Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
[platform/kernel/linux-starfive.git] / scripts / recordmcount.h
1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * recordmcount.h
4  *
5  * This code was taken out of recordmcount.c written by
6  * Copyright 2009 John F. Reiser <jreiser@BitWagon.com>.  All rights reserved.
7  *
8  * The original code had the same algorithms for both 32bit
9  * and 64bit ELF files, but the code was duplicated to support
10  * the difference in structures that were used. This
11  * file creates a macro of everything that is different between
12  * the 64 and 32 bit code, such that by including this header
13  * twice we can create both sets of functions by including this
14  * header once with RECORD_MCOUNT_64 undefined, and again with
15  * it defined.
16  *
17  * This conversion to macros was done by:
18  * Copyright 2010 Steven Rostedt <srostedt@redhat.com>, Red Hat Inc.
19  */
20 #undef append_func
21 #undef is_fake_mcount
22 #undef fn_is_fake_mcount
23 #undef MIPS_is_fake_mcount
24 #undef mcount_adjust
25 #undef sift_rel_mcount
26 #undef nop_mcount
27 #undef find_secsym_ndx
28 #undef __has_rel_mcount
29 #undef has_rel_mcount
30 #undef tot_relsize
31 #undef get_mcountsym
32 #undef find_symtab
33 #undef get_shnum
34 #undef set_shnum
35 #undef get_shstrndx
36 #undef get_symindex
37 #undef get_sym_str_and_relp
38 #undef do_func
39 #undef Elf_Addr
40 #undef Elf_Ehdr
41 #undef Elf_Shdr
42 #undef Elf_Rel
43 #undef Elf_Rela
44 #undef Elf_Sym
45 #undef ELF_R_SYM
46 #undef Elf_r_sym
47 #undef ELF_R_INFO
48 #undef Elf_r_info
49 #undef ELF_ST_BIND
50 #undef ELF_ST_TYPE
51 #undef fn_ELF_R_SYM
52 #undef fn_ELF_R_INFO
53 #undef uint_t
54 #undef _w
55 #undef _align
56 #undef _size
57
58 #ifdef RECORD_MCOUNT_64
59 # define append_func            append64
60 # define sift_rel_mcount        sift64_rel_mcount
61 # define nop_mcount             nop_mcount_64
62 # define find_secsym_ndx        find64_secsym_ndx
63 # define __has_rel_mcount       __has64_rel_mcount
64 # define has_rel_mcount         has64_rel_mcount
65 # define tot_relsize            tot64_relsize
66 # define find_symtab            find_symtab64
67 # define get_shnum              get_shnum64
68 # define set_shnum              set_shnum64
69 # define get_shstrndx           get_shstrndx64
70 # define get_symindex           get_symindex64
71 # define get_sym_str_and_relp   get_sym_str_and_relp_64
72 # define do_func                do64
73 # define get_mcountsym          get_mcountsym_64
74 # define is_fake_mcount         is_fake_mcount64
75 # define fn_is_fake_mcount      fn_is_fake_mcount64
76 # define MIPS_is_fake_mcount    MIPS64_is_fake_mcount
77 # define mcount_adjust          mcount_adjust_64
78 # define Elf_Addr               Elf64_Addr
79 # define Elf_Ehdr               Elf64_Ehdr
80 # define Elf_Shdr               Elf64_Shdr
81 # define Elf_Rel                Elf64_Rel
82 # define Elf_Rela               Elf64_Rela
83 # define Elf_Sym                Elf64_Sym
84 # define ELF_R_SYM              ELF64_R_SYM
85 # define Elf_r_sym              Elf64_r_sym
86 # define ELF_R_INFO             ELF64_R_INFO
87 # define Elf_r_info             Elf64_r_info
88 # define ELF_ST_BIND            ELF64_ST_BIND
