2 * sortextable.c: Sort the kernel's exception table
4 * Copyright 2011 - 2012 Cavium, Inc.
6 * Based on code taken from recortmcount.c which is:
8 * Copyright 2009 John F. Reiser <jreiser@BitWagon.com>. All rights reserved.
9 * Licensed under the GNU General Public License, version 2 (GPLv2).
11 * Restructured to fit Linux format, as well as other updates:
12 * Copyright 2010 Steven Rostedt <srostedt@redhat.com>, Red Hat Inc.
16 * Strategy: alter the vmlinux file in-place.
19 #include <sys/types.h>
31 #include <tools/be_byteshift.h>
32 #include <tools/le_byteshift.h>
35 #define EM_ARCOMPACT 93
43 #define EM_AARCH64 183
47 #define EM_MICROBLAZE 189
50 static int fd_map; /* File descriptor for file being modified. */
51 static int mmap_failed; /* Boolean flag. */
52 static void *ehdr_curr; /* current ElfXX_Ehdr * for resource cleanup */
53 static struct stat sb; /* Remember .st_size, etc. */
54 static jmp_buf jmpenv; /* setjmp/longjmp per-file error escape */
56 /* setjmp() return values */
58 SJ_SETJMP = 0, /* hardwired first return */
63 /* Per-file resource cleanup when multiple files. */
68 munmap(ehdr_curr, sb.st_size);
72 static void __attribute__((noreturn))
76 longjmp(jmpenv, SJ_FAIL);
80 * Get the whole file as a programming convenience in order to avoid
81 * malloc+lseek+read+free of many pieces. If successful, then mmap
82 * avoids copying unused pieces; else just read the whole file.
83 * Open for both read and write.
85 static void *mmap_file(char const *fname)
89 fd_map = open(fname, O_RDWR);
90 if (fd_map < 0 || fstat(fd_map, &sb) < 0) {
94 if (!S_ISREG(sb.st_mode)) {
95 fprintf(stderr, "not a regular file: %s\n", fname);
98 addr = mmap(0, sb.st_size, PROT_READ|PROT_WRITE, MAP_SHARED,
100 if (addr == MAP_FAILED) {
102 fprintf(stderr, "Could not mmap file: %s\n", fname);
108 static uint64_t r8be(const uint64_t *x)
110 return get_unaligned_be64(x);
112 static uint32_t rbe(const uint32_t *x)
114 return get_unaligned_be32(x);
116 static uint16_t r2be(const uint16_t *x)
118 return get_unaligned_be16(x);
120 static uint64_t r8le(const uint64_t *x)
122 return get_unaligned_le64(x);
124 static uint32_t rle(const uint32_t *x)
126 return get_unaligned_le32(x);
128 static uint16_t r2le(const uint16_t *x)
130 return get_unaligned_le16(x);
133 static void w8be(uint64_t val, uint64_t *x)
135 put_unaligned_be64(val, x);
137 static void wbe(uint32_t val, uint32_t *x)
139 put_unaligned_be32(val, x);
141 static void w2be(uint16_t val, uint16_t *x)
143 put_unaligned_be16(val, x);
145 static void w8le(uint64_t val, uint64_t *x)
147 put_unaligned_le64(val, x);
149 static void wle(uint32_t val, uint32_t *x)
151 put_unaligned_le32(val, x);
153 static void w2le(uint16_t val, uint16_t *x)
155 put_unaligned_le16(val, x);
158 static uint64_t (*r8)(const uint64_t *);
159 static uint32_t (*r)(const uint32_t *);
160 static uint16_t (*r2)(const uint16_t *);
161 static void (*w8)(uint64_t, uint64_t *);
162 static void (*w)(uint32_t, uint32_t *);
163 static void (*w2)(uint16_t, uint16_t *);
165 typedef void (*table_sort_t)(char *, int);
