Merge branch 'for-2.6.40/splice' of git://git.kernel.dk/linux-2.6-block
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / scripts / recordmcount.h
blob4be60364a40509eac1269eafc97393aadc1ac5e8
1 /*
2 * recordmcount.h
4 * This code was taken out of recordmcount.c written by
5 * Copyright 2009 John F. Reiser <jreiser@BitWagon.com>. All rights reserved.
7 * The original code had the same algorithms for both 32bit
8 * and 64bit ELF files, but the code was duplicated to support
9 * the difference in structures that were used. This
10 * file creates a macro of everything that is different between
11 * the 64 and 32 bit code, such that by including this header
12 * twice we can create both sets of functions by including this
13 * header once with RECORD_MCOUNT_64 undefined, and again with
14 * it defined.
16 * This conversion to macros was done by:
17 * Copyright 2010 Steven Rostedt <srostedt@redhat.com>, Red Hat Inc.
19 * Licensed under the GNU General Public License, version 2 (GPLv2).
21 #undef append_func
22 #undef is_fake_mcount
23 #undef fn_is_fake_mcount
24 #undef MIPS_is_fake_mcount
25 #undef mcount_adjust
26 #undef sift_rel_mcount
27 #undef nop_mcount
28 #undef find_secsym_ndx
29 #undef __has_rel_mcount
30 #undef has_rel_mcount
31 #undef tot_relsize
32 #undef get_mcountsym
33 #undef get_sym_str_and_relp
34 #undef do_func
35 #undef Elf_Addr
36 #undef Elf_Ehdr
37 #undef Elf_Shdr
38 #undef Elf_Rel
39 #undef Elf_Rela
40 #undef Elf_Sym
41 #undef ELF_R_SYM
42 #undef Elf_r_sym
43 #undef ELF_R_INFO
44 #undef Elf_r_info
45 #undef ELF_ST_BIND
46 #undef fn_ELF_R_SYM
47 #undef fn_ELF_R_INFO
48 #undef uint_t
49 #undef _w
50 #undef _align
51 #undef _size
53 #ifdef RECORD_MCOUNT_64
54 # define append_func append64
55 # define sift_rel_mcount sift64_rel_mcount
56 # define nop_mcount nop_mcount_64
57 # define find_secsym_ndx find64_secsym_ndx
58 # define __has_rel_mcount __has64_rel_mcount
59 # define has_rel_mcount has64_rel_mcount
60 # define tot_relsize tot64_relsize
61 # define get_sym_str_and_relp get_sym_str_and_relp_64
62 # define do_func do64
63 # define get_mcountsym get_mcountsym_64
64 # define is_fake_mcount is_fake_mcount64
65 # define fn_is_fake_mcount fn_is_fake_mcount64
66 # define MIPS_is_fake_mcount MIPS64_is_fake_mcount
67 # define mcount_adjust mcount_adjust_64
68 # define Elf_Addr Elf64_Addr
69 # define Elf_Ehdr Elf64_Ehdr
70 # define Elf_Shdr Elf64_Shdr
71 # define Elf_Rel Elf64_Rel
72 # define Elf_Rela Elf64_Rela
73 # define Elf_Sym Elf64_Sym
74 # define ELF_R_SYM ELF64_R_SYM
75 # define Elf_r_sym Elf64_r_sym
76 # define ELF_R_INFO ELF64_R_INFO
77 # define Elf_r_info Elf64_r_info
78 # define ELF_ST_BIND ELF64_ST_BIND
79 # define fn_ELF_R_SYM fn_ELF64_R_SYM
80 # define fn_ELF_R_INFO fn_ELF64_R_INFO
81 # define uint_t uint64_t
82 # define _w w8
83 # define _align 7u
84 # define _size 8
85 #else
86 # define append_func append32
87 # define sift_rel_mcount sift32_rel_mcount
