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[ARM] 5384/1: unwind: Add stack unwinding support for loadable modules 

This patch adds ELF section parsing for the unwinding tables in loadable
modules together with the PREL31 relocation symbol resolving.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Catalin Marinas 2009-02-11 13:09:54 +01:00 committed by Russell King
parent bff595c15c
commit 2e1926e7b5
3 changed files with 82 additions and 5 deletions
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1
arch/arm/include/asm/elf.h
View File

@ -50,6 +50,7 @@ typedef struct user_fp elf_fpregset_t;
#define R_ARM_ABS32 2
#define R_ARM_CALL 28
#define R_ARM_JUMP24 29
#define R_ARM_PREL31 42
/*
* These are used to set parameters in the core dumps.

22
arch/arm/include/asm/module.h
View File

@ -1,15 +1,27 @@
#ifndef _ASM_ARM_MODULE_H
#define _ASM_ARM_MODULE_H
struct mod_arch_specific
{
int foo;
};
#define Elf_Shdr Elf32_Shdr
#define Elf_Sym Elf32_Sym
#define Elf_Ehdr Elf32_Ehdr
struct unwind_table;
struct mod_arch_specific
{
#ifdef CONFIG_ARM_UNWIND
Elf_Shdr *unw_sec_init;
Elf_Shdr *unw_sec_devinit;
Elf_Shdr *unw_sec_core;
Elf_Shdr *sec_init_text;
Elf_Shdr *sec_devinit_text;
Elf_Shdr *sec_core_text;
struct unwind_table *unwind_init;
struct unwind_table *unwind_devinit;
struct unwind_table *unwind_core;
#endif
};
/*
* Include the ARM architecture version.
*/

64
arch/arm/kernel/module.c
View File

@ -22,6 +22,7 @@
#include <asm/pgtable.h>
#include <asm/sections.h>
#include <asm/unwind.h>
#ifdef CONFIG_XIP_KERNEL
/*
@ -66,6 +67,24 @@ 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;
for (s = sechdrs; s < sechdrs_end; s++) {
if (strcmp(".ARM.exidx.init.text", secstrings + s->sh_name) == 0)
mod->arch.unw_sec_init = s;
else if (strcmp(".ARM.exidx.devinit.text", secstrings + s->sh_name) == 0)
mod->arch.unw_sec_devinit = s;
else if (strcmp(".ARM.exidx", secstrings + s->sh_name) == 0)
mod->arch.unw_sec_core = s;
else if (strcmp(".init.text", secstrings + s->sh_name) == 0)
mod->arch.sec_init_text = s;
else if (strcmp(".devinit.text", secstrings + s->sh_name) == 0)
mod->arch.sec_devinit_text = s;
else if (strcmp(".text", secstrings + s->sh_name) == 0)
mod->arch.sec_core_text = s;
}
#endif
return 0;
}
@ -104,6 +123,10 @@ apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex,
loc = dstsec->sh_addr + rel->r_offset;
switch (ELF32_R_TYPE(rel->r_info)) {
case R_ARM_NONE:
/* ignore */
break;
case R_ARM_ABS32:
*(u32 *)loc += sym->st_value;
break;
@ -132,6 +155,11 @@ apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex,
*(u32 *)loc |= offset & 0x00ffffff;
break;
case R_ARM_PREL31:
offset = *(u32 *)loc + sym->st_value - loc;
*(u32 *)loc = offset & 0x7fffffff;
break;
default:
printk(KERN_ERR "%s: unknown relocation: %u\n",
module->name, ELF32_R_TYPE(rel->r_info));
@ -150,14 +178,50 @@ apply_relocate_add(Elf32_Shdr *sechdrs, const char *strtab,
return -ENOEXEC;
}
#ifdef CONFIG_ARM_UNWIND
static void register_unwind_tables(struct module *mod)
{
if (mod->arch.unw_sec_init && mod->arch.sec_init_text)
mod->arch.unwind_init =
unwind_table_add(mod->arch.unw_sec_init->sh_addr,
mod->arch.unw_sec_init->sh_size,
mod->arch.sec_init_text->sh_addr,
mod->arch.sec_init_text->sh_size);
if (mod->arch.unw_sec_devinit && mod->arch.sec_devinit_text)
mod->arch.unwind_devinit =
unwind_table_add(mod->arch.unw_sec_devinit->sh_addr,
mod->arch.unw_sec_devinit->sh_size,
mod->arch.sec_devinit_text->sh_addr,
mod->arch.sec_devinit_text->sh_size);
if (mod->arch.unw_sec_core && mod->arch.sec_core_text)
mod->arch.unwind_core =
unwind_table_add(mod->arch.unw_sec_core->sh_addr,
mod->arch.unw_sec_core->sh_size,
mod->arch.sec_core_text->sh_addr,
mod->arch.sec_core_text->sh_size);
}
static void unregister_unwind_tables(struct module *mod)
{
unwind_table_del(mod->arch.unwind_init);
unwind_table_del(mod->arch.unwind_devinit);
unwind_table_del(mod->arch.unwind_core);
}
#else
static inline void register_unwind_tables(struct module *mod) { }
static inline void unregister_unwind_tables(struct module *mod) { }
#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);
}