blob: 0c2fae8d929df154ff0324994df5f5341f2d4c52 [file] [log] [blame]
H. Peter Anvinc889ba82013-04-16 16:02:58 -07001/* This is included from relocs_32/64.c */
H. Peter Anvin873b5272009-12-14 13:55:20 -08002
Kees Cookbf116552013-04-12 13:13:42 -07003#define ElfW(type) _ElfW(ELF_BITS, type)
4#define _ElfW(bits, type) __ElfW(bits, type)
5#define __ElfW(bits, type) Elf##bits##_##type
6
Kees Cook946166a2013-04-12 13:13:44 -07007#define Elf_Addr ElfW(Addr)
Kees Cookbf116552013-04-12 13:13:42 -07008#define Elf_Ehdr ElfW(Ehdr)
9#define Elf_Phdr ElfW(Phdr)
10#define Elf_Shdr ElfW(Shdr)
11#define Elf_Sym ElfW(Sym)
12
Kees Cookbf116552013-04-12 13:13:42 -070013static Elf_Ehdr ehdr;
Kees Cook5d442e62013-04-12 13:13:43 -070014
15struct relocs {
16 uint32_t *offset;
17 unsigned long count;
18 unsigned long size;
19};
20
21static struct relocs relocs16;
22static struct relocs relocs32;
Jan Beulich6d24c5f2014-11-04 08:50:18 +000023#if ELF_BITS == 64
24static struct relocs relocs32neg;
Kees Cook946166a2013-04-12 13:13:44 -070025static struct relocs relocs64;
Jan Beulich6d24c5f2014-11-04 08:50:18 +000026#endif
Eric W. Biederman968de4f2006-12-07 02:14:04 +010027
H. Peter Anvin908ec7a2008-06-30 14:42:18 -070028struct section {
Kees Cookbf116552013-04-12 13:13:42 -070029 Elf_Shdr shdr;
H. Peter Anvin908ec7a2008-06-30 14:42:18 -070030 struct section *link;
Kees Cookbf116552013-04-12 13:13:42 -070031 Elf_Sym *symtab;
32 Elf_Rel *reltab;
H. Peter Anvin908ec7a2008-06-30 14:42:18 -070033 char *strtab;
34};
35static struct section *secs;
36
H. Peter Anvin6520fe52012-05-08 21:22:24 +030037static const char * const sym_regex_kernel[S_NSYMTYPES] = {
Vivek Goyal6a044b32006-12-07 02:14:04 +010038/*
39 * Following symbols have been audited. There values are constant and do
40 * not change if bzImage is loaded at a different physical address than
41 * the address for which it has been compiled. Don't warn user about
42 * absolute relocations present w.r.t these symbols.
43 */
H. Peter Anvin6520fe52012-05-08 21:22:24 +030044 [S_ABS] =
H. Peter Anvin873b5272009-12-14 13:55:20 -080045 "^(xen_irq_disable_direct_reloc$|"
46 "xen_save_fl_direct_reloc$|"
47 "VDSO|"
H. Peter Anvin6520fe52012-05-08 21:22:24 +030048 "__crc_)",
Vivek Goyal6a044b32006-12-07 02:14:04 +010049
H. Peter Anvin873b5272009-12-14 13:55:20 -080050/*
51 * These symbols are known to be relative, even if the linker marks them
52 * as absolute (typically defined outside any section in the linker script.)
53 */
H. Peter Anvin6520fe52012-05-08 21:22:24 +030054 [S_REL] =
H. Peter Anvina3e854d2012-05-18 00:24:09 -070055 "^(__init_(begin|end)|"
56 "__x86_cpu_dev_(start|end)|"
57 "(__parainstructions|__alt_instructions)(|_end)|"
58 "(__iommu_table|__apicdrivers|__smp_locks)(|_end)|"
H. Peter Anvinfd952812012-05-23 14:02:34 -070059 "__(start|end)_pci_.*|"
60 "__(start|end)_builtin_fw|"
61 "__(start|stop)___ksymtab(|_gpl|_unused|_unused_gpl|_gpl_future)|"
62 "__(start|stop)___kcrctab(|_gpl|_unused|_unused_gpl|_gpl_future)|"
63 "__(start|stop)___param|"
64 "__(start|stop)___modver|"
65 "__(start|stop)___bug_table|"
66 "__tracedata_(start|end)|"
67 "__(start|stop)_notes|"
68 "__end_rodata|"
69 "__initramfs_start|"
H. Peter Anvinea17e742012-05-24 07:01:38 -070070 "(jiffies|jiffies_64)|"
H. Peter Anvinc889ba82013-04-16 16:02:58 -070071#if ELF_BITS == 64
Kees Cook946166a2013-04-12 13:13:44 -070072 "__per_cpu_load|"
73 "init_per_cpu__.*|"
74 "__end_rodata_hpage_align|"
75#endif
Stefani Seiboldd2312e32014-03-17 23:22:01 +010076 "__vvar_page|"
H. Peter Anvina3e854d2012-05-18 00:24:09 -070077 "_end)$"
H. Peter Anvin6520fe52012-05-08 21:22:24 +030078};
79
80
81static const char * const sym_regex_realmode[S_NSYMTYPES] = {
82/*
H. Peter Anvin2a6de312012-05-08 21:22:31 +030083 * These symbols are known to be relative, even if the linker marks them
84 * as absolute (typically defined outside any section in the linker script.)
85 */
86 [S_REL] =
87 "^pa_",
88
89/*
H. Peter Anvin6520fe52012-05-08 21:22:24 +030090 * These are 16-bit segment symbols when compiling 16-bit code.
91 */
92 [S_SEG] =
93 "^real_mode_seg$",
94
95/*
96 * These are offsets belonging to segments, as opposed to linear addresses,
97 * when compiling 16-bit code.
