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ARC: DWARF2 .debug_frame based stack unwinder

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-Originally written by Rajeshwar Ranga
-Derived off of generic unwinder in 2.6.19 and adapted to ARC

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Rajeshwar Ranga <rajeshwar.ranga@gmail.com>
This commit is contained in:
Vineet Gupta
2013-01-22 17:03:19 +05:30
parent 41195d236e
commit 854a0d9505
9 changed files with 1612 additions and 1 deletions
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58
arch/arc/kernel/module.c
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@@ -14,6 +14,7 @@
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/string.h>
#include <asm/unwind.h>
static inline void arc_write_me(unsigned short *addr, unsigned long value)
{
@@ -21,6 +22,42 @@ static inline void arc_write_me(unsigned short *addr, unsigned long value)
*(addr + 1) = (value & 0xffff);
}
/* ARC specific section quirks - before relocation loop in generic loader
*
* For dwarf unwinding out of modules, this needs to
* 1. Ensure the .debug_frame is allocatable (ARC Linker bug: despite
* -fasynchronous-unwind-tables it doesn't).
* 2. Since we are iterating thru sec hdr tbl anyways, make a note of
* the exact section index, for later use.
*/
int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
char *secstr, struct module *mod)
{
#ifdef CONFIG_ARC_DW2_UNWIND
int i;
mod->arch.unw_sec_idx = 0;
mod->arch.unw_info = NULL;
for (i = 1; i < hdr->e_shnum; i++) {
if (strcmp(secstr+sechdrs[i].sh_name, ".debug_frame") == 0) {
sechdrs[i].sh_flags |= SHF_ALLOC;
mod->arch.unw_sec_idx = i;
break;
}
}
#endif
return 0;
}
void module_arch_cleanup(struct module *mod)
{
#ifdef CONFIG_ARC_DW2_UNWIND
if (mod->arch.unw_info)
unwind_remove_table(mod->arch.unw_info, 0);
#endif
}
int apply_relocate_add(Elf32_Shdr *sechdrs,
const char *strtab,
unsigned int symindex, /* sec index for sym tbl */
@@ -85,3 +122,24 @@ relo_err:
return -ENOEXEC;
}
/* Just before lift off: After sections have been relocated, we add the
* dwarf section to unwinder table pool
* This couldn't be done in module_frob_arch_sections() because
* relocations had not been applied by then
*/
int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
struct module *mod)
{
#ifdef CONFIG_ARC_DW2_UNWIND
void *unw;
int unwsec = mod->arch.unw_sec_idx;
if (unwsec) {
unw = unwind_add_table(mod, (void *)sechdrs[unwsec].sh_addr,
sechdrs[unwsec].sh_size);
mod->arch.unw_info = unw;
}
#endif
return 0;
}