89 # define ELF_ST_TYPE            ELF64_ST_TYPE
90 # define fn_ELF_R_SYM           fn_ELF64_R_SYM
91 # define fn_ELF_R_INFO          fn_ELF64_R_INFO
92 # define uint_t                 uint64_t
93 # define _w                     w8
94 # define _align                 7u
95 # define _size                  8
96 #else
97 # define append_func            append32
98 # define sift_rel_mcount        sift32_rel_mcount
99 # define nop_mcount             nop_mcount_32
100 # define find_secsym_ndx        find32_secsym_ndx
101 # define __has_rel_mcount       __has32_rel_mcount
102 # define has_rel_mcount         has32_rel_mcount
103 # define tot_relsize            tot32_relsize
104 # define find_symtab            find_symtab32
105 # define get_shnum              get_shnum32
106 # define set_shnum              set_shnum32
107 # define get_shstrndx           get_shstrndx32
108 # define get_symindex           get_symindex32
109 # define get_sym_str_and_relp   get_sym_str_and_relp_32
110 # define do_func                do32
111 # define get_mcountsym          get_mcountsym_32
112 # define is_fake_mcount         is_fake_mcount32
113 # define fn_is_fake_mcount      fn_is_fake_mcount32
114 # define MIPS_is_fake_mcount    MIPS32_is_fake_mcount
115 # define mcount_adjust          mcount_adjust_32
116 # define Elf_Addr               Elf32_Addr
117 # define Elf_Ehdr               Elf32_Ehdr
118 # define Elf_Shdr               Elf32_Shdr
119 # define Elf_Rel                Elf32_Rel
120 # define Elf_Rela               Elf32_Rela
121 # define Elf_Sym                Elf32_Sym
122 # define ELF_R_SYM              ELF32_R_SYM
123 # define Elf_r_sym              Elf32_r_sym
124 # define ELF_R_INFO             ELF32_R_INFO
125 # define Elf_r_info             Elf32_r_info
126 # define ELF_ST_BIND            ELF32_ST_BIND
127 # define ELF_ST_TYPE            ELF32_ST_TYPE
128 # define fn_ELF_R_SYM           fn_ELF32_R_SYM
129 # define fn_ELF_R_INFO          fn_ELF32_R_INFO
130 # define uint_t                 uint32_t
131 # define _w                     w
132 # define _align                 3u
133 # define _size                  4
134 #endif
135
136 /* Functions and pointers that do_file() may override for specific e_machine. */
137 static int fn_is_fake_mcount(Elf_Rel const *rp)
138 {
139         return 0;
140 }
141 static int (*is_fake_mcount)(Elf_Rel const *rp) = fn_is_fake_mcount;
142
143 static uint_t fn_ELF_R_SYM(Elf_Rel const *rp)
144 {
145         return ELF_R_SYM(_w(rp->r_info));
146 }
147 static uint_t (*Elf_r_sym)(Elf_Rel const *rp) = fn_ELF_R_SYM;
148
149 static void fn_ELF_R_INFO(Elf_Rel *const rp, unsigned sym, unsigned type)
150 {
151         rp->r_info = _w(ELF_R_INFO(sym, type));
152 }
153 static void (*Elf_r_info)(Elf_Rel *const rp, unsigned sym, unsigned type) = fn_ELF_R_INFO;
154
155 static int mcount_adjust = 0;
156
157 /*
158  * MIPS mcount long call has 2 _mcount symbols, only the position of the 1st
159  * _mcount symbol is needed for dynamic function tracer, with it, to disable
160  * tracing(ftrace_make_nop), the instruction in the position is replaced with
161  * the "b label" instruction, to enable tracing(ftrace_make_call), replace the
162  * instruction back. So, here, we set the 2nd one as fake and filter it.