98 */
99 [S_LIN] =
100 "^pa_",
101};
102
103static const char * const *sym_regex;
104
105static regex_t sym_regex_c[S_NSYMTYPES];
106static int is_reloc(enum symtype type, const char *sym_name)
H. Peter Anvin873b5272009-12-14 13:55:20 -0800107{
H. Peter Anvin6520fe52012-05-08 21:22:24 +0300108 return sym_regex[type] &&
109 !regexec(&sym_regex_c[type], sym_name, 0, NULL, 0);
H. Peter Anvin873b5272009-12-14 13:55:20 -0800110}
111
H. Peter Anvin6520fe52012-05-08 21:22:24 +0300112static void regex_init(int use_real_mode)
H. Peter Anvin873b5272009-12-14 13:55:20 -0800113{
114 char errbuf[128];
115 int err;
H. Peter Anvin6520fe52012-05-08 21:22:24 +0300116 int i;
H. Peter Anvin873b5272009-12-14 13:55:20 -0800117
H. Peter Anvin6520fe52012-05-08 21:22:24 +0300118 if (use_real_mode)
119 sym_regex = sym_regex_realmode;
120 else
121 sym_regex = sym_regex_kernel;
122
123 for (i = 0; i < S_NSYMTYPES; i++) {
124 if (!sym_regex[i])
125 continue;
126
127 err = regcomp(&sym_regex_c[i], sym_regex[i],
128 REG_EXTENDED|REG_NOSUB);
129
130 if (err) {
131 regerror(err, &sym_regex_c[i], errbuf, sizeof errbuf);
132 die("%s", errbuf);
133 }
H. Peter Anvin873b5272009-12-14 13:55:20 -0800134 }
Vivek Goyal6a044b32006-12-07 02:14:04 +0100135}
136
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100137static const char *sym_type(unsigned type)
138{
139 static const char *type_name[] = {
140#define SYM_TYPE(X) [X] = #X
141 SYM_TYPE(STT_NOTYPE),
142 SYM_TYPE(STT_OBJECT),
143 SYM_TYPE(STT_FUNC),
144 SYM_TYPE(STT_SECTION),
145 SYM_TYPE(STT_FILE),
146 SYM_TYPE(STT_COMMON),
147 SYM_TYPE(STT_TLS),
148#undef SYM_TYPE
149 };
150 const char *name = "unknown sym type name";
Robert P. J. Dayca820182007-02-17 19:10:01 +0100151 if (type < ARRAY_SIZE(type_name)) {
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100152 name = type_name[type];
153 }
154 return name;
155}
156
157static const char *sym_bind(unsigned bind)
158{
159 static const char *bind_name[] = {
160#define SYM_BIND(X) [X] = #X
161 SYM_BIND(STB_LOCAL),
162 SYM_BIND(STB_GLOBAL),
163 SYM_BIND(STB_WEAK),
164#undef SYM_BIND
165 };
166 const char *name = "unknown sym bind name";
Robert P. J. Dayca820182007-02-17 19:10:01 +0100167 if (bind < ARRAY_SIZE(bind_name)) {
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100168 name = bind_name[bind];
169 }
170 return name;
171}
172
173static const char *sym_visibility(unsigned visibility)
174{
175 static const char *visibility_name[] = {
176#define SYM_VISIBILITY(X) [X] = #X
177 SYM_VISIBILITY(STV_DEFAULT),
178 SYM_VISIBILITY(STV_INTERNAL),
179 SYM_VISIBILITY(STV_HIDDEN),
180 SYM_VISIBILITY(STV_PROTECTED),
181#undef SYM_VISIBILITY
182 };
183 const char *name = "unknown sym visibility name";
Robert P. J. Dayca820182007-02-17 19:10:01 +0100184 if (visibility < ARRAY_SIZE(visibility_name)) {
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100185 name = visibility_name[visibility];
186 }
187 return name;
188}
189
190static const char *rel_type(unsigned type)
191{
192 static const char *type_name[] = {
193#define REL_TYPE(X) [X] = #X
H. Peter Anvinc889ba82013-04-16 16:02:58 -0700194#if ELF_BITS == 64
Kees Cook946166a2013-04-12 13:13:44 -0700195 REL_TYPE(R_X86_64_NONE),
196 REL_TYPE(R_X86_64_64),
197 REL_TYPE(R_X86_64_PC32),
198 REL_TYPE(R_X86_64_GOT32),
199 REL_TYPE(R_X86_64_PLT32),
200 REL_TYPE(R_X86_64_COPY),
201 REL_TYPE(R_X86_64_GLOB_DAT),
202 REL_TYPE(R_X86_64_JUMP_SLOT),
203 REL_TYPE(R_X86_64_RELATIVE),
204 REL_TYPE(R_X86_64_GOTPCREL),
205 REL_TYPE(R_X86_64_32),
206 REL_TYPE(R_X86_64_32S),
207 REL_TYPE(R_X86_64_16),
208 REL_TYPE(R_X86_64_PC16),
209 REL_TYPE(R_X86_64_8),
210 REL_TYPE(R_X86_64_PC8),
211#else
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100212 REL_TYPE(R_386_NONE),
213 REL_TYPE(R_386_32),
214 REL_TYPE(R_386_PC32),
215 REL_TYPE(R_386_GOT32),
216 REL_TYPE(R_386_PLT32),
217 REL_TYPE(R_386_COPY),
218 REL_TYPE(R_386_GLOB_DAT),
219 REL_TYPE(R_386_JMP_SLOT),
220 REL_TYPE(R_386_RELATIVE),
221 REL_TYPE(R_386_GOTOFF),
222 REL_TYPE(R_386_GOTPC),
H. Peter Anvin6520fe52012-05-08 21:22:24 +0300223 REL_TYPE(R_386_8),
224 REL_TYPE(R_386_PC8),
225 REL_TYPE(R_386_16),
226 REL_TYPE(R_386_PC16),
Kees Cook946166a2013-04-12 13:13:44 -0700227#endif
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100228#undef REL_TYPE
229 };
230 const char *name = "unknown type rel type name";
H. Peter Anvin873b5272009-12-14 13:55:20 -0800231 if (type < ARRAY_SIZE(type_name) && type_name[type]) {
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100232 name = type_name[type];
233 }
234 return name;
235}
236
237static const char *sec_name(unsigned shndx)
238{
239 const char *sec_strtab;
240 const char *name;
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700241 sec_strtab = secs[ehdr.e_shstrndx].strtab;
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100242 name = "<noname>";
243 if (shndx < ehdr.e_shnum) {
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700244 name = sec_strtab + secs[shndx].shdr.sh_name;
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100245 }
246 else if (shndx == SHN_ABS) {
247 name = "ABSOLUTE";
248 }
249 else if (shndx == SHN_COMMON) {
250 name = "COMMON";
251 }
252 return name;
253}
254
Kees Cookbf116552013-04-12 13:13:42 -0700255static const char *sym_name(const char *sym_strtab, Elf_Sym *sym)
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100256{
257 const char *name;
258 name = "<noname>";
259 if (sym->st_name) {
260 name = sym_strtab + sym->st_name;
261 }
262 else {
H. Peter Anvin6520fe52012-05-08 21:22:24 +0300263 name = sec_name(sym->st_shndx);
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100264 }
265 return name;
266}
267
Kees Cook946166a2013-04-12 13:13:44 -0700268static Elf_Sym *sym_lookup(const char *symname)
269{
270 int i;
271 for (i = 0; i < ehdr.e_shnum; i++) {
272 struct section *sec = &secs[i];
273 long nsyms;
274 char *strtab;
275 Elf_Sym *symtab;
276 Elf_Sym *sym;
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100277
Kees Cook946166a2013-04-12 13:13:44 -0700278 if (sec->shdr.sh_type != SHT_SYMTAB)
279 continue;
280
281 nsyms = sec->shdr.sh_size/sizeof(Elf_Sym);
282 symtab = sec->symtab;
283 strtab = sec->link->strtab;
