ftrace: Add C version of recordmcount compile time code
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>
This commit is contained in:
John Reiser
Steven Rostedt
parent
3cba11d32b
commit
81d3858d31
1 changed files with 885 additions and 0 deletions
885
scripts/recordmcount.c
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885
scripts/recordmcount.c
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/*
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* recordmcount.c: construct a table of the locations of calls to 'mcount'
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* so that ftrace can find them quickly.
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* Copyright 2009 John F. Reiser <jreiser@BitWagon.com>. All rights reserved.
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* Licensed under the GNU General Public License, version 2 (GPLv2).
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*
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* Restructured to fit Linux format, as well as other updates:
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* Copyright 2010 Steven Rostedt <srostedt@redhat.com>, Red Hat Inc.
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*/
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/*
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* Strategy: alter the .o file in-place.
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*
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* Append a new STRTAB that has the new section names, followed by a new array
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* ElfXX_Shdr[] that has the new section headers, followed by the section
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* contents for __mcount_loc and its relocations. The old shstrtab strings,
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* and the old ElfXX_Shdr[] array, remain as "garbage" (commonly, a couple
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* kilobytes.) Subsequent processing by /bin/ld (or the kernel module loader)
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* will ignore the garbage regions, because they are not designated by the
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* new .e_shoff nor the new ElfXX_Shdr[]. [In order to remove the garbage,
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* then use "ld -r" to create a new file that omits the garbage.]
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*/
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#include <sys/types.h>
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <elf.h>
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#include <fcntl.h>
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#include <setjmp.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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static int fd_map; /* File descriptor for file being modified. */
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static int mmap_failed; /* Boolean flag. */
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static void *ehdr_curr; /* current ElfXX_Ehdr * for resource cleanup */
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static char gpfx; /* prefix for global symbol name (sometimes '_') */
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static struct stat sb; /* Remember .st_size, etc. */
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static jmp_buf jmpenv; /* setjmp/longjmp per-file error escape */
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/* setjmp() return values */
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enum {
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SJ_SETJMP = 0, /* hardwired first return */
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SJ_FAIL,
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SJ_SUCCEED
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};
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/* Per-file resource cleanup when multiple files. */
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static void
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cleanup(void)
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{
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if (!mmap_failed)
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munmap(ehdr_curr, sb.st_size);
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else
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free(ehdr_curr);
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close(fd_map);
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}
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static void __attribute__((noreturn))
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fail_file(void)
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{
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cleanup();
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longjmp(jmpenv, SJ_FAIL);
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}
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static void __attribute__((noreturn))
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succeed_file(void)
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{
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cleanup();
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longjmp(jmpenv, SJ_SUCCEED);
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}
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/* ulseek, uread, ...: Check return value for errors. */
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static off_t
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ulseek(int const fd, off_t const offset, int const whence)
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{
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off_t const w = lseek(fd, offset, whence);
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if ((off_t)-1 == w) {
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perror("lseek");
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fail_file();
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}
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return w;
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}
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static size_t
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uread(int const fd, void *const buf, size_t const count)
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{
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size_t const n = read(fd, buf, count);
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if (n != count) {
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perror("read");
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fail_file();
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}
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return n;
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}
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static size_t
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uwrite(int const fd, void const *const buf, size_t const count)
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{
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size_t const n = write(fd, buf, count);
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if (n != count) {
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perror("write");
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fail_file();
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}
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return n;
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}
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static void *
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umalloc(size_t size)
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{
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void *const addr = malloc(size);
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if (0 == addr) {
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fprintf(stderr, "malloc failed: %zu bytes\n", size);
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fail_file();
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}
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return addr;
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}
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/*
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* Get the whole file as a programming convenience in order to avoid
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* malloc+lseek+read+free of many pieces. If successful, then mmap
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* avoids copying unused pieces; else just read the whole file.
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* Open for both read and write; new info will be appended to the file.
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* Use MAP_PRIVATE so that a few changes to the in-memory ElfXX_Ehdr
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* do not propagate to the file until an explicit overwrite at the last.
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* This preserves most aspects of consistency (all except .st_size)
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* for simultaneous readers of the file while we are appending to it.
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* However, multiple writers still are bad. We choose not to use
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* locking because it is expensive and the use case of kernel build
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* makes multiple writers unlikely.
