* [PATCH 1/3] ftrace: Add C version of recordmcount compile time code
2010-10-14 21:00 [PATCH 0/3] [GIT PULL][2.6.37] ftrace: C version of recordmcount Steven Rostedt
@ 2010-10-14 21:00 ` Steven Rostedt
2010-10-14 21:00 ` Steven Rostedt
2010-10-14 21:00 ` [PATCH 3/3] ftrace: Remove duplicate code for 64 and 32 bit in recordmcount.c Steven Rostedt
2 siblings, 0 replies; 11+ messages in thread
From: Steven Rostedt @ 2010-10-14 21:00 UTC (permalink / raw)
To: linux-kernel; +Cc: Ingo Molnar, Andrew Morton, Frederic Weisbecker, John Reiser
[-- Attachment #1: 0001-ftrace-Add-C-version-of-recordmcount-compile-time-co.patch --]
[-- Type: text/plain, Size: 27856 bytes --]
From: John Reiser <jreiser@bitwagon.com>
Currently, the mcount callers are found with a perl script that does
an objdump on every file in the kernel. This is a C version of that
same code which should increase the performance time of compiling
the kernel with dynamic ftrace enabled.
Signed-off-by: John Reiser <jreiser@bitwagon.com>
[ Updated the code to include .text.unlikely section as well as
changing the format to follow Linux coding style. ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
scripts/recordmcount.c | 885 ++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 885 insertions(+), 0 deletions(-)
create mode 100644 scripts/recordmcount.c
diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c
new file mode 100644
index 0000000..34f32be
--- /dev/null
+++ b/scripts/recordmcount.c
@@ -0,0 +1,885 @@
+/*
+ * recordmcount.c: construct a table of the locations of calls to 'mcount'
+ * so that ftrace can find them quickly.
+ * Copyright 2009 John F. Reiser <jreiser@BitWagon.com>. All rights reserved.
+ * Licensed under the GNU General Public License, version 2 (GPLv2).
+ *
+ * Restructured to fit Linux format, as well as other updates:
+ * Copyright 2010 Steven Rostedt <srostedt@redhat.com>, Red Hat Inc.
+ */
+
+/*
+ * Strategy: alter the .o file in-place.
+ *
+ * Append a new STRTAB that has the new section names, followed by a new array
+ * ElfXX_Shdr[] that has the new section headers, followed by the section
+ * contents for __mcount_loc and its relocations. The old shstrtab strings,
+ * and the old ElfXX_Shdr[] array, remain as "garbage" (commonly, a couple
+ * kilobytes.) Subsequent processing by /bin/ld (or the kernel module loader)
+ * will ignore the garbage regions, because they are not designated by the
+ * new .e_shoff nor the new ElfXX_Shdr[]. [In order to remove the garbage,
+ * then use "ld -r" to create a new file that omits the garbage.]
+ */
+
+#include <sys/types.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <elf.h>
+#include <fcntl.h>
+#include <setjmp.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+static int fd_map; /* File descriptor for file being modified. */
+static int mmap_failed; /* Boolean flag. */
+static void *ehdr_curr; /* current ElfXX_Ehdr * for resource cleanup */
+static char gpfx; /* prefix for global symbol name (sometimes '_') */
+static struct stat sb; /* Remember .st_size, etc. */
+static jmp_buf jmpenv; /* setjmp/longjmp per-file error escape */
+
+/* setjmp() return values */
+enum {
+ SJ_SETJMP = 0, /* hardwired first return */
+ SJ_FAIL,
+ SJ_SUCCEED
+};
+
+/* Per-file resource cleanup when multiple files. */
+static void
+cleanup(void)
+{
+ if (!mmap_failed)
+ munmap(ehdr_curr, sb.st_size);
+ else
+ free(ehdr_curr);
+ close(fd_map);
+}
+
+static void __attribute__((noreturn))
+fail_file(void)
+{
+ cleanup();
+ longjmp(jmpenv, SJ_FAIL);
+}
+
+static void __attribute__((noreturn))
+succeed_file(void)
+{
+ cleanup();
+ longjmp(jmpenv, SJ_SUCCEED);
+}
+
+/* ulseek, uread, ...: Check return value for errors. */
+
+static off_t
+ulseek(int const fd, off_t const offset, int const whence)
+{
+ off_t const w = lseek(fd, offset, whence);
+ if ((off_t)-1 == w) {
+ perror("lseek");
+ fail_file();
+ }
+ return w;
+}
+
+static size_t
+uread(int const fd, void *const buf, size_t const count)
+{
+ size_t const n = read(fd, buf, count);
+ if (n != count) {
+ perror("read");
+ fail_file();
+ }
+ return n;
+}
+
+static size_t
+uwrite(int const fd, void const *const buf, size_t const count)
+{
+ size_t const n = write(fd, buf, count);
+ if (n != count) {
+ perror("write");
+ fail_file();
+ }
+ return n;
+}
+
+static void *
+umalloc(size_t size)
+{
+ void *const addr = malloc(size);
+ if (0 == addr) {
+ fprintf(stderr, "malloc failed: %zu bytes\n", size);
+ fail_file();
+ }
+ return addr;
+}
+
+/*
+ * Get the whole file as a programming convenience in order to avoid
+ * malloc+lseek+read+free of many pieces. If successful, then mmap
+ * avoids copying unused pieces; else just read the whole file.
+ * Open for both read and write; new info will be appended to the file.
+ * Use MAP_PRIVATE so that a few changes to the in-memory ElfXX_Ehdr
+ * do not propagate to the file until an explicit overwrite at the last.
+ * This preserves most aspects of consistency (all except .st_size)
+ * for simultaneous readers of the file while we are appending to it.
+ * However, multiple writers still are bad. We choose not to use
+ * locking because it is expensive and the use case of kernel build
+ * makes multiple writers unlikely.
