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authorVineet Gupta <vgupta@synopsys.com>2013-01-22 12:33:19 +0100
committerVineet Gupta <vgupta@synopsys.com>2013-02-15 18:46:03 +0100
commit854a0d95056c265d96cb449bc97bc5ef9bbed835 (patch)
tree798c834ae188bd570b861a47765fce8ed633f85a /arch/arc/kernel/module.c
parentARC: SMP support (diff)
downloadlinux-854a0d95056c265d96cb449bc97bc5ef9bbed835.tar.xz
linux-854a0d95056c265d96cb449bc97bc5ef9bbed835.zip
ARC: DWARF2 .debug_frame based stack unwinder
-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>
Diffstat (limited to 'arch/arc/kernel/module.c')
-rw-r--r--arch/arc/kernel/module.c58
1 files changed, 58 insertions, 0 deletions
diff --git a/arch/arc/kernel/module.c b/arch/arc/kernel/module.c
index a1bb70d6e97d..cdd359352c0a 100644
--- a/arch/arc/kernel/module.c
+++ b/arch/arc/kernel/module.c
@@ -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;
+}