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*/
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static void *mmap_file(char const *fname)
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{
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void *addr;
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fd_map = open(fname, O_RDWR);
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if (0 > fd_map || 0 > fstat(fd_map, &sb)) {
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perror(fname);
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fail_file();
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}
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if (!S_ISREG(sb.st_mode)) {
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fprintf(stderr, "not a regular file: %s\n", fname);
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fail_file();
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}
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addr = mmap(0, sb.st_size, PROT_READ|PROT_WRITE, MAP_PRIVATE,
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fd_map, 0);
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mmap_failed = 0;
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if (MAP_FAILED == addr) {
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mmap_failed = 1;
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addr = umalloc(sb.st_size);
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uread(fd_map, addr, sb.st_size);
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}
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return addr;
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}
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/* w8rev, w8nat, ...: Handle endianness. */
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static uint64_t w8rev(uint64_t const x)
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{
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return ((0xff & (x >> (0 * 8))) << (7 * 8))
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| ((0xff & (x >> (1 * 8))) << (6 * 8))
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| ((0xff & (x >> (2 * 8))) << (5 * 8))
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| ((0xff & (x >> (3 * 8))) << (4 * 8))
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| ((0xff & (x >> (4 * 8))) << (3 * 8))
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| ((0xff & (x >> (5 * 8))) << (2 * 8))
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| ((0xff & (x >> (6 * 8))) << (1 * 8))
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| ((0xff & (x >> (7 * 8))) << (0 * 8));
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}
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static uint32_t w4rev(uint32_t const x)
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{
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return ((0xff & (x >> (0 * 8))) << (3 * 8))
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| ((0xff & (x >> (1 * 8))) << (2 * 8))
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| ((0xff & (x >> (2 * 8))) << (1 * 8))
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| ((0xff & (x >> (3 * 8))) << (0 * 8));
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}
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static uint32_t w2rev(uint16_t const x)
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{
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return ((0xff & (x >> (0 * 8))) << (1 * 8))
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| ((0xff & (x >> (1 * 8))) << (0 * 8));
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}
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static uint64_t w8nat(uint64_t const x)
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{
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return x;
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}
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static uint32_t w4nat(uint32_t const x)
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{
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return x;
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}
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static uint32_t w2nat(uint16_t const x)
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{
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return x;
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}
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static uint64_t (*w8)(uint64_t);
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static uint32_t (*w)(uint32_t);
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static uint32_t (*w2)(uint16_t);
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/* Names of the sections that could contain calls to mcount. */
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static int
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is_mcounted_section_name(char const *const txtname)
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{
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return 0 == strcmp(".text", txtname) ||
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0 == strcmp(".sched.text", txtname) ||
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0 == strcmp(".spinlock.text", txtname) ||
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0 == strcmp(".irqentry.text", txtname) ||
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0 == strcmp(".text.unlikely", txtname);
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}
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/* Append the new shstrtab, Elf32_Shdr[], __mcount_loc and its relocations. */
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static void append32(Elf32_Ehdr *const ehdr,
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Elf32_Shdr *const shstr,
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uint32_t const *const mloc0,
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uint32_t const *const mlocp,
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Elf32_Rel const *const mrel0,
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Elf32_Rel const *const mrelp,
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unsigned int const rel_entsize,
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unsigned int const symsec_sh_link)
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{
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/* Begin constructing output file */
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Elf32_Shdr mcsec;
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char const *mc_name = (sizeof(Elf32_Rela) == rel_entsize)
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? ".rela__mcount_loc"
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: ".rel__mcount_loc";
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unsigned const old_shnum = w2(ehdr->e_shnum);
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uint32_t const old_shoff = w(ehdr->e_shoff);
