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Message-Id: <1280360876-2571-2-git-send-email-vda.linux@googlemail.com>
Date: Thu, 29 Jul 2010 01:47:53 +0200
From: Denys Vlasenko <vda.linux@...glemail.com>
To: Michal Marek <mmarek@...e.cz>,
linux-kbuild <linux-kbuild@...r.kernel.org>,
linux-arch@...r.kernel.org,
Parisc List <linux-parisc@...r.kernel.org>
Cc: lkml <linux-kernel@...r.kernel.org>,
Sam Ravnborg <sam@...nborg.org>,
Tim Abbott <tabbott@...lice.com>,
Tim Bird <tim.bird@...sony.com>,
James Bottomley <James.Bottomley@...senpartnership.com>,
Matt Fleming <matt@...sole-pimps.org>,
Arnd Bergmann <arnd@...db.de>,
Anders Kaseorg <andersk@....edu>,
Andi Kleen <andi@...stfloor.org>,
Stephen Rothwell <sfr@...b.auug.org.au>,
Denys Vlasenko <vda.linux@...glemail.com>,
Rusty Russell <rusty@...tcorp.com.au>
Subject: [PATCH 1/4] modpost: support objects with more than 64k sections
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 <vda.linux@...glemail.com>
Signed-off-by: Anders Kaseorg <andersk@....edu>
Acked-by: Sam Ravnborg <sam@...nborg.org>
Cc: Rusty Russell <rusty@...tcorp.com.au>
Cc: Andi Kleen <andi@...stfloor.org>
---
scripts/mod/file2alias.c | 6 +-
scripts/mod/modpost.c | 102 ++++++++++++++++++++++++++++++++++------------
scripts/mod/modpost.h | 43 +++++++++++++++++++
3 files changed, 122 insertions(+), 29 deletions(-)
diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c
index 5758aab..88f3f07 100644
--- a/scripts/mod/file2alias.c
+++ b/scripts/mod/file2alias.c
@@ -884,16 +884,16 @@ 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 f6127b9..c827309 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -253,7 +253,7 @@ 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;
@@ -373,6 +373,8 @@ 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) {
@@ -417,8 +419,27 @@ static int parse_elf(struct elf_info *info, const char *filename)
return 0;
}
+ if (hdr->e_shnum == 0) {
+ /*
+ * There are more than 64k sections,
+ * read count from .sh_size.
+ * note: it doesn't need shndx2secindex()
+ */
+ info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
+ }
+ else {
+ info->num_sections = hdr->e_shnum;
+ }
+ if (hdr->e_shstrndx == SHN_XINDEX) {
+ info->secindex_strings =
+ shndx2secindex(TO_NATIVE(sechdrs[0].sh_link));
+ }
+ else {
+ info->secindex_strings = hdr->e_shstrndx;
+ }
+
/* Fix endianness in section headers */
- for (i = 0; i < hdr->e_shnum; i++) {
+ for (i = 0; i < info->num_sections; i++) {
sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
sechdrs[i].sh_flags = TO_NATIVE(sechdrs[i].sh_flags);
@@ -431,9 +452,8 @@ static int parse_elf(struct elf_info *info, const char *filename)
sechdrs[i].sh_entsize = TO_NATIVE(sechdrs[i].sh_entsize);
}
/* 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;
int nobits = sechdrs[i].sh_type == SHT_NOBITS;
@@ -461,14 +481,26 @@ static int parse_elf(struct elf_info *info, const char *filename)
else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
info->export_gpl_future_sec = i;
- if (sechdrs[i].sh_type != SHT_SYMTAB)
- continue;
+ if (sechdrs[i].sh_type == SHT_SYMTAB) {
+ unsigned int sh_link_idx;
+ 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;
+ sh_link_idx = shndx2secindex(sechdrs[i].sh_link);
+ info->strtab = (void *)hdr +
+ sechdrs[sh_link_idx].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);
@@ -480,6 +512,21 @@ 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;
}
@@ -519,7 +566,7 @@ 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:
@@ -661,19 +708,19 @@ 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 +
- sechdr->sh_name;
+ elf->sechdrs[elf->secindex_strings].sh_offset +
+ sechdr->sh_name;
}
/* if sym is empty or point to a string
@@ -1052,11 +1099,14 @@ 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;
@@ -1118,9 +1168,9 @@ 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))
@@ -1316,7 +1366,7 @@ static void check_section_mismatch(const char *modname, struct elf_info *elf,
const char *tosec;
const struct sectioncheck *mismatch;
- tosec = sec_name(elf, sym->st_shndx);
+ tosec = sec_name(elf, get_secindex(elf, sym));
mismatch = section_mismatch(fromsec, tosec);
if (mismatch) {
Elf_Sym *to;
@@ -1344,7 +1394,7 @@ 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;
@@ -1452,7 +1502,7 @@ 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);
}
@@ -1510,7 +1560,7 @@ 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);
}
@@ -1535,7 +1585,7 @@ 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)
diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
index be987a4..0388cfc 100644
--- a/scripts/mod/modpost.h
+++ b/scripts/mod/modpost.h
@@ -129,8 +129,51 @@ 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,
--
1.6.2.4
--
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