+ */
+static void *mmap_file(char const *fname)
+{
+ void *addr;
+
+ fd_map = open(fname, O_RDWR);
+ if (0 > fd_map || 0 > fstat(fd_map, &sb)) {
+ perror(fname);
+ fail_file();
+ }
+ if (!S_ISREG(sb.st_mode)) {
+ fprintf(stderr, "not a regular file: %s\n", fname);
+ fail_file();
+ }
+ addr = mmap(0, sb.st_size, PROT_READ|PROT_WRITE, MAP_PRIVATE,
+ fd_map, 0);
+ mmap_failed = 0;
+ if (MAP_FAILED == addr) {
+ mmap_failed = 1;
+ addr = umalloc(sb.st_size);
+ uread(fd_map, addr, sb.st_size);
+ }
+ return addr;
+}
+
+/* w8rev, w8nat, ...: Handle endianness. */
+
+static uint64_t w8rev(uint64_t const x)
+{
+ return ((0xff & (x >> (0 * 8))) << (7 * 8))
+ | ((0xff & (x >> (1 * 8))) << (6 * 8))
+ | ((0xff & (x >> (2 * 8))) << (5 * 8))
+ | ((0xff & (x >> (3 * 8))) << (4 * 8))
+ | ((0xff & (x >> (4 * 8))) << (3 * 8))
+ | ((0xff & (x >> (5 * 8))) << (2 * 8))
+ | ((0xff & (x >> (6 * 8))) << (1 * 8))
+ | ((0xff & (x >> (7 * 8))) << (0 * 8));
+}
+
+static uint32_t w4rev(uint32_t const x)
+{
+ return ((0xff & (x >> (0 * 8))) << (3 * 8))
+ | ((0xff & (x >> (1 * 8))) << (2 * 8))
+ | ((0xff & (x >> (2 * 8))) << (1 * 8))
+ | ((0xff & (x >> (3 * 8))) << (0 * 8));
+}
+
+static uint32_t w2rev(uint16_t const x)
+{
+ return ((0xff & (x >> (0 * 8))) << (1 * 8))
+ | ((0xff & (x >> (1 * 8))) << (0 * 8));
+}
+
+static uint64_t w8nat(uint64_t const x)
+{
+ return x;
+}
+
+static uint32_t w4nat(uint32_t const x)
+{
+ return x;
+}
+
+static uint32_t w2nat(uint16_t const x)
+{
+ return x;
+}
+
+static uint64_t (*w8)(uint64_t);
+static uint32_t (*w)(uint32_t);
+static uint32_t (*w2)(uint16_t);
+
+/* Names of the sections that could contain calls to mcount. */
+static int
+is_mcounted_section_name(char const *const txtname)
+{
+ return 0 == strcmp(".text", txtname) ||
+ 0 == strcmp(".sched.text", txtname) ||
+ 0 == strcmp(".spinlock.text", txtname) ||
+ 0 == strcmp(".irqentry.text", txtname) ||
+ 0 == strcmp(".text.unlikely", txtname);
+}
+
+/* Append the new shstrtab, Elf32_Shdr[], __mcount_loc and its relocations. */
+static void append32(Elf32_Ehdr *const ehdr,
+ Elf32_Shdr *const shstr,
+ uint32_t const *const mloc0,
+ uint32_t const *const mlocp,
+ Elf32_Rel const *const mrel0,
+ Elf32_Rel const *const mrelp,
+ unsigned int const rel_entsize,
+ unsigned int const symsec_sh_link)
+{
+ /* Begin constructing output file */
+ Elf32_Shdr mcsec;
+ char const *mc_name = (sizeof(Elf32_Rela) == rel_entsize)
+ ? ".rela__mcount_loc"
+ : ".rel__mcount_loc";
+ unsigned const old_shnum = w2(ehdr->e_shnum);
+ uint32_t const old_shoff = w(ehdr->e_shoff);
+ uint32_t const old_shstr_sh_size = w(shstr->sh_size);
+ uint32_t const old_shstr_sh_offset = w(shstr->sh_offset);
+ uint32_t t = 1 + strlen(mc_name) + w(shstr->sh_size);
+ uint32_t new_e_shoff;
+
+ shstr->sh_size = w(t);
+ shstr->sh_offset = w(sb.st_size);
+ t += sb.st_size;
+ t += (3u & -t); /* 4-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) Elf32_Shdr table, 4-byte aligned */
+ ulseek(fd_map, t, SEEK_SET);
+ t += sizeof(Elf32_Shdr) * old_shnum;
+ uwrite(fd_map, old_shoff + (void *)ehdr,
+ sizeof(Elf32_Shdr) * old_shnum);
+
+ /* new sections __mcount_loc and .rel__mcount_loc */
+ t += 2*sizeof(mcsec);
+ mcsec.sh_name = w((sizeof(Elf32_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(4);
+ mcsec.sh_entsize = w(4);
+ uwrite(fd_map, &mcsec, sizeof(mcsec));
+
+ mcsec.sh_name = w(old_shstr_sh_size);
+ mcsec.sh_type = (sizeof(Elf32_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(4);
+ 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));
+}
+
+/*
+ * append64 and append32 (and other analogous pairs) could be templated
+ * using C++, but the complexity is high. (For an example, look at p_elf.h
+ * in the source for UPX, http://upx.sourceforge.net) So: remember to make
+ * the corresponding change in the routine for the other size.
+ */
+static void append64(Elf64_Ehdr *const ehdr,
+ Elf64_Shdr *const shstr,
+ uint64_t const *const mloc0,
+ uint64_t const *const mlocp,
+ Elf64_Rel const *const mrel0,
+ Elf64_Rel const *const mrelp,
+ unsigned int const rel_entsize,
+ unsigned int const symsec_sh_link)
+{
+ /* Begin constructing output file */
+ Elf64_Shdr mcsec;
+ char const *mc_name = (sizeof(Elf64_Rela) == rel_entsize)
+ ? ".rela__mcount_loc"
+ : ".rel__mcount_loc";
+ unsigned const old_shnum = w2(ehdr->e_shnum);
+ uint64_t const old_shoff = w8(ehdr->e_shoff);
+ uint64_t const old_shstr_sh_size = w8(shstr->sh_size);
+ uint64_t const old_shstr_sh_offset = w8(shstr->sh_offset);
+ uint64_t t = 1 + strlen(mc_name) + w8(shstr->sh_size);
+ uint64_t new_e_shoff;
+
+ shstr->sh_size = w8(t);
+ shstr->sh_offset = w8(sb.st_size);
+ t += sb.st_size;
+ t += (7u & -t); /* 8-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) Elf64_Shdr table, 8-byte aligned */
+ ulseek(fd_map, t, SEEK_SET);
+ t += sizeof(Elf64_Shdr) * old_shnum;
+ uwrite(fd_map, old_shoff + (void *)ehdr,
+ sizeof(Elf64_Shdr) * old_shnum);
+
+ /* new sections __mcount_loc and .rel__mcount_loc */
+ t += 2*sizeof(mcsec);
+ mcsec.sh_name = w((sizeof(Elf64_Rela) == rel_entsize) + strlen(".rel")
+ + old_shstr_sh_size);
+ mcsec.sh_type = w(SHT_PROGBITS);
+ mcsec.sh_flags = w8(SHF_ALLOC);
+ mcsec.sh_addr = 0;
+ mcsec.sh_offset = w8(t);
+ mcsec.sh_size = w8((void *)mlocp - (void *)mloc0);
+ mcsec.sh_link = 0;
+ mcsec.sh_info = 0;
+ mcsec.sh_addralign = w8(8);