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uint32_t const old_shstr_sh_size = w(shstr->sh_size);
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uint32_t const old_shstr_sh_offset = w(shstr->sh_offset);
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uint32_t t = 1 + strlen(mc_name) + w(shstr->sh_size);
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uint32_t new_e_shoff;
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shstr->sh_size = w(t);
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shstr->sh_offset = w(sb.st_size);
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t += sb.st_size;
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t += (3u & -t); /* 4-byte align */
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new_e_shoff = t;
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/* body for new shstrtab */
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ulseek(fd_map, sb.st_size, SEEK_SET);
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uwrite(fd_map, old_shstr_sh_offset + (void *)ehdr, old_shstr_sh_size);
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uwrite(fd_map, mc_name, 1 + strlen(mc_name));
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/* old(modified) Elf32_Shdr table, 4-byte aligned */
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ulseek(fd_map, t, SEEK_SET);
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t += sizeof(Elf32_Shdr) * old_shnum;
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uwrite(fd_map, old_shoff + (void *)ehdr,
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sizeof(Elf32_Shdr) * old_shnum);
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/* new sections __mcount_loc and .rel__mcount_loc */
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t += 2*sizeof(mcsec);
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mcsec.sh_name = w((sizeof(Elf32_Rela) == rel_entsize) + strlen(".rel")
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+ old_shstr_sh_size);
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mcsec.sh_type = w(SHT_PROGBITS);
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mcsec.sh_flags = w(SHF_ALLOC);
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mcsec.sh_addr = 0;
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mcsec.sh_offset = w(t);
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mcsec.sh_size = w((void *)mlocp - (void *)mloc0);
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mcsec.sh_link = 0;
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mcsec.sh_info = 0;
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mcsec.sh_addralign = w(4);
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mcsec.sh_entsize = w(4);
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uwrite(fd_map, &mcsec, sizeof(mcsec));
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mcsec.sh_name = w(old_shstr_sh_size);
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mcsec.sh_type = (sizeof(Elf32_Rela) == rel_entsize)
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? w(SHT_RELA)
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: w(SHT_REL);
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mcsec.sh_flags = 0;
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mcsec.sh_addr = 0;
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mcsec.sh_offset = w((void *)mlocp - (void *)mloc0 + t);
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mcsec.sh_size = w((void *)mrelp - (void *)mrel0);
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mcsec.sh_link = w(symsec_sh_link);
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mcsec.sh_info = w(old_shnum);
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mcsec.sh_addralign = w(4);
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mcsec.sh_entsize = w(rel_entsize);
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uwrite(fd_map, &mcsec, sizeof(mcsec));
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uwrite(fd_map, mloc0, (void *)mlocp - (void *)mloc0);
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uwrite(fd_map, mrel0, (void *)mrelp - (void *)mrel0);
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ehdr->e_shoff = w(new_e_shoff);
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ehdr->e_shnum = w2(2 + w2(ehdr->e_shnum)); /* {.rel,}__mcount_loc */
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ulseek(fd_map, 0, SEEK_SET);
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uwrite(fd_map, ehdr, sizeof(*ehdr));
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}
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/*
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* append64 and append32 (and other analogous pairs) could be templated
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* using C++, but the complexity is high. (For an example, look at p_elf.h
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* in the source for UPX, http://upx.sourceforge.net) So: remember to make
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* the corresponding change in the routine for the other size.
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*/
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static void append64(Elf64_Ehdr *const ehdr,
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Elf64_Shdr *const shstr,
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uint64_t const *const mloc0,
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uint64_t const *const mlocp,
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Elf64_Rel const *const mrel0,
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Elf64_Rel const *const mrelp,
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unsigned int const rel_entsize,
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unsigned int const symsec_sh_link)
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{
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/* Begin constructing output file */
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Elf64_Shdr mcsec;
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char const *mc_name = (sizeof(Elf64_Rela) == rel_entsize)
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? ".rela__mcount_loc"
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: ".rel__mcount_loc";
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unsigned const old_shnum = w2(ehdr->e_shnum);
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uint64_t const old_shoff = w8(ehdr->e_shoff);
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uint64_t const old_shstr_sh_size = w8(shstr->sh_size);
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uint64_t const old_shstr_sh_offset = w8(shstr->sh_offset);
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uint64_t t = 1 + strlen(mc_name) + w8(shstr->sh_size);
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uint64_t new_e_shoff;
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shstr->sh_size = w8(t);
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shstr->sh_offset = w8(sb.st_size);
