[linux.git] / scripts / recordmcount.c

/*
 * recordmcount.c: construct a table of the locations of calls to 'mcount'
 * so that ftrace can find them quickly.
 * Copyright 2009 John F. Reiser <[email protected]>.  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 <[email protected]>, 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 <getopt.h>
#include <elf.h>
#include <fcntl.h>
#include <setjmp.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#ifndef EM_METAG
/* Remove this when these make it to the standard system elf.h. */
#define EM_METAG      174
#define R_METAG_ADDR32                   2
#define R_METAG_NONE                     3
#endif

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 */
static const char *altmcount;	/* alternate mcount symbol name */
static int warn_on_notrace_sect; /* warn when section has mcount not being recorded */

/* 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 (w == (off_t)-1) {
		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 (addr == 0) {
		fprintf(stderr, "malloc failed: %zu bytes\n", size);
		fail_file();
	}
	return addr;
}

static unsigned char ideal_nop5_x86_64[5] = { 0x0f, 0x1f, 0x44, 0x00, 0x00 };
static unsigned char ideal_nop5_x86_32[5] = { 0x3e, 0x8d, 0x74, 0x26, 0x00 };
static unsigned char *ideal_nop;

static char rel_type_nop;

static int (*make_nop)(void *map, size_t const offset);

static int make_nop_x86(void *map, size_t const offset)
{
	uint32_t *ptr;
	unsigned char *op;

	/* Confirm we have 0xe8 0x0 0x0 0x0 0x0 */
	ptr = map + offset;
	if (*ptr != 0)
		return -1;

	op = map + offset - 1;
	if (*op != 0xe8)
		return -1;

	/* convert to nop */
	ulseek(fd_map, offset - 1, SEEK_SET);
	uwrite(fd_map, ideal_nop, 5);
	return 0;
}

/*
 * 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 (fd_map < 0 || fstat(fd_map, &sb) < 0) {
		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 (addr == MAP_FAILED) {
		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 strcmp(".text",           txtname) == 0 ||
		strcmp(".ref.text",      txtname) == 0 ||
		strcmp(".sched.text",    txtname) == 0 ||
		strcmp(".spinlock.text", txtname) == 0 ||
		strcmp(".irqentry.text", txtname) == 0 ||
		strcmp(".kprobes.text", txtname) == 0 ||
		strcmp(".text.unlikely", txtname) == 0;
}

/* 32 bit and 64 bit are very similar */
#include "recordmcount.h"
#define RECORD_MCOUNT_64
#include "recordmcount.h"

/* 64-bit EM_MIPS has weird ELF64_Rela.r_info.
 * http://techpubs.sgi.com/library/manuals/4000/007-4658-001/pdf/007-4658-001.pdf
 * We interpret Table 29 Relocation Operation (Elf64_Rel, Elf64_Rela) [p.40]
 * to imply the order of the members; the spec does not say so.
 *	typedef unsigned char Elf64_Byte;
 * fails on MIPS64 because their <elf.h> already has it!
 */

typedef uint8_t myElf64_Byte;		/* Type for a 8-bit quantity.  */

union mips_r_info {
	Elf64_Xword r_info;
	struct {
		Elf64_Word r_sym;		/* Symbol index.  */
		myElf64_Byte r_ssym;		/* Special symbol.  */
		myElf64_Byte r_type3;		/* Third relocation.  */
		myElf64_Byte r_type2;		/* Second relocation.  */
		myElf64_Byte r_type;		/* First relocation.  */
	} r_mips;
};

static uint64_t MIPS64_r_sym(Elf64_Rel const *rp)
{
	return w(((union mips_r_info){ .r_info = rp->r_info }).r_mips.r_sym);
}

static void MIPS64_r_info(Elf64_Rel *const rp, unsigned sym, unsigned type)
{
	rp->r_info = ((union mips_r_info){
		.r_mips = { .r_sym = w(sym), .r_type = type }
	}).r_info;
}