+ mcsec.sh_entsize = w8(8);
+ uwrite(fd_map, &mcsec, sizeof(mcsec));
+
+ mcsec.sh_name = w(old_shstr_sh_size);
+ mcsec.sh_type = (sizeof(Elf64_Rela) == rel_entsize)
+ ? w(SHT_RELA)
+ : w(SHT_REL);
+ mcsec.sh_flags = 0;
+ mcsec.sh_addr = 0;
+ mcsec.sh_offset = w8((void *)mlocp - (void *)mloc0 + t);
+ mcsec.sh_size = w8((void *)mrelp - (void *)mrel0);
+ mcsec.sh_link = w(symsec_sh_link);
+ mcsec.sh_info = w(old_shnum);
+ mcsec.sh_addralign = w8(8);
+ mcsec.sh_entsize = w8(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 = w8(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 uint32_t *sift32_rel_mcount(uint32_t *mlocp,
+ unsigned const offbase,
+ Elf32_Rel **const mrelpp,
+ Elf32_Shdr const *const relhdr,
+ Elf32_Ehdr const *const ehdr,
+ unsigned const recsym,
+ uint32_t const recval,
+ unsigned const reltype)
+{
+ uint32_t *const mloc0 = mlocp;
+ Elf32_Rel *mrelp = *mrelpp;
+ Elf32_Shdr *const shdr0 = (Elf32_Shdr *)(w(ehdr->e_shoff)
+ + (void *)ehdr);
+ unsigned const symsec_sh_link = w(relhdr->sh_link);
+ Elf32_Shdr const *const symsec = &shdr0[symsec_sh_link];
+ Elf32_Sym const *const sym0 = (Elf32_Sym const *)(w(symsec->sh_offset)
+ + (void *)ehdr);
+
+ Elf32_Shdr const *const strsec = &shdr0[w(symsec->sh_link)];
+ char const *const str0 = (char const *)(w(strsec->sh_offset)
+ + (void *)ehdr);
+
+ Elf32_Rel const *const rel0 = (Elf32_Rel const *)(w(relhdr->sh_offset)
+ + (void *)ehdr);
+ unsigned rel_entsize = w(relhdr->sh_entsize);
+ unsigned const nrel = w(relhdr->sh_size) / rel_entsize;
+ Elf32_Rel const *relp = rel0;
+
+ unsigned mcountsym = 0;
+ unsigned t;
+
+ for (t = nrel; t; --t) {
+ if (!mcountsym) {
+ Elf32_Sym const *const symp =
+ &sym0[ELF32_R_SYM(w(relp->r_info))];
+
+ if (0 == strcmp((('_' == gpfx) ? "_mcount" : "mcount"),
+ &str0[w(symp->st_name)]))
+ mcountsym = ELF32_R_SYM(w(relp->r_info));
+ }
+ if (mcountsym == ELF32_R_SYM(w(relp->r_info))) {
+ uint32_t const addend = w(w(relp->r_offset) - recval);
+ mrelp->r_offset = w(offbase
+ + ((void *)mlocp - (void *)mloc0));
+ mrelp->r_info = w(ELF32_R_INFO(recsym, reltype));
+ if (sizeof(Elf32_Rela) == rel_entsize) {
+ ((Elf32_Rela *)mrelp)->r_addend = addend;
+ *mlocp++ = 0;
+ } else
+ *mlocp++ = addend;
+
+ mrelp = (Elf32_Rel *)(rel_entsize + (void *)mrelp);
+ }
+ relp = (Elf32_Rel const *)(rel_entsize + (void *)relp);
+ }
+ *mrelpp = mrelp;
+ return mlocp;
+}
+
+static uint64_t *sift64_rel_mcount(uint64_t *mlocp,
+ unsigned const offbase,
+ Elf64_Rel **const mrelpp,
+ Elf64_Shdr const *const relhdr,
+ Elf64_Ehdr const *const ehdr,
+ unsigned const recsym,
+ uint64_t const recval,
+ unsigned const reltype)
+{
+ uint64_t *const mloc0 = mlocp;
+ Elf64_Rel *mrelp = *mrelpp;
+ Elf64_Shdr *const shdr0 = (Elf64_Shdr *)(w8(ehdr->e_shoff)
+ + (void *)ehdr);
+ unsigned const symsec_sh_link = w(relhdr->sh_link);
+ Elf64_Shdr const *const symsec = &shdr0[symsec_sh_link];
+ Elf64_Sym const *const sym0 = (Elf64_Sym const *)(w8(symsec->sh_offset)
+ + (void *)ehdr);
+
+ Elf64_Shdr const *const strsec = &shdr0[w(symsec->sh_link)];
+ char const *const str0 = (char const *)(w8(strsec->sh_offset)
+ + (void *)ehdr);
+
+ Elf64_Rel const *const rel0 = (Elf64_Rel const *)(w8(relhdr->sh_offset)
+ + (void *)ehdr);
+ unsigned rel_entsize = w8(relhdr->sh_entsize);
+ unsigned const nrel = w8(relhdr->sh_size) / rel_entsize;
+ Elf64_Rel const *relp = rel0;
+
+ unsigned mcountsym = 0;
+ unsigned t;
+
+ for (t = nrel; 0 != t; --t) {
+ if (!mcountsym) {
+ Elf64_Sym const *const symp =
+ &sym0[ELF64_R_SYM(w8(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 = ELF64_R_SYM(w8(relp->r_info));
+ }
+
+ if (mcountsym == ELF64_R_SYM(w8(relp->r_info))) {
+ uint64_t const addend = w8(w8(relp->r_offset) - recval);
+
+ mrelp->r_offset = w8(offbase
+ + ((void *)mlocp - (void *)mloc0));
+ mrelp->r_info = w8(ELF64_R_INFO(recsym, reltype));
+ if (sizeof(Elf64_Rela) == rel_entsize) {
+ ((Elf64_Rela *)mrelp)->r_addend = addend;
+ *mlocp++ = 0;
+ } else
+ *mlocp++ = addend;
+
+ mrelp = (Elf64_Rel *)(rel_entsize + (void *)mrelp);
+ }
+ relp = (Elf64_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 find32_secsym_ndx(unsigned const txtndx,
+ char const *const txtname,
+ uint32_t *const recvalp,
+ Elf32_Shdr const *const symhdr,
+ Elf32_Ehdr const *const ehdr)
+{
+ Elf32_Sym const *const sym0 = (Elf32_Sym const *)(w(symhdr->sh_offset)
+ + (void *)ehdr);
+ unsigned const nsym = w(symhdr->sh_size) / w(symhdr->sh_entsize);
+ Elf32_Sym const *symp;
+ unsigned t;
+
+ for (symp = sym0, t = nsym; t; --t, ++symp) {
+ unsigned int const st_bind = ELF32_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();
+}
+
+static unsigned find64_secsym_ndx(unsigned const txtndx,
+ char const *const txtname,
+ uint64_t *const recvalp,
+ Elf64_Shdr const *const symhdr,
+ Elf64_Ehdr const *const ehdr)
+{
+ Elf64_Sym const *const sym0 = (Elf64_Sym const *)(w8(symhdr->sh_offset)
+ + (void *)ehdr);
+ unsigned const nsym = w8(symhdr->sh_size) / w8(symhdr->sh_entsize);
+ Elf64_Sym const *symp;
+ unsigned t;
+
+ for (symp = sym0, t = nsym; t; --t, ++symp) {
+ unsigned int const st_bind = ELF64_ST_BIND(symp->st_info);
+
+ if (txtndx == w2(symp->st_shndx)
+ /* avoid STB_WEAK */
+ && (STB_LOCAL == st_bind || STB_GLOBAL == st_bind)) {
+ *recvalp = w8(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
+ * has32_rel_mcount.
