/*
 * arch/score/kernel/traps.c
 *
 * Score Processor version.
 *
 * Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
 *  Chen Liqin <liqin.chen@sunplusct.com>
 *  Lennox Wu <lennox.wu@sunplusct.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see the file COPYING, or write
 * to the Free Software Foundation, Inc.,
 * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include <linux/extable.h>
#include <linux/ptrace.h>
#include <linux/sched/mm.h>
#include <linux/sched/signal.h>
#include <linux/sched/debug.h>
#include <linux/mm_types.h>

#include <asm/cacheflush.h>
#include <asm/irq.h>
#include <asm/irq_regs.h>
#include <linux/uaccess.h>

unsigned long exception_handlers[32];

/*
 * The architecture-independent show_stack generator
 */
void show_stack(struct task_struct *task, unsigned long *sp)
{
	int i;
	long stackdata;

	sp = sp ? sp : (unsigned long *)&sp;

	printk(KERN_NOTICE "Stack: ");
	i = 1;
	while ((long) sp & (PAGE_SIZE - 1)) {
		if (i && ((i % 8) == 0))
			printk(KERN_NOTICE "\n");
		if (i > 40) {
			printk(KERN_NOTICE " ...");
			break;
		}

		if (__get_user(stackdata, sp++)) {
			printk(KERN_NOTICE " (Bad stack address)");
			break;
		}

		printk(KERN_NOTICE " %08lx", stackdata);
		i++;
	}
	printk(KERN_NOTICE "\n");
}

static void show_trace(long *sp)
{
	int i;
	long addr;

	sp = sp ? sp : (long *) &sp;

	printk(KERN_NOTICE "Call Trace:  ");
	i = 1;
	while ((long) sp & (PAGE_SIZE - 1)) {
		if (__get_user(addr, sp++)) {
			if (i && ((i % 6) == 0))
				printk(KERN_NOTICE "\n");
			printk(KERN_NOTICE " (Bad stack address)\n");
			break;
		}

		if (kernel_text_address(addr)) {
			if (i && ((i % 6) == 0))
				printk(KERN_NOTICE "\n");
			if (i > 40) {
				printk(KERN_NOTICE " ...");
				break;
			}

			printk(KERN_NOTICE " [<%08lx>]", addr);
			i++;
		}
	}
	printk(KERN_NOTICE "\n");
}

static void show_code(unsigned int *pc)
{
	long i;

	printk(KERN_NOTICE "\nCode:");

	for (i = -3; i < 6; i++) {
		unsigned long insn;
		if (__get_user(insn, pc + i)) {
			printk(KERN_NOTICE " (Bad address in epc)\n");
			break;
		}
		printk(KERN_NOTICE "%c%08lx%c", (i ? ' ' : '<'),
			insn, (i ? ' ' : '>'));
	}
}

/*
 * FIXME: really the generic show_regs should take a const pointer argument.
 */
void show_regs(struct pt_regs *regs)
{
	show_regs_print_info(KERN_DEFAULT);

	printk("r0 : %08lx %08lx %08lx %08lx %08lx %08lx %08lx %08lx\n",
		regs->regs[0], regs->regs[1], regs->regs[2], regs->regs[3],
		regs->regs[4], regs->regs[5], regs->regs[6], regs->regs[7]);
	printk("r8 : %08lx %08lx %08lx %08lx %08lx %08lx %08lx %08lx\n",
		regs->regs[8], regs->regs[9], regs->regs[10], regs->regs[11],
		regs->regs[12], regs->regs[13], regs->regs[14], regs->regs[15]);
	printk("r16: %08lx %08lx %08lx %08lx %08lx %08lx %08lx %08lx\n",
		regs->regs[16], regs->regs[17], regs->regs[18], regs->regs[19],
		regs->regs[20], regs->regs[21], regs->regs[22], regs->regs[23]);
	printk("r24: %08lx %08lx %08lx %08lx %08lx %08lx %08lx %08lx\n",
		regs->regs[24], regs->regs[25], regs->regs[26], regs->regs[27],
		regs->regs[28], regs->regs[29], regs->regs[30], regs->regs[31]);

	printk("CEH : %08lx\n", regs->ceh);
	printk("CEL : %08lx\n", regs->cel);

	printk("EMA:%08lx, epc:%08lx %s\nPSR: %08lx\nECR:%08lx\nCondition : %08lx\n",
		regs->cp0_ema, regs->cp0_epc, print_tainted(), regs->cp0_psr,
		regs->cp0_ecr, regs->cp0_condition);
}

static void show_registers(struct pt_regs *regs)
{
	show_regs(regs);
	printk(KERN_NOTICE "Process %s (pid: %d, stackpage=%08lx)\n",
		current->comm, current->pid, (unsigned long) current);
	show_stack(current_thread_info()->task, (long *) regs->regs[0]);
	show_trace((long *) regs->regs[0]);
	show_code((unsigned int *) regs->cp0_epc);
	printk(KERN_NOTICE "\n");
}

void __die(const char *str, struct pt_regs *regs, const char *file,
	const char *func, unsigned long line)
{
	console_verbose();
	printk("%s", str);
	if (file && func)
		printk(" in %s:%s, line %ld", file, func, line);
	printk(":\n");
	show_registers(regs);
	do_exit(SIGSEGV);
}

void __die_if_kernel(const char *str, struct pt_regs *regs,
		const char *file, const char *func, unsigned long line)
{
	if (!user_mode(regs))
		__die(str, regs, file, func, line);
}

