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Commit 80c0120a authored by David Ahern's avatar David Ahern Committed by Arnaldo Carvalho de Melo
Browse files

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: default avatarDavid Ahern <dsahern@gmail.com>
Reviewed-by: default avatarJiri Olsa <jolsa@redhat.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/4FBBB539.5010805@gmail.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 9ee6ddc9

tools/perf/util/header.c

+9 −7
Original line number Diff line number Diff line
@@ -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)) {

tools/perf/util/include/linux/bitops.h

+2 −0
Original line number Diff line number Diff line
@@ -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));		\

tools/perf/util/session.c

+10 −0
Original line number Diff line number Diff line
@@ -443,6 +443,16 @@ static void perf_tool__fill_defaults(struct perf_tool *tool) 
	}

}

 

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)

{

	u64 *m = src;

tools/perf/util/session.h

+1 −0
Original line number Diff line number Diff line
@@ -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);