+ */
+static char const *
+__has32_rel_mcount(Elf32_Shdr const *const relhdr, /* is SHT_REL or SHT_RELA */
+ Elf32_Shdr const *const shdr0,
+ char const *const shstrtab,
+ char const *const fname)
+{
+ /* .sh_info depends on .sh_type == SHT_REL[,A] */
+ Elf32_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 *has32_rel_mcount(Elf32_Shdr const *const relhdr,
+ Elf32_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 __has32_rel_mcount(relhdr, shdr0, shstrtab, fname);
+}
+
+static char const *__has64_rel_mcount(Elf64_Shdr const *const relhdr,
+ Elf64_Shdr const *const shdr0,
+ char const *const shstrtab,
+ char const *const fname)
+{
+ /* .sh_info depends on .sh_type == SHT_REL[,A] */
+ Elf64_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 *has64_rel_mcount(Elf64_Shdr const *const relhdr,
+ Elf64_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 __has64_rel_mcount(relhdr, shdr0, shstrtab, fname);
+}
+
+static unsigned tot32_relsize(Elf32_Shdr const *const shdr0,
+ unsigned nhdr,
+ const char *const shstrtab,
+ const char *const fname)
+{
+ unsigned totrelsz = 0;
+ Elf32_Shdr const *shdrp = shdr0;
+ for (; 0 != nhdr; --nhdr, ++shdrp) {
+ if (has32_rel_mcount(shdrp, shdr0, shstrtab, fname))
+ totrelsz += w(shdrp->sh_size);
+ }
+ return totrelsz;
+}
+
+static unsigned tot64_relsize(Elf64_Shdr const *const shdr0,
+ unsigned nhdr,
+ const char *const shstrtab,
+ const char *const fname)
+{
+ unsigned totrelsz = 0;
+ Elf64_Shdr const *shdrp = shdr0;
+
+ for (; nhdr; --nhdr, ++shdrp) {
+ if (has64_rel_mcount(shdrp, shdr0, shstrtab, fname))
+ totrelsz += w8(shdrp->sh_size);
+ }
+ return totrelsz;
+}
+
+/* Overall supervision for Elf32 ET_REL file. */
+static void
+do32(Elf32_Ehdr *const ehdr, char const *const fname, unsigned const reltype)
+{
+ Elf32_Shdr *const shdr0 = (Elf32_Shdr *)(w(ehdr->e_shoff)
+ + (void *)ehdr);
+ unsigned const nhdr = w2(ehdr->e_shnum);
+ Elf32_Shdr *const shstr = &shdr0[w2(ehdr->e_shstrndx)];
+ char const *const shstrtab = (char const *)(w(shstr->sh_offset)
+ + (void *)ehdr);
+
+ Elf32_Shdr const *relhdr;
+ unsigned k;
+
+ /* Upper bound on space: assume all relevant relocs are for mcount. */
+ unsigned const totrelsz = tot32_relsize(shdr0, nhdr, shstrtab, fname);
+ Elf32_Rel *const mrel0 = umalloc(totrelsz);
+ Elf32_Rel * mrelp = mrel0;
+
+ /* 2*sizeof(address) <= sizeof(Elf32_Rel) */
+ uint32_t *const mloc0 = umalloc(totrelsz>>1);
+ uint32_t * mlocp = mloc0;
+
+ unsigned rel_entsize = 0;
+ unsigned symsec_sh_link = 0;
+
+ for (relhdr = shdr0, k = nhdr; k; --k, ++relhdr) {
+ char const *const txtname = has32_rel_mcount(relhdr, shdr0,
+ shstrtab, fname);
+ if (txtname) {
+ uint32_t recval = 0;
+ unsigned const recsym = find32_secsym_ndx(
+ w(relhdr->sh_info), txtname, &recval,
+ &shdr0[symsec_sh_link = w(relhdr->sh_link)],
+ ehdr);
+
+ rel_entsize = w(relhdr->sh_entsize);
+ mlocp = sift32_rel_mcount(mlocp,
+ (void *)mlocp - (void *)mloc0, &mrelp,
+ relhdr, ehdr, recsym, recval, reltype);
+ }
+ }
+ if (mloc0 != mlocp) {
+ append32(ehdr, shstr, mloc0, mlocp, mrel0, mrelp,
+ rel_entsize, symsec_sh_link);
+ }
+ free(mrel0);
+ free(mloc0);
+}
+
+static void
+do64(Elf64_Ehdr *const ehdr, char const *const fname, unsigned const reltype)
+{
+ Elf64_Shdr *const shdr0 = (Elf64_Shdr *)(w8(ehdr->e_shoff)
+ + (void *)ehdr);
+ unsigned const nhdr = w2(ehdr->e_shnum);
+ Elf64_Shdr *const shstr = &shdr0[w2(ehdr->e_shstrndx)];
+ char const *const shstrtab = (char const *)(w8(shstr->sh_offset)
+ + (void *)ehdr);
+
+ Elf64_Shdr const *relhdr;
+ unsigned k;
+
+ /* Upper bound on space: assume all relevant relocs are for mcount. */
+ unsigned const totrelsz = tot64_relsize(shdr0, nhdr, shstrtab, fname);
+ Elf64_Rel *const mrel0 = umalloc(totrelsz);
+ Elf64_Rel * mrelp = mrel0;
+
+ /* 2*sizeof(address) <= sizeof(Elf64_Rel) */
+ uint64_t *const mloc0 = umalloc(totrelsz>>1);
+ uint64_t * mlocp = mloc0;
+
+ unsigned rel_entsize = 0;
+ unsigned symsec_sh_link = 0;
+
+ for ((relhdr = shdr0), k = nhdr; k; --k, ++relhdr) {
+ char const *const txtname = has64_rel_mcount(relhdr, shdr0,
+ shstrtab, fname);
+ if (txtname) {
+ uint64_t recval = 0;
+ unsigned const recsym = find64_secsym_ndx(
+ w(relhdr->sh_info), txtname, &recval,
+ &shdr0[symsec_sh_link = w(relhdr->sh_link)],
+ ehdr);
+
+ rel_entsize = w8(relhdr->sh_entsize);
+ mlocp = sift64_rel_mcount(mlocp,
+ (void *)mlocp - (void *)mloc0, &mrelp,
+ relhdr, ehdr, recsym, recval, reltype);
