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-rw-r--r--scripts/sortextable.c322
1 files changed, 322 insertions, 0 deletions
diff --git a/scripts/sortextable.c b/scripts/sortextable.c
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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
34static int fd_map; /* File descriptor for file being modified. */
35static int mmap_failed; /* Boolean flag. */
36static void *ehdr_curr; /* current ElfXX_Ehdr * for resource cleanup */
37static struct stat sb; /* Remember .st_size, etc. */
38static jmp_buf jmpenv; /* setjmp/longjmp per-file error escape */
39
40/* setjmp() return values */
41enum {
42 SJ_SETJMP = 0, /* hardwired first return */
43 SJ_FAIL,
44 SJ_SUCCEED
45};
46
47/* Per-file resource cleanup when multiple files. */
48static void
49cleanup(void)
50{
51 if (!mmap_failed)
52 munmap(ehdr_curr, sb.st_size);
53 close(fd_map);
54}
55
56static void __attribute__((noreturn))
57fail_file(void)
58{
59 cleanup();
60 longjmp(jmpenv, SJ_FAIL);
61}
62
63static void __attribute__((noreturn))
64succeed_file(void)
65{
66 cleanup();
67 longjmp(jmpenv, SJ_SUCCEED);
68}
69
70
71/*
72 * Get the whole file as a programming convenience in order to avoid
73 * malloc+lseek+read+free of many pieces. If successful, then mmap
74 * avoids copying unused pieces; else just read the whole file.
75 * Open for both read and write.
76 */
77static void *mmap_file(char const *fname)
78{
79 void *addr;
80
81 fd_map = open(fname, O_RDWR);
82 if (fd_map < 0 || fstat(fd_map, &sb) < 0) {
83 perror(fname);
84 fail_file();
85 }
86 if (!S_ISREG(sb.st_mode)) {
87 fprintf(stderr, "not a regular file: %s\n", fname);
88 fail_file();
89 }
90 addr = mmap(0, sb.st_size, PROT_READ|PROT_WRITE, MAP_SHARED,
91 fd_map, 0);
92 if (addr == MAP_FAILED) {
93 mmap_failed = 1;
94 fprintf(stderr, "Could not mmap file: %s\n", fname);
95 fail_file();
96 }
97 return addr;
98}
99
100static uint64_t r8be(const uint64_t *x)
101{
102 return get_unaligned_be64(x);
103}
104static uint32_t rbe(const uint32_t *x)
105{
106 return get_unaligned_be32(x);
107}
108static uint16_t r2be(const uint16_t *x)
109{
110 return get_unaligned_be16(x);
111}
112static uint64_t r8le(const uint64_t *x)
113{
114 return get_unaligned_le64(x);
115}
116static uint32_t rle(const uint32_t *x)
117{
118 return get_unaligned_le32(x);
119}
120static uint16_t r2le(const uint16_t *x)
121{
122 return get_unaligned_le16(x);
123}
124
125static void w8be(uint64_t val, uint64_t *x)
126{
127 put_unaligned_be64(val, x);
128}
129static void wbe(uint32_t val, uint32_t *x)
130{
131 put_unaligned_be32(val, x);
132}
133static void w2be(uint16_t val, uint16_t *x)
134{
135 put_unaligned_be16(val, x);
136}
137static void w8le(uint64_t val, uint64_t *x)
138{
139 put_unaligned_le64(val, x);
140}
141static void wle(uint32_t val, uint32_t *x)
142{
143 put_unaligned_le32(val, x);
144}
145static void w2le(uint16_t val, uint16_t *x)
146{
147 put_unaligned_le16(val, x);
148}
149
150static uint64_t (*r8)(const uint64_t *);
151static uint32_t (*r)(const uint32_t *);
152static uint16_t (*r2)(const uint16_t *);
153static void (*w8)(uint64_t, uint64_t *);
154static void (*w)(uint32_t, uint32_t *);
155static void (*w2)(uint16_t, uint16_t *);
156
157typedef void (*table_sort_t)(char *, int);
158
159/* 32 bit and 64 bit are very similar */
160#include "sortextable.h"
161#define SORTEXTABLE_64
162#include "sortextable.h"
163
164static int compare_x86_table(const void *a, const void *b)
165{
166 int32_t av = (int32_t)r(a);
167 int32_t bv = (int32_t)r(b);
168
169 if (av < bv)
170 return -1;
171 if (av > bv)
172 return 1;
173 return 0;
174}
175
176static void sort_x86_table(char *extab_image, int image_size)
177{
178 int i;
179
180 /*
181 * Do the same thing the runtime sort does, first normalize to
182 * being relative to the start of the section.