88 # define nop_mcount nop_mcount_32
89 # define find_secsym_ndx find32_secsym_ndx
90 # define __has_rel_mcount __has32_rel_mcount
91 # define has_rel_mcount has32_rel_mcount
92 # define tot_relsize tot32_relsize
93 # define get_sym_str_and_relp get_sym_str_and_relp_32
94 # define do_func do32
95 # define get_mcountsym get_mcountsym_32
96 # define is_fake_mcount is_fake_mcount32
97 # define fn_is_fake_mcount fn_is_fake_mcount32
98 # define MIPS_is_fake_mcount MIPS32_is_fake_mcount
99 # define mcount_adjust mcount_adjust_32
100 # define Elf_Addr Elf32_Addr
101 # define Elf_Ehdr Elf32_Ehdr
102 # define Elf_Shdr Elf32_Shdr
103 # define Elf_Rel Elf32_Rel
104 # define Elf_Rela Elf32_Rela
105 # define Elf_Sym Elf32_Sym
106 # define ELF_R_SYM ELF32_R_SYM
107 # define Elf_r_sym Elf32_r_sym
108 # define ELF_R_INFO ELF32_R_INFO
109 # define Elf_r_info Elf32_r_info
110 # define ELF_ST_BIND ELF32_ST_BIND
111 # define fn_ELF_R_SYM fn_ELF32_R_SYM
112 # define fn_ELF_R_INFO fn_ELF32_R_INFO
113 # define uint_t uint32_t
114 # define _w w
115 # define _align 3u
116 # define _size 4
117 #endif
119 /* Functions and pointers that do_file() may override for specific e_machine. */
120 static int fn_is_fake_mcount(Elf_Rel const *rp)
122 return 0;
124 static int (*is_fake_mcount)(Elf_Rel const *rp) = fn_is_fake_mcount;
126 static uint_t fn_ELF_R_SYM(Elf_Rel const *rp)
128 return ELF_R_SYM(_w(rp->r_info));
130 static uint_t (*Elf_r_sym)(Elf_Rel const *rp) = fn_ELF_R_SYM;
132 static void fn_ELF_R_INFO(Elf_Rel *const rp, unsigned sym, unsigned type)
134 rp->r_info = _w(ELF_R_INFO(sym, type));
136 static void (*Elf_r_info)(Elf_Rel *const rp, unsigned sym, unsigned type) = fn_ELF_R_INFO;
138 static int mcount_adjust = 0;
141 * MIPS mcount long call has 2 _mcount symbols, only the position of the 1st
142 * _mcount symbol is needed for dynamic function tracer, with it, to disable
143 * tracing(ftrace_make_nop), the instruction in the position is replaced with
144 * the "b label" instruction, to enable tracing(ftrace_make_call), replace the
145 * instruction back. So, here, we set the 2nd one as fake and filter it.
147 * c: 3c030000 lui v1,0x0 <--> b label
148 * c: R_MIPS_HI16 _mcount
149 * c: R_MIPS_NONE *ABS*
150 * c: R_MIPS_NONE *ABS*
151 * 10: 64630000 daddiu v1,v1,0
152 * 10: R_MIPS_LO16 _mcount
153 * 10: R_MIPS_NONE *ABS*
154 * 10: R_MIPS_NONE *ABS*
155 * 14: 03e0082d move at,ra
156 * 18: 0060f809 jalr v1
157 * label:
159 #define MIPS_FAKEMCOUNT_OFFSET 4
161 static int MIPS_is_fake_mcount(Elf_Rel const *rp)
163 static Elf_Addr old_r_offset;
164 Elf_Addr current_r_offset = _w(rp->r_offset);
165 int is_fake;
167 is_fake = old_r_offset &&
168 (current_r_offset - old_r_offset == MIPS_FAKEMCOUNT_OFFSET);
169 old_r_offset = current_r_offset;
171 return is_fake;
174 /* Append the new shstrtab, Elf_Shdr[], __mcount_loc and its relocations. */
175 static void append_func(Elf_Ehdr *const ehdr,
