diff options
Diffstat (limited to 'scripts/recordmcount.h')
| -rw-r--r-- | scripts/recordmcount.h | 182 |
1 files changed, 146 insertions, 36 deletions
diff --git a/scripts/recordmcount.h b/scripts/recordmcount.h index baf187b..f40a6af6 100644 --- a/scripts/recordmcount.h +++ b/scripts/recordmcount.h @@ -22,11 +22,15 @@ #undef is_fake_mcount #undef fn_is_fake_mcount #undef MIPS_is_fake_mcount +#undef mcount_adjust #undef sift_rel_mcount +#undef nop_mcount #undef find_secsym_ndx #undef __has_rel_mcount #undef has_rel_mcount #undef tot_relsize +#undef get_mcountsym +#undef get_sym_str_and_relp #undef do_func #undef Elf_Addr #undef Elf_Ehdr @@ -39,6 +43,7 @@ #undef ELF_R_INFO #undef Elf_r_info #undef ELF_ST_BIND +#undef ELF_ST_TYPE #undef fn_ELF_R_SYM #undef fn_ELF_R_INFO #undef uint_t @@ -49,14 +54,18 @@ #ifdef RECORD_MCOUNT_64 # define append_func append64 # define sift_rel_mcount sift64_rel_mcount +# define nop_mcount nop_mcount_64 # define find_secsym_ndx find64_secsym_ndx # define __has_rel_mcount __has64_rel_mcount # define has_rel_mcount has64_rel_mcount # define tot_relsize tot64_relsize +# define get_sym_str_and_relp get_sym_str_and_relp_64 # define do_func do64 +# define get_mcountsym get_mcountsym_64 # define is_fake_mcount is_fake_mcount64 # define fn_is_fake_mcount fn_is_fake_mcount64 # define MIPS_is_fake_mcount MIPS64_is_fake_mcount +# define mcount_adjust mcount_adjust_64 # define Elf_Addr Elf64_Addr # define Elf_Ehdr Elf64_Ehdr # define Elf_Shdr Elf64_Shdr @@ -68,6 +77,7 @@ # define ELF_R_INFO ELF64_R_INFO # define Elf_r_info Elf64_r_info # define ELF_ST_BIND ELF64_ST_BIND +# define ELF_ST_TYPE ELF64_ST_TYPE # define fn_ELF_R_SYM fn_ELF64_R_SYM # define fn_ELF_R_INFO fn_ELF64_R_INFO # define uint_t uint64_t @@ -77,14 +87,18 @@ #else # define append_func append32 # define sift_rel_mcount sift32_rel_mcount +# define nop_mcount nop_mcount_32 # define find_secsym_ndx find32_secsym_ndx # define __has_rel_mcount __has32_rel_mcount # define has_rel_mcount has32_rel_mcount # define tot_relsize tot32_relsize +# define get_sym_str_and_relp get_sym_str_and_relp_32 # define do_func do32 +# define get_mcountsym get_mcountsym_32 # define is_fake_mcount is_fake_mcount32 # define fn_is_fake_mcount fn_is_fake_mcount32 # define MIPS_is_fake_mcount MIPS32_is_fake_mcount +# define mcount_adjust mcount_adjust_32 # define Elf_Addr Elf32_Addr # define Elf_Ehdr Elf32_Ehdr # define Elf_Shdr Elf32_Shdr @@ -96,6 +110,7 @@ # define ELF_R_INFO ELF32_R_INFO # define Elf_r_info Elf32_r_info # define ELF_ST_BIND ELF32_ST_BIND +# define ELF_ST_TYPE ELF32_ST_TYPE # define fn_ELF_R_SYM fn_ELF32_R_SYM # define fn_ELF_R_INFO fn_ELF32_R_INFO # define uint_t uint32_t @@ -123,6 +138,8 @@ static void fn_ELF_R_INFO(Elf_Rel *const rp, unsigned sym, unsigned type) } static void (*Elf_r_info)(Elf_Rel *const rp, unsigned sym, unsigned type) = fn_ELF_R_INFO; +static int mcount_adjust = 0; + /* * MIPS mcount long call has 2 _mcount symbols, only the position of the 1st * _mcount symbol is needed for dynamic function tracer, with it, to disable @@ -234,6 +251,49 @@ static void append_func(Elf_Ehdr *const ehdr, uwrite(fd_map, ehdr, sizeof(*ehdr)); } +static unsigned get_mcountsym(Elf_Sym const *const sym0, + Elf_Rel const *relp, + char const *const str0) +{ + unsigned mcountsym = 0; + + Elf_Sym const *const symp = + &sym0[Elf_r_sym(relp)]; + char const *symname = &str0[w(symp->st_name)]; + char const *mcount = gpfx == '_' ? "_mcount" : "mcount"; + + if (symname[0] == '.') + ++symname; /* ppc64 hack */ + if (strcmp(mcount, symname) == 0 || + (altmcount && strcmp(altmcount, symname) == 0)) + mcountsym = Elf_r_sym(relp); + + return mcountsym; +} + +static void get_sym_str_and_relp(Elf_Shdr const *const relhdr, + Elf_Ehdr const *const ehdr, + Elf_Sym const **sym0, + char const **str0, + Elf_Rel const **relp) +{ + Elf_Shdr *const shdr0 = (Elf_Shdr *)(_w(ehdr->e_shoff) + + (void *)ehdr); + unsigned const symsec_sh_link = w(relhdr->sh_link); + Elf_Shdr const *const symsec = &shdr0[symsec_sh_link]; + Elf_Shdr const *const strsec = &shdr0[w(symsec->sh_link)]; + Elf_Rel const *const rel0 = (Elf_Rel const *)(_w(relhdr->sh_offset) + + (void *)ehdr); + + *sym0 = (Elf_Sym const *)(_w(symsec->sh_offset) + + (void *)ehdr); + + *str0 = (char const *)(_w(strsec->sh_offset) + + (void *)ehdr); + + *relp = rel0; +} + /* * Look at the relocations in order to find the calls to mcount. * Accumulate the section offsets that are found, and their relocation info, @@ -250,47 +310,27 @@ static uint_t *sift_rel_mcount(uint_t *mlocp, { uint_t *const mloc0 = mlocp; Elf_Rel *mrelp = *mrelpp; - Elf_Shdr *const shdr0 = (Elf_Shdr *)(_w(ehdr->e_shoff) - + (void *)ehdr); - unsigned const symsec_sh_link = w(relhdr->sh_link); - Elf_Shdr const *const symsec = &shdr0[symsec_sh_link]; - Elf_Sym const *const sym0 = (Elf_Sym const *)(_w(symsec->sh_offset) - + (void *)ehdr); - - Elf_Shdr const *const strsec = &shdr0[w(symsec->sh_link)]; - char const *const str0 = (char const *)(_w(strsec->sh_offset) - + (void *)ehdr); - - Elf_Rel const *const rel0 = (Elf_Rel const *)(_w(relhdr->sh_offset) - + (void *)ehdr); + Elf_Sym const *sym0; + char const *str0; + Elf_Rel const *relp; unsigned rel_entsize = _w(relhdr->sh_entsize); unsigned const nrel = _w(relhdr->sh_size) / rel_entsize; - Elf_Rel const *relp = rel0; - unsigned mcountsym = 0; unsigned t; + get_sym_str_and_relp(relhdr, ehdr, &sym0, &str0, &relp); + for (t = nrel; t; --t) { - if (!mcountsym) { - Elf_Sym const *const symp = - &sym0[Elf_r_sym(relp)]; - char const *symname = &str0[w(symp->st_name)]; - char const *mcount = '_' == gpfx ? "_mcount" : "mcount"; - - if ('.' == symname[0]) - ++symname; /* ppc64 hack */ - if (0 == strcmp(mcount, symname) || - (altmcount && 0 == strcmp(altmcount, symname))) - mcountsym = Elf_r_sym(relp); - } + if (!mcountsym) + mcountsym = get_mcountsym(sym0, relp, str0); if (mcountsym == Elf_r_sym(relp) && !is_fake_mcount(relp)) { - uint_t const addend = _w(_w(relp->r_offset) - recval); - + uint_t const addend = + _w(_w(relp->r_offset) - recval + mcount_adjust); mrelp->r_offset = _w(offbase + ((void *)mlocp - (void *)mloc0)); Elf_r_info(mrelp, recsym, reltype); - if (sizeof(Elf_Rela) == rel_entsize) { + if (rel_entsize == sizeof(Elf_Rela)) { ((Elf_Rela *)mrelp)->r_addend = addend; *mlocp++ = 0; } else @@ -304,6 +344,63 @@ static uint_t *sift_rel_mcount(uint_t *mlocp, return mlocp; } +/* + * Read the relocation table again, but this time its called on sections + * that are not going to be traced. The mcount calls here will be converted + * into nops. + */ +static void nop_mcount(Elf_Shdr const *const relhdr, + Elf_Ehdr const *const ehdr, + const char *const txtname) +{ + Elf_Shdr *const shdr0 = (Elf_Shdr *)(_w(ehdr->e_shoff) + + (void *)ehdr); + Elf_Sym const *sym0; + char const *str0; + Elf_Rel const *relp; + Elf_Shdr const *const shdr = &shdr0[w(relhdr->sh_info)]; + unsigned rel_entsize = _w(relhdr->sh_entsize); + unsigned const nrel = _w(relhdr->sh_size) / rel_entsize; + unsigned mcountsym = 0; + unsigned t; + int once = 