+ }
+ }
+ if (mloc0 != mlocp) {
+ append64(ehdr, shstr, mloc0, mlocp, mrel0, mrelp,
+ rel_entsize, symsec_sh_link);
+ }
+ free(mrel0);
+ free(mloc0);
+}
+
+static void
+do_file(char const *const fname)
+{
+ Elf32_Ehdr *const ehdr = mmap_file(fname);
+ unsigned int reltype = 0;
+
+ ehdr_curr = ehdr;
+ w = w4nat;
+ w2 = w2nat;
+ w8 = w8nat;
+ switch (ehdr->e_ident[EI_DATA]) {
+ static unsigned int const endian = 1;
+ default: {
+ fprintf(stderr, "unrecognized ELF data encoding %d: %s\n",
+ ehdr->e_ident[EI_DATA], fname);
+ fail_file();
+ } break;
+ case ELFDATA2LSB: {
+ if (1 != *(unsigned char const *)&endian) {
+ /* main() is big endian, file.o is little endian. */
+ w = w4rev;
+ w2 = w2rev;
+ w8 = w8rev;
+ }
+ } break;
+ case ELFDATA2MSB: {
+ if (0 != *(unsigned char const *)&endian) {
+ /* main() is little endian, file.o is big endian. */
+ w = w4rev;
+ w2 = w2rev;
+ w8 = w8rev;
+ }
+ } break;
+ } /* end switch */
+ if (0 != memcmp(ELFMAG, ehdr->e_ident, SELFMAG)
+ || ET_REL != w2(ehdr->e_type)
+ || EV_CURRENT != ehdr->e_ident[EI_VERSION]) {
+ fprintf(stderr, "unrecognized ET_REL file %s\n", fname);
+ fail_file();
+ }
+
+ gpfx = 0;
+ switch (w2(ehdr->e_machine)) {
+ default: {
+ fprintf(stderr, "unrecognized e_machine %d %s\n",
+ w2(ehdr->e_machine), fname);
+ fail_file();
+ } break;
+ case EM_386: reltype = R_386_32; break;
+ case EM_ARM: reltype = R_ARM_ABS32; break;
+ case EM_IA_64: reltype = R_IA64_IMM64; gpfx = '_'; break;
+ case EM_PPC: reltype = R_PPC_ADDR32; gpfx = '_'; break;
+ case EM_PPC64: reltype = R_PPC64_ADDR64; gpfx = '_'; break;
+ case EM_S390: /* reltype: e_class */ gpfx = '_'; break;
+ case EM_SH: reltype = R_SH_DIR32; break;
+ case EM_SPARCV9: reltype = R_SPARC_64; gpfx = '_'; break;
+ case EM_X86_64: reltype = R_X86_64_64; break;
+ } /* end switch */
+
+ switch (ehdr->e_ident[EI_CLASS]) {
+ default: {
+ fprintf(stderr, "unrecognized ELF class %d %s\n",
+ ehdr->e_ident[EI_CLASS], fname);
+ fail_file();
+ } break;
+ case ELFCLASS32: {
+ if (sizeof(Elf32_Ehdr) != w2(ehdr->e_ehsize)
+ || sizeof(Elf32_Shdr) != w2(ehdr->e_shentsize)) {
+ fprintf(stderr,
+ "unrecognized ET_REL file: %s\n", fname);
+ fail_file();
+ }
+ if (EM_S390 == w2(ehdr->e_machine))
+ reltype = R_390_32;
+ do32(ehdr, fname, reltype);
+ } break;
+ case ELFCLASS64: {
+ Elf64_Ehdr *const ghdr = (Elf64_Ehdr *)ehdr;
+ if (sizeof(Elf64_Ehdr) != w2(ghdr->e_ehsize)
+ || sizeof(Elf64_Shdr) != w2(ghdr->e_shentsize)) {
+ fprintf(stderr,
+ "unrecognized ET_REL file: %s\n", fname);
+ fail_file();
+ }
+ if (EM_S390 == w2(ghdr->e_machine))
+ reltype = R_390_64;
+ do64(ghdr, fname, reltype);
+ } break;
+ } /* end switch */
+
+ cleanup();
+}
+
+int
+main(int argc, char const *argv[])
+{
+ int n_error = 0; /* gcc-4.3.0 false positive complaint */
+ if (argc <= 1)
+ fprintf(stderr, "usage: recordmcount file.o...\n");
+ else /* Process each file in turn, allowing deep failure. */
+ for (--argc, ++argv; 0 < argc; --argc, ++argv) {
+ int const sjval = setjmp(jmpenv);
+ switch (sjval) {
+ default: {
+ fprintf(stderr, "internal error: %s\n", argv[0]);
+ exit(1);
+ } break;
+ case SJ_SETJMP: { /* normal sequence */
+ /* Avoid problems if early cleanup() */
+ fd_map = -1;
+ ehdr_curr = NULL;
+ mmap_failed = 1;
+ do_file(argv[0]);
+ } break;
+ case SJ_FAIL: { /* error in do_file or below */
+ ++n_error;
+ } break;
+ case SJ_SUCCEED: { /* premature success */
+ /* do nothing */
+ } break;
+ } /* end switch */
+ }
+ return !!n_error;
+}
+
+
--
1.7.1
^ permalink raw reply related [flat|nested] 11+ messages in thread* [PATCH 3/3] ftrace: Remove duplicate code for 64 and 32 bit in recordmcount.c
2010-10-14 21:00 [PATCH 0/3] [GIT PULL][2.6.37] ftrace: C version of recordmcount Steven Rostedt
2010-10-14 21:00 ` [PATCH 1/3] ftrace: Add C version of recordmcount compile time code Steven Rostedt
2010-10-14 21:00 ` Steven Rostedt
@ 2010-10-14 21:00 ` Steven Rostedt
2 siblings, 0 replies; 11+ messages in thread
From: Steven Rostedt @ 2010-10-14 21:00 UTC (permalink / raw)
To: linux-kernel; +Cc: Ingo Molnar, Andrew Morton, Frederic Weisbecker, John Reiser
[-- Attachment #1: 0003-ftrace-Remove-duplicate-code-for-64-and-32-bit-in-re.patch --]
[-- Type: text/plain, Size: 30636 bytes --]
From: Steven Rostedt <srostedt@redhat.com>
The elf reader for recordmcount.c had duplicate functions for both
32 bit and 64 bit elf handling. This was due to the need of using
the 32 and 64 bit elf structures.