284
285 for (sym = symtab; --nsyms >= 0; sym++) {
286 if (!sym->st_name)
287 continue;
288 if (strcmp(symname, strtab + sym->st_name) == 0)
289 return sym;
290 }
291 }
292 return 0;
293}
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100294
Linus Torvalds13da9e22010-05-26 08:30:15 -0700295#if BYTE_ORDER == LITTLE_ENDIAN
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100296#define le16_to_cpu(val) (val)
297#define le32_to_cpu(val) (val)
Kees Cook946166a2013-04-12 13:13:44 -0700298#define le64_to_cpu(val) (val)
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100299#endif
Linus Torvalds13da9e22010-05-26 08:30:15 -0700300#if BYTE_ORDER == BIG_ENDIAN
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100301#define le16_to_cpu(val) bswap_16(val)
302#define le32_to_cpu(val) bswap_32(val)
Kees Cook946166a2013-04-12 13:13:44 -0700303#define le64_to_cpu(val) bswap_64(val)
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100304#endif
305
306static uint16_t elf16_to_cpu(uint16_t val)
307{
308 return le16_to_cpu(val);
309}
310
311static uint32_t elf32_to_cpu(uint32_t val)
312{
313 return le32_to_cpu(val);
314}
315
Kees Cookbf116552013-04-12 13:13:42 -0700316#define elf_half_to_cpu(x) elf16_to_cpu(x)
317#define elf_word_to_cpu(x) elf32_to_cpu(x)
Kees Cook946166a2013-04-12 13:13:44 -0700318
H. Peter Anvinc889ba82013-04-16 16:02:58 -0700319#if ELF_BITS == 64
Kees Cook946166a2013-04-12 13:13:44 -0700320static uint64_t elf64_to_cpu(uint64_t val)
321{
322 return le64_to_cpu(val);
323}
324#define elf_addr_to_cpu(x) elf64_to_cpu(x)
325#define elf_off_to_cpu(x) elf64_to_cpu(x)
326#define elf_xword_to_cpu(x) elf64_to_cpu(x)
327#else
Kees Cookbf116552013-04-12 13:13:42 -0700328#define elf_addr_to_cpu(x) elf32_to_cpu(x)
329#define elf_off_to_cpu(x) elf32_to_cpu(x)
330#define elf_xword_to_cpu(x) elf32_to_cpu(x)
Kees Cook946166a2013-04-12 13:13:44 -0700331#endif
Kees Cookbf116552013-04-12 13:13:42 -0700332
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100333static void read_ehdr(FILE *fp)
334{
335 if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
336 die("Cannot read ELF header: %s\n",
337 strerror(errno));
338 }
Cyrill Gorcunov8bd17962008-05-03 14:18:03 +0400339 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) {
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100340 die("No ELF magic\n");
341 }
Kees Cookbf116552013-04-12 13:13:42 -0700342 if (ehdr.e_ident[EI_CLASS] != ELF_CLASS) {
343 die("Not a %d bit executable\n", ELF_BITS);
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100344 }
345 if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
346 die("Not a LSB ELF executable\n");
347 }
348 if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
349 die("Unknown ELF version\n");
350 }
351 /* Convert the fields to native endian */
Kees Cookbf116552013-04-12 13:13:42 -0700352 ehdr.e_type = elf_half_to_cpu(ehdr.e_type);
353 ehdr.e_machine = elf_half_to_cpu(ehdr.e_machine);
354 ehdr.e_version = elf_word_to_cpu(ehdr.e_version);
355 ehdr.e_entry = elf_addr_to_cpu(ehdr.e_entry);
356 ehdr.e_phoff = elf_off_to_cpu(ehdr.e_phoff);
357 ehdr.e_shoff = elf_off_to_cpu(ehdr.e_shoff);
358 ehdr.e_flags = elf_word_to_cpu(ehdr.e_flags);
359 ehdr.e_ehsize = elf_half_to_cpu(ehdr.e_ehsize);
360 ehdr.e_phentsize = elf_half_to_cpu(ehdr.e_phentsize);
361 ehdr.e_phnum = elf_half_to_cpu(ehdr.e_phnum);
362 ehdr.e_shentsize = elf_half_to_cpu(ehdr.e_shentsize);
363 ehdr.e_shnum = elf_half_to_cpu(ehdr.e_shnum);
364 ehdr.e_shstrndx = elf_half_to_cpu(ehdr.e_shstrndx);
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100365
366 if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
367 die("Unsupported ELF header type\n");
368 }
Kees Cookbf116552013-04-12 13:13:42 -0700369 if (ehdr.e_machine != ELF_MACHINE) {
370 die("Not for %s\n", ELF_MACHINE_NAME);
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100371 }
372 if (ehdr.e_version != EV_CURRENT) {
373 die("Unknown ELF version\n");
374 }
Kees Cookbf116552013-04-12 13:13:42 -0700375 if (ehdr.e_ehsize != sizeof(Elf_Ehdr)) {
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100376 die("Bad Elf header size\n");
377 }
Kees Cookbf116552013-04-12 13:13:42 -0700378 if (ehdr.e_phentsize != sizeof(Elf_Phdr)) {
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100379 die("Bad program header entry\n");
380 }
Kees Cookbf116552013-04-12 13:13:42 -0700381 if (ehdr.e_shentsize != sizeof(Elf_Shdr)) {
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100382 die("Bad section header entry\n");
383 }
384 if (ehdr.e_shstrndx >= ehdr.e_shnum) {
385 die("String table index out of bounds\n");
386 }
387}
388
389static void read_shdrs(FILE *fp)
390{
391 int i;
Kees Cookbf116552013-04-12 13:13:42 -0700392 Elf_Shdr shdr;
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700393
394 secs = calloc(ehdr.e_shnum, sizeof(struct section));
395 if (!secs) {
396 die("Unable to allocate %d section headers\n",
397 ehdr.e_shnum);
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100398 }
399 if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
400 die("Seek to %d failed: %s\n",
401 ehdr.e_shoff, strerror(errno));
402 }
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700403 for (i = 0; i < ehdr.e_shnum; i++) {
404 struct section *sec = &secs[i];
405 if (fread(&shdr, sizeof shdr, 1, fp) != 1)
406 die("Cannot read ELF section headers %d/%d: %s\n",
407 i, ehdr.e_shnum, strerror(errno));
Kees Cookbf116552013-04-12 13:13:42 -0700408 sec->shdr.sh_name = elf_word_to_cpu(shdr.sh_name);
409 sec->shdr.sh_type = elf_word_to_cpu(shdr.sh_type);
410 sec->shdr.sh_flags = elf_xword_to_cpu(shdr.sh_flags);
411 sec->shdr.sh_addr = elf_addr_to_cpu(shdr.sh_addr);
412 sec->shdr.sh_offset = elf_off_to_cpu(shdr.sh_offset);
413 sec->shdr.sh_size = elf_xword_to_cpu(shdr.sh_size);
414 sec->shdr.sh_link = elf_word_to_cpu(shdr.sh_link);
415 sec->shdr.sh_info = elf_word_to_cpu(shdr.sh_info);
416 sec->shdr.sh_addralign = elf_xword_to_cpu(shdr.sh_addralign);
417 sec->shdr.sh_entsize = elf_xword_to_cpu(shdr.sh_entsize);
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700418 if (sec->shdr.sh_link < ehdr.e_shnum)
419 sec->link = &secs[sec->shdr.sh_link];