0; + + get_sym_str_and_relp(relhdr, ehdr, &sym0, &str0, &relp); + + for (t = nrel; t; --t) { + int ret = -1; + + if (!mcountsym) + mcountsym = get_mcountsym(sym0, relp, str0); + + if (mcountsym == Elf_r_sym(relp) && !is_fake_mcount(relp)) { + if (make_nop) + ret = make_nop((void *)ehdr, shdr->sh_offset + relp->r_offset); + if (warn_on_notrace_sect && !once) { + printf("Section %s has mcount callers being ignored\n", + txtname); + once = 1; + /* just warn? */ + if (!make_nop) + return; + } + } + + /* + * If we successfully removed the mcount, mark the relocation + * as a nop (don't do anything with it). + */ + if (!ret) { + Elf_Rel rel; + rel = *(Elf_Rel *)relp; + Elf_r_info(&rel, Elf_r_sym(relp), rel_type_nop); + ulseek(fd_map, (void *)relp - (void *)ehdr, SEEK_SET); + uwrite(fd_map, &rel, sizeof(rel)); + } + relp = (Elf_Rel const *)(rel_entsize + (void *)relp); + } +} + /* * Find a symbol in the given section, to be used as the base for relocating @@ -333,6 +430,11 @@ static unsigned find_secsym_ndx(unsigned const txtndx, if (txtndx == w2(symp->st_shndx) /* avoid STB_WEAK */ && (STB_LOCAL == st_bind || STB_GLOBAL == st_bind)) { + /* function symbols on ARM have quirks, avoid them */ + if (w2(ehdr->e_machine) == EM_ARM + && ELF_ST_TYPE(symp->st_info) == STT_FUNC) + continue; + *recvalp = _w(symp->st_value); return symp - sym0; } @@ -354,13 +456,13 @@ __has_rel_mcount(Elf_Shdr const *const relhdr, /* is SHT_REL or SHT_RELA */ Elf_Shdr const *const txthdr = &shdr0[w(relhdr->sh_info)]; char const *const txtname = &shstrtab[w(txthdr->sh_name)]; - if (0 == strcmp("__mcount_loc", txtname)) { + if (strcmp("__mcount_loc", txtname) == 0) { fprintf(stderr, "warning: __mcount_loc already exists: %s\n", fname); succeed_file(); } - if (SHT_PROGBITS != w(txthdr->sh_type) || - !is_mcounted_section_name(txtname)) + if (w(txthdr->sh_type) != SHT_PROGBITS || + !(w(txthdr->sh_flags) & SHF_EXECINSTR)) return NULL; return txtname; } @@ -370,7 +472,7 @@ static char const *has_rel_mcount(Elf_Shdr const *const relhdr, char const *const shstrtab, char const *const fname) { - if (SHT_REL != w(relhdr->sh_type) && SHT_RELA != w(relhdr->sh_type)) + if (w(relhdr->sh_type) != SHT_REL && w(relhdr->sh_type) != SHT_RELA) return NULL; return __has_rel_mcount(relhdr, shdr0, shstrtab, fname); } @@ -383,9 +485,11 @@ static unsigned tot_relsize(Elf_Shdr const *const shdr0, { unsigned totrelsz = 0; Elf_Shdr const *shdrp = shdr0; + char const *txtname; for (; nhdr; --nhdr, ++shdrp) { - if (has_rel_mcount(shdrp, shdr0, shstrtab, fname)) + txtname = has_rel_mcount(shdrp, shdr0, shstrtab, fname); + if (txtname && is_mcounted_section_name(txtname)) totrelsz += _w(shdrp->sh_size); } return totrelsz; @@ -421,7 +525,7 @@ do_func(Elf_Ehdr *const ehdr, char const *const fname, unsigned const reltype) for (relhdr = shdr0, k = nhdr; k; --k, ++relhdr) { char const *const txtname = has_rel_mcount(relhdr, shdr0, shstrtab, fname); - if (txtname) { + if (txtname && is_mcounted_section_name(txtname)) { uint_t recval = 0; unsigned const recsym = find_secsym_ndx( w(relhdr->sh_info), txtname, &recval, @@ -432,6 +536,12 @@ do_func(Elf_Ehdr *const ehdr, char const *const fname, unsigned const reltype) mlocp = sift_rel_mcount(mlocp, (void *)mlocp - (void *)mloc0, &mrelp, relhdr, ehdr, recsym, recval, reltype); + } else if (txtname && (warn_on_notrace_sect || make_nop)) { + /* + * This section is ignored by ftrace, but still + * has mcount calls. Convert them to nops now. + */ + nop_mcount(relhdr, ehdr, txtname); } } if (mloc0 != mlocp) { |