163  *
164  * c:   3c030000        lui     v1,0x0          <-->    b       label
165  *              c: R_MIPS_HI16  _mcount
166  *              c: R_MIPS_NONE  *ABS*
167  *              c: R_MIPS_NONE  *ABS*
168  * 10:  64630000        daddiu  v1,v1,0
169  *              10: R_MIPS_LO16 _mcount
170  *              10: R_MIPS_NONE *ABS*
171  *              10: R_MIPS_NONE *ABS*
172  * 14:  03e0082d        move    at,ra
173  * 18:  0060f809        jalr    v1
174  * label:
175  */
176 #define MIPS_FAKEMCOUNT_OFFSET  4
177
178 static int MIPS_is_fake_mcount(Elf_Rel const *rp)
179 {
180         static Elf_Addr old_r_offset = ~(Elf_Addr)0;
181         Elf_Addr current_r_offset = _w(rp->r_offset);
182         int is_fake;
183
184         is_fake = (old_r_offset != ~(Elf_Addr)0) &&
185                 (current_r_offset - old_r_offset == MIPS_FAKEMCOUNT_OFFSET);
186         old_r_offset = current_r_offset;
187
188         return is_fake;
189 }
190
191 static unsigned int get_symindex(Elf_Sym const *sym, Elf32_Word const *symtab,
192                                  Elf32_Word const *symtab_shndx)
193 {
194         unsigned long offset;
195         unsigned short shndx = w2(sym->st_shndx);
196         int index;
197
198         if (shndx > SHN_UNDEF && shndx < SHN_LORESERVE)
199                 return shndx;
200
201         if (shndx == SHN_XINDEX) {
202                 offset = (unsigned long)sym - (unsigned long)symtab;
203                 index = offset / sizeof(*sym);
204
205                 return w(symtab_shndx[index]);
206         }
207
208         return 0;
209 }
210
211 static unsigned int get_shnum(Elf_Ehdr const *ehdr, Elf_Shdr const *shdr0)
212 {
213         if (shdr0 && !ehdr->e_shnum)
214                 return w(shdr0->sh_size);
215
216         return w2(ehdr->e_shnum);
217 }
218
219 static void set_shnum(Elf_Ehdr *ehdr, Elf_Shdr *shdr0, unsigned int new_shnum)
220 {
221         if (new_shnum >= SHN_LORESERVE) {
222                 ehdr->e_shnum = 0;
223                 shdr0->sh_size = w(new_shnum);
224         } else
225                 ehdr->e_shnum = w2(new_shnum);
226 }
227
228 static int get_shstrndx(Elf_Ehdr const *ehdr, Elf_Shdr const *shdr0)
229 {
230         if (ehdr->e_shstrndx != SHN_XINDEX)
231                 return w2(ehdr->e_shstrndx);
232
233         return w(shdr0->sh_link);
234 }
235
236 static void find_symtab(Elf_Ehdr *const ehdr, Elf_Shdr const *shdr0,
237                         unsigned const nhdr, Elf32_Word **symtab,
238                         Elf32_Word **symtab_shndx)
239 {
240         Elf_Shdr const *relhdr;
241         unsigned k;
242
243         *symtab = NULL;
244         *symtab_shndx = NULL;
245
246         for (relhdr = shdr0, k = nhdr; k; --k, ++relhdr) {
247                 if (relhdr->sh_type == SHT_SYMTAB)
248                         *symtab = (void *)ehdr + relhdr->sh_offset;
249                 else if (relhdr->sh_type == SHT_SYMTAB_SHNDX)
250                         *symtab_shndx = (void *)ehdr + relhdr->sh_offset;
251
252                 if (*symtab && *symtab_shndx)
253                         break;
254         }
255 }
256
257 /* Append the new shstrtab, Elf_Shdr[], __mcount_loc and its relocations. */
258 static int append_func(Elf_Ehdr *const ehdr,
259                         Elf_Shdr *const shstr,
260                         uint_t const *const mloc0,
261                         uint_t const *const mlocp,
262                         Elf_Rel const *const mrel0,
263                         Elf_Rel const *const mrelp,
264                         unsigned int const rel_entsize,
265                         unsigned int const symsec_sh_link)
266 {
267         /* Begin constructing output file */
268         Elf_Shdr mcsec;
269         char const *mc_name = (sizeof(Elf_Rela) == rel_entsize)
270                 ? ".rela__mcount_loc"
271                 :  ".rel__mcount_loc";
272         uint_t const old_shoff = _w(ehdr->e_shoff);
273         uint_t const old_shstr_sh_size   = _w(shstr->sh_size);
274         uint_t const old_shstr_sh_offset = _w(shstr->sh_offset);
275         Elf_Shdr *const shdr0 = (Elf_Shdr *)(old_shoff + (void *)ehdr);
276         unsigned int const old_shnum = get_shnum(ehdr, shdr0);
277         unsigned int const new_shnum = 2 + old_shnum; /* {.rel,}__mcount_loc */
278         uint_t t = 1 + strlen(mc_name) + _w(shstr->sh_size);
279         uint_t new_e_shoff;
280
281         shstr->sh_size = _w(t);
282         shstr->sh_offset = _w(sb.st_size);
