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David Daneya79f2482012-04-19 14:59:55 -07001/*
2 * sortextable.c: Sort the kernel's exception table
3 *
David Daneyd59a1682012-04-24 11:23:14 -07004 * Copyright 2011 - 2012 Cavium, Inc.
David Daneya79f2482012-04-19 14:59:55 -07005 *
6 * Based on code taken from recortmcount.c which is:
7 *
8 * Copyright 2009 John F. Reiser <jreiser@BitWagon.com>. All rights reserved.
9 * Licensed under the GNU General Public License, version 2 (GPLv2).
10 *
11 * Restructured to fit Linux format, as well as other updates:
12 * Copyright 2010 Steven Rostedt <srostedt@redhat.com>, Red Hat Inc.
13 */
14
15/*
16 * Strategy: alter the vmlinux file in-place.
17 */
18
19#include <sys/types.h>
20#include <sys/mman.h>
21#include <sys/stat.h>
22#include <getopt.h>
23#include <elf.h>
24#include <fcntl.h>
25#include <setjmp.h>
26#include <stdio.h>
27#include <stdlib.h>
28#include <string.h>
29#include <unistd.h>
30
David Daneyd59a1682012-04-24 11:23:14 -070031#include <tools/be_byteshift.h>
32#include <tools/le_byteshift.h>
33
Vineet Guptaf06d19e2013-11-15 12:08:05 +053034#ifndef EM_ARCOMPACT
35#define EM_ARCOMPACT 93
36#endif
37
Max Filippov25df8192014-02-18 15:29:11 +040038#ifndef EM_XTENSA
39#define EM_XTENSA 94
40#endif
41
Will Deaconadace892013-05-08 17:29:24 +010042#ifndef EM_AARCH64
43#define EM_AARCH64 183
44#endif
45
Michal Simek372c7202014-01-23 15:52:46 -080046#ifndef EM_MICROBLAZE
47#define EM_MICROBLAZE 189
48#endif
49
Vineet Guptab3210d12013-11-22 13:05:58 +053050#ifndef EM_ARCV2
51#define EM_ARCV2 195
52#endif
53
David Daneya79f2482012-04-19 14:59:55 -070054static int fd_map; /* File descriptor for file being modified. */
55static int mmap_failed; /* Boolean flag. */
56static void *ehdr_curr; /* current ElfXX_Ehdr * for resource cleanup */
57static struct stat sb; /* Remember .st_size, etc. */
58static jmp_buf jmpenv; /* setjmp/longjmp per-file error escape */
59
60/* setjmp() return values */
61enum {
62 SJ_SETJMP = 0, /* hardwired first return */
63 SJ_FAIL,
64 SJ_SUCCEED
65};
66
67/* Per-file resource cleanup when multiple files. */
68static void
69cleanup(void)
70{
71 if (!mmap_failed)
72 munmap(ehdr_curr, sb.st_size);
73 close(fd_map);
74}
75
76static void __attribute__((noreturn))
77fail_file(void)
78{
79 cleanup();
80 longjmp(jmpenv, SJ_FAIL);
81}
82
David Daneya79f2482012-04-19 14:59:55 -070083/*
84 * Get the whole file as a programming convenience in order to avoid
85 * malloc+lseek+read+free of many pieces. If successful, then mmap
86 * avoids copying unused pieces; else just read the whole file.
87 * Open for both read and write.
