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a79f248b DD |
1 | /* |
2 | * sortextable.c: Sort the kernel's exception table | |
3 | * | |
d59a1683 | 4 | * Copyright 2011 - 2012 Cavium, Inc. |
a79f248b DD |
5 | * |
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 | ||
d59a1683 DD |
31 | #include <tools/be_byteshift.h> |
32 | #include <tools/le_byteshift.h> | |
33 | ||
adace895 WD |
34 | #ifndef EM_AARCH64 |
35 | #define EM_AARCH64 183 | |
36 | #endif | |
37 | ||
a79f248b DD |
38 | static int fd_map; /* File descriptor for file being modified. */ |
39 | static int mmap_failed; /* Boolean flag. */ | |
40 | static void *ehdr_curr; /* current ElfXX_Ehdr * for resource cleanup */ | |
41 | static struct stat sb; /* Remember .st_size, etc. */ | |
42 | static jmp_buf jmpenv; /* setjmp/longjmp per-file error escape */ | |
43 | ||
44 | /* setjmp() return values */ | |
45 | enum { | |
46 | SJ_SETJMP = 0, /* hardwired first return */ | |
47 | SJ_FAIL, | |
48 | SJ_SUCCEED | |
49 | }; | |
50 | ||
51 | /* Per-file resource cleanup when multiple files. */ | |
52 | static void | |
53 | cleanup(void) | |
54 | { | |
55 | if (!mmap_failed) | |
56 | munmap(ehdr_curr, sb.st_size); | |
57 | close(fd_map); | |
58 | } | |
59 | ||
60 | static void __attribute__((noreturn)) | |
61 | fail_file(void) | |
62 | { | |
63 | cleanup(); | |
64 | longjmp(jmpenv, SJ_FAIL); | |
65 | } | |
66 | ||
67 | static void __attribute__((noreturn)) | |
68 | succeed_file(void) | |
69 | { | |
70 | cleanup(); | |
71 | longjmp(jmpenv, SJ_SUCCEED); | |
72 | } | |
73 | ||
74 | ||
75 | /* | |
76 | * Get the whole file as a programming convenience in order to avoid | |
77 | * malloc+lseek+read+free of many pieces. If successful, then mmap | |
78 | * avoids copying unused pieces; else just read the whole file. | |
79 | * Open for both read and write. | |
80 | */ | |
81 | static void *mmap_file(char const *fname) | |
82 | { | |
83 | void *addr; | |
84 | ||
85 | fd_map = open(fname, O_RDWR); | |
86 | if (fd_map < 0 || fstat(fd_map, &sb) < 0) { | |
87 | perror(fname); | |
88 | fail_file(); | |
89 | } | |
90 | if (!S_ISREG(sb.st_mode)) { | |
91 | fprintf(stderr, "not a regular file: %s\n", fname); | |
92 | fail_file(); | |
93 | } | |
94 | addr = mmap(0, sb.st_size, PROT_READ|PROT_WRITE, MAP_SHARED, | |
95 | fd_map, 0); | |
96 | if (addr == MAP_FAILED) { | |
97 | mmap_failed = 1; | |
98 | fprintf(stderr, "Could not mmap file: %s\n", fname); | |
99 | fail_file(); | |
100 | } | |
101 | return addr; | |
102 | } | |
103 | ||
d59a1683 | 104 | static uint64_t r8be(const uint64_t *x) |
a79f248b | 105 | { |
d59a1683 | 106 | return get_unaligned_be64(x); |
a79f248b | 107 | } |
d59a1683 | 108 | static uint32_t rbe(const uint32_t *x) |
a79f248b | 109 | { |
d59a1683 | 110 | return get_unaligned_be32(x); |
a79f248b | 111 | } |
d59a1683 | 112 | static uint16_t r2be(const uint16_t *x) |
a79f248b | 113 | { |
d59a1683 | 114 | return get_unaligned_be16(x); |
a79f248b | 115 | } |
d59a1683 | 116 | static uint64_t r8le(const uint64_t *x) |
a79f248b | 117 | { |
d59a1683 | 118 | return get_unaligned_le64(x); |
a79f248b | 119 | } |
d59a1683 DD |
120 | static uint32_t rle(const uint32_t *x) |
121 | { | |
122 | return get_unaligned_le32(x); | |
123 | } | |
124 | static uint16_t r2le(const uint16_t *x) | |