This patch consolidates the two by using macros to define the 32
and 64 bit names in a recordmcount.h file, and then by just defining
a RECORD_MCOUNT_64 macro and including recordmcount.h twice we
create the funtions for both the 32 bit version as well as the
64 bit version using one code source.
Cc: John Reiser <jreiser@bitwagon.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
scripts/recordmcount.c | 548 +-----------------------------------------------
scripts/recordmcount.h | 366 ++++++++++++++++++++++++++++++++
2 files changed, 370 insertions(+), 544 deletions(-)
create mode 100644 scripts/recordmcount.h
diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c
index 34f32be..7f7f718 100644
--- a/scripts/recordmcount.c
+++ b/scripts/recordmcount.c
@@ -212,550 +212,10 @@ is_mcounted_section_name(char const *const txtname)
0 == strcmp(".text.unlikely", txtname);
}
-/* Append the new shstrtab, Elf32_Shdr[], __mcount_loc and its relocations. */
-static void append32(Elf32_Ehdr *const ehdr,
- Elf32_Shdr *const shstr,
- uint32_t const *const mloc0,
- uint32_t const *const mlocp,
- Elf32_Rel const *const mrel0,
- Elf32_Rel const *const mrelp,
- unsigned int const rel_entsize,
- unsigned int const symsec_sh_link)
-{
- /* Begin constructing output file */
- Elf32_Shdr mcsec;
- char const *mc_name = (sizeof(Elf32_Rela) == rel_entsize)
- ? ".rela__mcount_loc"
- : ".rel__mcount_loc";
- unsigned const old_shnum = w2(ehdr->e_shnum);
- uint32_t const old_shoff = w(ehdr->e_shoff);
- uint32_t const old_shstr_sh_size = w(shstr->sh_size);
- uint32_t const old_shstr_sh_offset = w(shstr->sh_offset);
- uint32_t t = 1 + strlen(mc_name) + w(shstr->sh_size);
- uint32_t new_e_shoff;
-
- shstr->sh_size = w(t);
- shstr->sh_offset = w(sb.st_size);
- t += sb.st_size;
- t += (3u & -t); /* 4-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) Elf32_Shdr table, 4-byte aligned */
- ulseek(fd_map, t, SEEK_SET);
- t += sizeof(Elf32_Shdr) * old_shnum;
- uwrite(fd_map, old_shoff + (void *)ehdr,
- sizeof(Elf32_Shdr) * old_shnum);
-
- /* new sections __mcount_loc and .rel__mcount_loc */
- t += 2*sizeof(mcsec);
- mcsec.sh_name = w((sizeof(Elf32_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(4);
- mcsec.sh_entsize = w(4);
- uwrite(fd_map, &mcsec, sizeof(mcsec));
-
- mcsec.sh_name = w(old_shstr_sh_size);
- mcsec.sh_type = (sizeof(Elf32_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(4);
- 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));
-}
-
-/*
- * append64 and append32 (and other analogous pairs) could be templated
- * using C++, but the complexity is high. (For an example, look at p_elf.h
- * in the source for UPX, http://upx.sourceforge.net) So: remember to make
- * the corresponding change in the routine for the other size.
- */
-static void append64(Elf64_Ehdr *const ehdr,
- Elf64_Shdr *const shstr,
- uint64_t const *const mloc0,
- uint64_t const *const mlocp,
- Elf64_Rel const *const mrel0,
- Elf64_Rel const *const mrelp,
- unsigned int const rel_entsize,
- unsigned int const symsec_sh_link)
-{
- /* Begin constructing output file */
- Elf64_Shdr mcsec;
- char const *mc_name = (sizeof(Elf64_Rela) == rel_entsize)
- ? ".rela__mcount_loc"
- : ".rel__mcount_loc";
- unsigned const old_shnum = w2(ehdr->e_shnum);
- uint64_t const old_shoff = w8(ehdr->e_shoff);
- uint64_t const old_shstr_sh_size = w8(shstr->sh_size);
- uint64_t const old_shstr_sh_offset = w8(shstr->sh_offset);
- uint64_t t = 1 + strlen(mc_name) + w8(shstr->sh_size);
- uint64_t new_e_shoff;
-
- shstr->sh_size = w8(t);
- shstr->sh_offset = w8(sb.st_size);
- t += sb.st_size;
- t += (7u & -t); /* 8-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) Elf64_Shdr table, 8-byte aligned */
- ulseek(fd_map, t, SEEK_SET);
- t += sizeof(Elf64_Shdr) * old_shnum;
- uwrite(fd_map, old_shoff + (void *)ehdr,
- sizeof(Elf64_Shdr) * old_shnum);
-
- /* new sections __mcount_loc and .rel__mcount_loc */
- t += 2*sizeof(mcsec);
- mcsec.sh_name = w((sizeof(Elf64_Rela) == rel_entsize) + strlen(".rel")
- + old_shstr_sh_size);
- mcsec.sh_type = w(SHT_PROGBITS);
- mcsec.sh_flags = w8(SHF_ALLOC);
- mcsec.sh_addr = 0;
- mcsec.sh_offset = w8(t);
- mcsec.sh_size = w8((void *)mlocp - (void *)mloc0);
- mcsec.sh_link = 0;
- mcsec.sh_info = 0;
- mcsec.sh_addralign = w8(8);
- mcsec.sh_entsize = w8(8);
- uwrite(fd_map, &mcsec, sizeof(mcsec));
-
- mcsec.sh_name = w(old_shstr_sh_size);
- mcsec.sh_type = (sizeof(Elf64_Rela) == rel_entsize)
- ? w(SHT_RELA)
- : w(SHT_REL);
- mcsec.sh_flags = 0;
- mcsec.sh_addr = 0;
- mcsec.sh_offset = w8((void *)mlocp - (void *)mloc0 + t);
- mcsec.sh_size = w8((void *)mrelp - (void *)mrel0);
- mcsec.sh_link = w(symsec_sh_link);
- mcsec.sh_info = w(old_shnum);
- mcsec.sh_addralign = w8(8);
