#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
#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
#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
# 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
#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
# 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
}
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
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,
{
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 (strcmp(mcount, symname) == 0 ||
- (altmcount && strcmp(altmcount, symname) == 0))
- 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);
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
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;
}
succeed_file();
}
if (w(txthdr->sh_type) != SHT_PROGBITS ||
- !is_mcounted_section_name(txtname))
+ !(w(txthdr->sh_flags) & SHF_EXECINSTR))
return NULL;
return txtname;
}
{
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;
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,
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) {
Code Review / linux-2.6.git / blobdiff