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sh: unwinder: Use a special bug flag for unwinder traps.

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This simplifies the unwinder trap handling, dropping the use of the
special trapa vector and simply piggybacking on top of the BUG support. A
new BUGFLAG_UNWINDER is added for flagging the unwinder fault, before
continuing on with regular BUG dispatch.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This commit is contained in:
Paul Mundt 2009-08-22 05:28:25 +09:00
parent c153a58e71
commit e115f2c17c
4 changed files with 24 additions and 35 deletions
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11
arch/sh/include/asm/bug.h
View file

@ -1,8 +1,8 @@
#ifndef __ASM_SH_BUG_H
#define __ASM_SH_BUG_H
#define TRAPA_UNWINDER_BUG_OPCODE 0xc33b /* trapa #0x3b */
#define TRAPA_BUG_OPCODE 0xc33e /* trapa #0x3e */
#define BUGFLAG_UNWINDER (1 << 1)
#ifdef CONFIG_GENERIC_BUG
#define HAVE_ARCH_BUG
@ -73,15 +73,16 @@ do { \
unlikely(__ret_warn_on); \
})
#define UNWINDER_BUG() \
#define UNWINDER_BUG() \
do { \
__asm__ __volatile__ ( \
"1:\t.short %O0\n" \
_EMIT_BUG_ENTRY \
_EMIT_BUG_ENTRY \
: \
: "n" (TRAPA_UNWINDER_BUG_OPCODE), \
: "n" (TRAPA_BUG_OPCODE), \
"i" (__FILE__), \
"i" (__LINE__), "i" (0), \
"i" (__LINE__), \
"i" (BUGFLAG_UNWINDER), \
"i" (sizeof(struct bug_entry))); \
} while (0)

6
arch/sh/kernel/debugtraps.S
View file

@ -19,10 +19,6 @@
#if !defined(CONFIG_SH_STANDARD_BIOS)
#define sh_bios_handler debug_trap_handler
#endif
#if !defined(CONFIG_DWARF_UNWINDER)
#define unwinder_trap_handler debug_trap_handler
#endif
.data
@ -39,7 +35,7 @@ ENTRY(debug_trap_table)
.long debug_trap_handler /* 0x38 */
.long debug_trap_handler /* 0x39 */
.long debug_trap_handler /* 0x3a */
.long unwinder_trap_handler /* 0x3b */
.long debug_trap_handler /* 0x3b */
.long breakpoint_trap_handler /* 0x3c */
.long singlestep_trap_handler /* 0x3d */
.long bug_trap_handler /* 0x3e */

21
arch/sh/kernel/traps.c
View file

@ -5,18 +5,32 @@
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/uaccess.h>
#include <asm/unwinder.h>
#include <asm/system.h>
#ifdef CONFIG_BUG
void handle_BUG(struct pt_regs *regs)
{
const struct bug_entry *bug;
unsigned long bugaddr = regs->pc;
enum bug_trap_type tt;
tt = report_bug(regs->pc, regs);
if (!is_valid_bugaddr(bugaddr))
goto invalid;
bug = find_bug(bugaddr);
/* Switch unwinders when unwind_stack() is called */
if (bug->flags & BUGFLAG_UNWINDER)
unwinder_faulted = 1;
tt = report_bug(bugaddr, regs);
if (tt == BUG_TRAP_TYPE_WARN) {
regs->pc += instruction_size(regs->pc);
regs->pc += instruction_size(bugaddr);
return;
}
invalid:
die("Kernel BUG", regs, TRAPA_BUG_OPCODE & 0xff);
}
@ -28,8 +42,7 @@ int is_valid_bugaddr(unsigned long addr)
return 0;
if (probe_kernel_address((insn_size_t *)addr, opcode))
return 0;
if (opcode == TRAPA_BUG_OPCODE || opcode == TRAPA_UNWINDER_BUG_OPCODE)
if (opcode == TRAPA_BUG_OPCODE)
return 1;
return 0;

21
arch/sh/kernel/unwinder.c
View file

@ -161,25 +161,4 @@ void unwind_stack(struct task_struct *task, struct pt_regs *regs,
curr_unwinder->dump(task, regs, sp, ops, data);
}
/*
* Trap handler for UWINDER_BUG() statements. We must switch to the
* unwinder with the next highest rating.
*/
BUILD_TRAP_HANDLER(unwinder)
{
insn_size_t insn;
TRAP_HANDLER_DECL;
/* Rewind */
regs->pc -= instruction_size(ctrl_inw(regs->pc - 4));
insn = *(insn_size_t *)instruction_pointer(regs);
/* Switch unwinders when unwind_stack() is called */
unwinder_faulted = 1;
#ifdef CONFIG_BUG
handle_BUG(regs);
#endif
}
EXPORT_SYMBOL_GPL(unwind_stack);