/* $Id: traps.c,v 1.60 1999/08/14 03:51:31 anton Exp $
 * arch/sparc/kernel/traps.c
 *
 * Copyright 1995 David S. Miller (davem@caip.rutgers.edu)
 */

/*
 * I hate traps on the sparc, grrr...
 */

#include <linux/sched.h>  /* for jiffies */
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>

#include <asm/delay.h>
#include <asm/system.h>
#include <asm/ptrace.h>
#include <asm/oplib.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/kdebug.h>
#include <asm/unistd.h>
#include <asm/traps.h>

/* #define TRAP_DEBUG */

struct trap_trace_entry {
	unsigned long pc;
	unsigned long type;
};

int trap_curbuf = 0;
struct trap_trace_entry trapbuf[1024];

void syscall_trace_entry(struct pt_regs *regs)
{
	printk("%s[%d]: ", current->comm, current->pid);
	printk("scall<%d> (could be %d)\n", (int) regs->u_regs[UREG_G1],
	       (int) regs->u_regs[UREG_I0]);
}

void syscall_trace_exit(struct pt_regs *regs)
{
}

void sun4m_nmi(struct pt_regs *regs)
{
	unsigned long afsr, afar;

	printk("Aieee: sun4m NMI received!\n");
	/* XXX HyperSparc hack XXX */
	__asm__ __volatile__("mov 0x500, %%g1\n\t"
			     "lda [%%g1] 0x4, %0\n\t"
			     "mov 0x600, %%g1\n\t"
			     "lda [%%g1] 0x4, %1\n\t" :
			     "=r" (afsr), "=r" (afar));
	printk("afsr=%08lx afar=%08lx\n", afsr, afar);
	printk("you lose buddy boy...\n");
	show_regs(regs);
	prom_halt();
}

void sun4d_nmi(struct pt_regs *regs)
{
	printk("Aieee: sun4d NMI received!\n");
	printk("you lose buddy boy...\n");
	show_regs(regs);
	prom_halt();
}

void instruction_dump (unsigned long *pc)
{
	int i;
	
	if((((unsigned long) pc) & 3))
                return;

	for(i = -3; i < 6; i++)
		printk("%c%08lx%c",i?' ':'<',pc[i],i?' ':'>');
	printk("\n");
}

#define __SAVE __asm__ __volatile__("save %sp, -0x40, %sp\n\t")
#define __RESTORE __asm__ __volatile__("restore %g0, %g0, %g0\n\t")

void die_if_kernel(char *str, struct pt_regs *regs)
{
	int count = 0;

	/* Amuse the user. */
	printk(
"              \\|/ ____ \\|/\n"
"              \"@'/ ,. \\`@\"\n"
"              /_| \\__/ |_\\\n"
"                 \\__U_/\n");

	printk("%s(%d): %s\n", current->comm, current->pid, str);
	show_regs(regs);

	__SAVE; __SAVE; __SAVE; __SAVE;
	__SAVE; __SAVE; __SAVE; __SAVE;
	__RESTORE; __RESTORE; __RESTORE; __RESTORE;
	__RESTORE; __RESTORE; __RESTORE; __RESTORE;

	{
		struct reg_window *rw = (struct reg_window *)regs->u_regs[UREG_FP];

		/* Stop the back trace when we hit userland or we
		 * find some badly aligned kernel stack. Set an upper
		 * bound in case our stack is trashed and we loop.
		 */
		while(rw					&&
		      count++ < 30				&&
                      (((unsigned long) rw) >= PAGE_OFFSET)	&&
		      !(((unsigned long) rw) & 0x7)) {
			printk("Caller[%08lx]\n", rw->ins[7]);
			rw = (struct reg_window *)rw->ins[6];
		}
	}
	printk("Instruction DUMP:");
	instruction_dump ((unsigned long *) regs->pc);
	if(regs->psr & PSR_PS)
		do_exit(SIGKILL);
	do_exit(SIGSEGV);
}

void do_hw_interrupt(unsigned long type, unsigned long psr, unsigned long pc)
{
	lock_kernel();
	if(type < 0x80) {
		/* Sun OS's puke from bad traps, Linux survives! */
		printk("Unimplemented Sparc TRAP, type = %02lx\n", type);
		die_if_kernel("Whee... Hello Mr. Penguin", current->thread.kregs);
	}	

	if(type == SP_TRAP_SBPT) {
		send_sig(SIGTRAP, current, 1);
	} else {
		if(psr & PSR_PS)
			die_if_kernel("Kernel bad trap", current->thread.kregs);

		current->thread.sig_desc = SUBSIG_BADTRAP(type - 0x80);
		current->thread.sig_address = pc;
		send_sig(SIGILL, current, 1);
	}
	unlock_kernel();
}