a79f248b | 125 | { |
d59a1683 | 126 | return get_unaligned_le16(x); |
a79f248b DD |
127 | } |
128 | ||
d59a1683 DD |
129 | static void w8be(uint64_t val, uint64_t *x) |
130 | { | |
131 | put_unaligned_be64(val, x); | |
132 | } | |
133 | static void wbe(uint32_t val, uint32_t *x) | |
134 | { | |
135 | put_unaligned_be32(val, x); | |
136 | } | |
137 | static void w2be(uint16_t val, uint16_t *x) | |
138 | { | |
139 | put_unaligned_be16(val, x); | |
140 | } | |
141 | static void w8le(uint64_t val, uint64_t *x) | |
142 | { | |
143 | put_unaligned_le64(val, x); | |
144 | } | |
145 | static void wle(uint32_t val, uint32_t *x) | |
146 | { | |
147 | put_unaligned_le32(val, x); | |
148 | } | |
149 | static void w2le(uint16_t val, uint16_t *x) | |
a79f248b | 150 | { |
d59a1683 | 151 | put_unaligned_le16(val, x); |
a79f248b DD |
152 | } |
153 | ||
d59a1683 DD |
154 | static uint64_t (*r8)(const uint64_t *); |
155 | static uint32_t (*r)(const uint32_t *); | |
156 | static uint16_t (*r2)(const uint16_t *); | |
157 | static void (*w8)(uint64_t, uint64_t *); | |
158 | static void (*w)(uint32_t, uint32_t *); | |
159 | static void (*w2)(uint16_t, uint16_t *); | |
a79f248b | 160 | |
d59a1683 | 161 | typedef void (*table_sort_t)(char *, int); |
a79f248b DD |
162 | |
163 | /* 32 bit and 64 bit are very similar */ | |
164 | #include "sortextable.h" | |
165 | #define SORTEXTABLE_64 | |
166 | #include "sortextable.h" | |
167 | ||
eb608fb3 | 168 | static int compare_relative_table(const void *a, const void *b) |
d59a1683 DD |
169 | { |
170 | int32_t av = (int32_t)r(a); | |
171 | int32_t bv = (int32_t)r(b); | |
172 | ||
173 | if (av < bv) | |
174 | return -1; | |
175 | if (av > bv) | |
176 | return 1; | |
177 | return 0; | |
178 | } | |
179 | ||
eb608fb3 | 180 | static void sort_relative_table(char *extab_image, int image_size) |
d59a1683 DD |
181 | { |
182 | int i; | |
183 | ||
184 | /* | |
185 | * Do the same thing the runtime sort does, first normalize to | |
186 | * being relative to the start of the section. | |
187 | */ | |
188 | i = 0; | |
189 | while (i < image_size) { | |
190 | uint32_t *loc = (uint32_t *)(extab_image + i); | |
191 | w(r(loc) + i, loc); | |
192 | i += 4; | |
193 | } | |
194 | ||
eb608fb3 | 195 | qsort(extab_image, image_size / 8, 8, compare_relative_table); |
d59a1683 DD |
196 | |
197 | /* Now denormalize. */ | |
198 | i = 0; | |
199 | while (i < image_size) { | |
200 | uint32_t *loc = (uint32_t *)(extab_image + i); | |
201 | w(r(loc) - i, loc); | |
202 | i += 4; | |
203 | } | |
204 | } | |
a79f248b DD |
205 | |
206 | static void | |
207 | do_file(char const *const fname) | |
208 | { | |
d59a1683 DD |
209 | table_sort_t custom_sort; |
210 | Elf32_Ehdr *ehdr = mmap_file(fname); | |
a79f248b DD |
211 | |
212 | ehdr_curr = ehdr; | |
a79f248b | 213 | switch (ehdr->e_ident[EI_DATA]) { |
a79f248b DD |
214 | default: |
215 | fprintf(stderr, "unrecognized ELF data encoding %d: %s\n", | |
216 | ehdr->e_ident[EI_DATA], fname); | |
217 | fail_file(); | |
218 | break; | |
219 | case ELFDATA2LSB: | |
d59a1683 DD |
220 | r = rle; |
221 | r2 = r2le; | |
222 | r8 = r8le; | |
223 | w = wle; | |
224 | w2 = w2le; | |
225 | w8 = w8le; | |
a79f248b DD |
226 | break; |
227 | case ELFDATA2MSB: | |
