Re: [RFC PATCH 4/4] objtool/powerpc: Add --mcount specific implementation
From: Christophe Leroy <hidden>
Date: 2022-05-24 09:35:53
Also in:
lkml
Le 23/05/2022 à 19:55, Sathvika Vasireddy a écrit :
quoted hunk ↗ jump to hunk
This patch enables objtool --mcount on powerpc, and adds implementation specific to powerpc. Signed-off-by: Sathvika Vasireddy <redacted> --- 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_REGSdiff --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.
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+ + 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.
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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'.
+{
+ 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 ?
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+ int elf_add_reloc_to_insn(struct elf *elf, struct section *sec, unsigned long offset, unsigned int type, struct section *insn_sec, unsigned long insn_off)diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h index adebfbc2b518..c43e23c0b3c8 100644 --- a/tools/objtool/include/objtool/elf.h +++ b/tools/objtool/include/objtool/elf.h@@ -144,6 +144,7 @@ static inline bool has_multiple_files(struct elf *elf) struct elf *elf_open_read(const char *name, int flags); struct section *elf_create_section(struct elf *elf, const char *name, unsigned int sh_flags, size_t entsize, int nr); +int elf_reloc_type_long(struct elf *elf); int elf_add_reloc(struct elf *elf, struct section *sec, unsigned long offset, unsigned int type, struct symbol *sym, s64 addend); int elf_add_reloc_to_insn(struct elf *elf, struct section *sec,