283         t += sb.st_size;
284         t += (_align & -t);  /* word-byte align */
285         new_e_shoff = t;
286
287         set_shnum(ehdr, shdr0, new_shnum);
288
289         /* body for new shstrtab */
290         if (ulseek(sb.st_size, SEEK_SET) < 0)
291                 return -1;
292         if (uwrite(old_shstr_sh_offset + (void *)ehdr, old_shstr_sh_size) < 0)
293                 return -1;
294         if (uwrite(mc_name, 1 + strlen(mc_name)) < 0)
295                 return -1;
296
297         /* old(modified) Elf_Shdr table, word-byte aligned */
298         if (ulseek(t, SEEK_SET) < 0)
299                 return -1;
300         t += sizeof(Elf_Shdr) * old_shnum;
301         if (uwrite(old_shoff + (void *)ehdr,
302                sizeof(Elf_Shdr) * old_shnum) < 0)
303                 return -1;
304
305         /* new sections __mcount_loc and .rel__mcount_loc */
306         t += 2*sizeof(mcsec);
307         mcsec.sh_name = w((sizeof(Elf_Rela) == rel_entsize) + strlen(".rel")
308                 + old_shstr_sh_size);
309         mcsec.sh_type = w(SHT_PROGBITS);
310         mcsec.sh_flags = _w(SHF_ALLOC);
311         mcsec.sh_addr = 0;
312         mcsec.sh_offset = _w(t);
313         mcsec.sh_size = _w((void *)mlocp - (void *)mloc0);
314         mcsec.sh_link = 0;
315         mcsec.sh_info = 0;
316         mcsec.sh_addralign = _w(_size);
317         mcsec.sh_entsize = _w(_size);
318         if (uwrite(&mcsec, sizeof(mcsec)) < 0)
319                 return -1;
320
321         mcsec.sh_name = w(old_shstr_sh_size);
322         mcsec.sh_type = (sizeof(Elf_Rela) == rel_entsize)
323                 ? w(SHT_RELA)
324                 : w(SHT_REL);
325         mcsec.sh_flags = 0;
326         mcsec.sh_addr = 0;
327         mcsec.sh_offset = _w((void *)mlocp - (void *)mloc0 + t);
328         mcsec.sh_size   = _w((void *)mrelp - (void *)mrel0);
329         mcsec.sh_link = w(symsec_sh_link);
330         mcsec.sh_info = w(old_shnum);
331         mcsec.sh_addralign = _w(_size);
332         mcsec.sh_entsize = _w(rel_entsize);
333
334         if (uwrite(&mcsec, sizeof(mcsec)) < 0)
335                 return -1;
336
337         if (uwrite(mloc0, (void *)mlocp - (void *)mloc0) < 0)
338                 return -1;
339         if (uwrite(mrel0, (void *)mrelp - (void *)mrel0) < 0)
340                 return -1;
341
342         ehdr->e_shoff = _w(new_e_shoff);
343         if (ulseek(0, SEEK_SET) < 0)
344                 return -1;
345         if (uwrite(ehdr, sizeof(*ehdr)) < 0)
346                 return -1;
347         return 0;
348 }
349
350 static unsigned get_mcountsym(Elf_Sym const *const sym0,
351                               Elf_Rel const *relp,
352                               char const *const str0)
353 {
354         unsigned mcountsym = 0;
355
356         Elf_Sym const *const symp =
357                 &sym0[Elf_r_sym(relp)];
358         char const *symname = &str0[w(symp->st_name)];
359         char const *mcount = gpfx == '_' ? "_mcount" : "mcount";
360         char const *fentry = "__fentry__";
361
362         if (symname[0] == '.')
363                 ++symname;  /* ppc64 hack */
364         if (strcmp(mcount, symname) == 0 ||
365             (altmcount && strcmp(altmcount, symname) == 0) ||
366             (strcmp(fentry, symname) == 0))
367                 mcountsym = Elf_r_sym(relp);
368
369         return mcountsym;
370 }
371
372 static void get_sym_str_and_relp(Elf_Shdr const *const relhdr,
373                                  Elf_Ehdr const *const ehdr,
374                                  Elf_Sym const **sym0,
375                                  char const **str0,
376                                  Elf_Rel const **relp)
377 {
378         Elf_Shdr *const shdr0 = (Elf_Shdr *)(_w(ehdr->e_shoff)
379                 + (void *)ehdr);
380         unsigned const symsec_sh_link = w(relhdr->sh_link);
381         Elf_Shdr const *const symsec = &shdr0[symsec_sh_link];
382         Elf_Shdr const *const strsec = &shdr0[w(symsec->sh_link)];
383         Elf_Rel const *const rel0 = (Elf_Rel const *)(_w(relhdr->sh_offset)
384                 + (void *)ehdr);
385
386         *sym0 = (Elf_Sym const *)(_w(symsec->sh_offset)
387                                   + (void *)ehdr);
388
389         *str0 = (char const *)(_w(strsec->sh_offset)
390                                + (void *)ehdr);
391
392         *relp = rel0;
393 }
394
395 /*
396  * Look at the relocations in order to find the calls to mcount.