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100420 }
421
422}
423
424static void read_strtabs(FILE *fp)
425{
426 int i;
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700427 for (i = 0; i < ehdr.e_shnum; i++) {
428 struct section *sec = &secs[i];
429 if (sec->shdr.sh_type != SHT_STRTAB) {
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100430 continue;
431 }
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700432 sec->strtab = malloc(sec->shdr.sh_size);
433 if (!sec->strtab) {
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100434 die("malloc of %d bytes for strtab failed\n",
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700435 sec->shdr.sh_size);
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100436 }
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700437 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100438 die("Seek to %d failed: %s\n",
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700439 sec->shdr.sh_offset, strerror(errno));
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100440 }
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700441 if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
442 != sec->shdr.sh_size) {
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100443 die("Cannot read symbol table: %s\n",
444 strerror(errno));
445 }
446 }
447}
448
449static void read_symtabs(FILE *fp)
450{
451 int i,j;
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700452 for (i = 0; i < ehdr.e_shnum; i++) {
453 struct section *sec = &secs[i];
454 if (sec->shdr.sh_type != SHT_SYMTAB) {
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100455 continue;
456 }
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700457 sec->symtab = malloc(sec->shdr.sh_size);
458 if (!sec->symtab) {
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100459 die("malloc of %d bytes for symtab failed\n",
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700460 sec->shdr.sh_size);
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100461 }
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700462 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100463 die("Seek to %d failed: %s\n",
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700464 sec->shdr.sh_offset, strerror(errno));
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100465 }
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700466 if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
467 != sec->shdr.sh_size) {
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100468 die("Cannot read symbol table: %s\n",
469 strerror(errno));
470 }
Kees Cookbf116552013-04-12 13:13:42 -0700471 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Sym); j++) {
472 Elf_Sym *sym = &sec->symtab[j];
473 sym->st_name = elf_word_to_cpu(sym->st_name);
474 sym->st_value = elf_addr_to_cpu(sym->st_value);
475 sym->st_size = elf_xword_to_cpu(sym->st_size);
476 sym->st_shndx = elf_half_to_cpu(sym->st_shndx);
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100477 }
478 }
479}
480
481
482static void read_relocs(FILE *fp)
483{
484 int i,j;
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700485 for (i = 0; i < ehdr.e_shnum; i++) {
486 struct section *sec = &secs[i];
Kees Cookbf116552013-04-12 13:13:42 -0700487 if (sec->shdr.sh_type != SHT_REL_TYPE) {
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100488 continue;
489 }
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700490 sec->reltab = malloc(sec->shdr.sh_size);
491 if (!sec->reltab) {
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100492 die("malloc of %d bytes for relocs failed\n",
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700493 sec->shdr.sh_size);
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100494 }
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700495 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100496 die("Seek to %d failed: %s\n",
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700497 sec->shdr.sh_offset, strerror(errno));
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100498 }
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700499 if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
500 != sec->shdr.sh_size) {
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100501 die("Cannot read symbol table: %s\n",
502 strerror(errno));
503 }
Kees Cookbf116552013-04-12 13:13:42 -0700504 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
505 Elf_Rel *rel = &sec->reltab[j];
506 rel->r_offset = elf_addr_to_cpu(rel->r_offset);
507 rel->r_info = elf_xword_to_cpu(rel->r_info);
Kees Cook946166a2013-04-12 13:13:44 -0700508#if (SHT_REL_TYPE == SHT_RELA)
509 rel->r_addend = elf_xword_to_cpu(rel->r_addend);
510#endif
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100511 }
512 }
513}
514
515
516static void print_absolute_symbols(void)
517{
518 int i;
Kees Cook946166a2013-04-12 13:13:44 -0700519 const char *format;
520
H. Peter Anvinc889ba82013-04-16 16:02:58 -0700521 if (ELF_BITS == 64)
Kees Cook946166a2013-04-12 13:13:44 -0700522 format = "%5d %016"PRIx64" %5"PRId64" %10s %10s %12s %s\n";
523 else
524 format = "%5d %08"PRIx32" %5"PRId32" %10s %10s %12s %s\n";
525
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100526 printf("Absolute symbols\n");
527 printf(" Num: Value Size Type Bind Visibility Name\n");
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700528 for (i = 0; i < ehdr.e_shnum; i++) {
529 struct section *sec = &secs[i];
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100530 char *sym_strtab;
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100531 int j;
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700532
533 if (sec->shdr.sh_type != SHT_SYMTAB) {
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100534 continue;
535 }
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700536 sym_strtab = sec->link->strtab;
Kees Cookbf116552013-04-12 13:13:42 -0700537 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Sym); j++) {
538 Elf_Sym *sym;
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100539 const char *name;
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700540 sym = &sec->symtab[j];
