Re: [PATCH 3/3] perf tools: adjust symbol address

[Arnaldo Carvalho de Melo <acme@infradead.org>]

Em Wed, Dec 30, 2009 at 11:18:55AM +0800, Xiao Guangrong escreveu:
> Using relocation offset adjust symbol address if we get
> kernel symbol name form elf file
> 
> diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
> index 79ca6a0..5b58d34 100644
> --- a/tools/perf/util/symbol.c
> +++ b/tools/perf/util/symbol.c
> @@ -19,6 +19,18 @@
>  #define NT_GNU_BUILD_ID 3
>  #endif
>  
> +static s32 relocate_offset;
> +void update_relocate_offset(s32 offset)
> +{
> +	relocate_offset = offset;
> +}
> +
> +static inline void update_kernel_address(GElf_Sym *sym, bool kernel)
> +{
> +	if (kernel)
> +		sym->st_value += relocate_offset;
> +}

This should be done on the dso level, we may process multiple kernels,
some with relocation, some without.

Humm, even at the _map_ level, because then we can just use the normal
map_ip mechanism, this time the not using the identity map stuff, i.e.
we have to get an IP from some event, then subtract the relocate_offset
that will be in map->start.

- Arnaldo