void do_illegal_instruction(struct pt_regs *regs, unsigned long pc, unsigned long npc,
			    unsigned long psr)
{
	lock_kernel();
	if(psr & PSR_PS)
		die_if_kernel("Kernel illegal instruction", regs);
#ifdef TRAP_DEBUG
	printk("Ill instr. at pc=%08lx instruction is %08lx\n",
	       regs->pc, *(unsigned long *)regs->pc);
#endif
	if (sparc_cpu_model == sun4c || sparc_cpu_model == sun4) {
		extern int do_user_muldiv (struct pt_regs *, unsigned long);
		if (!do_user_muldiv (regs, pc))
			goto out;
	}
	current->thread.sig_address = pc;
	current->thread.sig_desc = SUBSIG_ILLINST;
	send_sig(SIGILL, current, 1);
out:
	unlock_kernel();
}

void do_priv_instruction(struct pt_regs *regs, unsigned long pc, unsigned long npc,
			 unsigned long psr)
{
	lock_kernel();
	if(psr & PSR_PS)
		die_if_kernel("Penguin instruction from Penguin mode??!?!", regs);
	current->thread.sig_address = pc;
	current->thread.sig_desc = SUBSIG_PRIVINST;
	send_sig(SIGILL, current, 1);
	unlock_kernel();
}

/* XXX User may want to be allowed to do this. XXX */

void do_memaccess_unaligned(struct pt_regs *regs, unsigned long pc, unsigned long npc,
			    unsigned long psr)
{
	lock_kernel();
	if(regs->psr & PSR_PS) {
		printk("KERNEL MNA at pc %08lx npc %08lx called by %08lx\n", pc, npc,
		       regs->u_regs[UREG_RETPC]);
		die_if_kernel("BOGUS", regs);
		/* die_if_kernel("Kernel MNA access", regs); */
	}
	current->thread.sig_address = pc;
	current->thread.sig_desc = SUBSIG_PRIVINST;
#if 0
	show_regs (regs);
	instruction_dump ((unsigned long *) regs->pc);
	printk ("do_MNA!\n");
#endif
	send_sig(SIGBUS, current, 1);
	unlock_kernel();
}

extern void fpsave(unsigned long *fpregs, unsigned long *fsr,
		   void *fpqueue, unsigned long *fpqdepth);
extern void fpload(unsigned long *fpregs, unsigned long *fsr);

static unsigned long init_fsr = 0x0UL;
static unsigned long init_fregs[32] __attribute__ ((aligned (8))) =
                { ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL,
		  ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL,
		  ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL,
		  ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL };

void do_fpd_trap(struct pt_regs *regs, unsigned long pc, unsigned long npc,
		 unsigned long psr)
{
	lock_kernel();
	/* Sanity check... */
	if(psr & PSR_PS)
		die_if_kernel("Kernel gets FloatingPenguinUnit disabled trap", regs);

	put_psr(get_psr() | PSR_EF);    /* Allow FPU ops. */
	regs->psr |= PSR_EF;
#ifndef __SMP__
	if(last_task_used_math == current)
		goto out;
	if(last_task_used_math) {
		/* Other processes fpu state, save away */
		struct task_struct *fptask = last_task_used_math;
		fpsave(&fptask->thread.float_regs[0], &fptask->thread.fsr,
		       &fptask->thread.fpqueue[0], &fptask->thread.fpqdepth);
	}
	last_task_used_math = current;
	if(current->used_math) {
		fpload(&current->thread.float_regs[0], &current->thread.fsr);
	} else {
		/* Set initial sane state. */
		fpload(&init_fregs[0], &init_fsr);
		current->used_math = 1;
	}
#else
	if(!current->used_math) {
		fpload(&init_fregs[0], &init_fsr);
		current->used_math = 1;
	} else {
		fpload(&current->thread.float_regs[0], &current->thread.fsr);
	}
	current->flags |= PF_USEDFPU;
#endif
#ifndef __SMP__
out:
#endif
	unlock_kernel();
}

static unsigned long fake_regs[32] __attribute__ ((aligned (8)));
static unsigned long fake_fsr;
static unsigned long fake_queue[32] __attribute__ ((aligned (8)));
static unsigned long fake_depth;

extern int do_mathemu(struct pt_regs *, struct task_struct *);

void do_fpe_trap(struct pt_regs *regs, unsigned long pc, unsigned long npc,
		 unsigned long psr)
{
	static int calls = 0;
	int ret = 0;
#ifndef __SMP__
	struct task_struct *fpt = last_task_used_math;
#else
	struct task_struct *fpt = current;
#endif
	lock_kernel();
	put_psr(get_psr() | PSR_EF);
	/* If nobody owns the fpu right now, just clear the
	 * error into our fake static buffer and hope it don't
	 * happen again.  Thank you crashme...
	 */
#ifndef __SMP__
	if(!fpt) {
#else
        if(!(fpt->flags & PF_USEDFPU)) {
#endif
		fpsave(&fake_regs[0], &fake_fsr, &fake_queue[0], &fake_depth);
		regs->psr &= ~PSR_EF;
		goto out;
	}
	fpsave(&fpt->thread.float_regs[0], &fpt->thread.fsr,
	       &fpt->thread.fpqueue[0], &fpt->thread.fpqdepth);
#ifdef DEBUG_FPU
	printk("Hmm, FP exception, fsr was %016lx\n", fpt->thread.fsr);
#endif

