aboutsummaryrefslogtreecommitdiffstats
path: root/scripts/recordmcount.h
diff options
context:
space:
mode:
Diffstat (limited to 'scripts/recordmcount.h')
-rw-r--r--scripts/recordmcount.h366
1 files changed, 366 insertions, 0 deletions
diff --git a/scripts/recordmcount.h b/scripts/recordmcount.h
new file mode 100644
index 000000000000..7f39d0943d2d
--- /dev/null
+++ b/scripts/recordmcount.h
@@ -0,0 +1,366 @@
+/*
+ * recordmcount.h
+ *
+ * This code was taken out of recordmcount.c written by
+ * Copyright 2009 John F. Reiser <jreiser@BitWagon.com>. All rights reserved.
+ *
+ * The original code had the same algorithms for both 32bit
+ * and 64bit ELF files, but the code was duplicated to support
+ * the difference in structures that were used. This
+ * file creates a macro of everything that is different between
+ * the 64 and 32 bit code, such that by including this header
+ * twice we can create both sets of functions by including this
+ * header once with RECORD_MCOUNT_64 undefined, and again with
+ * it defined.
+ *
+ * This conversion to macros was done by:
+ * Copyright 2010 Steven Rostedt <srostedt@redhat.com>, Red Hat Inc.
+ *
+ * Licensed under the GNU General Public License, version 2 (GPLv2).
+ */
+#undef append_func
+#undef sift_rel_mcount
+#undef find_secsym_ndx
+#undef __has_rel_mcount
+#undef has_rel_mcount
+#undef tot_relsize
+#undef do_func
+#undef Elf_Ehdr
+#undef Elf_Shdr
+#undef Elf_Rel
+#undef Elf_Rela
+#undef Elf_Sym
+#undef ELF_R_SYM
+#undef ELF_R_INFO
+#undef ELF_ST_BIND
+#undef uint_t
+#undef _w
+#undef _align
+#undef _size
+
+#ifdef RECORD_MCOUNT_64
+# define append_func append64
+# define sift_rel_mcount sift64_rel_mcount
+# 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 do_func do64
+# define Elf_Ehdr Elf64_Ehdr
+# define Elf_Shdr Elf64_Shdr
+# define Elf_Rel Elf64_Rel
+# define Elf_Rela Elf64_Rela
+# define Elf_Sym Elf64_Sym
+# define ELF_R_SYM ELF64_R_SYM
+# define ELF_R_INFO ELF64_R_INFO
+# define ELF_ST_BIND ELF64_ST_BIND
+# define uint_t uint64_t
+# define _w w8
+# define _align 7u
+# define _size 8
+#else
+# define append_func append32
+# define sift_rel_mcount sift32_rel_mcount
+# 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 do_func do32
+# define Elf_Ehdr Elf32_Ehdr
+# define Elf_Shdr Elf32_Shdr
+# define Elf_Rel Elf32_Rel
+# define Elf_Rela Elf32_Rela
+# define Elf_Sym Elf32_Sym
+# define ELF_R_SYM ELF32_R_SYM
+# define ELF_R_INFO ELF32_R_INFO
+# define ELF_ST_BIND ELF32_ST_BIND
+# define uint_t uint32_t
+# define _w w
+# define _align 3u
+# define _size 4
+#endif
+
+/* Append the new shstrtab, Elf_Shdr[], __mcount_loc and its relocations. */
+static void append_func(Elf_Ehdr *const ehdr,
+ Elf_Shdr *const shstr,
+ uint_t const *const mloc0,
+ uint_t const *const mlocp,
+ Elf_Rel const *const mrel0,
+ Elf_Rel const *const mrelp,
+ unsigned int const rel_entsize,
+ unsigned int const symsec_sh_link)
+{
+ /* Begin constructing output file */
+ Elf_Shdr mcsec;
+ char const *mc_name = (sizeof(Elf_Rela) == rel_entsize)
+ ? ".rela__mcount_loc"
+ : ".rel__mcount_loc";
+ unsigned const old_shnum = w2(ehdr->e_shnum);
+ uint_t const old_shoff = _w(ehdr->e_shoff);
+ uint_t const old_shstr_sh_size = _w(shstr->sh_size);
+ uint_t const old_shstr_sh_offset = _w(shstr->sh_offset);
+ uint_t t = 1 + strlen(mc_name) + _w(shstr->sh_size);
+ uint_t new_e_shoff;
+
+ shstr->sh_size = _w(t);
+ shstr->sh_offset = _w(sb.st_size);
+ t += sb.st_size;