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100541 name = sym_name(sym_strtab, sym);
542 if (sym->st_shndx != SHN_ABS) {
543 continue;
544 }
Kees Cook946166a2013-04-12 13:13:44 -0700545 printf(format,
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100546 j, sym->st_value, sym->st_size,
Kees Cookbf116552013-04-12 13:13:42 -0700547 sym_type(ELF_ST_TYPE(sym->st_info)),
548 sym_bind(ELF_ST_BIND(sym->st_info)),
549 sym_visibility(ELF_ST_VISIBILITY(sym->st_other)),
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100550 name);
551 }
552 }
553 printf("\n");
554}
555
556static void print_absolute_relocs(void)
557{
Vivek Goyal6a044b32006-12-07 02:14:04 +0100558 int i, printed = 0;
Kees Cook946166a2013-04-12 13:13:44 -0700559 const char *format;
560
H. Peter Anvinc889ba82013-04-16 16:02:58 -0700561 if (ELF_BITS == 64)
Kees Cook946166a2013-04-12 13:13:44 -0700562 format = "%016"PRIx64" %016"PRIx64" %10s %016"PRIx64" %s\n";
563 else
564 format = "%08"PRIx32" %08"PRIx32" %10s %08"PRIx32" %s\n";
Vivek Goyal6a044b32006-12-07 02:14:04 +0100565
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700566 for (i = 0; i < ehdr.e_shnum; i++) {
567 struct section *sec = &secs[i];
568 struct section *sec_applies, *sec_symtab;
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100569 char *sym_strtab;
Kees Cookbf116552013-04-12 13:13:42 -0700570 Elf_Sym *sh_symtab;
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100571 int j;
Kees Cookbf116552013-04-12 13:13:42 -0700572 if (sec->shdr.sh_type != SHT_REL_TYPE) {
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100573 continue;
574 }
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700575 sec_symtab = sec->link;
576 sec_applies = &secs[sec->shdr.sh_info];
577 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100578 continue;
579 }
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700580 sh_symtab = sec_symtab->symtab;
581 sym_strtab = sec_symtab->link->strtab;
Kees Cookbf116552013-04-12 13:13:42 -0700582 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
583 Elf_Rel *rel;
584 Elf_Sym *sym;
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100585 const char *name;
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700586 rel = &sec->reltab[j];
Kees Cookbf116552013-04-12 13:13:42 -0700587 sym = &sh_symtab[ELF_R_SYM(rel->r_info)];
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100588 name = sym_name(sym_strtab, sym);
589 if (sym->st_shndx != SHN_ABS) {
590 continue;
591 }
Vivek Goyal6a044b32006-12-07 02:14:04 +0100592
593 /* Absolute symbols are not relocated if bzImage is
594 * loaded at a non-compiled address. Display a warning
595 * to user at compile time about the absolute
596 * relocations present.
597 *
598 * User need to audit the code to make sure
599 * some symbols which should have been section
600 * relative have not become absolute because of some
601 * linker optimization or wrong programming usage.
602 *
603 * Before warning check if this absolute symbol
604 * relocation is harmless.
605 */
H. Peter Anvin6520fe52012-05-08 21:22:24 +0300606 if (is_reloc(S_ABS, name) || is_reloc(S_REL, name))
Vivek Goyal6a044b32006-12-07 02:14:04 +0100607 continue;
608
609 if (!printed) {
610 printf("WARNING: Absolute relocations"
611 " present\n");
612 printf("Offset Info Type Sym.Value "
613 "Sym.Name\n");
614 printed = 1;
615 }
616
Kees Cook946166a2013-04-12 13:13:44 -0700617 printf(format,
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100618 rel->r_offset,
619 rel->r_info,
Kees Cookbf116552013-04-12 13:13:42 -0700620 rel_type(ELF_R_TYPE(rel->r_info)),
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100621 sym->st_value,
622 name);
623 }
624 }
Vivek Goyal6a044b32006-12-07 02:14:04 +0100625
626 if (printed)
627 printf("\n");
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100628}
629
Kees Cook5d442e62013-04-12 13:13:43 -0700630static void add_reloc(struct relocs *r, uint32_t offset)
631{
632 if (r->count == r->size) {
633 unsigned long newsize = r->size + 50000;
634 void *mem = realloc(r->offset, newsize * sizeof(r->offset[0]));
635
636 if (!mem)
637 die("realloc of %ld entries for relocs failed\n",
638 newsize);
639 r->offset = mem;
640 r->size = newsize;
641 }
642 r->offset[r->count++] = offset;
643}
644
645static void walk_relocs(int (*process)(struct section *sec, Elf_Rel *rel,
646 Elf_Sym *sym, const char *symname))
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100647{
648 int i;
649 /* Walk through the relocations */
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700650 for (i = 0; i < ehdr.e_shnum; i++) {
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100651 char *sym_strtab;
Kees Cookbf116552013-04-12 13:13:42 -0700652 Elf_Sym *sh_symtab;
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700653 struct section *sec_applies, *sec_symtab;
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100654 int j;
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700655 struct section *sec = &secs[i];
656
Kees Cookbf116552013-04-12 13:13:42 -0700657 if (sec->shdr.sh_type != SHT_REL_TYPE) {
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100658 continue;
659 }
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700660 sec_symtab = sec->link;
661 sec_applies = &secs[sec->shdr.sh_info];
662 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100663 continue;
664 }
H. Peter Anvin908ec7a2008-06-30 14:42:18 -0700665 sh_symtab = sec_symtab->symtab;
H. Peter Anvincc65f1e2008-10-03 13:00:56 -0700666 sym_strtab = sec_symtab->link->strtab;
Kees Cookbf116552013-04-12 13:13:42 -0700667 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
Kees Cook5d442e62013-04-12 13:13:43 -0700668 Elf_Rel *rel = &sec->reltab[j];
669 Elf_Sym *sym = &sh_symtab[ELF_R_SYM(rel->r_info)];
670 const char *symname = sym_name(sym_strtab, sym);
H. Peter Anvin24ab82b2012-05-18 09:52:01 -0700671
Kees Cook5d442e62013-04-12 13:13:43 -0700672 process(sec, rel, sym, symname);
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100673 }
674 }
675}
676
Kees Cook946166a2013-04-12 13:13:44 -0700677/*
678 * The .data..percpu section is a special case for x86_64 SMP kernels.