88 */
89static void *mmap_file(char const *fname)
90{
91 void *addr;
92
93 fd_map = open(fname, O_RDWR);
94 if (fd_map < 0 || fstat(fd_map, &sb) < 0) {
95 perror(fname);
96 fail_file();
97 }
98 if (!S_ISREG(sb.st_mode)) {
99 fprintf(stderr, "not a regular file: %s\n", fname);
100 fail_file();
101 }
102 addr = mmap(0, sb.st_size, PROT_READ|PROT_WRITE, MAP_SHARED,
103 fd_map, 0);
104 if (addr == MAP_FAILED) {
105 mmap_failed = 1;
106 fprintf(stderr, "Could not mmap file: %s\n", fname);
107 fail_file();
108 }
109 return addr;
110}
111
David Daneyd59a1682012-04-24 11:23:14 -0700112static uint64_t r8be(const uint64_t *x)
David Daneya79f2482012-04-19 14:59:55 -0700113{
David Daneyd59a1682012-04-24 11:23:14 -0700114 return get_unaligned_be64(x);
115}
116static uint32_t rbe(const uint32_t *x)
117{
118 return get_unaligned_be32(x);
119}
120static uint16_t r2be(const uint16_t *x)
121{
122 return get_unaligned_be16(x);
123}
124static uint64_t r8le(const uint64_t *x)
125{
126 return get_unaligned_le64(x);
127}
128static uint32_t rle(const uint32_t *x)
129{
130 return get_unaligned_le32(x);
131}
132static uint16_t r2le(const uint16_t *x)
133{
134 return get_unaligned_le16(x);
David Daneya79f2482012-04-19 14:59:55 -0700135}
136
David Daneyd59a1682012-04-24 11:23:14 -0700137static void w8be(uint64_t val, uint64_t *x)
David Daneya79f2482012-04-19 14:59:55 -0700138{
David Daneyd59a1682012-04-24 11:23:14 -0700139 put_unaligned_be64(val, x);
140}
141static void wbe(uint32_t val, uint32_t *x)
142{
143 put_unaligned_be32(val, x);
144}
145static void w2be(uint16_t val, uint16_t *x)
146{
147 put_unaligned_be16(val, x);
148}
149static void w8le(uint64_t val, uint64_t *x)
150{
151 put_unaligned_le64(val, x);
152}
153static void wle(uint32_t val, uint32_t *x)
154{
155 put_unaligned_le32(val, x);
156}
157static void w2le(uint16_t val, uint16_t *x)
158{
159 put_unaligned_le16(val, x);
David Daneya79f2482012-04-19 14:59:55 -0700160}
161
David Daneyd59a1682012-04-24 11:23:14 -0700162static uint64_t (*r8)(const uint64_t *);
163static uint32_t (*r)(const uint32_t *);
164static uint16_t (*r2)(const uint16_t *);
165static void (*w8)(uint64_t, uint64_t *);
166static void (*w)(uint32_t, uint32_t *);
167static void (*w2)(uint16_t, uint16_t *);
David Daneya79f2482012-04-19 14:59:55 -0700168
David Daneyd59a1682012-04-24 11:23:14 -0700169typedef void (*table_sort_t)(char *, int);
David Daneya79f2482012-04-19 14:59:55 -0700170
Jamie Iles59c36452013-11-12 15:06:51 -0800171/*
172 * Move reserved section indices SHN_LORESERVE..SHN_HIRESERVE out of
173 * the way to -256..-1, to avoid conflicting with real section
174 * indices.
175 */
176#define SPECIAL(i) ((i) - (SHN_HIRESERVE + 1))
177
178static inline int is_shndx_special(unsigned int i)
179{
180 return i != SHN_XINDEX && i >= SHN_LORESERVE && i <= SHN_HIRESERVE;
181}
182
183/* Accessor for sym->st_shndx, hides ugliness of "64k sections" */
184static inline unsigned int get_secindex(unsigned int shndx,
185 unsigned int sym_offs,
186 const Elf32_Word *symtab_shndx_start)
187{
188 if (is_shndx_special(shndx))
189 return SPECIAL(shndx);
190 if (shndx != SHN_XINDEX)
191 return shndx;
192 return r(&symtab_shndx_start[sym_offs]);
193}
194
David Daneya79f2482012-04-19 14:59:55 -0700195/* 32 bit and 64 bit are very similar */
196#include "sortextable.h"
197#define SORTEXTABLE_64
198#include "sortextable.h"
199
Heiko Carstenseb608fb2012-09-05 13:26:11 +0200200static int compare_relative_table(const void *a, const void *b)
David Daneyd59a1682012-04-24 11:23:14 -0700201{
202 int32_t av = (int32_t)r(a);
203 int32_t bv = (int32_t)r(b);
204
205 if (av < bv)
206 return -1;
207 if (av > bv)
208 return 1;
209 return 0;
210}
211
Heiko Carstenseb608fb2012-09-05 13:26:11 +0200212static void sort_relative_table(char *extab_image, int image_size)
David Daneyd59a1682012-04-24 11:23:14 -0700213{
214 int i;
215
216 /*
217 * Do the same thing the runtime sort does, first normalize to
218 * being relative to the start of the section.