397  * Accumulate the section offsets that are found, and their relocation info,
398  * onto the end of the existing arrays.
399  */
400 static uint_t *sift_rel_mcount(uint_t *mlocp,
401                                unsigned const offbase,
402                                Elf_Rel **const mrelpp,
403                                Elf_Shdr const *const relhdr,
404                                Elf_Ehdr const *const ehdr,
405                                unsigned const recsym,
406                                uint_t const recval,
407                                unsigned const reltype)
408 {
409         uint_t *const mloc0 = mlocp;
410         Elf_Rel *mrelp = *mrelpp;
411         Elf_Sym const *sym0;
412         char const *str0;
413         Elf_Rel const *relp;
414         unsigned rel_entsize = _w(relhdr->sh_entsize);
415         unsigned const nrel = _w(relhdr->sh_size) / rel_entsize;
416         unsigned mcountsym = 0;
417         unsigned t;
418
419         get_sym_str_and_relp(relhdr, ehdr, &sym0, &str0, &relp);
420
421         for (t = nrel; t; --t) {
422                 if (!mcountsym)
423                         mcountsym = get_mcountsym(sym0, relp, str0);
424
425                 if (mcountsym && mcountsym == Elf_r_sym(relp) &&
426                                 !is_fake_mcount(relp)) {
427                         uint_t const addend =
428                                 _w(_w(relp->r_offset) - recval + mcount_adjust);
429                         mrelp->r_offset = _w(offbase
430                                 + ((void *)mlocp - (void *)mloc0));
431                         Elf_r_info(mrelp, recsym, reltype);
432                         if (rel_entsize == sizeof(Elf_Rela)) {
433                                 ((Elf_Rela *)mrelp)->r_addend = addend;
434                                 *mlocp++ = 0;
435                         } else
436                                 *mlocp++ = addend;
437
438                         mrelp = (Elf_Rel *)(rel_entsize + (void *)mrelp);
439                 }
440                 relp = (Elf_Rel const *)(rel_entsize + (void *)relp);
441         }
442         *mrelpp = mrelp;
443         return mlocp;
444 }
445
446 /*
447  * Read the relocation table again, but this time its called on sections
448  * that are not going to be traced. The mcount calls here will be converted
449  * into nops.
450  */
451 static int nop_mcount(Elf_Shdr const *const relhdr,
452                       Elf_Ehdr const *const ehdr,
453                       const char *const txtname)
454 {
455         Elf_Shdr *const shdr0 = (Elf_Shdr *)(_w(ehdr->e_shoff)
456                 + (void *)ehdr);
457         Elf_Sym const *sym0;
458         char const *str0;
459         Elf_Rel const *relp;
460         Elf_Shdr const *const shdr = &shdr0[w(relhdr->sh_info)];
461         unsigned rel_entsize = _w(relhdr->sh_entsize);
462         unsigned const nrel = _w(relhdr->sh_size) / rel_entsize;
463         unsigned mcountsym = 0;
464         unsigned t;
465         int once = 0;
466
467         get_sym_str_and_relp(relhdr, ehdr, &sym0, &str0, &relp);
468
469         for (t = nrel; t; --t) {
470                 int ret = -1;
471
472                 if (!mcountsym)
473                         mcountsym = get_mcountsym(sym0, relp, str0);
474
475                 if (mcountsym == Elf_r_sym(relp) && !is_fake_mcount(relp)) {
476                         if (make_nop)
477                                 ret = make_nop((void *)ehdr, _w(shdr->sh_offset) + _w(relp->r_offset));
478                         if (warn_on_notrace_sect && !once) {
479                                 printf("Section %s has mcount callers being ignored\n",
480                                        txtname);
481                                 once = 1;
482                                 /* just warn? */
483                                 if (!make_nop)
484                                         return 0;
485                         }
486                 }
487
488                 /*
489                  * If we successfully removed the mcount, mark the relocation
490                  * as a nop (don't do anything with it).