176 Elf_Shdr *const shstr,
177 uint_t const *const mloc0,
178 uint_t const *const mlocp,
179 Elf_Rel const *const mrel0,
180 Elf_Rel const *const mrelp,
181 unsigned int const rel_entsize,
182 unsigned int const symsec_sh_link)
184 /* Begin constructing output file */
185 Elf_Shdr mcsec;
186 char const *mc_name = (sizeof(Elf_Rela) == rel_entsize)
187 ? ".rela__mcount_loc"
188 : ".rel__mcount_loc";
189 unsigned const old_shnum = w2(ehdr->e_shnum);
190 uint_t const old_shoff = _w(ehdr->e_shoff);
191 uint_t const old_shstr_sh_size = _w(shstr->sh_size);
192 uint_t const old_shstr_sh_offset = _w(shstr->sh_offset);
193 uint_t t = 1 + strlen(mc_name) + _w(shstr->sh_size);
194 uint_t new_e_shoff;
196 shstr->sh_size = _w(t);
197 shstr->sh_offset = _w(sb.st_size);
198 t += sb.st_size;
199 t += (_align & -t); /* word-byte align */
200 new_e_shoff = t;
202 /* body for new shstrtab */
203 ulseek(fd_map, sb.st_size, SEEK_SET);
204 uwrite(fd_map, old_shstr_sh_offset + (void *)ehdr, old_shstr_sh_size);
205 uwrite(fd_map, mc_name, 1 + strlen(mc_name));
207 /* old(modified) Elf_Shdr table, word-byte aligned */
208 ulseek(fd_map, t, SEEK_SET);
209 t += sizeof(Elf_Shdr) * old_shnum;
210 uwrite(fd_map, old_shoff + (void *)ehdr,
211 sizeof(Elf_Shdr) * old_shnum);
213 /* new sections __mcount_loc and .rel__mcount_loc */
214 t += 2*sizeof(mcsec);
215 mcsec.sh_name = w((sizeof(Elf_Rela) == rel_entsize) + strlen(".rel")
216 + old_shstr_sh_size);
217 mcsec.sh_type = w(SHT_PROGBITS);
218 mcsec.sh_flags = _w(SHF_ALLOC);
219 mcsec.sh_addr = 0;
220 mcsec.sh_offset = _w(t);
221 mcsec.sh_size = _w((void *)mlocp - (void *)mloc0);
222 mcsec.sh_link = 0;
223 mcsec.sh_info = 0;
224 mcsec.sh_addralign = _w(_size);
225 mcsec.sh_entsize = _w(_size);
226 uwrite(fd_map, &mcsec, sizeof(mcsec));
228 mcsec.sh_name = w(old_shstr_sh_size);
229 mcsec.sh_type = (sizeof(Elf_Rela) == rel_entsize)
230 ? w(SHT_RELA)
231 : w(SHT_REL);
232 mcsec.sh_flags = 0;
233 mcsec.sh_addr = 0;
234 mcsec.sh_offset = _w((void *)mlocp - (void *)mloc0 + t);
235 mcsec.sh_size = _w((void *)mrelp - (void *)mrel0);
236 mcsec.sh_link = w(symsec_sh_link);
237 mcsec.sh_info = w(old_shnum);
238 mcsec.sh_addralign = _w(_size);
239 mcsec.sh_entsize = _w(rel_entsize);
240 uwrite(fd_map, &mcsec, sizeof(mcsec));
242 uwrite(fd_map, mloc0, (void *)mlocp - (void *)mloc0);
243 uwrite(fd_map, mrel0, (void *)mrelp - (void *)mrel0);
245 ehdr->e_shoff = _w(new_e_shoff);
246 ehdr->e_shnum = w2(2 + w2(ehdr->e_shnum)); /* {.rel,}__mcount_loc */
247 ulseek(fd_map, 0, SEEK_SET);
248 uwrite(fd_map, ehdr, sizeof(*ehdr));
251 static unsigned get_mcountsym(Elf_Sym const *const sym0,
252 Elf_Rel const *relp,
253 char const *const str0)
255 unsigned mcountsym = 0;
257 Elf_Sym const *const symp =
258 &sym0[Elf_r_sym(relp)];
259 char const *symname = &str0[w(symp->st_name)];
260 char const *mcount = gpfx == '_' ? "_mcount" : "mcount";
262 if (symname[0] == '.')
