// SPDX-License-Identifier: GPL-2.0-only/* * sortextable.c: Sort the kernel's exception table * * Copyright 2011 - 2012 Cavium, Inc. * * Based on code taken from recortmcount.c which is: * * Copyright 2009 John F. Reiser <jreiser@BitWagon.com>.  All rights reserved. * * Restructured to fit Linux format, as well as other updates: *  Copyright 2010 Steven Rostedt <srostedt@redhat.com>, Red Hat Inc. */ /* * Strategy: alter the vmlinux file in-place. */ #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> #include <tools/be_byteshift.h>#include <tools/le_byteshift.h> #ifndef EM_ARCOMPACT#define EM_ARCOMPACT	93#endif #ifndef EM_XTENSA#define EM_XTENSA	94#endif #ifndef EM_AARCH64#define EM_AARCH64	183#endif #ifndef EM_MICROBLAZE#define EM_MICROBLAZE	189#endif #ifndef EM_ARCV2#define EM_ARCV2	195#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 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 voidcleanup(void){	if (!mmap_failed)		munmap(ehdr_curr, sb.st_size);	close(fd_map);} static void __attribute__((noreturn))fail_file(void){	cleanup();	longjmp(jmpenv, SJ_FAIL);} /* * 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. */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_SHARED,		    fd_map, 0);	if (addr == MAP_FAILED) {		mmap_failed = 1;		fprintf(stderr, "Could not mmap file: %s\n", fname);		fail_file();	}	return addr;} static uint64_t r8be(const uint64_t *x){	return get_unaligned_be64(x);}static uint32_t rbe(const uint32_t *x){	return get_unaligned_be32(x);}static uint16_t r2be(const uint16_t *x){	return get_unaligned_be16(x);}static uint64_t r8le(const uint64_t *x){	return get_unaligned_le64(x);}static uint32_t rle(const uint32_t *x){	return get_unaligned_le32(x);}static uint16_t r2le(const uint16_t *x){	return get_unaligned_le16(x);} static void w8be(uint64_t val, uint64_t *x){	put_unaligned_be64(val, x);}static void wbe(uint32_t val, uint32_t *x){	put_unaligned_be32(val, x);}static void w2be(uint16_t val, uint16_t *x){	put_unaligned_be16(val, x);}static void w8le(uint64_t val, uint64_t *x){	put_unaligned_le64(val, x);}static void wle(uint32_t val, uint32_t *x){	put_unaligned_le32(val, x);}static void w2le(uint16_t val, uint16_t *x){	put_unaligned_le16(val, x);} static uint64_t (*r8)(const uint64_t *);static uint32_t (*r)(const uint32_t *);static uint16_t (*r2)(const uint16_t *);static void (*w8)(uint64_t, uint64_t *);static void (*w)(uint32_t, uint32_t *);static void (*w2)(uint16_t, uint16_t *); typedef void (*table_sort_t)(char *, int); /* * Move reserved section indices SHN_LORESERVE..SHN_HIRESERVE out of * the way to -256..-1, to avoid conflicting with real section * indices. */#define SPECIAL(i) ((i) - (SHN_HIRESERVE + 1)) static inline int is_shndx_special(unsigned int i){	return i != SHN_XINDEX && i >= SHN_LORESERVE && i <= SHN_HIRESERVE;} /* Accessor for sym->st_shndx, hides ugliness of "64k sections" */static inline unsigned int get_secindex(unsigned int shndx,					unsigned int sym_offs,					const Elf32_Word *symtab_shndx_start){	if (is_shndx_special(shndx))		return SPECIAL(shndx);	if (shndx != SHN_XINDEX)		return shndx;	return r(&symtab_shndx_start[sym_offs]);} /* 32 bit and 64 bit are very similar */#include "sortextable.h"#define SORTEXTABLE_64#include "sortextable.h" static int compare_relative_table(const void *a, const void *b){	int32_t av = (int32_t)r(a);	