219 */
220 i = 0;
221 while (i < image_size) {
222 uint32_t *loc = (uint32_t *)(extab_image + i);
223 w(r(loc) + i, loc);
224 i += 4;
225 }
226
Heiko Carstenseb608fb2012-09-05 13:26:11 +0200227 qsort(extab_image, image_size / 8, 8, compare_relative_table);
David Daneyd59a1682012-04-24 11:23:14 -0700228
229 /* Now denormalize. */
230 i = 0;
231 while (i < image_size) {
232 uint32_t *loc = (uint32_t *)(extab_image + i);
233 w(r(loc) - i, loc);
234 i += 4;
235 }
236}
David Daneya79f2482012-04-19 14:59:55 -0700237
238static void
239do_file(char const *const fname)
240{
David Daneyd59a1682012-04-24 11:23:14 -0700241 table_sort_t custom_sort;
242 Elf32_Ehdr *ehdr = mmap_file(fname);
David Daneya79f2482012-04-19 14:59:55 -0700243
244 ehdr_curr = ehdr;
David Daneya79f2482012-04-19 14:59:55 -0700245 switch (ehdr->e_ident[EI_DATA]) {
David Daneya79f2482012-04-19 14:59:55 -0700246 default:
247 fprintf(stderr, "unrecognized ELF data encoding %d: %s\n",
248 ehdr->e_ident[EI_DATA], fname);
249 fail_file();
250 break;
251 case ELFDATA2LSB:
David Daneyd59a1682012-04-24 11:23:14 -0700252 r = rle;
253 r2 = r2le;
254 r8 = r8le;
255 w = wle;
256 w2 = w2le;
257 w8 = w8le;
David Daneya79f2482012-04-19 14:59:55 -0700258 break;
259 case ELFDATA2MSB:
David Daneyd59a1682012-04-24 11:23:14 -0700260 r = rbe;
261 r2 = r2be;
262 r8 = r8be;
263 w = wbe;
264 w2 = w2be;
265 w8 = w8be;
David Daneya79f2482012-04-19 14:59:55 -0700266 break;
267 } /* end switch */
268 if (memcmp(ELFMAG, ehdr->e_ident, SELFMAG) != 0
David Daneyd59a1682012-04-24 11:23:14 -0700269 || r2(&ehdr->e_type) != ET_EXEC
David Daneya79f2482012-04-19 14:59:55 -0700270 || ehdr->e_ident[EI_VERSION] != EV_CURRENT) {
271 fprintf(stderr, "unrecognized ET_EXEC file %s\n", fname);
272 fail_file();
273 }
274
David Daneyd59a1682012-04-24 11:23:14 -0700275 custom_sort = NULL;
276 switch (r2(&ehdr->e_machine)) {
David Daneya79f2482012-04-19 14:59:55 -0700277 default:
278 fprintf(stderr, "unrecognized e_machine %d %s\n",
David Daneyd59a1682012-04-24 11:23:14 -0700279 r2(&ehdr->e_machine), fname);
David Daneya79f2482012-04-19 14:59:55 -0700280 fail_file();
281 break;
282 case EM_386:
David Daneya79f2482012-04-19 14:59:55 -0700283 case EM_X86_64:
Heiko Carstens3193a982012-07-24 14:51:34 +0200284 case EM_S390:
Heiko Carstenseb608fb2012-09-05 13:26:11 +0200285 custom_sort = sort_relative_table;
286 break;
Vineet Guptaf06d19e2013-11-15 12:08:05 +0530287 case EM_ARCOMPACT:
Vineet Guptab3210d12013-11-22 13:05:58 +0530288 case EM_ARCV2:
Stephen Boydee951c62012-10-29 19:19:34 +0100289 case EM_ARM:
Will Deaconadace892013-05-08 17:29:24 +0100290 case EM_AARCH64:
Michal Simek372c7202014-01-23 15:52:46 -0800291 case EM_MICROBLAZE:
David Daneyd59a1682012-04-24 11:23:14 -0700292 case EM_MIPS:
Max Filippov25df8192014-02-18 15:29:11 +0400293 case EM_XTENSA:
David Daneya79f2482012-04-19 14:59:55 -0700294 break;
295 } /* end switch */
296
297 switch (ehdr->e_ident[EI_CLASS]) {
298 default:
299 fprintf(stderr, "unrecognized ELF class %d %s\n",
300 ehdr->e_ident[EI_CLASS], fname);
301 fail_file();
302 break;
303 case ELFCLASS32:
David Daneyd59a1682012-04-24 11:23:14 -0700304 if (r2(&ehdr->e_ehsize) != sizeof(Elf32_Ehdr)
305 || r2(&ehdr->e_shentsize) != sizeof(Elf32_Shdr)) {
David Daneya79f2482012-04-19 14:59:55 -0700306 fprintf(stderr,
307 "unrecognized ET_EXEC file: %s\n", fname);
308 fail_file();
309 }
David Daneyd59a1682012-04-24 11:23:14 -0700310 do32(ehdr, fname, custom_sort);
David Daneya79f2482012-04-19 14:59:55 -0700311 break;
312 case ELFCLASS64: {
313 Elf64_Ehdr *const ghdr = (Elf64_Ehdr *)ehdr;
David Daneyd59a1682012-04-24 11:23:14 -0700314 if (r2(&ghdr->e_ehsize) != sizeof(Elf64_Ehdr)
315 || r2(&ghdr->e_shentsize) != sizeof(Elf64_Shdr)) {
David Daneya79f2482012-04-19 14:59:55 -0700316 fprintf(stderr,
317 "unrecognized ET_EXEC file: %s\n", fname);
318 fail_file();
319 }
David Daneyd59a1682012-04-24 11:23:14 -0700320 do64(ghdr, fname, custom_sort);
David Daneya79f2482012-04-19 14:59:55 -0700321 break;
322 }
323 } /* end switch */
324
325 cleanup();
326}
327
328int
329main(int argc, char *argv[])
330{
331 int n_error = 0; /* gcc-4.3.0 false positive complaint */
332 int i;
333
334 if (argc < 2) {
335 fprintf(stderr, "usage: sortextable vmlinux...\n");
336 return 0;
337 }
338
339 /* Process each file in turn, allowing deep failure. */
340 for (i = 1; i < argc; i++) {
341 char *file = argv[i];
342 int const sjval = setjmp(jmpenv);
343
344 switch (sjval) {
345 default:
346 fprintf(stderr, "internal error: %s\n", file);
347 exit(1);
348 break;
349 case SJ_SETJMP: /* normal sequence */
350 /* Avoid problems if early cleanup() */
351 fd_map = -1;
352 ehdr_curr = NULL;
353 mmap_failed = 1;
354 do_file(file);
355 break;
356 case SJ_FAIL: /* error in do_file or below */
357 ++n_error;
358 break;
359 case SJ_SUCCEED: /* premature success */
360 /* do nothing */
361 break;
362 } /* end switch */
363 }
364 return !!n_error;
365}