Em Wed, Oct 14, 2015 at 12:41:25PM +0000, Wang Nan escreveu:
> If both LIBBPF and DWARF are detected, it is possible to create prologue
> for eBPF programs to help them accessing kernel data. HAVE_BPF_PROLOGUE
what kernel data? you mean to be
able to map from variable/function argument name to where they are in
memory/registers?
> and CONFIG_BPF_PROLOGUE is added as flags for this feature.
>
> PERF_HAVE_ARCH_REGS_QUERY_REGISTER_OFFSET indicates an architecture
> supports converting name of a register to its offset in
> 'struct pt_regs'. Without this support, BPF_PROLOGUE should be turned off.
>
> HAVE_ARCH_REGS_QUERY_REGISTER_OFFSET is introduced as the corresponding
> CFLAGS of PERF_HAVE_ARCH_REGS_QUERY_REGISTER_OFFSET.
>
> Signed-off-by: Wang Nan <[email protected]>
> Cc: Alexei Starovoitov <[email protected]>
> Cc: Brendan Gregg <[email protected]>
> Cc: Daniel Borkmann <[email protected]>
> Cc: David Ahern <[email protected]>
> Cc: He Kuang <[email protected]>
> Cc: Jiri Olsa <[email protected]>
> Cc: Kaixu Xia <[email protected]>
> Cc: Masami Hiramatsu <[email protected]>
> Cc: Namhyung Kim <[email protected]>
> Cc: Paul Mackerras <[email protected]>
> Cc: Peter Zijlstra <[email protected]>
> Cc: Zefan Li <[email protected]>
> Cc: [email protected]
> Cc: Arnaldo Carvalho de Melo <[email protected]>
> Link: http://lkml.kernel.org/n/[email protected]
> ---
> tools/perf/config/Makefile | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/tools/perf/config/Makefile b/tools/perf/config/Makefile
> index de89ec5..6eb9a95 100644
> --- a/tools/perf/config/Makefile
> +++ b/tools/perf/config/Makefile
> @@ -318,6 +318,18 @@ ifndef NO_LIBELF
> CFLAGS += -DHAVE_LIBBPF_SUPPORT
> $(call detected,CONFIG_LIBBPF)
> endif
> +
> + ifndef NO_DWARF
> + ifdef PERF_HAVE_ARCH_REGS_QUERY_REGISTER_OFFSET
> + CFLAGS += -DHAVE_BPF_PROLOGUE
> + $(call detected,CONFIG_BPF_PROLOGUE)
> + else
> + msg := $(warning BPF prologue is not supported by architecture
> $(ARCH), missing regs_query_register_offset());
> + endif
> + else
> + msg := $(warning DWARF support is off, BPF prologue is disabled);
> + endif
> +
> endif # NO_LIBBPF
> endif # NO_LIBELF
>
> --
> 1.8.3.4
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