491                  */
492                 if (!ret) {
493                         Elf_Rel rel;
494                         rel = *(Elf_Rel *)relp;
495                         Elf_r_info(&rel, Elf_r_sym(relp), rel_type_nop);
496                         if (ulseek((void *)relp - (void *)ehdr, SEEK_SET) < 0)
497                                 return -1;
498                         if (uwrite(&rel, sizeof(rel)) < 0)
499                                 return -1;
500                 }
501                 relp = (Elf_Rel const *)(rel_entsize + (void *)relp);
502         }
503         return 0;
504 }
505
506 /*
507  * Find a symbol in the given section, to be used as the base for relocating
508  * the table of offsets of calls to mcount.  A local or global symbol suffices,
509  * but avoid a Weak symbol because it may be overridden; the change in value
510  * would invalidate the relocations of the offsets of the calls to mcount.
511  * Often the found symbol will be the unnamed local symbol generated by
512  * GNU 'as' for the start of each section.  For example:
513  *    Num:    Value  Size Type    Bind   Vis      Ndx Name
514  *      2: 00000000     0 SECTION LOCAL  DEFAULT    1
515  */
516 static int find_secsym_ndx(unsigned const txtndx,
517                                 char const *const txtname,
518                                 uint_t *const recvalp,
519                                 unsigned int *sym_index,
520                                 Elf_Shdr const *const symhdr,
521                                 Elf32_Word const *symtab,
522                                 Elf32_Word const *symtab_shndx,
523                                 Elf_Ehdr const *const ehdr)
524 {
525         Elf_Sym const *const sym0 = (Elf_Sym const *)(_w(symhdr->sh_offset)
526                 + (void *)ehdr);
527         unsigned const nsym = _w(symhdr->sh_size) / _w(symhdr->sh_entsize);
528         Elf_Sym const *symp;
529         unsigned t;
530
531         for (symp = sym0, t = nsym; t; --t, ++symp) {
532                 unsigned int const st_bind = ELF_ST_BIND(symp->st_info);
533
534                 if (txtndx == get_symindex(symp, symtab, symtab_shndx)
535                         /* avoid STB_WEAK */
536                     && (STB_LOCAL == st_bind || STB_GLOBAL == st_bind)) {
537                         /* function symbols on ARM have quirks, avoid them */
538                         if (w2(ehdr->e_machine) == EM_ARM
539                             && ELF_ST_TYPE(symp->st_info) == STT_FUNC)
540                                 continue;
541
542                         *recvalp = _w(symp->st_value);
543                         *sym_index = symp - sym0;
544                         return 0;
545                 }
546         }
547         fprintf(stderr, "Cannot find symbol for section %u: %s.\n",
548                 txtndx, txtname);
549         return -1;
550 }
551
552 /* Evade ISO C restriction: no declaration after statement in has_rel_mcount. */
553 static char const * __has_rel_mcount(Elf_Shdr const *const relhdr, /* reltype */
554                                      Elf_Shdr const *const shdr0,
555                                      char const *const shstrtab,
556                                      char const *const fname)
557 {
558         /* .sh_info depends on .sh_type == SHT_REL[,A] */
559         Elf_Shdr const *const txthdr = &shdr0[w(relhdr->sh_info)];
560         char const *const txtname = &shstrtab[w(txthdr->sh_name)];
561
562         if (strcmp("__mcount_loc", txtname) == 0) {
563                 fprintf(stderr, "warning: __mcount_loc already exists: %s\n",
564                         fname);
565                 return already_has_rel_mcount;
566         }
567         if (w(txthdr->sh_type) != SHT_PROGBITS ||
568             !(_w(txthdr->sh_flags) & SHF_EXECINSTR))
569                 return NULL;
570         return txtname;
571 }
572
573 static char const *has_rel_mcount(Elf_Shdr const *const relhdr,
574                                   Elf_Shdr const *const shdr0,
575                                   char const *const shstrtab,
576                                   char const *const fname)
577 {
578         if (w(relhdr->sh_type) != SHT_REL && w(relhdr->sh_type) != SHT_RELA)
579                 return NULL;
580         return __has_rel_mcount(relhdr, shdr0, shstrtab, fname);
581 }
582
583
584 static unsigned tot_relsize(Elf_Shdr const *const shdr0,
585                             unsigned nhdr,
