Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751958AbZCXFaw (ORCPT ); Tue, 24 Mar 2009 01:30:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753929AbZCXFaO (ORCPT ); Tue, 24 Mar 2009 01:30:14 -0400 Received: from BISCAYNE-ONE-STATION.MIT.EDU ([18.7.7.80]:34524 "EHLO biscayne-one-station.mit.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753225AbZCXFaM (ORCPT ); Tue, 24 Mar 2009 01:30:12 -0400 From: Tim Abbott To: Linus Torvalds Cc: Linux kernel mailing list , Tim Abbott , Anders Kaseorg , Waseem Daher , Denys Vlasenko , Rusty Russell , Andi Kleen , "H. Peter Anvin" Subject: [PATCH 3/4] modpost: Support objects with more than 64k sections Date: Tue, 24 Mar 2009 01:28:44 -0400 Message-Id: <1237872525-31014-4-git-send-email-tabbott@mit.edu> X-Mailer: git-send-email 1.6.2.1 In-Reply-To: <1237872525-31014-3-git-send-email-tabbott@mit.edu> References: <1237872525-31014-1-git-send-email-tabbott@mit.edu> <1237872525-31014-2-git-send-email-tabbott@mit.edu> <1237872525-31014-3-git-send-email-tabbott@mit.edu> X-Spam-Flag: NO X-Spam-Score: 0.00 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 12193 Lines: 335 From: Denys Vlasenko This patch makes modpost able to process object files with more than 64k sections. Needed for huge kernel builds (allyesconfig, for example) with -ffunction-sections. Signed-off-by: Denys Vlasenko [andersk@mit.edu: updated for 2.6.29] Signed-off-by: Anders Kaseorg --- scripts/mod/file2alias.c | 6 +- scripts/mod/modpost.c | 94 ++++++++++++++++++++++++++++++++------------- scripts/mod/modpost.h | 43 +++++++++++++++++++++ 3 files changed, 113 insertions(+), 30 deletions(-) diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c index 4eea60b..7d3ebb5 100644 --- a/scripts/mod/file2alias.c +++ b/scripts/mod/file2alias.c @@ -753,16 +753,16 @@ void handle_moddevtable(struct module *mod, struct elf_info *info, char *zeros = NULL; /* We're looking for a section relative symbol */ - if (!sym->st_shndx || sym->st_shndx >= info->hdr->e_shnum) + if (!sym->st_shndx || get_secindex(info, sym) >= info->num_sections) return; /* Handle all-NULL symbols allocated into .bss */ - if (info->sechdrs[sym->st_shndx].sh_type & SHT_NOBITS) { + if (info->sechdrs[get_secindex(info, sym)].sh_type & SHT_NOBITS) { zeros = calloc(1, sym->st_size); symval = zeros; } else { symval = (void *)info->hdr - + info->sechdrs[sym->st_shndx].sh_offset + + info->sechdrs[get_secindex(info, sym)].sh_offset + sym->st_value; } diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index fba468a..8ee2034 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -244,7 +244,7 @@ static enum export export_no(const char *s) return export_unknown; } -static enum export export_from_sec(struct elf_info *elf, Elf_Section sec) +static enum export export_from_sec(struct elf_info *elf, unsigned int sec) { if (sec == elf->export_sec) return export_plain; @@ -364,6 +364,8 @@ static int parse_elf(struct elf_info *info, const char *filename) Elf_Ehdr *hdr; Elf_Shdr *sechdrs; Elf_Sym *sym; + const char *secstrings; + unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U; hdr = grab_file(filename, &info->size); if (!hdr) { @@ -400,8 +402,19 @@ static int parse_elf(struct elf_info *info, const char *filename) return 0; } + /* Fixups for more than 64k sections */ + info->num_sections = hdr->e_shnum; + if (info->num_sections == 0) { /* more than 64k sections? */ + /* doesn't need shndx2secindex() */ + info->num_sections = TO_NATIVE(sechdrs[0].sh_size); + } + info->secindex_strings = hdr->e_shstrndx; + if (info->secindex_strings == SHN_XINDEX) + info->secindex_strings = + shndx2secindex(TO_NATIVE(sechdrs[0].sh_link)); + /* Fix endianness in section headers */ - for (i = 0; i < hdr->e_shnum; i++) { + for (i = 0; i < info->num_sections; i++) { sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type); sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset); sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size); @@ -411,9 +424,8 @@ static int parse_elf(struct elf_info *info, const char *filename) sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr); } /* Find