263 ++symname; /* ppc64 hack */
264 if (strcmp(mcount, symname) == 0 ||
265 (altmcount && strcmp(altmcount, symname) == 0))
266 mcountsym = Elf_r_sym(relp);
268 return mcountsym;
271 static void get_sym_str_and_relp(Elf_Shdr const *const relhdr,
272 Elf_Ehdr const *const ehdr,
273 Elf_Sym const **sym0,
274 char const **str0,
275 Elf_Rel const **relp)
277 Elf_Shdr *const shdr0 = (Elf_Shdr *)(_w(ehdr->e_shoff)
278 + (void *)ehdr);
279 unsigned const symsec_sh_link = w(relhdr->sh_link);
280 Elf_Shdr const *const symsec = &shdr0[symsec_sh_link];
281 Elf_Shdr const *const strsec = &shdr0[w(symsec->sh_link)];
282 Elf_Rel const *const rel0 = (Elf_Rel const *)(_w(relhdr->sh_offset)
283 + (void *)ehdr);
285 *sym0 = (Elf_Sym const *)(_w(symsec->sh_offset)
286 + (void *)ehdr);
288 *str0 = (char const *)(_w(strsec->sh_offset)
289 + (void *)ehdr);
291 *relp = rel0;
295 * Look at the relocations in order to find the calls to mcount.
296 * Accumulate the section offsets that are found, and their relocation info,
297 * onto the end of the existing arrays.
299 static uint_t *sift_rel_mcount(uint_t *mlocp,
300 unsigned const offbase,
301 Elf_Rel **const mrelpp,
302 Elf_Shdr const *const relhdr,
303 Elf_Ehdr const *const ehdr,
304 unsigned const recsym,
305 uint_t const recval,
306 unsigned const reltype)
308 uint_t *const mloc0 = mlocp;
309 Elf_Rel *mrelp = *mrelpp;
310 Elf_Sym const *sym0;
311 char const *str0;
312 Elf_Rel const *relp;
313 unsigned rel_entsize = _w(relhdr->sh_entsize);
314 unsigned const nrel = _w(relhdr->sh_size) / rel_entsize;
315 unsigned mcountsym = 0;
316 unsigned t;
318 get_sym_str_and_relp(relhdr, ehdr, &sym0, &str0, &relp);
320 for (t = nrel; t; --t) {
321 if (!mcountsym)
322 mcountsym = get_mcountsym(sym0, relp, str0);
324 if (mcountsym == Elf_r_sym(relp) && !is_fake_mcount(relp)) {
325 uint_t const addend =
326 _w(_w(relp->r_offset) - recval + mcount_adjust);
327 mrelp->r_offset = _w(offbase
328 + ((void *)mlocp - (void *)mloc0));
329 Elf_r_info(mrelp, recsym, reltype);
330 if (rel_entsize == sizeof(Elf_Rela)) {
331 ((Elf_Rela *)mrelp)->r_addend = addend;
332 *mlocp++ = 0;
333 } else
334 *mlocp++ = addend;
336 mrelp = (Elf_Rel *)(rel_entsize + (void *)mrelp);
338 relp = (Elf_Rel const *)(rel_entsize + (void *)relp);
340 *mrelpp = mrelp;
341 return mlocp;
345 * Read the relocation table again, but this time its called on sections
346 * that are not going to be traced. The mcount calls here will be converted
347 * into nops.