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 (*(unsigned char const *)&endian != 1) {
			/* main() is big endian, file.o is little endian. */
			w = w4rev;
			w2 = w2rev;
			w8 = w8rev;
		}
		break;
	case ELFDATA2MSB:
		if (*(unsigned char const *)&endian != 0) {
			/* main() is little endian, file.o is big endian. */
			w = w4rev;
			w2 = w2rev;
			w8 = w8rev;
		}
		break;
	}  /* end switch */
	if (memcmp(ELFMAG, ehdr->e_ident, SELFMAG) != 0
	||  w2(ehdr->e_type) != ET_REL
	||  ehdr->e_ident[EI_VERSION] != EV_CURRENT) {
		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;
		make_nop = make_nop_x86;
		ideal_nop = ideal_nop5_x86_32;
		mcount_adjust_32 = -1;
		break;
	case EM_ARM:	 reltype = R_ARM_ABS32;
			 altmcount = "__gnu_mcount_nc";
			 break;
	case EM_IA_64:	 reltype = R_IA64_IMM64;   gpfx = '_'; break;
	case EM_METAG:	 reltype = R_METAG_ADDR32;
			 altmcount = "_mcount_wrapper";
			 rel_type_nop = R_METAG_NONE;
			 /* We happen to have the same requirement as MIPS */
			 is_fake_mcount32 = MIPS32_is_fake_mcount;
			 break;
	case EM_MIPS:	 /* reltype: e_class    */ 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:
		make_nop = make_nop_x86;
		ideal_nop = ideal_nop5_x86_64;
		reltype = R_X86_64_64;
		mcount_adjust_64 = -1;
		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 (w2(ehdr->e_ehsize) != sizeof(Elf32_Ehdr)
		||  w2(ehdr->e_shentsize) != sizeof(Elf32_Shdr)) {
			fprintf(stderr,
				"unrecognized ET_REL file: %s\n", fname);
			fail_file();
		}
		if (w2(ehdr->e_machine) == EM_S390) {
			reltype = R_390_32;
			mcount_adjust_32 = -4;
		}
		if (w2(ehdr->e_machine) == EM_MIPS) {
			reltype = R_MIPS_32;
			is_fake_mcount32 = MIPS32_is_fake_mcount;
		}
		do32(ehdr, fname, reltype);
		break;
	case ELFCLASS64: {
		Elf64_Ehdr *const ghdr = (Elf64_Ehdr *)ehdr;
		if (w2(ghdr->e_ehsize) != sizeof(Elf64_Ehdr)
		||  w2(ghdr->e_shentsize) != sizeof(Elf64_Shdr)) {
			fprintf(stderr,
				"unrecognized ET_REL file: %s\n", fname);
			fail_file();
		}
		if (w2(ghdr->e_machine) == EM_S390) {
			reltype = R_390_64;
			mcount_adjust_64 = -8;
		}
		if (w2(ghdr->e_machine) == EM_MIPS) {
			reltype = R_MIPS_64;
			Elf64_r_sym = MIPS64_r_sym;
			Elf64_r_info = MIPS64_r_info;
			is_fake_mcount64 = MIPS64_is_fake_mcount;
		}
		do64(ghdr, fname, reltype);
		break;
	}
	}  /* end switch */

	cleanup();
}

int
main(int argc, char *argv[])
{
	const char ftrace[] = "/ftrace.o";
	int ftrace_size = sizeof(ftrace) - 1;
	int n_error = 0;  /* gcc-4.3.0 false positive complaint */
	int c;
	int i;

	while ((c = getopt(argc, argv, "w")) >= 0) {
		switch (c) {
		case 'w':
			warn_on_notrace_sect = 1;
			break;
		default:
			fprintf(stderr, "usage: recordmcount [-w] file.o...\n");
			return 0;
		}
	}

	if ((argc - optind) < 1) {
		fprintf(stderr, "usage: recordmcount [-w] file.o...\n");
		return 0;
	}

	/* Process each file in turn, allowing deep failure. */
	for (i = optind; i < argc; i++) {
		char *file = argv[i];
		int const sjval = setjmp(jmpenv);
		int len;