183 */
184 i = 0;
185 while (i < image_size) {
186 uint32_t *loc = (uint32_t *)(extab_image + i);
187 w(r(loc) + i, loc);
188 i += 4;
189 }
190
191 qsort(extab_image, image_size / 8, 8, compare_x86_table);
192
193 /* Now denormalize. */
194 i = 0;
195 while (i < image_size) {
196 uint32_t *loc = (uint32_t *)(extab_image + i);
197 w(r(loc) - i, loc);
198 i += 4;
199 }
200}
201
202static void
203do_file(char const *const fname)
204{
205 table_sort_t custom_sort;
206 Elf32_Ehdr *ehdr = mmap_file(fname);
207
208 ehdr_curr = ehdr;
209 switch (ehdr->e_ident[EI_DATA]) {
210 default:
211 fprintf(stderr, "unrecognized ELF data encoding %d: %s\n",
212 ehdr->e_ident[EI_DATA], fname);
213 fail_file();
214 break;
215 case ELFDATA2LSB:
216 r = rle;
217 r2 = r2le;
218 r8 = r8le;
219 w = wle;
220 w2 = w2le;
221 w8 = w8le;
222 break;
223 case ELFDATA2MSB:
224 r = rbe;
225 r2 = r2be;
226 r8 = r8be;
227 w = wbe;
228 w2 = w2be;
229 w8 = w8be;
230 break;
231 } /* end switch */
232 if (memcmp(ELFMAG, ehdr->e_ident, SELFMAG) != 0
233 || r2(&ehdr->e_type) != ET_EXEC
234 || ehdr->e_ident[EI_VERSION] != EV_CURRENT) {
235 fprintf(stderr, "unrecognized ET_EXEC file %s\n", fname);
236 fail_file();
237 }
238
239 custom_sort = NULL;
240 switch (r2(&ehdr->e_machine)) {
241 default:
242 fprintf(stderr, "unrecognized e_machine %d %s\n",
243 r2(&ehdr->e_machine), fname);
244 fail_file();
245 break;
246 case EM_386:
247 case EM_X86_64:
248 custom_sort = sort_x86_table;
249 break;
250 case EM_MIPS:
251 break;
252 } /* end switch */
253
254 switch (ehdr->e_ident[EI_CLASS]) {
255 default:
256 fprintf(stderr, "unrecognized ELF class %d %s\n",
257 ehdr->e_ident[EI_CLASS], fname);
258 fail_file();
259 break;
260 case ELFCLASS32:
261 if (r2(&ehdr->e_ehsize) != sizeof(Elf32_Ehdr)
262 || r2(&ehdr->e_shentsize) != sizeof(Elf32_Shdr)) {
263 fprintf(stderr,
264 "unrecognized ET_EXEC file: %s\n", fname);
265 fail_file();
266 }
267 do32(ehdr, fname, custom_sort);
268 break;
269 case ELFCLASS64: {
270 Elf64_Ehdr *const ghdr = (Elf64_Ehdr *)ehdr;
271 if (r2(&ghdr->e_ehsize) != sizeof(Elf64_Ehdr)
272 || r2(&ghdr->e_shentsize) != sizeof(Elf64_Shdr)) {
273 fprintf(stderr,
274 "unrecognized ET_EXEC file: %s\n", fname);
275 fail_file();
276 }
277 do64(ghdr, fname, custom_sort);
278 break;
279 }
280 } /* end switch */
281
282 cleanup();
283}
284
285int
286main(int argc, char *argv[])
287{
288 int n_error = 0; /* gcc-4.3.0 false positive complaint */
289 int i;
290
291 if (argc < 2) {
292 fprintf(stderr, "usage: sortextable vmlinux...\n");
293 return 0;
294 }
295
296 /* Process each file in turn, allowing deep failure. */
297 for (i = 1; i < argc; i++) {
298 char *file = argv[i];
299 int const sjval = setjmp(jmpenv);
300
301 switch (sjval) {
302 default:
303 fprintf(stderr, "internal error: %s\n", file);
304 exit(1);
305 break;
306 case SJ_SETJMP: /* normal sequence */
307 /* Avoid problems if early cleanup() */
308 fd_map = -1;
309 ehdr_curr = NULL;
310 mmap_failed = 1;
311 do_file(file);
312 break;
313 case SJ_FAIL: /* error in do_file or below */
314 ++n_error;
315 break;
316 case SJ_SUCCEED: /* premature success */
317 /* do nothing */
318 break;
319 } /* end switch */
320 }
321 return !!n_error;
322}
generated by cgit v1.2.2 (git 2.25.0) at 2025-10-01 06:49:06 -0400