symbol table. */ - for (i = 1; i < hdr->e_shnum; i++) { - const char *secstrings - = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; + secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset; + for (i = 1; i < info->num_sections; i++) { const char *secname; if (sechdrs[i].sh_offset > info->size) { @@ -440,14 +452,24 @@ static int parse_elf(struct elf_info *info, const char *filename) else if (strcmp(secname, "__markers_strings") == 0) info->markers_strings_sec = i; - if (sechdrs[i].sh_type != SHT_SYMTAB) - continue; + if (sechdrs[i].sh_type == SHT_SYMTAB) { + symtab_idx = i; + info->symtab_start = (void *)hdr + + sechdrs[i].sh_offset; + info->symtab_stop = (void *)hdr + + sechdrs[i].sh_offset + sechdrs[i].sh_size; + info->strtab = (void *)hdr + + sechdrs[shndx2secindex(sechdrs[i].sh_link)].sh_offset; + } - info->symtab_start = (void *)hdr + sechdrs[i].sh_offset; - info->symtab_stop = (void *)hdr + sechdrs[i].sh_offset - + sechdrs[i].sh_size; - info->strtab = (void *)hdr + - sechdrs[sechdrs[i].sh_link].sh_offset; + /* 32bit section no. table? ("more than 64k sections") */ + if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) { + symtab_shndx_idx = i; + info->symtab_shndx_start = (void *)hdr + + sechdrs[i].sh_offset; + info->symtab_shndx_stop = (void *)hdr + + sechdrs[i].sh_offset + sechdrs[i].sh_size; + } } if (!info->symtab_start) fatal("%s has no symtab?\n", filename); @@ -459,6 +481,21 @@ static int parse_elf(struct elf_info *info, const char *filename) sym->st_value = TO_NATIVE(sym->st_value); sym->st_size = TO_NATIVE(sym->st_size); } + + if (symtab_shndx_idx != ~0U) { + Elf32_Word *p; + if (symtab_idx != + shndx2secindex(sechdrs[symtab_shndx_idx].sh_link)) + fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n", + filename, + shndx2secindex(sechdrs[symtab_shndx_idx].sh_link), + symtab_idx); + /* Fix endianness */ + for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop; + p++) + *p = TO_NATIVE(*p); + } + return 1; } @@ -493,7 +530,7 @@ static void handle_modversions(struct module *mod, struct elf_info *info, Elf_Sym *sym, const char *symname) { unsigned int crc; - enum export export = export_from_sec(info, sym->st_shndx); + enum export export = export_from_sec(info, get_secindex(info, sym)); switch (sym->st_shndx) { case SHN_COMMON: @@ -635,18 +672,18 @@ static const char *sym_name(struct elf_info *elf, Elf_Sym *sym) return "(unknown)"; } -static const char *sec_name(struct elf_info *elf, int shndx) +static const char *sec_name(struct elf_info *elf, int secindex) { Elf_Shdr *sechdrs = elf->sechdrs; return (void *)elf->hdr + - elf->sechdrs[elf->hdr->e_shstrndx].sh_offset + - sechdrs[shndx].sh_name; + elf->sechdrs[elf->secindex_strings].sh_offset + + sechdrs[secindex].sh_name; } static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr) { return (void *)elf->hdr + - elf->sechdrs[elf->hdr->e_shstrndx].sh_offset + + elf->sechdrs[elf->secindex_strings].sh_offset + sechdr->sh_name; } @@ -983,11 +1020,14 @@ static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr, Elf_Sym *near = NULL; Elf64_Sword distance = 20; Elf64_Sword d; + unsigned int relsym_secindex; if (relsym->st_name != 0) return relsym; + + relsym_secindex = get_secindex(elf, relsym); for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { - if (sym->st_shndx != relsym->st_shndx) + if (get_secindex(elf, sym) != relsym_secindex) continue; if (ELF_ST_TYPE(sym->st_info) == STT_SECTION) continue; @@ -1049,9 +1089,9 @@ static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr, for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { const char *symsec; - if (sym->st_shndx >= SHN_LORESERVE) + if (is_shndx_special(sym->st_shndx)) continue; - symsec = sec_name(elf, sym->st_shndx); + symsec = sec_name(elf, get_secindex(elf, sym)); if (strcmp(symsec, sec) != 0) continue; if (!is_valid_name(elf, sym)) @@ -1248,7 +1288,7 @@ static void check_section_mismatch(const char *modname, struct elf_info *elf, const char *tosec; enum mismatch mismatch; - tosec = sec_name(elf, sym->st_shndx); + tosec = sec_name(elf, get_secindex(elf, sym)); mismatch = section_mismatch(fromsec, tosec); if (mismatch != NO_MISMATCH) { Elf_Sym *to; @@ -1275,7 +1315,7 @@ static unsigned int *reloc_location(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) { Elf_Shdr *sechdrs = elf->sechdrs; - int section = sechdr->sh_info; + int section = shndx2secindex(sechdr->sh_info); return (void *)elf->hdr + sechdrs[section].sh_offset + (r->r_offset - sechdrs[section].sh_addr); @@ -1383,7 +1423,7 @@ static void section_rela(const char *modname, struct elf_info *elf, r.r_addend = TO_NATIVE(rela->r_addend); sym = elf->symtab_start + r_sym; /* Skip special sections */ - if (sym->st_shndx >= SHN_LORESERVE) + if (is_shndx_special(sym->st_shndx)) continue; check_section_mismatch(modname, elf, &r, sym, fromsec); } @@ -1441,7 +1481,7 @@ static void section_rel(const char *modname, struct elf_info *elf, } sym = elf->symtab_start + r_sym; /* Skip special sections */ - if (sym->st_shndx >= SHN_LORESERVE) + if (is_shndx_special(sym->st_shndx)) continue; check_section_mismatch(modname, elf, &r, sym, fromsec); } @@ -1466,7 +1506,7 @@ static void check_sec_ref(struct module *mod, const char *modname, Elf_Shdr *sechdrs = elf->sechdrs; /* Walk through all sections */ - for (i = 0; i < elf->hdr->e_shnum; i++) { + for (i = 0; i < elf->num_sections; i++) { check_section(modname, elf, &elf->sechdrs[i]); /* We want to process only relocation sections and not .init */ if (sechdrs[i].sh_type == SHT_RELA) @@ -1496,7 +1536,7 @@ static void get_markers(struct elf_info *info, struct module *mod) n = 0; for (sym = info->symtab_start; sym < info->symtab_stop; sym++) if (ELF_ST_TYPE(sym->st_info) == STT_OBJECT && - sym->st_shndx == info->markers_strings_sec && + get_secindex(info, sym) == info->markers_strings_sec && !strncmp(info->strtab + sym->st_name, "__mstrtab_", sizeof "__mstrtab_" - 1)) { if (first_sym == NULL) @@ -1520,7 +1560,7 @@ static void get_markers(struct elf_info *info, struct module *mod) n = 0; for (sym = first_sym; sym <= last_sym; sym++) if (ELF_ST_TYPE(sym->st_info) == STT_OBJECT && - sym->st_shndx == info->markers_strings_sec && + get_secindex(info, sym) == info->markers_strings_sec && !strncmp(info->strtab + sym->st_name, "__mstrtab_", sizeof "__mstrtab_" - 1)) { const char *name = strings + sym->st_value; diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h index 09f58e3..dbde650 100644 --- a/scripts/mod/modpost.h +++ b/scripts/mod/modpost.h @@ -132,8 +132,51 @@ struct elf_info { const char *strtab; char *modinfo; unsigned int modinfo_len; + + /* support for 32bit section numbers */ + + unsigned int num_sections; /* max_secindex + 1 */ + unsigned int secindex_strings; + /* if Nth symbol table entry has .st_shndx = SHN_XINDEX, + * take shndx from symtab_shndx_start[N] instead */ + Elf32_Word *symtab_shndx_start; + Elf32_Word *symtab_shndx_stop; }; +static inline int is_shndx_special(unsigned int i) +{ + return i != SHN_XINDEX && i >= SHN_LORESERVE && i <= SHN_HIRESERVE; +} + +/* shndx is in [0..SHN_LORESERVE) U (SHN_HIRESERVE, 0xfffffff], thus: + * shndx == 0 <=> sechdrs[0] + * ...... + * shndx == SHN_LORESERVE-1 <=> sechdrs[SHN_LORESERVE-1] + * shndx == SHN_HIRESERVE+1 <=> sechdrs[SHN_LORESERVE] + * shndx == SHN_HIRESERVE+2 <=> sechdrs[SHN_LORESERVE+1] + * ...... + * fyi: sym->st_shndx is uint16, SHN_LORESERVE = ff00, SHN_HIRESERVE = ffff, + * so basically we map 0000..feff -> 0000..feff + * ff00..ffff -> (you are a bad boy, dont do it) + * 10000..xxxx -> ff00..(xxxx-0x100) + */ +static inline unsigned int shndx2secindex(unsigned int i) +{ + if (i <= SHN_HIRESERVE) + return i; + return i - (SHN_HIRESERVE + 1 - SHN_LORESERVE); +} + +/* Accessor for sym->st_shndx, hides ugliness of "64k sections" */ +static inline unsigned int get_secindex(const struct elf_info *info, + const Elf_Sym *sym) +{ + if (sym->st_shndx != SHN_XINDEX) + return sym->st_shndx; + return shndx2secindex(info->symtab_shndx_start[sym - + info->symtab_start]); +} + /* file2alias.c */ extern unsigned int cross_build; void handle_moddevtable(struct module *mod, struct elf_info *info, -- 1.6.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/