- mcsec.sh_entsize = w8(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 = w8(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 uint32_t *sift32_rel_mcount(uint32_t *mlocp,
- unsigned const offbase,
- Elf32_Rel **const mrelpp,
- Elf32_Shdr const *const relhdr,
- Elf32_Ehdr const *const ehdr,
- unsigned const recsym,
- uint32_t const recval,
- unsigned const reltype)
-{
- uint32_t *const mloc0 = mlocp;
- Elf32_Rel *mrelp = *mrelpp;
- Elf32_Shdr *const shdr0 = (Elf32_Shdr *)(w(ehdr->e_shoff)
- + (void *)ehdr);
- unsigned const symsec_sh_link = w(relhdr->sh_link);
- Elf32_Shdr const *const symsec = &shdr0[symsec_sh_link];
- Elf32_Sym const *const sym0 = (Elf32_Sym const *)(w(symsec->sh_offset)
- + (void *)ehdr);
-
- Elf32_Shdr const *const strsec = &shdr0[w(symsec->sh_link)];
- char const *const str0 = (char const *)(w(strsec->sh_offset)
- + (void *)ehdr);
-
- Elf32_Rel const *const rel0 = (Elf32_Rel const *)(w(relhdr->sh_offset)
- + (void *)ehdr);
- unsigned rel_entsize = w(relhdr->sh_entsize);
- unsigned const nrel = w(relhdr->sh_size) / rel_entsize;
- Elf32_Rel const *relp = rel0;
-
- unsigned mcountsym = 0;
- unsigned t;
-
- for (t = nrel; t; --t) {
- if (!mcountsym) {
- Elf32_Sym const *const symp =
- &sym0[ELF32_R_SYM(w(relp->r_info))];
-
- if (0 == strcmp((('_' == gpfx) ? "_mcount" : "mcount"),
- &str0[w(symp->st_name)]))
- mcountsym = ELF32_R_SYM(w(relp->r_info));
- }
- if (mcountsym == ELF32_R_SYM(w(relp->r_info))) {
- uint32_t const addend = w(w(relp->r_offset) - recval);
- mrelp->r_offset = w(offbase
- + ((void *)mlocp - (void *)mloc0));
- mrelp->r_info = w(ELF32_R_INFO(recsym, reltype));
- if (sizeof(Elf32_Rela) == rel_entsize) {
- ((Elf32_Rela *)mrelp)->r_addend = addend;
- *mlocp++ = 0;
- } else
- *mlocp++ = addend;
-
- mrelp = (Elf32_Rel *)(rel_entsize + (void *)mrelp);
- }
- relp = (Elf32_Rel const *)(rel_entsize + (void *)relp);
- }
- *mrelpp = mrelp;
- return mlocp;
-}
-
-static uint64_t *sift64_rel_mcount(uint64_t *mlocp,
- unsigned const offbase,
- Elf64_Rel **const mrelpp,
- Elf64_Shdr const *const relhdr,
- Elf64_Ehdr const *const ehdr,
- unsigned const recsym,
- uint64_t const recval,
- unsigned const reltype)
-{
- uint64_t *const mloc0 = mlocp;
- Elf64_Rel *mrelp = *mrelpp;
- Elf64_Shdr *const shdr0 = (Elf64_Shdr *)(w8(ehdr->e_shoff)
- + (void *)ehdr);
- unsigned const symsec_sh_link = w(relhdr->sh_link);
- Elf64_Shdr const *const symsec = &shdr0[symsec_sh_link];
- Elf64_Sym const *const sym0 = (Elf64_Sym const *)(w8(symsec->sh_offset)
- + (void *)ehdr);
-
- Elf64_Shdr const *const strsec = &shdr0[w(symsec->sh_link)];
- char const *const str0 = (char const *)(w8(strsec->sh_offset)
- + (void *)ehdr);
-
- Elf64_Rel const *const rel0 = (Elf64_Rel const *)(w8(relhdr->sh_offset)
- + (void *)ehdr);
- unsigned rel_entsize = w8(relhdr->sh_entsize);
- unsigned const nrel = w8(relhdr->sh_size) / rel_entsize;
- Elf64_Rel const *relp = rel0;
-
- unsigned mcountsym = 0;
- unsigned t;
-
- for (t = nrel; 0 != t; --t) {
- if (!mcountsym) {
- Elf64_Sym const *const symp =
- &sym0[ELF64_R_SYM(w8(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 = ELF64_R_SYM(w8(relp->r_info));
- }
-
- if (mcountsym == ELF64_R_SYM(w8(relp->r_info))) {
- uint64_t const addend = w8(w8(relp->r_offset) - recval);
-
- mrelp->r_offset = w8(offbase
- + ((void *)mlocp - (void *)mloc0));
- mrelp->r_info = w8(ELF64_R_INFO(recsym, reltype));
- if (sizeof(Elf64_Rela) == rel_entsize) {
- ((Elf64_Rela *)mrelp)->r_addend = addend;
- *mlocp++ = 0;
- } else
- *mlocp++ = addend;
-
- mrelp = (Elf64_Rel *)(rel_entsize + (void *)mrelp);
- }
- relp = (Elf64_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 find32_secsym_ndx(unsigned const txtndx,
- char const *const txtname,
- uint32_t *const recvalp,
- Elf32_Shdr const *const symhdr,
- Elf32_Ehdr const *const ehdr)
-{
- Elf32_Sym const *const sym0 = (Elf32_Sym const *)(w(symhdr->sh_offset)
- + (void *)ehdr);
- unsigned const nsym = w(symhdr->sh_size) / w(symhdr->sh_entsize);
- Elf32_Sym const *symp;
- unsigned t;
-
- for (symp = sym0, t = nsym; t; --t, ++symp) {
- unsigned int const st_bind = ELF32_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();
-}
-
-static unsigned find64_secsym_ndx(unsigned const txtndx,
- char const *const txtname,
- uint64_t *const recvalp,
- Elf64_Shdr const *const symhdr,
- Elf64_Ehdr const *const ehdr)
-{
- Elf64_Sym const *const sym0 = (Elf64_Sym const *)(w8(symhdr->sh_offset)
- + (void *)ehdr);
- unsigned const nsym = w8(symhdr->sh_size) / w8(symhdr->sh_entsize);
- Elf64_Sym const *symp;
- unsigned t;
-
- for (symp = sym0, t = nsym; t; --t, ++symp) {
- unsigned int const st_bind = ELF64_ST_BIND(symp->st_info);
-
- if (txtndx == w2(symp->st_shndx)
- /* avoid STB_WEAK */
- && (STB_LOCAL == st_bind || STB_GLOBAL == st_bind)) {
- *recvalp = w8(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
- * has32_rel_mcount.
