/*
 * arch/alpha/kernel/traps.c
 *
 * (C) Copyright 1994 Linus Torvalds
 */

/*
 * This file initializes the trap entry points
 */

#include <linux/jiffies.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/tty.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/kallsyms.h>
#include <linux/ratelimit.h>

#include <asm/gentrap.h>
#include <asm/uaccess.h>
#include <asm/unaligned.h>
#include <asm/sysinfo.h>
#include <asm/hwrpb.h>
#include <asm/mmu_context.h>
#include <asm/special_insns.h>

#include "proto.h"

/* Work-around for some SRMs which mishandle opDEC faults.  */

static int opDEC_fix;

static void __cpuinit
opDEC_check(void)
{
	__asm__ __volatile__ (
	/* Load the address of... */
	"	br	$16, 1f\n"
	/* A stub instruction fault handler.  Just add 4 to the
	   pc and continue.  */
	"	ldq	$16, 8($sp)\n"
	"	addq	$16, 4, $16\n"
	"	stq	$16, 8($sp)\n"
	"	call_pal %[rti]\n"
	/* Install the instruction fault handler.  */
	"1:	lda	$17, 3\n"
	"	call_pal %[wrent]\n"
	/* With that in place, the fault from the round-to-minf fp
	   insn will arrive either at the "lda 4" insn (bad) or one
	   past that (good).  This places the correct fixup in %0.  */
	"	lda %[fix], 0\n"
	"	cvttq/svm $f31,$f31\n"
	"	lda %[fix], 4"
	: [fix] "=r" (opDEC_fix)
	: [rti] "n" (PAL_rti), [wrent] "n" (PAL_wrent)
	: "$0", "$1", "$16", "$17", "$22", "$23", "$24", "$25");

	if (opDEC_fix)
		printk("opDEC fixup enabled.\n");
}

void
dik_show_regs(struct pt_regs *regs, unsigned long *r9_15)
{
	printk("pc = [<%016lx>]  ra = [<%016lx>]  ps = %04lx    %s\n",
	       regs->pc, regs->r26, regs->ps, print_tainted());
	print_symbol("pc is at %s\n", regs->pc);
	print_symbol("ra is at %s\n", regs->r26 );
	printk("v0 = %016lx  t0 = %016lx  t1 = %016lx\n",
	       regs->r0, regs->r1, regs->r2);
	printk("t2 = %016lx  t3 = %016lx  t4 = %016lx\n",
 	       regs->r3, regs->r4, regs->r5);
	printk("t5 = %016lx  t6 = %016lx  t7 = %016lx\n",
	       regs->r6, regs->r7, regs->r8);

	if (r9_15) {
		printk("s0 = %016lx  s1 = %016lx  s2 = %016lx\n",
		       r9_15[9], r9_15[10], r9_15[11]);
		printk("s3 = %016lx  s4 = %016lx  s5 = %016lx\n",
		       r9_15[12], r9_15[13], r9_15[14]);
		printk("s6 = %016lx\n", r9_15[15]);
	}

	printk("a0 = %016lx  a1 = %016lx  a2 = %016lx\n",
	       regs->r16, regs->r17, regs->r18);
	printk("a3 = %016lx  a4 = %016lx  a5 = %016lx\n",
 	       regs->r19, regs->r20, regs->r21);
 	printk("t8 = %016lx  t9 = %016lx  t10= %016lx\n",
	       regs->r22, regs->r23, regs->r24);
	printk("t11= %016lx  pv = %016lx  at = %016lx\n",
	       regs->r25, regs->r27, regs->r28);
	printk("gp = %016lx  sp = %p\n", regs->gp, regs+1);
#if 0
__halt();
#endif
}

#if 0
static char * ireg_name[] = {"v0", "t0", "t1", "t2", "t3", "t4", "t5", "t6",
			   "t7", "s0", "s1", "s2", "s3", "s4", "s5", "s6",
			   "a0", "a1", "a2", "a3", "a4", "a5", "t8", "t9",
			   "t10", "t11", "ra", "pv", "at", "gp", "sp", "zero"};
#endif

