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1 | /* | |
2 | * sortextable.c: Sort the kernel's exception table | |
3 | * | |
4 | * Copyright 2011 - 2012 Cavium, Inc. | |
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 | ||
31 | #include <tools/be_byteshift.h> | |
32 | #include <tools/le_byteshift.h> | |
33 | ||
34 | #ifndef EM_ARCOMPACT | |
35 | #define EM_ARCOMPACT 93 | |
36 | #endif | |
37 | ||
38 | #ifndef EM_XTENSA | |
39 | #define EM_XTENSA 94 | |
40 | #endif | |
41 | ||
42 | #ifndef EM_AARCH64 | |
43 | #define EM_AARCH64 183 | |
44 | #endif | |
45 | ||
46 | #ifndef EM_MICROBLAZE | |
47 | #define EM_MICROBLAZE 189 | |
48 | #endif | |
49 | ||
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 */ | |
55 | ||
56 | /* setjmp() return values */ | |
57 | enum { | |
58 | SJ_SETJMP = 0, /* hardwired first return */ | |
59 | SJ_FAIL, | |
60 | SJ_SUCCEED | |
61 | }; | |
62 | ||
63 | /* Per-file resource cleanup when multiple files. */ | |
64 | static void | |
65 | cleanup(void) | |
66 | { | |
67 | if (!mmap_failed) | |
68 | munmap(ehdr_curr, sb.st_size); | |
69 | close(fd_map); | |
70 | } | |
71 | ||
72 | static void __attribute__((noreturn)) | |
73 | fail_file(void) | |
74 | { | |
75 | cleanup(); | |
76 | longjmp(jmpenv, SJ_FAIL); | |
77 | } | |
78 | ||
79 | /* | |
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. | |
84 | */ | |
85 | static void *mmap_file(char const *fname) | |
86 | { | |
87 | void *addr; | |
88 | ||
89 | fd_map = open(fname, O_RDWR); | |
90 | if (fd_map < 0 || fstat(fd_map, &sb) < 0) { | |
91 | perror(fname); | |
92 | fail_file(); | |
93 | } | |
94 | if (!S_ISREG(sb.st_mode)) { | |
95 | fprintf(stderr, "not a regular file: %s\n", fname); | |
96 | fail_file(); | |
97 | } | |
98 | addr = mmap(0, sb.st_size, PROT_READ|PROT_WRITE, MAP_SHARED, | |
99 | fd_map, 0); | |
100 | if (addr == MAP_FAILED) { | |
101 | mmap_failed = 1; | |
102 | fprintf(stderr, "Could not mmap file: %s\n", fname); | |
103 | fail_file(); | |
104 | } | |
105 | return addr; | |
106 | } | |
107 | ||
108 | static uint64_t r8be(const uint64_t *x) | |
109 | { | |
110 | return get_unaligned_be64(x); | |
111 | } | |
112 | static uint32_t rbe(const uint32_t *x) | |
113 | { | |
114 | return get_unaligned_be32(x); | |
115 | } | |
116 | static uint16_t r2be(const uint16_t *x) | |
117 | { | |
118 | return get_unaligned_be16(x); | |
119 | } | |
120 | static uint64_t r8le(const uint64_t *x) | |
121 | { | |
122 | return get_unaligned_le64(x); | |
123 | } | |
124 | static uint32_t rle(const uint32_t *x) | |
125 | { | |
126 | return get_unaligned_le32(x); | |
127 | } | |
128 | static uint16_t r2le(const uint16_t *x) | |
129 | { | |
130 | return get_unaligned_le16(x); | |
131 | } | |
132 | ||
133 | static void w8be(uint64_t val, uint64_t *x) | |
134 | { | |
135 | put_unaligned_be64(val, x); | |
136 | } | |
137 | static void wbe(uint32_t val, uint32_t *x) | |
138 | { | |
139 | put_unaligned_be32(val, x); | |
140 | } | |
141 | static void w2be(uint16_t val, uint16_t *x) | |
142 | { | |
143 | put_unaligned_be16(val, x); | |
144 | } | |
145 | static void w8le(uint64_t val, uint64_t *x) | |
146 | { | |
147 | put_unaligned_le64(val, x); | |
148 | } | |
149 | static void wle(uint32_t val, uint32_t *x) | |
150 | { | |
151 | put_unaligned_le32(val, x); | |
152 | } | |
153 | static void w2le(uint16_t val, uint16_t *x) | |
154 | { | |
155 | put_unaligned_le16(val, x); | |
156 | } | |
157 | ||
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 *); | |
164 | ||
165 | typedef void (*table_sort_t)(char *, int); | |
166 | ||
167 | /* | |
168 | * Move reserved section indices SHN_LORESERVE..SHN_HIRESERVE out of | |
169 | * the way to -256..-1, to avoid conflicting with real section | |
170 | * indices. | |
171 | */ | |
172 | #define SPECIAL(i) ((i) - (SHN_HIRESERVE + 1)) | |
173 | ||
174 | static inline int is_shndx_special(unsigned int i) | |
175 | { | |
176 | return i != SHN_XINDEX && i >= SHN_LORESERVE && i <= SHN_HIRESERVE; | |
177 | } | |
178 | ||
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) | |
183 | { | |
184 | if (is_shndx_special(shndx)) | |
185 | return SPECIAL(shndx); | |
186 | if (shndx != SHN_XINDEX) | |
187 | return shndx; | |
188 | return r(&symtab_shndx_start[sym_offs]); | |
189 | } | |
190 | ||
191 | /* 32 bit and 64 bit are very similar */ | |
192 | #include "sortextable.h" | |
193 | #define SORTEXTABLE_64 | |