		/*
		 * The file kernel/trace/ftrace.o references the mcount
		 * function but does not call it. Since ftrace.o should
		 * not be traced anyway, we just skip it.
		 */
		len = strlen(file);
		if (len >= ftrace_size &&
		    strcmp(file + (len - ftrace_size), ftrace) == 0)
			continue;

		switch (sjval) {
		default:
			fprintf(stderr, "internal error: %s\n", file);
			exit(1);
			break;
		case SJ_SETJMP:    /* normal sequence */
			/* Avoid problems if early cleanup() */
			fd_map = -1;
			ehdr_curr = NULL;
			mmap_failed = 1;
			do_file(file);
			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;
}
Commit	Line	Data
81d3858d JR	1	/*
	2	* recordmcount.c: construct a table of the locations of calls to 'mcount'
	3	* so that ftrace can find them quickly.
	4	* Copyright 2009 John F. Reiser <[email protected]>. All rights reserved.
	5	* Licensed under the GNU General Public License, version 2 (GPLv2).
	6	*
	7	* Restructured to fit Linux format, as well as other updates:
	8	* Copyright 2010 Steven Rostedt <[email protected]>, Red Hat Inc.
	9	*/
	10
	11	/*
	12	* Strategy: alter the .o file in-place.
	13	*
	14	* Append a new STRTAB that has the new section names, followed by a new array
	15	* ElfXX_Shdr[] that has the new section headers, followed by the section
	16	* contents for __mcount_loc and its relocations. The old shstrtab strings,
	17	* and the old ElfXX_Shdr[] array, remain as "garbage" (commonly, a couple
	18	* kilobytes.) Subsequent processing by /bin/ld (or the kernel module loader)
	19	* will ignore the garbage regions, because they are not designated by the
	20	* new .e_shoff nor the new ElfXX_Shdr[]. [In order to remove the garbage,
	21	* then use "ld -r" to create a new file that omits the garbage.]
	22	*/
	23
	24	#include <sys/types.h>
	25	#include <sys/mman.h>
	26	#include <sys/stat.h>
dfad3d59	27	#include <getopt.h>
81d3858d JR	28	#include <elf.h>
	29	#include <fcntl.h>
	30	#include <setjmp.h>
	31	#include <stdio.h>
	32	#include <stdlib.h>
	33	#include <string.h>
	34	#include <unistd.h>
	35
00512bdd JH	36	#ifndef EM_METAG
	37	/* Remove this when these make it to the standard system elf.h. */
	38	#define EM_METAG 174
	39	#define R_METAG_ADDR32 2
	40	#define R_METAG_NONE 3
	41	#endif
	42
81d3858d JR	43	static int fd_map; /* File descriptor for file being modified. */
	44	static int mmap_failed; /* Boolean flag. */
	45	static void ehdr_curr; / current ElfXX_Ehdr * for resource cleanup */
	46	static char gpfx; /* prefix for global symbol name (sometimes '_') */
	47	static struct stat sb; /* Remember .st_size, etc. */
	48	static jmp_buf jmpenv; /* setjmp/longjmp per-file error escape */
ed60453f	49	static const char altmcount; / alternate mcount symbol name */
dfad3d59	50	static int warn_on_notrace_sect; /* warn when section has mcount not being recorded */
81d3858d JR	51
	52	/* setjmp() return values */
	53	enum {
	54	SJ_SETJMP = 0, /* hardwired first return */
	55	SJ_FAIL,
	56	SJ_SUCCEED
	57	};
	58
	59	/* Per-file resource cleanup when multiple files. */
	60	static void
	61	cleanup(void)
	62	{
	63	if (!mmap_failed)
	64	munmap(ehdr_curr, sb.st_size);
	65	else
	66	free(ehdr_curr);
	67	close(fd_map);
	68	}
	69
	70	static void __attribute__((noreturn))
