Re: [PATCH v3 1/7] perf tools: Set vdso name to vdso[64,32] depending on platform

[Adrian Hunter]

On 12/05/16 11:43, He Kuang wrote:
> This is a preparation for cross-platform vdso lookup.
> 
> There is a naming confusion about vdso name, vdso buildid generated by
> a 32-bit machine stores it with the name 'vdso', but when processing
> buildid on a 64-bit machine with the same 'perf.data', perf will
> search for vdso named as 'vdso32' and get failed.
> 
> This patch uses different names when storing the buildid, i.e. vdso64
> for 64-bit machine and vdso32 for 32-bit machine, and eliminates this
> naming confusion.

That looks like it will break existing perf.data files because they will
have a different name recorded in the buildid section.

Also it doesn't look like it would work the other way around i.e. recording
on a 64-bit machine and processing on a 32-bit machine.

> 
> Signed-off-by: He Kuang <hekuang@xxxxxxxxxx>
> ---
>  tools/perf/util/vdso.h | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/perf/util/vdso.h b/tools/perf/util/vdso.h
> index cdc4fab..45e9ef4 100644
> --- a/tools/perf/util/vdso.h
> +++ b/tools/perf/util/vdso.h
> @@ -4,10 +4,15 @@
>  #include <linux/types.h>
>  #include <string.h>
>  #include <stdbool.h>
> +#include "util.h"
>  
>  #define VDSO__MAP_NAME "[vdso]"
>  
> -#define DSO__NAME_VDSO    "[vdso]"
> +#if BITS_PER_LONG == 64
> +#define DSO__NAME_VDSO    "[vdso64]"
> +#else
> +#define DSO__NAME_VDSO    "[vdso32]"
> +#endif
>  #define DSO__NAME_VDSO32  "[vdso32]"
>  #define DSO__NAME_VDSOX32 "[vdsox32]"
>  
>