Re: Re: [RFT PATCH -next v3] [BUGFIX] kprobes: Fix "Failed to find blacklist" error on ia64 and ppc6

Masami Hiramatsu
2014-06-18T08:46:57Z

(2014/06/18 16:56), Michael Ellerman wrote:
> On Fri, 2014-06-06 at 15:38 +0900, Masami Hiramatsu wrote:
>> Ping?
>>
>> I guess this should go to 3.16 branch, shouldn't it?
>
>>> diff --git a/arch/powerpc/include/asm/types.h b/arch/powerpc/include/asm/types.h
>>> index bfb6ded..8b89d65 100644
>>> --- a/arch/powerpc/include/asm/types.h
>>> +++ b/arch/powerpc/include/asm/types.h
>>> @@ -25,6 +25,17 @@ typedef struct {
>>> unsigned long env;
>>> } func_descr_t;
>>>
>>> +#if defined(CONFIG_PPC64) && (!defined(_CALL_ELF) || _CALL_ELF = 1)
>>> +/*
>>> + * On PPC64 ABIv1 the function pointer actually points to the
>>> + * function's descriptor. The first entry in the descriptor is the
>>> + * address of the function text.
>>> + */
>>> +#define function_entry(fn) (((func_descr_t *)(fn))->entry)
>>> +#else
>>> +#define function_entry(fn) ((unsigned long)(fn))
>>> +#endif
>
> We already have ppc_function_entry(), can't you use that?

I'd like to ask you whether the address which ppc_function_entry() returns on
PPC ABIv2 is really same address in kallsyms or not.
As you can see, kprobes uses function_entry() to get the actual entry address
where kallsyms knows. I have not much information about that, but it seems that
the "global entry point" is the address which kallsyms knows, isn't it?

Thank you,