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ARM: module: clean up handling of ELF unwind tables
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There's no need to keep pointers to the ELF sections available while
the module is loaded - we only need the section pointers while we're
finding and registering the unwind tables, which can all be done during
the finalize stage of loading.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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Russell King committed Dec 1, 2010
1 parent f6614b7 commit 8931360
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Showing 2 changed files with 56 additions and 65 deletions.
15 changes: 5 additions & 10 deletions arch/arm/include/asm/module.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -8,11 +8,6 @@
struct unwind_table;

#ifdef CONFIG_ARM_UNWIND
struct arm_unwind_mapping {
Elf_Shdr *unw_sec;
Elf_Shdr *sec_text;
struct unwind_table *unwind;
};
enum {
ARM_SEC_INIT,
ARM_SEC_DEVINIT,
Expand All @@ -21,13 +16,13 @@ enum {
ARM_SEC_DEVEXIT,
ARM_SEC_MAX,
};
#endif

struct mod_arch_specific {
struct arm_unwind_mapping map[ARM_SEC_MAX];
};
#else
struct mod_arch_specific {
};
#ifdef CONFIG_ARM_UNWIND
struct unwind_table *unwind[ARM_SEC_MAX];
#endif
};

/*
* Include the ARM architecture version.
Expand Down
106 changes: 51 additions & 55 deletions arch/arm/kernel/module.c
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Original file line number Diff line number Diff line change
Expand Up @@ -67,35 +67,6 @@ int module_frob_arch_sections(Elf_Ehdr *hdr,
char *secstrings,
struct module *mod)
{
#ifdef CONFIG_ARM_UNWIND
Elf_Shdr *s, *sechdrs_end = sechdrs + hdr->e_shnum;
struct arm_unwind_mapping *maps = mod->arch.map;

for (s = sechdrs; s < sechdrs_end; s++) {
char const *secname = secstrings + s->sh_name;

if (strcmp(".ARM.exidx.init.text", secname) == 0)
maps[ARM_SEC_INIT].unw_sec = s;
else if (strcmp(".ARM.exidx.devinit.text", secname) == 0)
maps[ARM_SEC_DEVINIT].unw_sec = s;
else if (strcmp(".ARM.exidx", secname) == 0)
maps[ARM_SEC_CORE].unw_sec = s;
else if (strcmp(".ARM.exidx.exit.text", secname) == 0)
maps[ARM_SEC_EXIT].unw_sec = s;
else if (strcmp(".ARM.exidx.devexit.text", secname) == 0)
maps[ARM_SEC_DEVEXIT].unw_sec = s;
else if (strcmp(".init.text", secname) == 0)
maps[ARM_SEC_INIT].sec_text = s;
else if (strcmp(".devinit.text", secname) == 0)
maps[ARM_SEC_DEVINIT].sec_text = s;
else if (strcmp(".text", secname) == 0)
maps[ARM_SEC_CORE].sec_text = s;
else if (strcmp(".exit.text", secname) == 0)
maps[ARM_SEC_EXIT].sec_text = s;
else if (strcmp(".devexit.text", secname) == 0)
maps[ARM_SEC_DEVEXIT].sec_text = s;
}
#endif
return 0;
}

Expand Down Expand Up @@ -300,41 +271,66 @@ apply_relocate_add(Elf32_Shdr *sechdrs, const char *strtab,
return -ENOEXEC;
}

#ifdef CONFIG_ARM_UNWIND
static void register_unwind_tables(struct module *mod)
struct mod_unwind_map {
const Elf_Shdr *unw_sec;
const Elf_Shdr *txt_sec;
};

int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
struct module *mod)
{
#ifdef CONFIG_ARM_UNWIND
const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
const Elf_Shdr *s, *sechdrs_end = sechdrs + hdr->e_shnum;
struct mod_unwind_map maps[ARM_SEC_MAX];
int i;
for (i = 0; i < ARM_SEC_MAX; ++i) {
struct arm_unwind_mapping *map = &mod->arch.map[i];
if (map->unw_sec && map->sec_text)
map->unwind = unwind_table_add(map->unw_sec->sh_addr,
map->unw_sec->sh_size,
map->sec_text->sh_addr,
map->sec_text->sh_size);

memset(maps, 0, sizeof(maps));

for (s = sechdrs; s < sechdrs_end; s++) {
const char *secname = secstrs + s->sh_name;

if (strcmp(".ARM.exidx.init.text", secname) == 0)
maps[ARM_SEC_INIT].unw_sec = s;
else if (strcmp(".ARM.exidx.devinit.text", secname) == 0)
maps[ARM_SEC_DEVINIT].unw_sec = s;
else if (strcmp(".ARM.exidx", secname) == 0)
maps[ARM_SEC_CORE].unw_sec = s;
else if (strcmp(".ARM.exidx.exit.text", secname) == 0)
maps[ARM_SEC_EXIT].unw_sec = s;
else if (strcmp(".ARM.exidx.devexit.text", secname) == 0)
maps[ARM_SEC_DEVEXIT].unw_sec = s;
else if (strcmp(".init.text", secname) == 0)
maps[ARM_SEC_INIT].txt_sec = s;
else if (strcmp(".devinit.text", secname) == 0)
maps[ARM_SEC_DEVINIT].txt_sec = s;
else if (strcmp(".text", secname) == 0)
maps[ARM_SEC_CORE].txt_sec = s;
else if (strcmp(".exit.text", secname) == 0)
maps[ARM_SEC_EXIT].txt_sec = s;
else if (strcmp(".devexit.text", secname) == 0)
maps[ARM_SEC_DEVEXIT].txt_sec = s;
}
}

static void unregister_unwind_tables(struct module *mod)
{
int i = ARM_SEC_MAX;
while (--i >= 0)
unwind_table_del(mod->arch.map[i].unwind);
}
#else
static inline void register_unwind_tables(struct module *mod) { }
static inline void unregister_unwind_tables(struct module *mod) { }
for (i = 0; i < ARM_SEC_MAX; i++)
if (maps[i].unw_sec && maps[i].txt_sec)
mod->arch.unwind[i] =
unwind_table_add(maps[i].unw_sec->sh_addr,
maps[i].unw_sec->sh_size,
maps[i].txt_sec->sh_addr,
maps[i].txt_sec->sh_size);
#endif

int
module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
struct module *module)
{
register_unwind_tables(module);
return 0;
}

void
module_arch_cleanup(struct module *mod)
{
unregister_unwind_tables(mod);
#ifdef CONFIG_ARM_UNWIND
int i;

for (i = 0; i < ARM_SEC_MAX; i++)
if (mod->arch.unwind[i])
unwind_table_del(mod->arch.unwind[i]);
#endif
}

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