349 static void nop_mcount(Elf_Shdr const *const relhdr,
350 Elf_Ehdr const *const ehdr,
351 const char *const txtname)
353 Elf_Shdr *const shdr0 = (Elf_Shdr *)(_w(ehdr->e_shoff)
354 + (void *)ehdr);
355 Elf_Sym const *sym0;
356 char const *str0;
357 Elf_Rel const *relp;
358 Elf_Shdr const *const shdr = &shdr0[w(relhdr->sh_info)];
359 unsigned rel_entsize = _w(relhdr->sh_entsize);
360 unsigned const nrel = _w(relhdr->sh_size) / rel_entsize;
361 unsigned mcountsym = 0;
362 unsigned t;
363 int once = 0;
365 get_sym_str_and_relp(relhdr, ehdr, &sym0, &str0, &relp);
367 for (t = nrel; t; --t) {
368 int ret = -1;
370 if (!mcountsym)
371 mcountsym = get_mcountsym(sym0, relp, str0);
373 if (mcountsym == Elf_r_sym(relp) && !is_fake_mcount(relp)) {
374 if (make_nop)
375 ret = make_nop((void *)ehdr, shdr->sh_offset + relp->r_offset);
376 if (warn_on_notrace_sect && !once) {
377 printf("Section %s has mcount callers being ignored\n",
378 txtname);
379 once = 1;
380 /* just warn? */
381 if (!make_nop)
382 return;
387 * If we successfully removed the mcount, mark the relocation
388 * as a nop (don't do anything with it).
390 if (!ret) {
391 Elf_Rel rel;
392 rel = *(Elf_Rel *)relp;
393 Elf_r_info(&rel, Elf_r_sym(relp), rel_type_nop);
394 ulseek(fd_map, (void *)relp - (void *)ehdr, SEEK_SET);
395 uwrite(fd_map, &rel, sizeof(rel));
397 relp = (Elf_Rel const *)(rel_entsize + (void *)relp);
403 * Find a symbol in the given section, to be used as the base for relocating
404 * the table of offsets of calls to mcount. A local or global symbol suffices,
405 * but avoid a Weak symbol because it may be overridden; the change in value
406 * would invalidate the relocations of the offsets of the calls to mcount.
407 * Often the found symbol will be the unnamed local symbol generated by
408 * GNU 'as' for the start of each section. For example:
409 * Num: Value Size Type Bind Vis Ndx Name
410 * 2: 00000000 0 SECTION LOCAL DEFAULT 1
412 static unsigned find_secsym_ndx(unsigned const txtndx,
413 char const *const txtname,
414 uint_t *const recvalp,
415 Elf_Shdr const *const symhdr,
416 Elf_Ehdr const *const ehdr)
418 Elf_Sym const *const sym0 = (Elf_Sym const *)(_w(symhdr->sh_offset)
419 + (void *)ehdr);
420 unsigned const nsym = _w(symhdr->sh_size) / _w(symhdr->sh_entsize);
421 Elf_Sym const *symp;
422 unsigned t;
424 for (symp = sym0, t = nsym; t; --t, ++symp) {
425 unsigned int const st_bind = ELF_ST_BIND(symp->st_info);
427 if (txtndx == w2(symp->st_shndx)
428 /* avoid STB_WEAK */
429 && (STB_LOCAL == st_bind || STB_GLOBAL == st_bind)) {
430 *recvalp = _w(symp->st_value);
431 return symp - sym0;
434 fprintf(stderr, "Cannot find symbol for section %d: %s.\n",
435 txtndx, txtname);
436 fail_file();
440 /* Evade ISO C restriction: no declaration after statement in has_rel_mcount. */
441 static char const *
442 __has_rel_mcount(Elf_Shdr const *const relhdr, /* is SHT_REL or SHT_RELA */
443 Elf_Shdr const *const shdr0,
444 char const *const shstrtab,