	71	fail_file(void)
	72	{
	73	cleanup();
	74	longjmp(jmpenv, SJ_FAIL);
	75	}
	76
	77	static void __attribute__((noreturn))
	78	succeed_file(void)
	79	{
	80	cleanup();
	81	longjmp(jmpenv, SJ_SUCCEED);
	82	}
	83
	84	/* ulseek, uread, ...: Check return value for errors. */
	85
	86	static off_t
	87	ulseek(int const fd, off_t const offset, int const whence)
	88	{
	89	off_t const w = lseek(fd, offset, whence);
dd5477ff	90	if (w == (off_t)-1) {
81d3858d JR	91	perror("lseek");
	92	fail_file();
	93	}
	94	return w;
	95	}
	96
	97	static size_t
	98	uread(int const fd, void *const buf, size_t const count)
	99	{
	100	size_t const n = read(fd, buf, count);
	101	if (n != count) {
	102	perror("read");
	103	fail_file();
	104	}
	105	return n;
	106	}
	107
	108	static size_t
	109	uwrite(int const fd, void const *const buf, size_t const count)
	110	{
	111	size_t const n = write(fd, buf, count);
	112	if (n != count) {
	113	perror("write");
	114	fail_file();
	115	}
	116	return n;
	117	}
	118
	119	static void *
	120	umalloc(size_t size)
	121	{
	122	void *const addr = malloc(size);
dd5477ff	123	if (addr == 0) {
81d3858d JR	124	fprintf(stderr, "malloc failed: %zu bytes\n", size);
	125	fail_file();
	126	}
	127	return addr;
	128	}
	129
ffd618fa SR	130	static unsigned char ideal_nop5_x86_64[5] = { 0x0f, 0x1f, 0x44, 0x00, 0x00 };
	131	static unsigned char ideal_nop5_x86_32[5] = { 0x3e, 0x8d, 0x74, 0x26, 0x00 };
	132	static unsigned char *ideal_nop;
	133
	134	static char rel_type_nop;
	135
	136	static int (make_nop)(void map, size_t const offset);
	137
	138	static int make_nop_x86(void *map, size_t const offset)
	139	{
	140	uint32_t *ptr;
	141	unsigned char *op;
	142
	143	/* Confirm we have 0xe8 0x0 0x0 0x0 0x0 */
	144	ptr = map + offset;
	145	if (*ptr != 0)
	146	return -1;
	147
	148	op = map + offset - 1;
	149	if (*op != 0xe8)
	150	return -1;
	151
	152	/* convert to nop */
	153	ulseek(fd_map, offset - 1, SEEK_SET);
	154	uwrite(fd_map, ideal_nop, 5);
	155	return 0;
	156	}
	157
81d3858d JR	158	/*
	159	* Get the whole file as a programming convenience in order to avoid
	160	* malloc+lseek+read+free of many pieces. If successful, then mmap
	161	* avoids copying unused pieces; else just read the whole file.
	162	* Open for both read and write; new info will be appended to the file.
	163	* Use MAP_PRIVATE so that a few changes to the in-memory ElfXX_Ehdr
	164	* do not propagate to the file until an explicit overwrite at the last.
	165	* This preserves most aspects of consistency (all except .st_size)
	166	* for simultaneous readers of the file while we are appending to it.
	167	* However, multiple writers still are bad. We choose not to use
	168	* locking because it is expensive and the use case of kernel build
	169	* makes multiple writers unlikely.
	170	*/
	171	static void mmap_file(char const fname)
	172	{
	173	void *addr;
	174
	175	fd_map = open(fname, O_RDWR);
dd5477ff	176	if (fd_map < 0 \|\| fstat(fd_map, &sb) < 0) {
81d3858d JR	177	perror(fname);
	178	fail_file();
	179	}
	180	if (!S_ISREG(sb.st_mode)) {
	181	fprintf(stderr, "not a regular file: %s\n", fname);
	182	fail_file();
	183	}
	184	addr = mmap(0, sb.st_size, PROT_READ\|PROT_WRITE, MAP_PRIVATE,
