Messages in this thread | | | Date | Tue, 24 May 2022 16:30:13 +0530 | Subject | Re: [RFC PATCH 4/4] objtool/powerpc: Add --mcount specific implementation | From | Sathvika Vasireddy <> |
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On 24/05/22 15:05, Christophe Leroy wrote: > > Le 23/05/2022 à 19:55, Sathvika Vasireddy a écrit : >> This patch enables objtool --mcount on powerpc, and >> adds implementation specific to powerpc. >> >> Signed-off-by: Sathvika Vasireddy <sv@linux.ibm.com> >> --- >> arch/powerpc/Kconfig | 1 + >> tools/objtool/arch/powerpc/decode.c | 14 ++++++++++++++ >> tools/objtool/check.c | 12 +++++++----- >> tools/objtool/elf.c | 13 +++++++++++++ >> tools/objtool/include/objtool/elf.h | 1 + >> 5 files changed, 36 insertions(+), 5 deletions(-) >> >> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig >> index 732a3f91ee5e..3373d44a1298 100644 >> --- a/arch/powerpc/Kconfig >> +++ b/arch/powerpc/Kconfig >> @@ -233,6 +233,7 @@ config PPC >> select HAVE_NMI if PERF_EVENTS || (PPC64 && PPC_BOOK3S) >> select HAVE_OPTPROBES >> select HAVE_OBJTOOL if PPC64 >> + select HAVE_OBJTOOL_MCOUNT if HAVE_OBJTOOL >> select HAVE_PERF_EVENTS >> select HAVE_PERF_EVENTS_NMI if PPC64 >> select HAVE_PERF_REGS >> diff --git a/tools/objtool/arch/powerpc/decode.c b/tools/objtool/arch/powerpc/decode.c >> index e3b77a6ce357..ad3d79fffac2 100644 >> --- a/tools/objtool/arch/powerpc/decode.c >> +++ b/tools/objtool/arch/powerpc/decode.c >> @@ -40,12 +40,26 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec >> struct list_head *ops_list) >> { >> u32 insn; >> + unsigned int opcode; >> >> *immediate = 0; >> memcpy(&insn, sec->data->d_buf+offset, 4); >> *len = 4; >> *type = INSN_OTHER; >> >> + opcode = (insn >> 26); > You dont need the brackets here. > >> + >> + switch (opcode) { >> + case 18: /* bl */ >> + if ((insn & 3) == 1) { >> + *type = INSN_CALL; >> + *immediate = insn & 0x3fffffc; >> + if (*immediate & 0x2000000) >> + *immediate -= 0x4000000; >> + } >> + break; >> + } >> + >> return 0; >> } >> >> diff --git a/tools/objtool/check.c b/tools/objtool/check.c >> index 056302d58e23..fd8bad092f89 100644 >> --- a/tools/objtool/check.c >> +++ b/tools/objtool/check.c >> @@ -832,7 +832,7 @@ static int create_mcount_loc_sections(struct objtool_file *file) >> >> if (elf_add_reloc_to_insn(file->elf, sec, >> idx * sizeof(unsigned long), >> - R_X86_64_64, >> + elf_reloc_type_long(file->elf), >> insn->sec, insn->offset)) >> return -1; >> >> @@ -2183,7 +2183,7 @@ static int classify_symbols(struct objtool_file *file) >> if (arch_is_retpoline(func)) >> func->retpoline_thunk = true; >> >> - if (!strcmp(func->name, "__fentry__")) >> + if ((!strcmp(func->name, "__fentry__")) || (!strcmp(func->name, "_mcount"))) >> func->fentry = true; >> >> if (is_profiling_func(func->name)) >> @@ -2259,9 +2259,11 @@ static int decode_sections(struct objtool_file *file) >> * Must be before add_jump_destinations(), which depends on 'func' >> * being set for alternatives, to enable proper sibling call detection. >> */ >> - ret = add_special_section_alts(file); >> - if (ret) >> - return ret; >> + if (opts.stackval || opts.orc || opts.uaccess || opts.noinstr) { >> + ret = add_special_section_alts(file); >> + if (ret) >> + return ret; >> + } > I think this change should be a patch by itself, it's not related to > powerpc. Makes sense. I'll make this a separate patch in the next revision. > >> >> ret = add_jump_destinations(file); >> if (ret) >> diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c >> index c25e957c1e52..95763060d551 100644 >> --- a/tools/objtool/elf.c >> +++ b/tools/objtool/elf.c >> @@ -793,6 +793,19 @@ elf_create_section_symbol(struct elf *elf, struct section *sec) >> return sym; >> } >> >> +int elf_reloc_type_long(struct elf *elf) > Not sure it's a good name, because for 32 bits we have to use 'int'. Sure, I'll rename it to elf_reloc_type() or some such. > >> +{ >> + 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.
Thanks for reviewing!
- Sathvika
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