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Commit e115f2c1 authored by Paul Mundt's avatar Paul Mundt
Browse files

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



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: default avatarPaul Mundt <lethal@linux-sh.org>
parent c153a58e

arch/sh/include/asm/bug.h

+6 −5
Original line number Diff line number Diff line 
#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
@@ -79,9 +79,10 @@ do { \ 
		"1:\t.short %O0\n"			\

		_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)

arch/sh/kernel/debugtraps.S

+1 −5
Original line number Diff line number Diff line
@@ -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 */

arch/sh/kernel/traps.c

+17 −4
Original line number Diff line number Diff line
@@ -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;

arch/sh/kernel/unwinder.c

+0 −21
Original line number Diff line number Diff line
@@ -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);