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-rw-r--r--scripts/recordmcount.h82
1 files changed, 78 insertions, 4 deletions
diff --git a/scripts/recordmcount.h b/scripts/recordmcount.h
index 7f8d5c4c780f..657dbedd1c7f 100644
--- a/scripts/recordmcount.h
+++ b/scripts/recordmcount.h
@@ -23,6 +23,7 @@
#undef fn_is_fake_mcount
#undef MIPS_is_fake_mcount
#undef sift_rel_mcount
+#undef nop_mcount
#undef find_secsym_ndx
#undef __has_rel_mcount
#undef has_rel_mcount
@@ -49,6 +50,7 @@
#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
@@ -77,6 +79,7 @@
#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
@@ -304,6 +307,70 @@ 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)
+{
+ 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);
+ unsigned rel_entsize = _w(relhdr->sh_entsize);
+ unsigned const nrel = _w(relhdr->sh_size) / rel_entsize;
+ Elf_Rel const *relp = rel0;
+
+ Elf_Shdr const *const shdr = &shdr0[w(relhdr->sh_info)];
+
+ unsigned mcountsym = 0;
+ unsigned t;
+
+ for (t = nrel; t; --t) {
+ int ret = -1;
+
+ 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 == Elf_r_sym(relp) && !is_fake_mcount(relp))
+ ret = make_nop((void *)ehdr, shdr->sh_offset + relp->r_offset);
+
+ /*
+ * 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
@@ -360,8 +427,7 @@ __has_rel_mcount(Elf_Shdr const *const relhdr, /* is SHT_REL or SHT_RELA */
succeed_file();
}
if (w(txthdr->sh_type) != SHT_PROGBITS ||
- !(w(txthdr->sh_flags) & SHF_EXECINSTR) ||
- !is_mcounted_section_name(txtname))
+ !(w(txthdr->sh_flags) & SHF_EXECINSTR))
return NULL;
return txtname;
}
@@ -384,9 +450,11 @@ 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;
@@ -422,7 +490,7 @@ 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,
@@ -433,6 +501,12 @@ 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 (make_nop && txtname) {
+ /*
+ * This section is ignored by ftrace, but still
+ * has mcount calls. Convert them to nops now.
+ */
+ nop_mcount(relhdr, ehdr);
}
}
if (mloc0 != mlocp) {