168 * Move reserved section indices SHN_LORESERVE..SHN_HIRESERVE out of
169 * the way to -256..-1, to avoid conflicting with real section
172 #define SPECIAL(i) ((i) - (SHN_HIRESERVE + 1))
174 static inline int is_shndx_special(unsigned int i)
176 return i != SHN_XINDEX && i >= SHN_LORESERVE && i <= SHN_HIRESERVE;
179 /* Accessor for sym->st_shndx, hides ugliness of "64k sections" */
180 static inline unsigned int get_secindex(unsigned int shndx,
181 unsigned int sym_offs,
182 const Elf32_Word *symtab_shndx_start)
184 if (is_shndx_special(shndx))
185 return SPECIAL(shndx);
186 if (shndx != SHN_XINDEX)
188 return r(&symtab_shndx_start[sym_offs]);
191 /* 32 bit and 64 bit are very similar */
192 #include "sortextable.h"
193 #define SORTEXTABLE_64
194 #include "sortextable.h"
196 static int compare_relative_table(const void *a, const void *b)
198 int32_t av = (int32_t)r(a);
199 int32_t bv = (int32_t)r(b);
208 static void sort_relative_table(char *extab_image, int image_size)
213 * Do the same thing the runtime sort does, first normalize to
214 * being relative to the start of the section.
217 while (i < image_size) {
218 uint32_t *loc = (uint32_t *)(extab_image + i);
223 qsort(extab_image, image_size / 8, 8, compare_relative_table);
225 /* Now denormalize. */
227 while (i < image_size) {
228 uint32_t *loc = (uint32_t *)(extab_image + i);
235 do_file(char const *const fname)
237 table_sort_t custom_sort;
238 Elf32_Ehdr *ehdr = mmap_file(fname);
241 switch (ehdr->e_ident[EI_DATA]) {
243 fprintf(stderr, "unrecognized ELF data encoding %d: %s\n",
244 ehdr->e_ident[EI_DATA], fname);
264 if (memcmp(ELFMAG, ehdr->e_ident, SELFMAG) != 0
265 || r2(&ehdr->e_type) != ET_EXEC
266 || ehdr->e_ident[EI_VERSION] != EV_CURRENT) {
267 fprintf(stderr, "unrecognized ET_EXEC file %s\n", fname);
272 switch (r2(&ehdr->e_machine)) {
274 fprintf(stderr, "unrecognized e_machine %d %s\n",
275 r2(&ehdr->e_machine), fname);
281 custom_sort = sort_relative_table;
292 switch (ehdr->e_ident[EI_CLASS]) {
294 fprintf(stderr, "unrecognized ELF class %d %s\n",
295 ehdr->e_ident[EI_CLASS], fname);
299 if (r2(&ehdr->e_ehsize) != sizeof(Elf32_Ehdr)
300 || r2(&ehdr->e_shentsize) != sizeof(Elf32_Shdr)) {
302 "unrecognized ET_EXEC file: %s\n", fname);
305 do32(ehdr, fname, custom_sort);
308 Elf64_Ehdr *const ghdr = (Elf64_Ehdr *)ehdr;
309 if (r2(&ghdr->e_ehsize) != sizeof(Elf64_Ehdr)
310 || r2(&ghdr->e_shentsize) != sizeof(Elf64_Shdr)) {
312 "unrecognized ET_EXEC file: %s\n", fname);
315 do64(ghdr, fname, custom_sort);
324 main(int argc, char *argv[])
326 int n_error = 0; /* gcc-4.3.0 false positive complaint */
330 fprintf(stderr, "usage: sortextable vmlinux...\n");
334 /* Process each file in turn, allowing deep failure. */
335 for (i = 1; i < argc; i++) {
336 char *file = argv[i];
337 int const sjval = setjmp(jmpenv);
341 fprintf(stderr, "internal error: %s\n", file);
344 case SJ_SETJMP: /* normal sequence */
345 /* Avoid problems if early cleanup() */
351 case SJ_FAIL: /* error in do_file or below */
354 case SJ_SUCCEED: /* premature success */