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

	printk("Code:");
	for (i = -6; i < 2; i++) {
		unsigned int insn;
		if (__get_user(insn, (unsigned int __user *)pc + i))
			break;
		printk("%c%08x%c", i ? ' ' : '<', insn, i ? ' ' : '>');
	}
	printk("\n");
}

static void
dik_show_trace(unsigned long *sp)
{
	long i = 0;
	printk("Trace:\n");
	while (0x1ff8 & (unsigned long) sp) {
		extern char _stext[], _etext[];
		unsigned long tmp = *sp;
		sp++;
		if (tmp < (unsigned long) &_stext)
			continue;
		if (tmp >= (unsigned long) &_etext)
			continue;
		printk("[<%lx>]", tmp);
		print_symbol(" %s", tmp);
		printk("\n");
		if (i > 40) {
			printk(" ...");
			break;
		}
	}
	printk("\n");
}

static int kstack_depth_to_print = 24;

void show_stack(struct task_struct *task, unsigned long *sp)
{
	unsigned long *stack;
	int i;

	/*
	 * debugging aid: "show_stack(NULL);" prints the
	 * back trace for this cpu.
	 */
	if(sp==NULL)
		sp=(unsigned long*)&sp;

	stack = sp;
	for(i=0; i < kstack_depth_to_print; i++) {
		if (((long) stack & (THREAD_SIZE-1)) == 0)
			break;
		if (i && ((i % 4) == 0))
			printk("\n       ");
		printk("%016lx ", *stack++);
	}
	printk("\n");
	dik_show_trace(sp);
}

void dump_stack(void)
{
	show_stack(NULL, NULL);
}

EXPORT_SYMBOL(dump_stack);

void
die_if_kernel(char * str, struct pt_regs *regs, long err, unsigned long *r9_15)
{
	if (regs->ps & 8)
		return;
#ifdef CONFIG_SMP
	printk("CPU %d ", hard_smp_processor_id());
#endif
	printk("%s(%d): %s %ld\n", current->comm, task_pid_nr(current), str, err);
	dik_show_regs(regs, r9_15);
	add_taint(TAINT_DIE);
	dik_show_trace((unsigned long *)(regs+1));
	dik_show_code((unsigned int *)regs->pc);

	if (test_and_set_thread_flag (TIF_DIE_IF_KERNEL)) {
		printk("die_if_kernel recursion detected.\n");
		local_irq_enable();
		while (1);
	}
	do_exit(SIGSEGV);
}

#ifndef CONFIG_MATHEMU
static long dummy_emul(void) { return 0; }
long (*alpha_fp_emul_imprecise)(struct pt_regs *regs, unsigned long writemask)
  = (void *)dummy_emul;
long (*alpha_fp_emul) (unsigned long pc)
  = (void *)dummy_emul;
#else
long alpha_fp_emul_imprecise(struct pt_regs *regs, unsigned long writemask);
long alpha_fp_emul (unsigned long pc);
#endif

asmlinkage void
do_entArith(unsigned long summary, unsigned long write_mask,
	    struct pt_regs *regs)
{
	long si_code = FPE_FLTINV;
	siginfo_t info;

	if (summary & 1) {
		/* Software-completion summary bit is set, so try to
		   emulate the instruction.  If the processor supports
		   precise exceptions, we don't have to search.  */
		if (!amask(AMASK_PRECISE_TRAP))
			si_code = alpha_fp_emul(regs->pc - 4);
		else
			si_code = alpha_fp_emul_imprecise(regs, write_mask);
		if (si_code == 0)
			return;
	}
	die_if_kernel("Arithmetic fault", regs, 0, NULL);

	info.si_signo = SIGFPE;
	info.si_errno = 0;
	info.si_code = si_code;
	info.si_addr = (void __user *) regs->pc;
	send_sig_info(SIGFPE, &info, current);
}

asmlinkage void
do_entIF(unsigned long type, struct pt_regs *regs)
{
	siginfo_t info;
	int signo, code;

	if ((regs->ps & ~IPL_MAX) == 0) {
		if (type == 1) {
			const unsigned int *data
			  = (const unsigned int *) regs->pc;
			printk("Kernel bug at %s:%d\n",
			       (const char *)(data[1] | (long)data[2] << 32), 
			       data[0]);
		}
		die_if_kernel((type == 1 ? "Kernel Bug" : "Instruction fault"),
			      regs, type, NULL);
	}

	switch (type) {
	      case 0: /* breakpoint */
		info.si_signo = SIGTRAP;
		info.si_errno = 0;
		info.si_code = TRAP_BRKPT;
		info.si_trapno = 0;
		info.si_addr = (void __user *) regs->pc;

		if (ptrace_cancel_bpt(current)) {
			regs->pc -= 4;	/* make pc point to former bpt */
		}

		send_sig_info(SIGTRAP, &info, current);
		return;