445 char const *const fname)
447 /* .sh_info depends on .sh_type == SHT_REL[,A] */
448 Elf_Shdr const *const txthdr = &shdr0[w(relhdr->sh_info)];
449 char const *const txtname = &shstrtab[w(txthdr->sh_name)];
451 if (strcmp("__mcount_loc", txtname) == 0) {
452 fprintf(stderr, "warning: __mcount_loc already exists: %s\n",
453 fname);
454 succeed_file();
456 if (w(txthdr->sh_type) != SHT_PROGBITS ||
457 !(w(txthdr->sh_flags) & SHF_EXECINSTR))
458 return NULL;
459 return txtname;
462 static char const *has_rel_mcount(Elf_Shdr const *const relhdr,
463 Elf_Shdr const *const shdr0,
464 char const *const shstrtab,
465 char const *const fname)
467 if (w(relhdr->sh_type) != SHT_REL && w(relhdr->sh_type) != SHT_RELA)
468 return NULL;
469 return __has_rel_mcount(relhdr, shdr0, shstrtab, fname);
473 static unsigned tot_relsize(Elf_Shdr const *const shdr0,
474 unsigned nhdr,
475 const char *const shstrtab,
476 const char *const fname)
478 unsigned totrelsz = 0;
479 Elf_Shdr const *shdrp = shdr0;
480 char const *txtname;
482 for (; nhdr; --nhdr, ++shdrp) {
483 txtname = has_rel_mcount(shdrp, shdr0, shstrtab, fname);
484 if (txtname && is_mcounted_section_name(txtname))
485 totrelsz += _w(shdrp->sh_size);
487 return totrelsz;
491 /* Overall supervision for Elf32 ET_REL file. */
492 static void
493 do_func(Elf_Ehdr *const ehdr, char const *const fname, unsigned const reltype)
495 Elf_Shdr *const shdr0 = (Elf_Shdr *)(_w(ehdr->e_shoff)
496 + (void *)ehdr);
497 unsigned const nhdr = w2(ehdr->e_shnum);
498 Elf_Shdr *const shstr = &shdr0[w2(ehdr->e_shstrndx)];
499 char const *const shstrtab = (char const *)(_w(shstr->sh_offset)
500 + (void *)ehdr);
502 Elf_Shdr const *relhdr;
503 unsigned k;
505 /* Upper bound on space: assume all relevant relocs are for mcount. */
506 unsigned const totrelsz = tot_relsize(shdr0, nhdr, shstrtab, fname);
507 Elf_Rel *const mrel0 = umalloc(totrelsz);
508 Elf_Rel * mrelp = mrel0;
510 /* 2*sizeof(address) <= sizeof(Elf_Rel) */
511 uint_t *const mloc0 = umalloc(totrelsz>>1);
512 uint_t * mlocp = mloc0;
514 unsigned rel_entsize = 0;
515 unsigned symsec_sh_link = 0;
517 for (relhdr = shdr0, k = nhdr; k; --k, ++relhdr) {
518 char const *const txtname = has_rel_mcount(relhdr, shdr0,
519 shstrtab, fname);
520 if (txtname && is_mcounted_section_name(txtname)) {
521 uint_t recval = 0;
522 unsigned const recsym = find_secsym_ndx(
523 w(relhdr->sh_info), txtname, &recval,
524 &shdr0[symsec_sh_link = w(relhdr->sh_link)],
525 ehdr);
527 rel_entsize = _w(relhdr->sh_entsize);
528 mlocp = sift_rel_mcount(mlocp,
529 (void *)mlocp - (void *)mloc0, &mrelp,
530 relhdr, ehdr, recsym, recval, reltype);
531 } else if (txtname && (warn_on_notrace_sect || make_nop)) {
533 * This section is ignored by ftrace, but still
534 * has mcount calls. Convert them to nops now.
536 nop_mcount(relhdr, ehdr, txtname);
539 if (mloc0 != mlocp) {
540 append_func(ehdr, shstr, mloc0, mlocp, mrel0, mrelp,
541 rel_entsize, symsec_sh_link);
543 free(mrel0);
544 free(mloc0);