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t += sb.st_size;
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t += (7u & -t); /* 8-byte align */
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new_e_shoff = t;
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/* body for new shstrtab */
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ulseek(fd_map, sb.st_size, SEEK_SET);
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uwrite(fd_map, old_shstr_sh_offset + (void *)ehdr, old_shstr_sh_size);
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uwrite(fd_map, mc_name, 1 + strlen(mc_name));
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/* old(modified) Elf64_Shdr table, 8-byte aligned */
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ulseek(fd_map, t, SEEK_SET);
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t += sizeof(Elf64_Shdr) * old_shnum;
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uwrite(fd_map, old_shoff + (void *)ehdr,
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sizeof(Elf64_Shdr) * old_shnum);
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/* new sections __mcount_loc and .rel__mcount_loc */
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t += 2*sizeof(mcsec);
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mcsec.sh_name = w((sizeof(Elf64_Rela) == rel_entsize) + strlen(".rel")
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+ old_shstr_sh_size);
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mcsec.sh_type = w(SHT_PROGBITS);
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mcsec.sh_flags = w8(SHF_ALLOC);
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mcsec.sh_addr = 0;
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mcsec.sh_offset = w8(t);
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mcsec.sh_size = w8((void *)mlocp - (void *)mloc0);
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mcsec.sh_link = 0;
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mcsec.sh_info = 0;
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mcsec.sh_addralign = w8(8);
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mcsec.sh_entsize = w8(8);
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uwrite(fd_map, &mcsec, sizeof(mcsec));
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mcsec.sh_name = w(old_shstr_sh_size);
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mcsec.sh_type = (sizeof(Elf64_Rela) == rel_entsize)
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? w(SHT_RELA)
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: w(SHT_REL);
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mcsec.sh_flags = 0;
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mcsec.sh_addr = 0;
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mcsec.sh_offset = w8((void *)mlocp - (void *)mloc0 + t);
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mcsec.sh_size = w8((void *)mrelp - (void *)mrel0);
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mcsec.sh_link = w(symsec_sh_link);
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mcsec.sh_info = w(old_shnum);
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mcsec.sh_addralign = w8(8);
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mcsec.sh_entsize = w8(rel_entsize);
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uwrite(fd_map, &mcsec, sizeof(mcsec));
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uwrite(fd_map, mloc0, (void *)mlocp - (void *)mloc0);
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uwrite(fd_map, mrel0, (void *)mrelp - (void *)mrel0);
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ehdr->e_shoff = w8(new_e_shoff);
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ehdr->e_shnum = w2(2 + w2(ehdr->e_shnum)); /* {.rel,}__mcount_loc */
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ulseek(fd_map, 0, SEEK_SET);
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uwrite(fd_map, ehdr, sizeof(*ehdr));
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}
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/*
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* Look at the relocations in order to find the calls to mcount.
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* Accumulate the section offsets that are found, and their relocation info,
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* onto the end of the existing arrays.
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*/
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static uint32_t *sift32_rel_mcount(uint32_t *mlocp,
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unsigned const offbase,
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Elf32_Rel **const mrelpp,
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Elf32_Shdr const *const relhdr,
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Elf32_Ehdr const *const ehdr,
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unsigned const recsym,
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uint32_t const recval,
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unsigned const reltype)
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{
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uint32_t *const mloc0 = mlocp;
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Elf32_Rel *mrelp = *mrelpp;
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Elf32_Shdr *const shdr0 = (Elf32_Shdr *)(w(ehdr->e_shoff)
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+ (void *)ehdr);
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unsigned const symsec_sh_link = w(relhdr->sh_link);
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Elf32_Shdr const *const symsec = &shdr0[symsec_sh_link];
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Elf32_Sym const *const sym0 = (Elf32_Sym const *)(w(symsec->sh_offset)
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+ (void *)ehdr);
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Elf32_Shdr const *const strsec = &shdr0[w(symsec->sh_link)];
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char const *const str0 = (char const *)(w(strsec->sh_offset)
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+ (void *)ehdr);
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Elf32_Rel const *const rel0 = (Elf32_Rel const *)(w(relhdr->sh_offset)
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+ (void *)ehdr);
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unsigned rel_entsize = w(relhdr->sh_entsize);
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unsigned const nrel = w(relhdr->sh_size) / rel_entsize;
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Elf32_Rel const *relp = rel0;
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unsigned mcountsym = 0;
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unsigned t;
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|
||||
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;
|
||||
}
|
||||
|
||||
|
||||
Loading…
Reference in a new issue