Merge branch 'tip/perf/recordmcount-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into perf/core
diff --git a/Makefile b/Makefile
index 534c09c..c2362c2 100644
--- a/Makefile
+++ b/Makefile
@@ -568,6 +568,12 @@
ifdef CONFIG_FUNCTION_TRACER
KBUILD_CFLAGS += -pg
+ifdef CONFIG_DYNAMIC_FTRACE
+ ifdef CONFIG_HAVE_C_RECORDMCOUNT
+ BUILD_C_RECORDMCOUNT := y
+ export BUILD_C_RECORDMCOUNT
+ endif
+endif
endif
# We trigger additional mismatches with less inlining
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index c14d8b4..9815221 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -33,6 +33,7 @@
select HAVE_KRETPROBES
select HAVE_OPTPROBES
select HAVE_FTRACE_MCOUNT_RECORD
+ select HAVE_C_RECORDMCOUNT
select HAVE_DYNAMIC_FTRACE
select HAVE_FUNCTION_TRACER
select HAVE_FUNCTION_GRAPH_TRACER
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 538501c..e550d2ed 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -49,6 +49,11 @@
help
See Documentation/trace/ftrace-design.txt
+config HAVE_C_RECORDMCOUNT
+ bool
+ help
+ C version of recordmcount available?
+
config TRACER_MAX_TRACE
bool
diff --git a/scripts/Makefile b/scripts/Makefile
index 842dbc2..2e08810 100644
--- a/scripts/Makefile
+++ b/scripts/Makefile
@@ -11,6 +11,7 @@
hostprogs-$(CONFIG_LOGO) += pnmtologo
hostprogs-$(CONFIG_VT) += conmakehash
hostprogs-$(CONFIG_IKCONFIG) += bin2c
+hostprogs-$(BUILD_C_RECORDMCOUNT) += recordmcount
always := $(hostprogs-y) $(hostprogs-m)
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index a1a5cf9..4d03a7ef 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -209,12 +209,16 @@
endif
ifdef CONFIG_FTRACE_MCOUNT_RECORD
+ifdef BUILD_C_RECORDMCOUNT
+cmd_record_mcount = $(srctree)/scripts/recordmcount "$(@)";
+else
cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
"$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \
"$(if $(CONFIG_64BIT),64,32)" \
"$(OBJDUMP)" "$(OBJCOPY)" "$(CC)" "$(LD)" "$(NM)" "$(RM)" "$(MV)" \
"$(if $(part-of-module),1,0)" "$(@)";
endif
+endif
define rule_cc_o_c
$(call echo-cmd,checksrc) $(cmd_checksrc) \
diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c
new file mode 100644
index 0000000..7f7f718
--- /dev/null
+++ b/scripts/recordmcount.c
@@ -0,0 +1,345 @@
+/*
+ * 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);
+}
+
+/* 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)
+{
+ 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;
+}
+
+
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);
+}