Re: [PATCH] perf tools: fix endian conversion reading event attr from header

Frederic Weisbecker
2011-07-15T15:47:19Z

On Tue, Jul 12, 2011 at 09:19:19AM -0600, David Ahern wrote:
> The perf_event_attr struct has 2 __u32's at the top and need to
> be swapped individually. With this change I was able to analyze
> a perf.data collected in a 32-bit PPC VM on an x86 system. I
> tested both 32-bit and 64-bit binaries for the Intel analysis
> side; both read the PPC perf.data file correctly.
>
> Signed-off-by: David Ahern <dsahern@gmail.com>
> ---
> tools/perf/util/header.c | 9 ++++++++-
> 1 files changed, 8 insertions(+), 1 deletions(-)
>
> diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
> index afb0849..8044c6f 100644
> --- a/tools/perf/util/header.c
> +++ b/tools/perf/util/header.c
> @@ -877,9 +877,16 @@ int perf_session__read_header(struct perf_session *session, int fd)
> struct perf_evsel *evsel;
> off_t tmp;
>
> - if (perf_header__getbuffer64(header, fd, &f_attr, sizeof(f_attr)))
> + if (readn(fd, &f_attr, sizeof(f_attr)) <= 0)
> goto out_errno;
>
> + if (header->needs_swap) {
> + f_attr.attr.type = bswap_32(f_attr.attr.type);
> + f_attr.attr.size = bswap_32(f_attr.attr.size);
> + mem_bswap_64(&f_attr.attr.config,
> + sizeof(struct perf_event_attr) - 8);
> + }
> +

Good catch!

But would be nice to also handle the wakeup_events and bp_type fields.

Thanks.

> tmp = lseek(fd, 0, SEEK_CUR);
> evsel = perf_evsel__new(&f_attr.attr, i);
>
> --
> 1.7.6
>