586                             const char *const shstrtab,
587                             const char *const fname)
588 {
589         unsigned totrelsz = 0;
590         Elf_Shdr const *shdrp = shdr0;
591         char const *txtname;
592
593         for (; nhdr; --nhdr, ++shdrp) {
594                 txtname = has_rel_mcount(shdrp, shdr0, shstrtab, fname);
595                 if (txtname == already_has_rel_mcount) {
596                         totrelsz = 0;
597                         break;
598                 }
599                 if (txtname && is_mcounted_section_name(txtname))
600                         totrelsz += _w(shdrp->sh_size);
601         }
602         return totrelsz;
603 }
604
605 /* Overall supervision for Elf32 ET_REL file. */
606 static int do_func(Elf_Ehdr *const ehdr, char const *const fname,
607                    unsigned const reltype)
608 {
609         Elf_Shdr *const shdr0 = (Elf_Shdr *)(_w(ehdr->e_shoff)
610                 + (void *)ehdr);
611         unsigned const nhdr = get_shnum(ehdr, shdr0);
612         Elf_Shdr *const shstr = &shdr0[get_shstrndx(ehdr, shdr0)];
613         char const *const shstrtab = (char const *)(_w(shstr->sh_offset)
614                 + (void *)ehdr);
615
616         Elf_Shdr const *relhdr;
617         unsigned k;
618
619         Elf32_Word *symtab;
620         Elf32_Word *symtab_shndx;
621
622         /* Upper bound on space: assume all relevant relocs are for mcount. */
623         unsigned       totrelsz;
624
625         Elf_Rel *      mrel0;
626         Elf_Rel *      mrelp;
627
628         uint_t *      mloc0;
629         uint_t *      mlocp;
630
631         unsigned rel_entsize = 0;
632         unsigned symsec_sh_link = 0;
633
634         int result = 0;
635
636         totrelsz = tot_relsize(shdr0, nhdr, shstrtab, fname);
637         if (totrelsz == 0)
638                 return 0;
639         mrel0 = umalloc(totrelsz);
640         mrelp = mrel0;
641         if (!mrel0)
642                 return -1;
643
644         /* 2*sizeof(address) <= sizeof(Elf_Rel) */
645         mloc0 = umalloc(totrelsz>>1);
646         mlocp = mloc0;
647         if (!mloc0) {
648                 free(mrel0);
649                 return -1;
650         }
651
652         find_symtab(ehdr, shdr0, nhdr, &symtab, &symtab_shndx);
653
654         for (relhdr = shdr0, k = nhdr; k; --k, ++relhdr) {
655                 char const *const txtname = has_rel_mcount(relhdr, shdr0,
656                         shstrtab, fname);
657                 if (txtname == already_has_rel_mcount) {
658                         result = 0;
659                         file_updated = 0;
660                         goto out; /* Nothing to be done; don't append! */
661                 }
662                 if (txtname && is_mcounted_section_name(txtname)) {
663                         unsigned int recsym;
664                         uint_t recval = 0;
665
666                         symsec_sh_link = w(relhdr->sh_link);
667                         result = find_secsym_ndx(w(relhdr->sh_info), txtname,
668                                                 &recval, &recsym,
669                                                 &shdr0[symsec_sh_link],
670                                                 symtab, symtab_shndx,
671                                                 ehdr);
672                         if (result)
673                                 goto out;
674
675                         rel_entsize = _w(relhdr->sh_entsize);
676                         mlocp = sift_rel_mcount(mlocp,
677                                 (void *)mlocp - (void *)mloc0, &mrelp,
678                                 relhdr, ehdr, recsym, recval, reltype);
679                 } else if (txtname && (warn_on_notrace_sect || make_nop)) {
680                         /*
681                          * This section is ignored by ftrace, but still
682                          * has mcount calls. Convert them to nops now.
683                          */
684                         if (nop_mcount(relhdr, ehdr, txtname) < 0) {
685                                 result = -1;
686                                 goto out;
687                         }
688                 }
689         }
690         if (!result && mloc0 != mlocp)
691                 result = append_func(ehdr, shstr, mloc0, mlocp, mrel0, mrelp,
692                                      rel_entsize, symsec_sh_link);
693 out:
694         free(mrel0);
695         free(mloc0);
696         return result;
697 }