	185	fd_map, 0);
	186	mmap_failed = 0;
dd5477ff	187	if (addr == MAP_FAILED) {
81d3858d JR	188	mmap_failed = 1;
	189	addr = umalloc(sb.st_size);
	190	uread(fd_map, addr, sb.st_size);
	191	}
	192	return addr;
	193	}
	194
	195	/* w8rev, w8nat, ...: Handle endianness. */
	196
	197	static uint64_t w8rev(uint64_t const x)
	198	{
	199	return ((0xff & (x >> (0 * 8))) << (7 * 8))
	200	\| ((0xff & (x >> (1 * 8))) << (6 * 8))
	201	\| ((0xff & (x >> (2 * 8))) << (5 * 8))
	202	\| ((0xff & (x >> (3 * 8))) << (4 * 8))
	203	\| ((0xff & (x >> (4 * 8))) << (3 * 8))
	204	\| ((0xff & (x >> (5 * 8))) << (2 * 8))
	205	\| ((0xff & (x >> (6 * 8))) << (1 * 8))
	206	\| ((0xff & (x >> (7 * 8))) << (0 * 8));
	207	}
	208
	209	static uint32_t w4rev(uint32_t const x)
	210	{
	211	return ((0xff & (x >> (0 * 8))) << (3 * 8))
	212	\| ((0xff & (x >> (1 * 8))) << (2 * 8))
	213	\| ((0xff & (x >> (2 * 8))) << (1 * 8))
	214	\| ((0xff & (x >> (3 * 8))) << (0 * 8));
	215	}
	216
	217	static uint32_t w2rev(uint16_t const x)
	218	{
	219	return ((0xff & (x >> (0 * 8))) << (1 * 8))
	220	\| ((0xff & (x >> (1 * 8))) << (0 * 8));
	221	}
	222
	223	static uint64_t w8nat(uint64_t const x)
	224	{
	225	return x;
	226	}
	227
	228	static uint32_t w4nat(uint32_t const x)
	229	{
	230	return x;
	231	}
	232
	233	static uint32_t w2nat(uint16_t const x)
	234	{
	235	return x;
	236	}
	237
	238	static uint64_t (*w8)(uint64_t);
	239	static uint32_t (*w)(uint32_t);
	240	static uint32_t (*w2)(uint16_t);
	241
	242	/* Names of the sections that could contain calls to mcount. */
	243	static int
	244	is_mcounted_section_name(char const *const txtname)
	245	{
dd5477ff SR	246	return strcmp(".text", txtname) == 0 \|\|
	247	strcmp(".ref.text", txtname) == 0 \|\|
	248	strcmp(".sched.text", txtname) == 0 \|\|
	249	strcmp(".spinlock.text", txtname) == 0 \|\|
	250	strcmp(".irqentry.text", txtname) == 0 \|\|
9f087e76	251	strcmp(".kprobes.text", txtname) == 0 \|\|
dd5477ff	252	strcmp(".text.unlikely", txtname) == 0;
81d3858d JR	253	}
81d3858d JR	254
c28d5077 SR	255	/* 32 bit and 64 bit are very similar */
	256	#include "recordmcount.h"
	257	#define RECORD_MCOUNT_64
	258	#include "recordmcount.h"
81d3858d	259
a2d49358 JR	260	/* 64-bit EM_MIPS has weird ELF64_Rela.r_info.
	261	* http://techpubs.sgi.com/library/manuals/4000/007-4658-001/pdf/007-4658-001.pdf
	262	* We interpret Table 29 Relocation Operation (Elf64_Rel, Elf64_Rela) [p.40]
	263	* to imply the order of the members; the spec does not say so.
	264	* typedef unsigned char Elf64_Byte;
	265	* fails on MIPS64 because their <elf.h> already has it!
	266	*/
	267
	268	typedef uint8_t myElf64_Byte; /* Type for a 8-bit quantity. */
	269
	270	union mips_r_info {
	271	Elf64_Xword r_info;
	272	struct {
	273	Elf64_Word r_sym; /* Symbol index. */
	274	myElf64_Byte r_ssym; /* Special symbol. */
	275	myElf64_Byte r_type3; /* Third relocation. */
	276	myElf64_Byte r_type2; /* Second relocation. */
	277	myElf64_Byte r_type; /* First relocation. */
	278	} r_mips;
	279	};
	280
	281	static uint64_t MIPS64_r_sym(Elf64_Rel const *rp)
	282	{
	283	return w(((union mips_r_info){ .r_info = rp->r_info }).r_mips.r_sym);
	284	}
	285
	286	static void MIPS64_r_info(Elf64_Rel *const rp, unsigned sym, unsigned type)
