When you put .section ".foo" in an assembly file instead of .section "foo", "ax" , one of the possible symptoms is that modpost will see an ld-generated section name ".foo.1" in section_rel() or section_rela(). But this heuristic has two problems: it will miss a bad section that has no relocations, and it will incorrectly flag many gcc-generated sections as bad when compiling with -ffunction-sections -fdata-sections. On mips it fixes a lot of bogus warnings with gcc 4.4.0 lije this one: WARNING: crypto/cryptd.o (.text.T.349): unexpected section name. So instead of checking whether the section name matches a particular pattern, we directly check for a missing SHF_ALLOC in the section flags.
Unified · Split
| @@ -716,41 +716,27 @@ int match(const char *sym, const char * const pat[]) · 715 unmodified lines | |||
| 716 | 716 | ||
| 717 | /* sections that we do not want to do full section mismatch check on */ | 717 | /* sections that we do not want to do full section mismatch check on */ |
| 718 | static const char *section_white_list[] = | 718 | static const char *section_white_list[] = |
| 719 | { ".debug*", ".stab*", ".note*", ".got*", ".toc*", NULL }; | 719 | { ".comment", ".debug*", ".stab*", ".note*", ".got*", ".toc*", NULL }; |
| 720 | 720 | ||
| 721 | /* | 721 | /* |
| 722 | * Is this section one we do not want to check? | 722 | * This is used to find sections missing the SHF_ALLOC flag. |
| 723 | * This is often debug sections. | ||
| 724 | * If we are going to check this section then | ||
| 725 | * test if section name ends with a dot and a number. | ||
| 726 | * This is used to find sections where the linker have | ||
| 727 | * appended a dot-number to make the name unique. | ||
| 728 | * The cause of this is often a section specified in assembler | 723 | * The cause of this is often a section specified in assembler |
| 729 | * without "ax" / "aw" and the same section used in .c | 724 | * without "ax" / "aw". |
| 730 | * code where gcc add these. | ||
| 731 | */ | 725 | */ |
| 732 | static int check_section(const char *modname, const char *sec) | 726 | static void check_section(const char *modname, struct elf_info *elf, |
| 733 | { | 727 | Elf_Shdr *sechdr) |
| 734 | const char *e = sec + strlen(sec) - 1; | 728 | { |
| 735 | if (match(sec, section_white_list)) | 729 | const char *sec = sech_name(elf, sechdr); |
| 736 | return 1; | 730 | |
| 737 | 731 | if (sechdr->sh_type == SHT_PROGBITS && | |
| 738 | if (*e && isdigit(*e)) { | 732 | !(sechdr->sh_flags & SHF_ALLOC) && |
| 739 | /* consume all digits */ | 733 | !match(sec, section_white_list)) { |
| 740 | while (*e && e != sec && isdigit(*e)) | 734 | warn("%s (%s): unexpected non-allocatable section.\n" |
| 741 | e--; | 735 | "Did you forget to use \"ax\"/\"aw\" in a .S file?\n" |
| 742 | if (*e == '.' && !strstr(sec, ".linkonce")) { | 736 | "Note that for example <linux/init.h> contains\n" |
| 743 | warn("%s (%s): unexpected section name.\n" | 737 | "section definitions for use in .S files.\n\n", |
| 744 | "The (.[number]+) following section name are " | 738 | modname, sec); |
| 745 | "ld generated and not expected.\n" | ||
| 746 | "Did you forget to use \"ax\"/\"aw\" " | ||
| 747 | "in a .S file?\n" | ||
| 748 | "Note that for example <linux/init.h> contains\n" | ||
| 749 | "section definitions for use in .S files.\n\n", | ||
| 750 | modname, sec); | ||
| 751 | } | ||
| 752 | } | 739 | } |
| 753 | return 0; | ||
| 754 | } | 740 | } |
| 755 | 741 | ||
| 756 | 742 | ||
| @@ -1358,7 +1344,7 @@ static void section_rela(const char *modname, struct elf_info *elf, · 601 unmodified lines | |||
| 1358 | fromsec = sech_name(elf, sechdr); | 1344 | fromsec = sech_name(elf, sechdr); |
| 1359 | fromsec += strlen(".rela"); | 1345 | fromsec += strlen(".rela"); |
| 1360 | /* if from section (name) is know good then skip it */ | 1346 | /* if from section (name) is know good then skip it */ |
| 1361 | if (check_section(modname, fromsec)) | 1347 | if (match(fromsec, section_white_list)) |
| 1362 | return; | 1348 | return; |
| 1363 | 1349 | ||
| 1364 | for (rela = start; rela < stop; rela++) { | 1350 | for (rela = start; rela < stop; rela++) { |
| @@ -1402,7 +1388,7 @@ static void section_rel(const char *modname, struct elf_info *elf, · 37 unmodified lines | |||
| 1402 | fromsec = sech_name(elf, sechdr); | 1388 | fromsec = sech_name(elf, sechdr); |
| 1403 | fromsec += strlen(".rel"); | 1389 | fromsec += strlen(".rel"); |
| 1404 | /* if from section (name) is know good then skip it */ | 1390 | /* if from section (name) is know good then skip it */ |
| 1405 | if (check_section(modname, fromsec)) | 1391 | if (match(fromsec, section_white_list)) |
| 1406 | return; | 1392 | return; |
| 1407 | 1393 | ||
| 1408 | for (rel = start; rel < stop; rel++) { | 1394 | for (rel = start; rel < stop; rel++) { |
| @@ -1465,6 +1451,7 @@ static void check_sec_ref(struct module *mod, const char *modname, · 56 unmodified lines | |||
| 1465 | 1451 | ||
| 1466 | /* Walk through all sections */ | 1452 | /* Walk through all sections */ |
| 1467 | for (i = 0; i < elf->hdr->e_shnum; i++) { | 1453 | for (i = 0; i < elf->hdr->e_shnum; i++) { |
| 1454 | check_section(modname, elf, &elf->sechdrs[i]); | ||
| 1468 | /* We want to process only relocation sections and not .init */ | 1455 | /* We want to process only relocation sections and not .init */ |
| 1469 | if (sechdrs[i].sh_type == SHT_RELA) | 1456 | if (sechdrs[i].sh_type == SHT_RELA) |
| 1470 | section_rela(modname, elf, &elf->sechdrs[i]); | 1457 | section_rela(modname, elf, &elf->sechdrs[i]); |