194 | #include "sortextable.h" | |
195 | ||
196 | static int compare_relative_table(const void *a, const void *b) | |
197 | { | |
198 | int32_t av = (int32_t)r(a); | |
199 | int32_t bv = (int32_t)r(b); | |
200 | ||
201 | if (av < bv) | |
202 | return -1; | |
203 | if (av > bv) | |
204 | return 1; | |
205 | return 0; | |
206 | } | |
207 | ||
208 | static void sort_relative_table(char *extab_image, int image_size) | |
209 | { | |
210 | int i; | |
211 | ||
212 | /* | |
213 | * Do the same thing the runtime sort does, first normalize to | |
214 | * being relative to the start of the section. | |
215 | */ | |
216 | i = 0; | |
217 | while (i < image_size) { | |
218 | uint32_t *loc = (uint32_t *)(extab_image + i); | |
219 | w(r(loc) + i, loc); | |
220 | i += 4; | |
221 | } | |
222 | ||
223 | qsort(extab_image, image_size / 8, 8, compare_relative_table); | |
224 | ||
225 | /* Now denormalize. */ | |
226 | i = 0; | |
227 | while (i < image_size) { | |
228 | uint32_t *loc = (uint32_t *)(extab_image + i); | |
229 | w(r(loc) - i, loc); | |
230 | i += 4; | |
231 | } | |
232 | } | |
233 | ||
234 | static void | |
235 | do_file(char const *const fname) | |
236 | { | |
237 | table_sort_t custom_sort; | |
238 | Elf32_Ehdr *ehdr = mmap_file(fname); | |
239 | ||
240 | ehdr_curr = ehdr; | |
241 | switch (ehdr->e_ident[EI_DATA]) { | |
242 | default: | |
243 | fprintf(stderr, "unrecognized ELF data encoding %d: %s\n", | |
244 | ehdr->e_ident[EI_DATA], fname); | |
245 | fail_file(); | |
246 | break; | |
247 | case ELFDATA2LSB: | |
248 | r = rle; | |
249 | r2 = r2le; | |
250 | r8 = r8le; | |
251 | w = wle; | |
252 | w2 = w2le; | |
253 | w8 = w8le; | |
254 | break; | |
255 | case ELFDATA2MSB: | |
256 | r = rbe; | |
257 | r2 = r2be; | |
258 | r8 = r8be; | |
259 | w = wbe; | |
260 | w2 = w2be; | |
261 | w8 = w8be; | |
262 | break; | |
263 | } /* end switch */ | |
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); | |
268 | fail_file(); | |
269 | } | |
270 | ||
271 | custom_sort = NULL; | |
272 | switch (r2(&ehdr->e_machine)) { | |
273 | default: | |
274 | fprintf(stderr, "unrecognized e_machine %d %s\n", | |
275 | r2(&ehdr->e_machine), fname); | |
276 | fail_file(); | |
277 | break; | |
278 | case EM_386: | |
279 | case EM_X86_64: | |
280 | case EM_S390: | |
281 | custom_sort = sort_relative_table; | |
282 | break; | |
283 | case EM_ARCOMPACT: | |
284 | case EM_ARM: | |
285 | case EM_AARCH64: | |
286 | case EM_MICROBLAZE: | |
287 | case EM_MIPS: | |
288 | case EM_XTENSA: | |
289 | break; | |
290 | } /* end switch */ | |
291 | ||
292 | switch (ehdr->e_ident[EI_CLASS]) { | |
293 | default: | |
294 | fprintf(stderr, "unrecognized ELF class %d %s\n", | |
295 | ehdr->e_ident[EI_CLASS], fname); | |
296 | fail_file(); | |
297 | break; | |
298 | case ELFCLASS32: | |
299 | if (r2(&ehdr->e_ehsize) != sizeof(Elf32_Ehdr) | |
300 | || r2(&ehdr->e_shentsize) != sizeof(Elf32_Shdr)) { | |
301 | fprintf(stderr, | |
302 | "unrecognized ET_EXEC file: %s\n", fname); | |
303 | fail_file(); | |
304 | } | |
305 | do32(ehdr, fname, custom_sort); | |
306 | break; | |
307 | case ELFCLASS64: { | |
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)) { | |
311 | fprintf(stderr, | |
312 | "unrecognized ET_EXEC file: %s\n", fname); | |
313 | fail_file(); | |
314 | } | |
315 | do64(ghdr, fname, custom_sort); | |
316 | break; | |
317 | } | |
318 | } /* end switch */ | |
319 | ||
320 | cleanup(); | |
321 | } | |
322 | ||
323 | int | |
324 | main(int argc, char *argv[]) | |
325 | { | |
326 | int n_error = 0; /* gcc-4.3.0 false positive complaint */ | |
327 | int i; | |
328 | ||
329 | if (argc < 2) { | |
330 | fprintf(stderr, "usage: sortextable vmlinux...\n"); | |
331 | return 0; | |
332 | } | |
333 | ||
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); | |
338 | ||
339 | switch (sjval) { | |
340 | default: | |
341 | fprintf(stderr, "internal error: %s\n", file); | |
342 | exit(1); | |
343 | break; | |
344 | case SJ_SETJMP: /* normal sequence */ | |
345 | /* Avoid problems if early cleanup() */ | |
346 | fd_map = -1; | |
347 | ehdr_curr = NULL; | |
348 | mmap_failed = 1; | |
349 | do_file(file); | |
350 | break; | |
351 | case SJ_FAIL: /* error in do_file or below */ | |
352 | ++n_error; | |
353 | break; | |
354 | case SJ_SUCCEED: /* premature success */ | |
355 | /* do nothing */ | |
356 | break; | |
357 | } /* end switch */ | |
358 | } | |
359 | return !!n_error; | |
360 | } |