	287	{
	288	rp->r_info = ((union mips_r_info){
	289	.r_mips = { .r_sym = w(sym), .r_type = type }
	290	}).r_info;
	291	}
	292
81d3858d JR	293	static void
	294	do_file(char const *const fname)
	295	{
	296	Elf32_Ehdr *const ehdr = mmap_file(fname);
	297	unsigned int reltype = 0;
	298
	299	ehdr_curr = ehdr;
	300	w = w4nat;
	301	w2 = w2nat;
	302	w8 = w8nat;
	303	switch (ehdr->e_ident[EI_DATA]) {
	304	static unsigned int const endian = 1;
e90b0c8b	305	default:
81d3858d JR	306	fprintf(stderr, "unrecognized ELF data encoding %d: %s\n",
	307	ehdr->e_ident[EI_DATA], fname);
	308	fail_file();
e90b0c8b SR	309	break;
e90b0c8b SR	310	case ELFDATA2LSB:
dd5477ff	311	if ((unsigned char const )&endian != 1) {
81d3858d JR	312	/* main() is big endian, file.o is little endian. */
	313	w = w4rev;
	314	w2 = w2rev;
	315	w8 = w8rev;
	316	}
e90b0c8b SR	317	break;
e90b0c8b SR	318	case ELFDATA2MSB:
dd5477ff	319	if ((unsigned char const )&endian != 0) {
81d3858d JR	320	/* main() is little endian, file.o is big endian. */
	321	w = w4rev;
	322	w2 = w2rev;
	323	w8 = w8rev;
	324	}
e90b0c8b	325	break;
81d3858d	326	} /* end switch */
dd5477ff SR	327	if (memcmp(ELFMAG, ehdr->e_ident, SELFMAG) != 0
	328	\|\| w2(ehdr->e_type) != ET_REL
	329	\|\| ehdr->e_ident[EI_VERSION] != EV_CURRENT) {
81d3858d JR	330	fprintf(stderr, "unrecognized ET_REL file %s\n", fname);
	331	fail_file();
	332	}
	333
	334	gpfx = 0;
	335	switch (w2(ehdr->e_machine)) {
e90b0c8b	336	default:
81d3858d JR	337	fprintf(stderr, "unrecognized e_machine %d %s\n",
	338	w2(ehdr->e_machine), fname);
	339	fail_file();
e90b0c8b	340	break;
ffd618fa SR	341	case EM_386:
	342	reltype = R_386_32;
	343	make_nop = make_nop_x86;
	344	ideal_nop = ideal_nop5_x86_32;
521ccb5c	345	mcount_adjust_32 = -1;
ffd618fa	346	break;
ed60453f RV	347	case EM_ARM: reltype = R_ARM_ABS32;
	348	altmcount = "__gnu_mcount_nc";
	349	break;
81d3858d	350	case EM_IA_64: reltype = R_IA64_IMM64; gpfx = '_'; break;
00512bdd JH	351	case EM_METAG: reltype = R_METAG_ADDR32;
	352	altmcount = "_mcount_wrapper";
	353	rel_type_nop = R_METAG_NONE;
	354	/* We happen to have the same requirement as MIPS */
	355	is_fake_mcount32 = MIPS32_is_fake_mcount;
	356	break;
a2d49358	357	case EM_MIPS: /* reltype: e_class */ gpfx = '_'; break;
81d3858d JR	358	case EM_PPC: reltype = R_PPC_ADDR32; gpfx = '_'; break;
	359	case EM_PPC64: reltype = R_PPC64_ADDR64; gpfx = '_'; break;
	360	case EM_S390: /* reltype: e_class */ gpfx = '_'; break;
	361	case EM_SH: reltype = R_SH_DIR32; break;
	362	case EM_SPARCV9: reltype = R_SPARC_64; gpfx = '_'; break;
ffd618fa SR	363	case EM_X86_64:
	364	make_nop = make_nop_x86;
	365	ideal_nop = ideal_nop5_x86_64;
	366	reltype = R_X86_64_64;
521ccb5c	367	mcount_adjust_64 = -1;
ffd618fa	368	break;
81d3858d JR	369	} /* end switch */
	370
	371	switch (ehdr->e_ident[EI_CLASS]) {
e90b0c8b	372	default:
81d3858d JR	373	fprintf(stderr, "unrecognized ELF class %d %s\n",
	374	ehdr->e_ident[EI_CLASS], fname);
	375	fail_file();
e90b0c8b SR	376	break;
e90b0c8b SR	377	case ELFCLASS32:
dd5477ff SR	378	if (w2(ehdr->e_ehsize) != sizeof(Elf32_Ehdr)
dd5477ff SR	379	\|\| w2(ehdr->e_shentsize) != sizeof(Elf32_Shdr)) {
81d3858d JR	380	fprintf(stderr,