+ t += (_align & -t); /* word-byte align */
+ new_e_shoff = t;
+
+ /* body for new shstrtab */
+ ulseek(fd_map, sb.st_size, SEEK_SET);
+ uwrite(fd_map, old_shstr_sh_offset + (void *)ehdr, old_shstr_sh_size);
+ uwrite(fd_map, mc_name, 1 + strlen(mc_name));
+
+ /* old(modified) Elf_Shdr table, word-byte aligned */
+ ulseek(fd_map, t, SEEK_SET);
+ t += sizeof(Elf_Shdr) * old_shnum;
+ uwrite(fd_map, old_shoff + (void *)ehdr,
+ sizeof(Elf_Shdr) * old_shnum);
+
+ /* new sections __mcount_loc and .rel__mcount_loc */
+ t += 2*sizeof(mcsec);
+ mcsec.sh_name = w((sizeof(Elf_Rela) == rel_entsize) + strlen(".rel")
+ + old_shstr_sh_size);
+ mcsec.sh_type = w(SHT_PROGBITS);
+ mcsec.sh_flags = _w(SHF_ALLOC);
+ mcsec.sh_addr = 0;
+ mcsec.sh_offset = _w(t);
+ mcsec.sh_size = _w((void *)mlocp - (void *)mloc0);
+ mcsec.sh_link = 0;
+ mcsec.sh_info = 0;
+ mcsec.sh_addralign = _w(_size);
+ mcsec.sh_entsize = _w(_size);
+ uwrite(fd_map, &mcsec, sizeof(mcsec));
+
+ mcsec.sh_name = w(old_shstr_sh_size);
+ mcsec.sh_type = (sizeof(Elf_Rela) == rel_entsize)
+ ? w(SHT_RELA)
+ : w(SHT_REL);
+ mcsec.sh_flags = 0;
+ mcsec.sh_addr = 0;
+ mcsec.sh_offset = _w((void *)mlocp - (void *)mloc0 + t);
+ mcsec.sh_size = _w((void *)mrelp - (void *)mrel0);
+ mcsec.sh_link = w(symsec_sh_link);
+ mcsec.sh_info = w(old_shnum);
+ mcsec.sh_addralign = _w(_size);
+ mcsec.sh_entsize = _w(rel_entsize);
+ uwrite(fd_map, &mcsec, sizeof(mcsec));
+
+ uwrite(fd_map, mloc0, (void *)mlocp - (void *)mloc0);
+ uwrite(fd_map, mrel0, (void *)mrelp - (void *)mrel0);
+
+ ehdr->e_shoff = _w(new_e_shoff);
+ ehdr->e_shnum = w2(2 + w2(ehdr->e_shnum)); /* {.rel,}__mcount_loc */
+ ulseek(fd_map, 0, SEEK_SET);
+ uwrite(fd_map, ehdr, sizeof(*ehdr));
+}
+
+
+/*
+ * Look at the relocations in order to find the calls to mcount.
+ * Accumulate the section offsets that are found, and their relocation info,
+ * onto the end of the existing arrays.
+ */
+static uint_t *sift_rel_mcount(uint_t *mlocp,
+ unsigned const offbase,
+ Elf_Rel **const mrelpp,
+ Elf_Shdr const *const relhdr,
+ Elf_Ehdr const *const ehdr,
+ unsigned const recsym,
+ uint_t const recval,
+ unsigned const reltype)
+{
+ 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);
+ 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;
+
+ for (t = nrel; t; --t) {
+ if (!mcountsym) {
+ Elf_Sym const *const symp =
+ &sym0[ELF_R_SYM(_w(relp->r_info))];
+ char const *symname = &str0[w(symp->st_name)];
+
+ if ('.' == symname[0])
+ ++symname; /* ppc64 hack */
+ if (0 == strcmp((('_' == gpfx) ? "_mcount" : "mcount"),
+ symname))
+ mcountsym = ELF_R_SYM(_w(relp->r_info));
+ }
+
+ if (mcountsym == ELF_R_SYM(_w(relp->r_info))) {
+ uint_t const addend = _w(_w(relp->r_offset) - recval);
+
+ mrelp->r_offset = _w(offbase
+ + ((void *)mlocp - (void *)mloc0));
+ mrelp->r_info = _w(ELF_R_INFO(recsym, reltype));
+ if (sizeof(Elf_Rela) == rel_entsize) {
+ ((Elf_Rela *)mrelp)->r_addend = addend;
+ *mlocp++ = 0;
+ } else
+ *mlocp++ = addend;
+
+ mrelp = (Elf_Rel *)(rel_entsize + (void *)mrelp);
+ }
+ relp = (Elf_Rel const *)(rel_entsize + (void *)relp);
+ }
+ *mrelpp = mrelp;
+ return mlocp;
+}
+
+
+/*
+ * Find a symbol in the given section, to be used as the base for relocating
+ * the table of offsets of calls to mcount. A local or global symbol suffices,
+ * but avoid a Weak symbol because it may be overridden; the change in value
+ * would invalidate the relocations of the offsets of the calls to mcount.