asmlinkage void do_adelinsn(struct pt_regs *regs)
{
	printk("do_ADE-linsn:ema:0x%08lx:epc:0x%08lx\n",
		 regs->cp0_ema, regs->cp0_epc);
	die_if_kernel("do_ade execution Exception\n", regs);
	force_sig(SIGBUS, current);
}

asmlinkage void do_adedata(struct pt_regs *regs)
{
	const struct exception_table_entry *fixup;
	fixup = search_exception_tables(regs->cp0_epc);
	if (fixup) {
		regs->cp0_epc = fixup->fixup;
		return;
	}
	printk("do_ADE-data:ema:0x%08lx:epc:0x%08lx\n",
		 regs->cp0_ema, regs->cp0_epc);
	die_if_kernel("do_ade execution Exception\n", regs);
	force_sig(SIGBUS, current);
}

asmlinkage void do_pel(struct pt_regs *regs)
{
	die_if_kernel("do_pel execution Exception", regs);
	force_sig(SIGFPE, current);
}

asmlinkage void do_cee(struct pt_regs *regs)
{
	die_if_kernel("do_cee execution Exception", regs);
	force_sig(SIGFPE, current);
}

asmlinkage void do_cpe(struct pt_regs *regs)
{
	die_if_kernel("do_cpe execution Exception", regs);
	force_sig(SIGFPE, current);
}

asmlinkage void do_be(struct pt_regs *regs)
{
	die_if_kernel("do_be execution Exception", regs);
	force_sig(SIGBUS, current);
}

asmlinkage void do_ov(struct pt_regs *regs)
{
	siginfo_t info;

	die_if_kernel("do_ov execution Exception", regs);

	info.si_code = FPE_INTOVF;
	info.si_signo = SIGFPE;
	info.si_errno = 0;
	info.si_addr = (void *)regs->cp0_epc;
	force_sig_info(SIGFPE, &info, current);
}

asmlinkage void do_tr(struct pt_regs *regs)
{
	die_if_kernel("do_tr execution Exception", regs);
	force_sig(SIGTRAP, current);
}

asmlinkage void do_ri(struct pt_regs *regs)
{
	unsigned long epc_insn;
	unsigned long epc = regs->cp0_epc;

	read_tsk_long(current, epc, &epc_insn);
	if (current->thread.single_step == 1) {
		if ((epc == current->thread.addr1) ||
		    (epc == current->thread.addr2)) {
			user_disable_single_step(current);
			force_sig(SIGTRAP, current);
			return;
		} else
			BUG();
	} else if ((epc_insn == BREAKPOINT32_INSN) ||
		   ((epc_insn & 0x0000FFFF) == 0x7002) ||
		   ((epc_insn & 0xFFFF0000) == 0x70020000)) {
			force_sig(SIGTRAP, current);
			return;
	} else {
		die_if_kernel("do_ri execution Exception", regs);
		force_sig(SIGILL, current);
	}
}

asmlinkage void do_ccu(struct pt_regs *regs)
{
	die_if_kernel("do_ccu execution Exception", regs);
	force_sig(SIGILL, current);
}

asmlinkage void do_reserved(struct pt_regs *regs)
{
	/*
	 * Game over - no way to handle this if it ever occurs.  Most probably
	 * caused by a new unknown cpu type or after another deadly
	 * hard/software error.
	 */
	die_if_kernel("do_reserved execution Exception", regs);
	show_regs(regs);
	panic("Caught reserved exception - should not happen.");
}

/*
 * NMI exception handler.
 */
void nmi_exception_handler(struct pt_regs *regs)
{
	die_if_kernel("nmi_exception_handler execution Exception", regs);
	die("NMI", regs);
}

/* Install CPU exception handler */
void *set_except_vector(int n, void *addr)
{
	unsigned long handler = (unsigned long) addr;
	unsigned long old_handler = exception_handlers[n];

	exception_handlers[n] = handler;
	return (void *)old_handler;
}

void __init trap_init(void)
{
	int i;

	pgd_current = (unsigned long)init_mm.pgd;
	/* DEBUG EXCEPTION */
	memcpy((void *)DEBUG_VECTOR_BASE_ADDR,
			&debug_exception_vector, DEBUG_VECTOR_SIZE);
	/* NMI EXCEPTION */
	memcpy((void *)GENERAL_VECTOR_BASE_ADDR,
			&general_exception_vector, GENERAL_VECTOR_SIZE);

	/*
	 * Initialise exception handlers
	 */
	for (i = 0; i <= 31; i++)
		set_except_vector(i, handle_reserved);

	set_except_vector(1, handle_nmi);
	set_except_vector(2, handle_adelinsn);
	set_except_vector(3, handle_tlb_refill);
	set_except_vector(4, handle_tlb_invaild);
	set_except_vector(5, handle_ibe);
	set_except_vector(6, handle_pel);
	set_except_vector(7, handle_sys);
	set_except_vector(8, handle_ccu);
	set_except_vector(9, handle_ri);
	set_except_vector(10, handle_tr);
	set_except_vector(11, handle_adedata);
	set_except_vector(12, handle_adedata);
	set_except_vector(13, handle_tlb_refill);
	set_except_vector(14, handle_tlb_invaild);
	set_except_vector(15, handle_mod);
	set_except_vector(16, handle_cee);
	set_except_vector(17, handle_cpe);
	set_except_vector(18, handle_dbe);
	flush_icache_range(DEBUG_VECTOR_BASE_ADDR, IRQ_VECTOR_BASE_ADDR);

	mmgrab(&init_mm);
	current->active_mm = &init_mm;
	cpu_cache_init();
}