int32_t bv = (int32_t)r(b); 	if (av < bv)		return -1;	if (av > bv)		return 1;	return 0;} static void x86_sort_relative_table(char *extab_image, int image_size){	int i; 	i = 0;	while (i < image_size) {		uint32_t *loc = (uint32_t *)(extab_image + i); 		w(r(loc) + i, loc);		w(r(loc + 1) + i + 4, loc + 1);		w(r(loc + 2) + i + 8, loc + 2); 		i += sizeof(uint32_t) * 3;	} 	qsort(extab_image, image_size / 12, 12, compare_relative_table); 	i = 0;	while (i < image_size) {		uint32_t *loc = (uint32_t *)(extab_image + i); 		w(r(loc) - i, loc);		w(r(loc + 1) - (i + 4), loc + 1);		w(r(loc + 2) - (i + 8), loc + 2); 		i += sizeof(uint32_t) * 3;	}} static void sort_relative_table(char *extab_image, int image_size){	int i; 	/*	 * Do the same thing the runtime sort does, first normalize to	 * being relative to the start of the section.	 */	i = 0;	while (i < image_size) {		uint32_t *loc = (uint32_t *)(extab_image + i);		w(r(loc) + i, loc);		i += 4;	} 	qsort(extab_image, image_size / 8, 8, compare_relative_table); 	/* Now denormalize. */	i = 0;	while (i < image_size) {		uint32_t *loc = (uint32_t *)(extab_image + i);		w(r(loc) - i, loc);		i += 4;	}} static voiddo_file(char const *const fname){	table_sort_t custom_sort;	Elf32_Ehdr *ehdr = mmap_file(fname); 	ehdr_curr = ehdr;	switch (ehdr->e_ident[EI_DATA]) {	default:		fprintf(stderr, "unrecognized ELF data encoding %d: %s\n",			ehdr->e_ident[EI_DATA], fname);		fail_file();		break;	case ELFDATA2LSB:		r = rle;		r2 = r2le;		r8 = r8le;		w = wle;		w2 = w2le;		w8 = w8le;		break;	case ELFDATA2MSB:		r = rbe;		r2 = r2be;		r8 = r8be;		w = wbe;		w2 = w2be;		w8 = w8be;		break;	}  /* end switch */	if (memcmp(ELFMAG, ehdr->e_ident, SELFMAG) != 0	||  (r2(&ehdr->e_type) != ET_EXEC && r2(&ehdr->e_type) != ET_DYN)	||  ehdr->e_ident[EI_VERSION] != EV_CURRENT) {		fprintf(stderr, "unrecognized ET_EXEC/ET_DYN file %s\n", fname);		fail_file();	} 	custom_sort = NULL;	switch (r2(&ehdr->e_machine)) {	default:		fprintf(stderr, "unrecognized e_machine %d %s\n",			r2(&ehdr->e_machine), fname);		fail_file();		break;	case EM_386:	case EM_X86_64:		custom_sort = x86_sort_relative_table;		break; 	case EM_S390:	case EM_AARCH64:	case EM_PARISC:	case EM_PPC:	case EM_PPC64:		custom_sort = sort_relative_table;		break;	case EM_ARCOMPACT:	case EM_ARCV2:	case EM_ARM:	case EM_MICROBLAZE:	case EM_MIPS:	case EM_XTENSA:		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 (r2(&ehdr->e_ehsize) != sizeof(Elf32_Ehdr)		||  r2(&ehdr->e_shentsize) != sizeof(Elf32_Shdr)) {			fprintf(stderr,				"unrecognized ET_EXEC/ET_DYN file: %s\n", fname);			fail_file();		}		do32(ehdr, fname, custom_sort);		break;	case ELFCLASS64: {		Elf64_Ehdr *const ghdr = (Elf64_Ehdr *)ehdr;		if (r2(&ghdr->e_ehsize) != sizeof(Elf64_Ehdr)		||  r2(&ghdr->e_shentsize) != sizeof(Elf64_Shdr)) {			fprintf(stderr,				"unrecognized ET_EXEC/ET_DYN file: %s\n", fname);			fail_file();		}		do64(ghdr, fname, custom_sort);		break;	}	}  /* end switch */ 	cleanup();} intmain(int argc, char *argv[]){	int n_error = 0;  /* gcc-4.3.0 false positive complaint */	int i; 	if (argc < 2) {		fprintf(stderr, "usage: sortextable vmlinux...\n");		return 0;	} 	/* Process each file in turn, allowing deep failure. */	for (i = 1; i < argc; i++) {		char *file = argv[i];		int const sjval = setjmp(jmpenv); 		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;}