679 * It is used to initialize the actual per_cpu areas and to provide
680 * definitions for the per_cpu variables that correspond to their offsets
681 * within the percpu area. Since the values of all of the symbols need
682 * to be offsets from the start of the per_cpu area the virtual address
683 * (sh_addr) of .data..percpu is 0 in SMP kernels.
684 *
685 * This means that:
686 *
687 * Relocations that reference symbols in the per_cpu area do not
688 * need further relocation (since the value is an offset relative
689 * to the start of the per_cpu area that does not change).
690 *
691 * Relocations that apply to the per_cpu area need to have their
692 * offset adjusted by by the value of __per_cpu_load to make them
693 * point to the correct place in the loaded image (because the
694 * virtual address of .data..percpu is 0).
695 *
696 * For non SMP kernels .data..percpu is linked as part of the normal
697 * kernel data and does not require special treatment.
698 *
699 */
700static int per_cpu_shndx = -1;
Ben Hutchingseeeda4c2014-09-24 13:30:12 +0100701static Elf_Addr per_cpu_load_addr;
Kees Cook946166a2013-04-12 13:13:44 -0700702
703static void percpu_init(void)
704{
705 int i;
706 for (i = 0; i < ehdr.e_shnum; i++) {
707 ElfW(Sym) *sym;
708 if (strcmp(sec_name(i), ".data..percpu"))
709 continue;
710
711 if (secs[i].shdr.sh_addr != 0) /* non SMP kernel */
712 return;
713
714 sym = sym_lookup("__per_cpu_load");
715 if (!sym)
716 die("can't find __per_cpu_load\n");
717
718 per_cpu_shndx = i;
719 per_cpu_load_addr = sym->st_value;
720 return;
721 }
722}
723
H. Peter Anvinc889ba82013-04-16 16:02:58 -0700724#if ELF_BITS == 64
725
Kees Cook946166a2013-04-12 13:13:44 -0700726/*
727 * Check to see if a symbol lies in the .data..percpu section.
Michael Davidsond751c162013-10-10 18:39:54 -0700728 *
729 * The linker incorrectly associates some symbols with the
730 * .data..percpu section so we also need to check the symbol
731 * name to make sure that we classify the symbol correctly.
732 *
733 * The GNU linker incorrectly associates:
734 * __init_begin
Kees Cookaec58ba2013-10-15 23:43:14 -0700735 * __per_cpu_load
Michael Davidsond751c162013-10-10 18:39:54 -0700736 *
737 * The "gold" linker incorrectly associates:
738 * init_per_cpu__irq_stack_union
739 * init_per_cpu__gdt_page
Kees Cook946166a2013-04-12 13:13:44 -0700740 */
741static int is_percpu_sym(ElfW(Sym) *sym, const char *symname)
742{
743 return (sym->st_shndx == per_cpu_shndx) &&
Michael Davidsond751c162013-10-10 18:39:54 -0700744 strcmp(symname, "__init_begin") &&
Kees Cookaec58ba2013-10-15 23:43:14 -0700745 strcmp(symname, "__per_cpu_load") &&
Michael Davidsond751c162013-10-10 18:39:54 -0700746 strncmp(symname, "init_per_cpu_", 13);
Kees Cook946166a2013-04-12 13:13:44 -0700747}
748
H. Peter Anvinc889ba82013-04-16 16:02:58 -0700749
Kees Cook946166a2013-04-12 13:13:44 -0700750static int do_reloc64(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
751 const char *symname)
752{
753 unsigned r_type = ELF64_R_TYPE(rel->r_info);
754 ElfW(Addr) offset = rel->r_offset;
755 int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
756
757 if (sym->st_shndx == SHN_UNDEF)
758 return 0;
759
760 /*
761 * Adjust the offset if this reloc applies to the percpu section.
762 */
763 if (sec->shdr.sh_info == per_cpu_shndx)
764 offset += per_cpu_load_addr;
765
766 switch (r_type) {
767 case R_X86_64_NONE:
Jan Beulich6d24c5f2014-11-04 08:50:18 +0000768 /* NONE can be ignored. */
769 break;
770
Kees Cook946166a2013-04-12 13:13:44 -0700771 case R_X86_64_PC32:
772 /*
Jan Beulich6d24c5f2014-11-04 08:50:18 +0000773 * PC relative relocations don't need to be adjusted unless
774 * referencing a percpu symbol.
Kees Cook946166a2013-04-12 13:13:44 -0700775 */
Jan Beulich6d24c5f2014-11-04 08:50:18 +0000776 if (is_percpu_sym(sym, symname))
777 add_reloc(&relocs32neg, offset);
Kees Cook946166a2013-04-12 13:13:44 -0700778 break;
779
780 case R_X86_64_32:
781 case R_X86_64_32S:
782 case R_X86_64_64:
783 /*
784 * References to the percpu area don't need to be adjusted.
785 */
786 if (is_percpu_sym(sym, symname))
787 break;
788
789 if (shn_abs) {
790 /*
791 * Whitelisted absolute symbols do not require
792 * relocation.
793 */
794 if (is_reloc(S_ABS, symname))
795 break;
796
797 die("Invalid absolute %s relocation: %s\n",
798 rel_type(r_type), symname);
799 break;
800 }
801
802 /*
803 * Relocation offsets for 64 bit kernels are output
804 * as 32 bits and sign extended back to 64 bits when
805 * the relocations are processed.