	381	"unrecognized ET_REL file: %s\n", fname);
	382	fail_file();
	383	}
f2963886	384	if (w2(ehdr->e_machine) == EM_S390) {
81d3858d	385	reltype = R_390_32;
f2963886 MS	386	mcount_adjust_32 = -4;
f2963886 MS	387	}
dd5477ff	388	if (w2(ehdr->e_machine) == EM_MIPS) {
a2d49358	389	reltype = R_MIPS_32;
412910cd WZ	390	is_fake_mcount32 = MIPS32_is_fake_mcount;
412910cd WZ	391	}
81d3858d	392	do32(ehdr, fname, reltype);
e90b0c8b	393	break;
81d3858d JR	394	case ELFCLASS64: {
81d3858d JR	395	Elf64_Ehdr const ghdr = (Elf64_Ehdr )ehdr;
dd5477ff SR	396	if (w2(ghdr->e_ehsize) != sizeof(Elf64_Ehdr)
dd5477ff SR	397	\|\| w2(ghdr->e_shentsize) != sizeof(Elf64_Shdr)) {
81d3858d JR	398	fprintf(stderr,
	399	"unrecognized ET_REL file: %s\n", fname);
	400	fail_file();
	401	}
f2963886	402	if (w2(ghdr->e_machine) == EM_S390) {
81d3858d	403	reltype = R_390_64;
f2963886 MS	404	mcount_adjust_64 = -8;
f2963886 MS	405	}
dd5477ff	406	if (w2(ghdr->e_machine) == EM_MIPS) {
a2d49358 JR	407	reltype = R_MIPS_64;
	408	Elf64_r_sym = MIPS64_r_sym;
	409	Elf64_r_info = MIPS64_r_info;
412910cd	410	is_fake_mcount64 = MIPS64_is_fake_mcount;
a2d49358	411	}
81d3858d	412	do64(ghdr, fname, reltype);
e90b0c8b SR	413	break;
e90b0c8b SR	414	}
81d3858d JR	415	} /* end switch */
	416
	417	cleanup();
	418	}
	419
	420	int
dfad3d59	421	main(int argc, char *argv[])
81d3858d	422	{
cd3478f2	423	const char ftrace[] = "/ftrace.o";
44475863	424	int ftrace_size = sizeof(ftrace) - 1;
81d3858d	425	int n_error = 0; /* gcc-4.3.0 false positive complaint */
dfad3d59 SR	426	int c;
dfad3d59 SR	427	int i;
44475863	428
dfad3d59 SR	429	while ((c = getopt(argc, argv, "w")) >= 0) {
	430	switch (c) {
	431	case 'w':
	432	warn_on_notrace_sect = 1;
	433	break;
	434	default:
	435	fprintf(stderr, "usage: recordmcount [-w] file.o...\n");
	436	return 0;
	437	}
	438	}
	439
	440	if ((argc - optind) < 1) {
	441	fprintf(stderr, "usage: recordmcount [-w] file.o...\n");
44475863 SR	442	return 0;
	443	}
	444
	445	/* Process each file in turn, allowing deep failure. */
dfad3d59 SR	446	for (i = optind; i < argc; i++) {
dfad3d59 SR	447	char *file = argv[i];
81d3858d	448	int const sjval = setjmp(jmpenv);
44475863 SR	449	int len;
	450
	451	/*
	452	* The file kernel/trace/ftrace.o references the mcount
	453	* function but does not call it. Since ftrace.o should
	454	* not be traced anyway, we just skip it.
	455	*/
dfad3d59	456	len = strlen(file);
44475863	457	if (len >= ftrace_size &&
dfad3d59	458	strcmp(file + (len - ftrace_size), ftrace) == 0)
44475863 SR	459	continue;
44475863 SR	460
81d3858d	461	switch (sjval) {
e90b0c8b	462	default:
dfad3d59	463	fprintf(stderr, "internal error: %s\n", file);
81d3858d	464	exit(1);
e90b0c8b SR	465	break;
e90b0c8b SR	466	case SJ_SETJMP: /* normal sequence */
81d3858d JR	467	/* Avoid problems if early cleanup() */
	468	fd_map = -1;
	469	ehdr_curr = NULL;
	470	mmap_failed = 1;
dfad3d59	471	do_file(file);
e90b0c8b SR	472	break;
e90b0c8b SR	473	case SJ_FAIL: /* error in do_file or below */
81d3858d	474	++n_error;
e90b0c8b SR	475	break;
e90b0c8b SR	476	case SJ_SUCCEED: /* premature success */
81d3858d	477	/* do nothing */
e90b0c8b	478	break;
81d3858d JR	479	} /* end switch */
	480	}
	481	return !!n_error;
	482	}
	483
	484