Messages in this thread | | | Date | Thu, 16 Jun 2022 19:04:20 +0530 | From | "Naveen N. Rao" <> | Subject | Re: [RFC PATCH 4/4] objtool/powerpc: Add --mcount specific implementation |
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Christophe Leroy wrote: > > > Le 25/05/2022 à 19:27, Christophe Leroy a écrit : >> >> >> Le 24/05/2022 à 15:33, Christophe Leroy a écrit : >>> >>> >>> Le 24/05/2022 à 13:00, Sathvika Vasireddy a écrit : >>>>> >>>>>> +{ >>>>>> + switch (elf->ehdr.e_machine) { >>>>>> + case EM_X86_64: >>>>>> + return R_X86_64_64; >>>>>> + case EM_PPC64: >>>>>> + return R_PPC64_ADDR64; >>>>>> + default: >>>>>> + WARN("unknown machine..."); >>>>>> + exit(-1); >>>>>> + } >>>>>> +} >>>>> Wouldn't it be better to make that function arch specific ? >>>> >>>> This is so that we can support cross architecture builds. >>>> >>> >>> >>> I'm not sure I follow you here. >>> >>> This is only based on the target, it doesn't depend on the build host so >>> I can't the link with cross arch builds. >>> >>> The same as you have arch_decode_instruction(), you could have >>> arch_elf_reloc_type_long() >>> It would make sense indeed, because there is no point in supporting X86 >>> relocation when you don't support X86 instruction decoding. >>> >> >> Could simply be some macro defined in >> tools/objtool/arch/powerpc/include/arch/elf.h and >> tools/objtool/arch/x86/include/arch/elf.h >> >> The x86 version would be: >> >> #define R_ADDR(elf) R_X86_64_64 >> >> And the powerpc version would be: >> >> #define R_ADDR(elf) (elf->ehdr.e_machine == EM_PPC64 ? R_PPC64_ADDR64 : >> R_PPC_ADDR32) >> > > Well, looking once more, and taking into account the patch from Chen > https://lore.kernel.org/lkml/20220531020744.236970-4-chenzhongjin@huawei.com/ > > It would be easier to just define two macros: > > #define R_ABS64 R_PPC64_ADDR64 > #define R_ABS32 R_PPC_ADDR32 > > And then in the caller, as we know the size, do something like > > size == sizeof(u64) ? R_ABS64 : R_ABS32;
How does 'sizeof(u64)' work here?
- Naveen
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