806 * Make sure that the offset will fit.
807 */
808 if ((int32_t)offset != (int64_t)offset)
809 die("Relocation offset doesn't fit in 32 bits\n");
810
811 if (r_type == R_X86_64_64)
812 add_reloc(&relocs64, offset);
813 else
814 add_reloc(&relocs32, offset);
815 break;
816
817 default:
818 die("Unsupported relocation type: %s (%d)\n",
819 rel_type(r_type), r_type);
820 break;
821 }
822
823 return 0;
824}
825
H. Peter Anvinc889ba82013-04-16 16:02:58 -0700826#else
Kees Cook946166a2013-04-12 13:13:44 -0700827
828static int do_reloc32(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
829 const char *symname)
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100830{
Kees Cook5d442e62013-04-12 13:13:43 -0700831 unsigned r_type = ELF32_R_TYPE(rel->r_info);
832 int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
833
834 switch (r_type) {
835 case R_386_NONE:
836 case R_386_PC32:
837 case R_386_PC16:
838 case R_386_PC8:
839 /*
840 * NONE can be ignored and PC relative relocations don't
841 * need to be adjusted.
842 */
843 break;
844
845 case R_386_32:
846 if (shn_abs) {
847 /*
848 * Whitelisted absolute symbols do not require
849 * relocation.
850 */
851 if (is_reloc(S_ABS, symname))
852 break;
853
854 die("Invalid absolute %s relocation: %s\n",
855 rel_type(r_type), symname);
856 break;
857 }
858
859 add_reloc(&relocs32, rel->r_offset);
860 break;
861
862 default:
863 die("Unsupported relocation type: %s (%d)\n",
864 rel_type(r_type), r_type);
865 break;
866 }
867
868 return 0;
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100869}
870
Kees Cook5d442e62013-04-12 13:13:43 -0700871static int do_reloc_real(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
872 const char *symname)
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100873{
Kees Cook5d442e62013-04-12 13:13:43 -0700874 unsigned r_type = ELF32_R_TYPE(rel->r_info);
875 int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
876
877 switch (r_type) {
878 case R_386_NONE:
879 case R_386_PC32:
880 case R_386_PC16:
881 case R_386_PC8:
882 /*
883 * NONE can be ignored and PC relative relocations don't
884 * need to be adjusted.
885 */
886 break;
887
888 case R_386_16:
889 if (shn_abs) {
890 /*
891 * Whitelisted absolute symbols do not require
892 * relocation.
893 */
894 if (is_reloc(S_ABS, symname))
895 break;
896
897 if (is_reloc(S_SEG, symname)) {
898 add_reloc(&relocs16, rel->r_offset);
899 break;
900 }
901 } else {
902 if (!is_reloc(S_LIN, symname))
903 break;
904 }
905 die("Invalid %s %s relocation: %s\n",
906 shn_abs ? "absolute" : "relative",
907 rel_type(r_type), symname);
908 break;
909
910 case R_386_32:
911 if (shn_abs) {
912 /*
913 * Whitelisted absolute symbols do not require
914 * relocation.
915 */
916 if (is_reloc(S_ABS, symname))
917 break;
918
919 if (is_reloc(S_REL, symname)) {
920 add_reloc(&relocs32, rel->r_offset);
921 break;
922 }
923 } else {
924 if (is_reloc(S_LIN, symname))
925 add_reloc(&relocs32, rel->r_offset);
926 break;
927 }
928 die("Invalid %s %s relocation: %s\n",
929 shn_abs ? "absolute" : "relative",
930 rel_type(r_type), symname);
931 break;
932
933 default:
934 die("Unsupported relocation type: %s (%d)\n",
935 rel_type(r_type), r_type);
936 break;
937 }
938
939 return 0;
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100940}
941
H. Peter Anvinc889ba82013-04-16 16:02:58 -0700942#endif
943
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100944static int cmp_relocs(const void *va, const void *vb)
945{
Kees Cook5d442e62013-04-12 13:13:43 -0700946 const uint32_t *a, *b;
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100947 a = va; b = vb;
948 return (*a == *b)? 0 : (*a > *b)? 1 : -1;
949}
950
Kees Cook5d442e62013-04-12 13:13:43 -0700951static void sort_relocs(struct relocs *r)
952{
953 qsort(r->offset, r->count, sizeof(r->offset[0]), cmp_relocs);
954}
955
956static int write32(uint32_t v, FILE *f)
H. Peter Anvin6520fe52012-05-08 21:22:24 +0300957{
958 unsigned char buf[4];
959
960 put_unaligned_le32(v, buf);
961 return fwrite(buf, 1, 4, f) == 4 ? 0 : -1;
962}
963
Kees Cook5d442e62013-04-12 13:13:43 -0700964static int write32_as_text(uint32_t v, FILE *f)
965{
966 return fprintf(f, "\t.long 0x%08"PRIx32"\n", v) > 0 ? 0 : -1;
967}
968
H. Peter Anvin6520fe52012-05-08 21:22:24 +0300969static void emit_relocs(int as_text, int use_real_mode)
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100970{
971 int i;
Kees Cook5d442e62013-04-12 13:13:43 -0700972 int (*write_reloc)(uint32_t, FILE *) = write32;
Kees Cook946166a2013-04-12 13:13:44 -0700973 int (*do_reloc)(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
974 const char *symname);
975
H. Peter Anvinc889ba82013-04-16 16:02:58 -0700976#if ELF_BITS == 64
977 if (!use_real_mode)
Kees Cook946166a2013-04-12 13:13:44 -0700978 do_reloc = do_reloc64;
H. Peter Anvinc889ba82013-04-16 16:02:58 -0700979 else
980 die("--realmode not valid for a 64-bit ELF file");
981#else
982 if (!use_real_mode)
Kees Cook946166a2013-04-12 13:13:44 -0700983 do_reloc = do_reloc32;
984 else
985 do_reloc = do_reloc_real;
H. Peter Anvinc889ba82013-04-16 16:02:58 -0700986#endif
H. Peter Anvin6520fe52012-05-08 21:22:24 +0300987
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100988 /* Collect up the relocations */
Kees Cook946166a2013-04-12 13:13:44 -0700989 walk_relocs(do_reloc);
H. Peter Anvin6520fe52012-05-08 21:22:24 +0300990
Kees Cook5d442e62013-04-12 13:13:43 -0700991 if (relocs16.count && !use_real_mode)
H. Peter Anvin6520fe52012-05-08 21:22:24 +0300992 die("Segment relocations found but --realmode not specified\n");
Eric W. Biederman968de4f2006-12-07 02:14:04 +0100993
994 /* Order the relocations for more efficient processing */
Kees Cook5d442e62013-04-12 13:13:43 -0700995 sort_relocs(&relocs16);
996 sort_relocs(&relocs32);
Jan Beulich6d24c5f2014-11-04 08:50:18 +0000997#if ELF_BITS == 64
998 sort_relocs(&relocs32neg);
Kees Cook946166a2013-04-12 13:13:44 -0700999 sort_relocs(&relocs64);
Jan Beulich6d24c5f2014-11-04 08:50:18 +00001000#endif
Eric W. Biederman968de4f2006-12-07 02:14:04 +01001001
1002 /* Print the relocations */
1003 if (as_text) {
1004 /* Print the relocations in a form suitable that
1005 * gas will like.