	switch ((fpt->thread.fsr & 0x1c000)) {
	/* switch on the contents of the ftt [floating point trap type] field */
#ifdef DEBUG_FPU
	case (1 << 14):
		printk("IEEE_754_exception\n");
		break;
#endif
	case (2 << 14):  /* unfinished_FPop (underflow & co) */
	case (3 << 14):  /* unimplemented_FPop (quad stuff, maybe sqrt) */
		ret = do_mathemu(regs, fpt);
		break;
#ifdef DEBUG_FPU
	case (4 << 14):
		printk("sequence_error (OS bug...)\n");
		break;
	case (5 << 14):
		printk("hardware_error (uhoh!)\n");
		break;
	case (6 << 14):
		printk("invalid_fp_register (user error)\n");
		break;
#endif /* DEBUG_FPU */
	}
	/* If we successfully emulated the FPop, we pretend the trap never happened :-> */
	if (ret) {
		fpload(&current->thread.float_regs[0], &current->thread.fsr);
		return;
	}
	/* nope, better SIGFPE the offending process... */
	       
	fpt->thread.sig_address = pc;
	fpt->thread.sig_desc = SUBSIG_FPERROR; /* as good as any */
#ifdef __SMP__
	fpt->flags &= ~PF_USEDFPU;
#endif
	if(psr & PSR_PS) {
		/* The first fsr store/load we tried trapped,
		 * the second one will not (we hope).
		 */
		printk("WARNING: FPU exception from kernel mode. at pc=%08lx\n",
		       regs->pc);
		regs->pc = regs->npc;
		regs->npc += 4;
		calls++;
		if(calls > 2)
			die_if_kernel("Too many Penguin-FPU traps from kernel mode",
				      regs);
		goto out;
	}
	send_sig(SIGFPE, fpt, 1);
#ifndef __SMP__
	last_task_used_math = NULL;
#endif
	regs->psr &= ~PSR_EF;
	if(calls > 0)
		calls=0;
out:
	unlock_kernel();
}

void handle_tag_overflow(struct pt_regs *regs, unsigned long pc, unsigned long npc,
			 unsigned long psr)
{
	lock_kernel();
	if(psr & PSR_PS)
		die_if_kernel("Penguin overflow trap from kernel mode", regs);
	current->thread.sig_address = pc;
	current->thread.sig_desc = SUBSIG_TAG; /* as good as any */
	send_sig(SIGEMT, current, 1);
	unlock_kernel();
}

void handle_watchpoint(struct pt_regs *regs, unsigned long pc, unsigned long npc,
		       unsigned long psr)
{
	lock_kernel();
#ifdef TRAP_DEBUG
	printk("Watchpoint detected at PC %08lx NPC %08lx PSR %08lx\n",
	       pc, npc, psr);
#endif
	if(psr & PSR_PS)
		panic("Tell me what a watchpoint trap is, and I'll then deal "
		      "with such a beast...");
	unlock_kernel();
}

void handle_reg_access(struct pt_regs *regs, unsigned long pc, unsigned long npc,
		       unsigned long psr)
{
	lock_kernel();
#ifdef TRAP_DEBUG
	printk("Register Access Exception at PC %08lx NPC %08lx PSR %08lx\n",
	       pc, npc, psr);
#endif
	send_sig(SIGILL, current, 1);
	unlock_kernel();
}

void handle_cp_disabled(struct pt_regs *regs, unsigned long pc, unsigned long npc,
			unsigned long psr)
{
	lock_kernel();
	send_sig(SIGILL, current, 1);
	unlock_kernel();
}

void handle_cp_exception(struct pt_regs *regs, unsigned long pc, unsigned long npc,
			 unsigned long psr)
{
	lock_kernel();
#ifdef TRAP_DEBUG
	printk("Co-Processor Exception at PC %08lx NPC %08lx PSR %08lx\n",
	       pc, npc, psr);
#endif
	send_sig(SIGILL, current, 1);
	unlock_kernel();
}

void handle_hw_divzero(struct pt_regs *regs, unsigned long pc, unsigned long npc,
		       unsigned long psr)
{
	lock_kernel();
	send_sig(SIGILL, current, 1);
	unlock_kernel();
}

/* Since we have our mappings set up, on multiprocessors we can spin them
 * up here so that timer interrupts work during initialization.
 */

extern void sparc_cpu_startup(void);

extern ctxd_t *srmmu_ctx_table_phys;

int linux_smp_still_initting;
unsigned int thiscpus_tbr;
int thiscpus_mid;

void trap_init(void)
{
	/* Attach to the address space of init_task. */
	atomic_inc(&init_mm.mm_count);
	current->active_mm = &init_mm;

	/* NOTE: Other cpus have this done as they are started
	 *       up on SMP.
	 */
}