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sh: Teach the DWARF unwinder about modules

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Pass a module's .eh_frame section to the DWARF unwinder at module load
time so that the section's FDEs and CIEs can be registered with the
DWARF unwinder. This allows us to unwind the stack through module code
when generating backtraces.

Signed-off-by: Matt Fleming <matt@console-pimps.org>
This commit is contained in:
Matt Fleming
2009-10-09 23:20:54 +01:00
parent c153a58e71
commit a6a2f2ad67
3 changed files with 175 additions and 53 deletions
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32
arch/sh/kernel/module.c
View File

@ -32,6 +32,7 @@
#include <linux/string.h>
#include <linux/kernel.h>
#include <asm/unaligned.h>
#include <asm/dwarf.h>
void *module_alloc(unsigned long size)
{
@ -145,10 +146,41 @@ int module_finalize(const Elf_Ehdr *hdr,
const Elf_Shdr *sechdrs,
struct module *me)
{
#ifdef CONFIG_DWARF_UNWINDER
unsigned int i, err;
unsigned long start, end;
char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
start = end = 0;
for (i = 1; i < hdr->e_shnum; i++) {
/* Alloc bit cleared means "ignore it." */
if ((sechdrs[i].sh_flags & SHF_ALLOC)
&& !strcmp(secstrings+sechdrs[i].sh_name, ".eh_frame")) {
start = sechdrs[i].sh_addr;
end = start + sechdrs[i].sh_size;
break;
}
}
/* Did we find the .eh_frame section? */
if (i != hdr->e_shnum) {
err = dwarf_parse_section((char *)start, (char *)end, me);
if (err)
printk(KERN_WARNING "%s: failed to parse DWARF info\n",
me->name);
}
#endif /* CONFIG_DWARF_UNWINDER */
return module_bug_finalize(hdr, sechdrs, me);
}
void module_arch_cleanup(struct module *mod)
{
module_bug_cleanup(mod);
#ifdef CONFIG_DWARF_UNWINDER
dwarf_module_unload(mod);
#endif /* CONFIG_DWARF_UNWINDER */
}