ARC: Non-MMU Exception Handling

/*

 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 */

/*

 * Traps/Non-MMU Exception handling for ARC

 *

 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 *

 * Rahul Trivedi: Codito Technologies 2004

 */

#include <linux/sched.h>

#include <linux/kdebug.h>

#include <linux/uaccess.h>

#include <asm/ptrace.h>

#include <asm/setup.h>

void __init trap_init(void)

{

	return;

}

void die(const char *str, struct pt_regs *regs, unsigned long address,

	 unsigned long cause_reg)

{

	show_kernel_fault_diag(str, regs, address, cause_reg);

	/* DEAD END */

	__asm__("flag 1");

}

/*

 * Helper called for bulk of exceptions NOT needing specific handling

 *  -for user faults enqueues requested signal

 *  -for kernel, chk if due to copy_(to|from)_user, otherwise die()

 */

static noinline int handle_exception(unsigned long cause, char *str,

				     struct pt_regs *regs, siginfo_t *info)

{

	if (user_mode(regs)) {

		struct task_struct *tsk = current;

		tsk->thread.fault_address = (__force unsigned int)info->si_addr;

		tsk->thread.cause_code = cause;

		force_sig_info(info->si_signo, info, tsk);

	} else {

		/* If not due to copy_(to|from)_user, we are doomed */

		if (fixup_exception(regs))

			return 0;

		die(str, regs, (unsigned long)info->si_addr, cause);

	}

	return 1;

}

#define DO_ERROR_INFO(signr, str, name, sicode) \

int name(unsigned long cause, unsigned long address, struct pt_regs *regs) \

{						\

	siginfo_t info = {			\

		.si_signo = signr,		\

		.si_errno = 0,			\

		.si_code  = sicode,		\

		.si_addr = (void __user *)address,	\

	};					\

	return handle_exception(cause, str, regs, &info);\

}

/*

 * Entry points for exceptions NOT needing specific handling

 */

DO_ERROR_INFO(SIGILL, "Priv Op/Disabled Extn", do_privilege_fault, ILL_PRVOPC)

DO_ERROR_INFO(SIGILL, "Invalid Extn Insn", do_extension_fault, ILL_ILLOPC)

DO_ERROR_INFO(SIGILL, "Illegal Insn (or Seq)", insterror_is_error, ILL_ILLOPC)

DO_ERROR_INFO(SIGBUS, "Invalid Mem Access", do_memory_error, BUS_ADRERR)

DO_ERROR_INFO(SIGTRAP, "Breakpoint Set", trap_is_brkpt, TRAP_BRKPT)

DO_ERROR_INFO(SIGSEGV, "Misaligned Access", do_misaligned_access, SEGV_ACCERR)

/*

 * Entry point for miscll errors such as Nested Exceptions

 *  -Duplicate TLB entry is handled seperately though

 */

void do_machine_check_fault(unsigned long cause, unsigned long address,

			    struct pt_regs *regs)

{

	die("Machine Check Exception", regs, address, cause);

}

/*

 * Entry point for traps induced by ARCompact TRAP_S <n> insn

 * This is same family as TRAP0/SWI insn (use the same vector).

 * The only difference being SWI insn take no operand, while TRAP_S does

 * which reflects in ECR Reg as 8 bit param.

 * Thus TRAP_S <n> can be used for specific purpose

 *  -1 used for software breakpointing (gdb)

 *  -2 used by kprobes

 */

void do_non_swi_trap(unsigned long cause, unsigned long address,

			struct pt_regs *regs)

{

	unsigned int param = cause & 0xff;

	switch (param) {

	case 1:

		trap_is_brkpt(cause, address, regs);

		break;

	default:

		break;

	}

}

/*

 * Entry point for Instruction Error Exception

 */

void do_insterror_or_kprobe(unsigned long cause,

				       unsigned long address,

				       struct pt_regs *regs)

{

	insterror_is_error(cause, address, regs);

}