- */
-static char const *
-__has32_rel_mcount(Elf32_Shdr const *const relhdr, /* is SHT_REL or SHT_RELA */
- Elf32_Shdr const *const shdr0,
- char const *const shstrtab,
- char const *const fname)
-{
- /* .sh_info depends on .sh_type == SHT_REL[,A] */
- Elf32_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 *has32_rel_mcount(Elf32_Shdr const *const relhdr,
- Elf32_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 __has32_rel_mcount(relhdr, shdr0, shstrtab, fname);
-}
-
-static char const *__has64_rel_mcount(Elf64_Shdr const *const relhdr,
- Elf64_Shdr const *const shdr0,
- char const *const shstrtab,
- char const *const fname)
-{
- /* .sh_info depends on .sh_type == SHT_REL[,A] */
- Elf64_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 *has64_rel_mcount(Elf64_Shdr const *const relhdr,
- Elf64_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 __has64_rel_mcount(relhdr, shdr0, shstrtab, fname);
-}
-
-static unsigned tot32_relsize(Elf32_Shdr const *const shdr0,
- unsigned nhdr,
- const char *const shstrtab,
- const char *const fname)
-{
- unsigned totrelsz = 0;
- Elf32_Shdr const *shdrp = shdr0;
- for (; 0 != nhdr; --nhdr, ++shdrp) {
- if (has32_rel_mcount(shdrp, shdr0, shstrtab, fname))
- totrelsz += w(shdrp->sh_size);
- }
- return totrelsz;
-}
-
-static unsigned tot64_relsize(Elf64_Shdr const *const shdr0,
- unsigned nhdr,
- const char *const shstrtab,
- const char *const fname)
-{
- unsigned totrelsz = 0;
- Elf64_Shdr const *shdrp = shdr0;
-
- for (; nhdr; --nhdr, ++shdrp) {
- if (has64_rel_mcount(shdrp, shdr0, shstrtab, fname))
- totrelsz += w8(shdrp->sh_size);
- }
- return totrelsz;
-}
-
-/* Overall supervision for Elf32 ET_REL file. */
-static void
-do32(Elf32_Ehdr *const ehdr, char const *const fname, unsigned const reltype)
-{
- Elf32_Shdr *const shdr0 = (Elf32_Shdr *)(w(ehdr->e_shoff)
- + (void *)ehdr);
- unsigned const nhdr = w2(ehdr->e_shnum);
- Elf32_Shdr *const shstr = &shdr0[w2(ehdr->e_shstrndx)];
- char const *const shstrtab = (char const *)(w(shstr->sh_offset)
- + (void *)ehdr);
-
- Elf32_Shdr const *relhdr;
- unsigned k;
-
- /* Upper bound on space: assume all relevant relocs are for mcount. */
- unsigned const totrelsz = tot32_relsize(shdr0, nhdr, shstrtab, fname);
- Elf32_Rel *const mrel0 = umalloc(totrelsz);
- Elf32_Rel * mrelp = mrel0;
-
- /* 2*sizeof(address) <= sizeof(Elf32_Rel) */
- uint32_t *const mloc0 = umalloc(totrelsz>>1);
- uint32_t * mlocp = mloc0;
-
- unsigned rel_entsize = 0;
- unsigned symsec_sh_link = 0;
-
- for (relhdr = shdr0, k = nhdr; k; --k, ++relhdr) {
- char const *const txtname = has32_rel_mcount(relhdr, shdr0,
- shstrtab, fname);
- if (txtname) {
- uint32_t recval = 0;
- unsigned const recsym = find32_secsym_ndx(
- w(relhdr->sh_info), txtname, &recval,
- &shdr0[symsec_sh_link = w(relhdr->sh_link)],
- ehdr);
-
- rel_entsize = w(relhdr->sh_entsize);
- mlocp = sift32_rel_mcount(mlocp,
- (void *)mlocp - (void *)mloc0, &mrelp,
- relhdr, ehdr, recsym, recval, reltype);
- }
- }
- if (mloc0 != mlocp) {
- append32(ehdr, shstr, mloc0, mlocp, mrel0, mrelp,
- rel_entsize, symsec_sh_link);
- }
- free(mrel0);
- free(mloc0);
-}
-
-static void
-do64(Elf64_Ehdr *const ehdr, char const *const fname, unsigned const reltype)
-{
- Elf64_Shdr *const shdr0 = (Elf64_Shdr *)(w8(ehdr->e_shoff)
- + (void *)ehdr);
- unsigned const nhdr = w2(ehdr->e_shnum);
- Elf64_Shdr *const shstr = &shdr0[w2(ehdr->e_shstrndx)];
- char const *const shstrtab = (char const *)(w8(shstr->sh_offset)
- + (void *)ehdr);
-
- Elf64_Shdr const *relhdr;
- unsigned k;
-
- /* Upper bound on space: assume all relevant relocs are for mcount. */
- unsigned const totrelsz = tot64_relsize(shdr0, nhdr, shstrtab, fname);
- Elf64_Rel *const mrel0 = umalloc(totrelsz);
- Elf64_Rel * mrelp = mrel0;
-
- /* 2*sizeof(address) <= sizeof(Elf64_Rel) */
- uint64_t *const mloc0 = umalloc(totrelsz>>1);
- uint64_t * mlocp = mloc0;
-
- unsigned rel_entsize = 0;
- unsigned symsec_sh_link = 0;
-
- for ((relhdr = shdr0), k = nhdr; k; --k, ++relhdr) {
- char const *const txtname = has64_rel_mcount(relhdr, shdr0,
- shstrtab, fname);
- if (txtname) {
- uint64_t recval = 0;
- unsigned const recsym = find64_secsym_ndx(
- w(relhdr->sh_info), txtname, &recval,
- &shdr0[symsec_sh_link = w(relhdr->sh_link)],
- ehdr);
-
- rel_entsize = w8(relhdr->sh_entsize);
- mlocp = sift64_rel_mcount(mlocp,
- (void *)mlocp - (void *)mloc0, &mrelp,
- relhdr, ehdr, recsym, recval, reltype);
- }
- }
- if (mloc0 != mlocp) {
- append64(ehdr, shstr, mloc0, mlocp, mrel0, mrelp,
- rel_entsize, symsec_sh_link);
- }
- free(mrel0);
- free(mloc0);
-}
+/* 32 bit and 64 bit are very similar */
+#include "recordmcount.h"
+#define RECORD_MCOUNT_64
+#include "recordmcount.h"
static void
do_file(char const *const fname)
diff --git a/scripts/recordmcount.h b/scripts/recordmcount.h
new file mode 100644
index 0000000..7f39d09
--- /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);
+}
--
1.7.1
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