d59a1683 DD |
228 | r = rbe; |
229 | r2 = r2be; | |
230 | r8 = r8be; | |
231 | w = wbe; | |
232 | w2 = w2be; | |
233 | w8 = w8be; | |
a79f248b DD |
234 | break; |
235 | } /* end switch */ | |
236 | if (memcmp(ELFMAG, ehdr->e_ident, SELFMAG) != 0 | |
d59a1683 | 237 | || r2(&ehdr->e_type) != ET_EXEC |
a79f248b DD |
238 | || ehdr->e_ident[EI_VERSION] != EV_CURRENT) { |
239 | fprintf(stderr, "unrecognized ET_EXEC file %s\n", fname); | |
240 | fail_file(); | |
241 | } | |
242 | ||
d59a1683 DD |
243 | custom_sort = NULL; |
244 | switch (r2(&ehdr->e_machine)) { | |
a79f248b DD |
245 | default: |
246 | fprintf(stderr, "unrecognized e_machine %d %s\n", | |
d59a1683 | 247 | r2(&ehdr->e_machine), fname); |
a79f248b DD |
248 | fail_file(); |
249 | break; | |
250 | case EM_386: | |
a79f248b | 251 | case EM_X86_64: |
3193a98d | 252 | case EM_S390: |
eb608fb3 HC |
253 | custom_sort = sort_relative_table; |
254 | break; | |
ee951c63 | 255 | case EM_ARM: |
adace895 | 256 | case EM_AARCH64: |
d59a1683 | 257 | case EM_MIPS: |
a79f248b DD |
258 | break; |
259 | } /* end switch */ | |
260 | ||
261 | switch (ehdr->e_ident[EI_CLASS]) { | |
262 | default: | |
263 | fprintf(stderr, "unrecognized ELF class %d %s\n", | |
264 | ehdr->e_ident[EI_CLASS], fname); | |
265 | fail_file(); | |
266 | break; | |
267 | case ELFCLASS32: | |
d59a1683 DD |
268 | if (r2(&ehdr->e_ehsize) != sizeof(Elf32_Ehdr) |
269 | || r2(&ehdr->e_shentsize) != sizeof(Elf32_Shdr)) { | |
a79f248b DD |
270 | fprintf(stderr, |
271 | "unrecognized ET_EXEC file: %s\n", fname); | |
272 | fail_file(); | |
273 | } | |
d59a1683 | 274 | do32(ehdr, fname, custom_sort); |
a79f248b DD |
275 | break; |
276 | case ELFCLASS64: { | |
277 | Elf64_Ehdr *const ghdr = (Elf64_Ehdr *)ehdr; | |
d59a1683 DD |
278 | if (r2(&ghdr->e_ehsize) != sizeof(Elf64_Ehdr) |
279 | || r2(&ghdr->e_shentsize) != sizeof(Elf64_Shdr)) { | |
a79f248b DD |
280 | fprintf(stderr, |
281 | "unrecognized ET_EXEC file: %s\n", fname); | |
282 | fail_file(); | |
283 | } | |
d59a1683 | 284 | do64(ghdr, fname, custom_sort); |
a79f248b DD |
285 | break; |
286 | } | |
287 | } /* end switch */ | |
288 | ||
289 | cleanup(); | |
290 | } | |
291 | ||
292 | int | |
293 | main(int argc, char *argv[]) | |
294 | { | |
295 | int n_error = 0; /* gcc-4.3.0 false positive complaint */ | |
296 | int i; | |
297 | ||
298 | if (argc < 2) { | |
299 | fprintf(stderr, "usage: sortextable vmlinux...\n"); | |
300 | return 0; | |
301 | } | |
302 | ||
303 | /* Process each file in turn, allowing deep failure. */ | |
304 | for (i = 1; i < argc; i++) { | |
305 | char *file = argv[i]; | |
306 | int const sjval = setjmp(jmpenv); | |
307 | ||
308 | switch (sjval) { | |
309 | default: | |
310 | fprintf(stderr, "internal error: %s\n", file); | |
311 | exit(1); | |
312 | break; | |
313 | case SJ_SETJMP: /* normal sequence */ | |
314 | /* Avoid problems if early cleanup() */ | |
315 | fd_map = -1; | |
316 | ehdr_curr = NULL; | |
317 | mmap_failed = 1; | |
318 | do_file(file); | |
319 | break; | |
320 | case SJ_FAIL: /* error in do_file or below */ | |
321 | ++n_error; | |
322 | break; | |
323 | case SJ_SUCCEED: /* premature success */ | |
324 | /* do nothing */ | |
325 | break; | |
326 | } /* end switch */ | |
327 | } | |
328 | return !!n_error; | |
329 | } |