools/perf/util/session.c @@ -442,6 +442,16 @@ static void perf_tool__fill_defaults(struct perf_tool *tool) tool->finished_round = process_finished_round_stub; } } + +void mem_bswap_32(void *src, int byte_size) +{ + u32 *m = src; + while (byte_size > 0) { + *m = bswap_32(*m); + byte_size -= sizeof(u32); + ++m; + } +} void mem_bswap_64(void *src, int byte_size) { diff --git a/tools/perf/util/session.h b/tools/perf/util/session.h index 7a5434c00565..0c702e3f0a36 100644 --- a/tools/perf/util/session.h +++ b/tools/perf/util/session.h @@ -80,6 +80,7 @@ struct branch_info *machine__resolve_bstack(struct machine *self, bool perf_session__has_traces(struct perf_session *self, const char *msg); void mem_bswap_64(void *src, int byte_size); +void mem_bswap_32(void *src, int byte_size); void perf_event__attr_swap(struct perf_event_attr *attr); int perf_session__create_kernel_maps(struct perf_session *self); -- GitLab