1006 */
1007 printf(".section \".data.reloc\",\"a\"\n");
1008 printf(".balign 4\n");
Kees Cook5d442e62013-04-12 13:13:43 -07001009 write_reloc = write32_as_text;
Eric W. Biederman968de4f2006-12-07 02:14:04 +01001010 }
H. Peter Anvin6520fe52012-05-08 21:22:24 +03001011
Kees Cook5d442e62013-04-12 13:13:43 -07001012 if (use_real_mode) {
1013 write_reloc(relocs16.count, stdout);
1014 for (i = 0; i < relocs16.count; i++)
1015 write_reloc(relocs16.offset[i], stdout);
H. Peter Anvin6520fe52012-05-08 21:22:24 +03001016
Kees Cook5d442e62013-04-12 13:13:43 -07001017 write_reloc(relocs32.count, stdout);
1018 for (i = 0; i < relocs32.count; i++)
1019 write_reloc(relocs32.offset[i], stdout);
1020 } else {
Jan Beulich6d24c5f2014-11-04 08:50:18 +00001021#if ELF_BITS == 64
1022 /* Print a stop */
1023 write_reloc(0, stdout);
Kees Cook946166a2013-04-12 13:13:44 -07001024
Jan Beulich6d24c5f2014-11-04 08:50:18 +00001025 /* Now print each relocation */
1026 for (i = 0; i < relocs64.count; i++)
1027 write_reloc(relocs64.offset[i], stdout);
1028
1029 /* Print a stop */
1030 write_reloc(0, stdout);
1031
1032 /* Now print each inverse 32-bit relocation */
1033 for (i = 0; i < relocs32neg.count; i++)
1034 write_reloc(relocs32neg.offset[i], stdout);
1035#endif
Kees Cook946166a2013-04-12 13:13:44 -07001036
Kees Cook5d442e62013-04-12 13:13:43 -07001037 /* Print a stop */
1038 write_reloc(0, stdout);
1039
1040 /* Now print each relocation */
1041 for (i = 0; i < relocs32.count; i++)
1042 write_reloc(relocs32.offset[i], stdout);
Eric W. Biederman968de4f2006-12-07 02:14:04 +01001043 }
1044}
1045
Michael Davidson214a8872014-01-21 12:32:23 -08001046/*
1047 * As an aid to debugging problems with different linkers
1048 * print summary information about the relocs.
1049 * Since different linkers tend to emit the sections in
1050 * different orders we use the section names in the output.
1051 */
1052static int do_reloc_info(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
1053 const char *symname)
1054{
1055 printf("%s\t%s\t%s\t%s\n",
1056 sec_name(sec->shdr.sh_info),
1057 rel_type(ELF_R_TYPE(rel->r_info)),
1058 symname,
1059 sec_name(sym->st_shndx));
1060 return 0;
1061}
1062
1063static void print_reloc_info(void)
1064{
1065 printf("reloc section\treloc type\tsymbol\tsymbol section\n");
1066 walk_relocs(do_reloc_info);
1067}
1068
H. Peter Anvinc889ba82013-04-16 16:02:58 -07001069#if ELF_BITS == 64
1070# define process process_64
1071#else
1072# define process process_32
1073#endif
Eric W. Biederman968de4f2006-12-07 02:14:04 +01001074
H. Peter Anvinc889ba82013-04-16 16:02:58 -07001075void process(FILE *fp, int use_real_mode, int as_text,
Michael Davidson214a8872014-01-21 12:32:23 -08001076 int show_absolute_syms, int show_absolute_relocs,
1077 int show_reloc_info)
Eric W. Biederman968de4f2006-12-07 02:14:04 +01001078{
H. Peter Anvin6520fe52012-05-08 21:22:24 +03001079 regex_init(use_real_mode);
Eric W. Biederman968de4f2006-12-07 02:14:04 +01001080 read_ehdr(fp);
1081 read_shdrs(fp);
1082 read_strtabs(fp);
1083 read_symtabs(fp);
1084 read_relocs(fp);
H. Peter Anvinc889ba82013-04-16 16:02:58 -07001085 if (ELF_BITS == 64)
Kees Cook946166a2013-04-12 13:13:44 -07001086 percpu_init();
Vivek Goyal6a044b32006-12-07 02:14:04 +01001087 if (show_absolute_syms) {
Eric W. Biederman968de4f2006-12-07 02:14:04 +01001088 print_absolute_symbols();
H. Peter Anvinc889ba82013-04-16 16:02:58 -07001089 return;
Vivek Goyal6a044b32006-12-07 02:14:04 +01001090 }
1091 if (show_absolute_relocs) {
Eric W. Biederman968de4f2006-12-07 02:14:04 +01001092 print_absolute_relocs();
H. Peter Anvinc889ba82013-04-16 16:02:58 -07001093 return;
Eric W. Biederman968de4f2006-12-07 02:14:04 +01001094 }
Michael Davidson214a8872014-01-21 12:32:23 -08001095 if (show_reloc_info) {
1096 print_reloc_info();
1097 return;
1098 }
H. Peter Anvin6520fe52012-05-08 21:22:24 +03001099 emit_relocs(as_text, use_real_mode);
Eric W. Biederman968de4f2006-12-07 02:14:04 +01001100}