+ * Often the found symbol will be the unnamed local symbol generated by
+ * GNU 'as' for the start of each section. For example:
+ * Num: Value Size Type Bind Vis Ndx Name
+ * 2: 00000000 0 SECTION LOCAL DEFAULT 1
+ */
+static unsigned find_secsym_ndx(unsigned const txtndx,
+ char const *const txtname,
+ uint_t *const recvalp,
+ Elf_Shdr const *const symhdr,
+ Elf_Ehdr const *const ehdr)
+{
+ Elf_Sym const *const sym0 = (Elf_Sym const *)(_w(symhdr->sh_offset)
+ + (void *)ehdr);
+ unsigned const nsym = _w(symhdr->sh_size) / _w(symhdr->sh_entsize);
+ Elf_Sym const *symp;
+ unsigned t;
+
+ for (symp = sym0, t = nsym; t; --t, ++symp) {
+ unsigned int const st_bind = ELF_ST_BIND(symp->st_info);
+
+ if (txtndx == w2(symp->st_shndx)
+ /* avoid STB_WEAK */
+ && (STB_LOCAL == st_bind || STB_GLOBAL == st_bind)) {
+ *recvalp = _w(symp->st_value);
+ return symp - sym0;
+ }
+ }
+ fprintf(stderr, "Cannot find symbol for section %d: %s.\n",
+ txtndx, txtname);
+ fail_file();
+}
+
+
+/* Evade ISO C restriction: no declaration after statement in has_rel_mcount. */
+static char const *
+__has_rel_mcount(Elf_Shdr const *const relhdr, /* is SHT_REL or SHT_RELA */
+ Elf_Shdr const *const shdr0,
+ char const *const shstrtab,
+ char const *const fname)
+{
+ /* .sh_info depends on .sh_type == SHT_REL[,A] */
+ 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)) {
+ fprintf(stderr, "warning: __mcount_loc already exists: %s\n",
+ fname);
+ succeed_file();
+ }
+ if (SHT_PROGBITS != w(txthdr->sh_type) ||
+ !is_mcounted_section_name(txtname))
+ return NULL;
+ return txtname;
+}
+
+static char const *has_rel_mcount(Elf_Shdr const *const relhdr,
+ Elf_Shdr const *const shdr0,
+ char const *const shstrtab,
+ char const *const fname)
+{
+ if (SHT_REL != w(relhdr->sh_type) && SHT_RELA != w(relhdr->sh_type))
+ return NULL;
+ return __has_rel_mcount(relhdr, shdr0, shstrtab, fname);
+}
+
+
+static unsigned tot_relsize(Elf_Shdr const *const shdr0,
+ unsigned nhdr,
+ const char *const shstrtab,
+ const char *const fname)
+{
+ unsigned totrelsz = 0;
+ Elf_Shdr const *shdrp = shdr0;
+
+ for (; nhdr; --nhdr, ++shdrp) {
+ if (has_rel_mcount(shdrp, shdr0, shstrtab, fname))
+ totrelsz += _w(shdrp->sh_size);
+ }
+ return totrelsz;
+}
+
+
+/* Overall supervision for Elf32 ET_REL file. */
+static void
+do_func(Elf_Ehdr *const ehdr, char const *const fname, unsigned const reltype)
+{
+ Elf_Shdr *const shdr0 = (Elf_Shdr *)(_w(ehdr->e_shoff)
+ + (void *)ehdr);
+ unsigned const nhdr = w2(ehdr->e_shnum);
+ Elf_Shdr *const shstr = &shdr0[w2(ehdr->e_shstrndx)];
+ char const *const shstrtab = (char const *)(_w(shstr->sh_offset)
+ + (void *)ehdr);
+
+ Elf_Shdr const *relhdr;
+ unsigned k;
+
+ /* Upper bound on space: assume all relevant relocs are for mcount. */
+ unsigned const totrelsz = tot_relsize(shdr0, nhdr, shstrtab, fname);
+ Elf_Rel *const mrel0 = umalloc(totrelsz);
+ Elf_Rel * mrelp = mrel0;
+
+ /* 2*sizeof(address) <= sizeof(Elf_Rel) */
+ uint_t *const mloc0 = umalloc(totrelsz>>1);
+ uint_t * mlocp = mloc0;
+
+ unsigned rel_entsize = 0;
+ unsigned symsec_sh_link = 0;
+
+ for (relhdr = shdr0, k = nhdr; k; --k, ++relhdr) {
+ char const *const txtname = has_rel_mcount(relhdr, shdr0,
+ shstrtab, fname);
+ if (txtname) {
+ uint_t recval = 0;
+ unsigned const recsym = find_secsym_ndx(
+ w(relhdr->sh_info), txtname, &recval,
+ &shdr0[symsec_sh_link = w(relhdr->sh_link)],
+ ehdr);
+
+ rel_entsize = _w(relhdr->sh_entsize);
+ mlocp = sift_rel_mcount(mlocp,
+ (void *)mlocp - (void *)mloc0, &mrelp,
+ relhdr, ehdr, recsym, recval, reltype);
+ }
+ }
+ if (mloc0 != mlocp) {
+ append_func(ehdr, shstr, mloc0, mlocp, mrel0, mrelp,
+ rel_entsize, symsec_sh_link);
+ }
+ free(mrel0);
+ free(mloc0);
+}
generated by cgit 1.2.3-korg (git 2.39.0) at 2024-04-19 14:32:17 +0000