traps.c 45.3 KB
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/*
 *  Copyright (C) 1995-1996  Gary Thomas (gdt@linuxppc.org)
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 *  Copyright 2007-2010 Freescale Semiconductor, Inc.
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 *
 *  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.
 *
 *  Modified by Cort Dougan (cort@cs.nmt.edu)
 *  and Paul Mackerras (paulus@samba.org)
 */

/*
 * This file handles the architecture-dependent parts of hardware exceptions
 */

#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
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#include <linux/ptrace.h>
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#include <linux/user.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/module.h>
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#include <linux/prctl.h>
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#include <linux/delay.h>
#include <linux/kprobes.h>
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#include <linux/kexec.h>
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#include <linux/backlight.h>
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#include <linux/bug.h>
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#include <linux/kdebug.h>
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#include <linux/debugfs.h>
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#include <linux/ratelimit.h>
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#include <asm/emulated_ops.h>
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#include <asm/pgtable.h>
#include <asm/uaccess.h>
#include <asm/io.h>
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#include <asm/machdep.h>
#include <asm/rtas.h>
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#include <asm/pmc.h>
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#ifdef CONFIG_PPC32
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#include <asm/reg.h>
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#endif
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#ifdef CONFIG_PMAC_BACKLIGHT
#include <asm/backlight.h>
#endif
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#ifdef CONFIG_PPC64
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#include <asm/firmware.h>
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#include <asm/processor.h>
#endif
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#include <asm/kexec.h>
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#include <asm/ppc-opcode.h>
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#include <asm/rio.h>
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#include <asm/fadump.h>
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#include <asm/switch_to.h>
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#include <asm/tm.h>
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#include <asm/debug.h>
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#if defined(CONFIG_DEBUGGER) || defined(CONFIG_KEXEC)
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int (*__debugger)(struct pt_regs *regs) __read_mostly;
int (*__debugger_ipi)(struct pt_regs *regs) __read_mostly;
int (*__debugger_bpt)(struct pt_regs *regs) __read_mostly;
int (*__debugger_sstep)(struct pt_regs *regs) __read_mostly;
int (*__debugger_iabr_match)(struct pt_regs *regs) __read_mostly;
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int (*__debugger_break_match)(struct pt_regs *regs) __read_mostly;
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int (*__debugger_fault_handler)(struct pt_regs *regs) __read_mostly;
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EXPORT_SYMBOL(__debugger);
EXPORT_SYMBOL(__debugger_ipi);
EXPORT_SYMBOL(__debugger_bpt);
EXPORT_SYMBOL(__debugger_sstep);
EXPORT_SYMBOL(__debugger_iabr_match);
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EXPORT_SYMBOL(__debugger_break_match);
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EXPORT_SYMBOL(__debugger_fault_handler);
#endif

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/* Transactional Memory trap debug */
#ifdef TM_DEBUG_SW
#define TM_DEBUG(x...) printk(KERN_INFO x)
#else
#define TM_DEBUG(x...) do { } while(0)
#endif

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/*
 * Trap & Exception support
 */

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#ifdef CONFIG_PMAC_BACKLIGHT
static void pmac_backlight_unblank(void)
{
	mutex_lock(&pmac_backlight_mutex);
	if (pmac_backlight) {
		struct backlight_properties *props;

		props = &pmac_backlight->props;
		props->brightness = props->max_brightness;
		props->power = FB_BLANK_UNBLANK;
		backlight_update_status(pmac_backlight);
	}
	mutex_unlock(&pmac_backlight_mutex);
}
#else
static inline void pmac_backlight_unblank(void) { }
#endif

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static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
static int die_owner = -1;
static unsigned int die_nest_count;
static int die_counter;

static unsigned __kprobes long oops_begin(struct pt_regs *regs)
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{
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	int cpu;
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	unsigned long flags;
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	if (debugger(regs))
		return 1;

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	oops_enter();

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	/* racy, but better than risking deadlock. */
	raw_local_irq_save(flags);
	cpu = smp_processor_id();
	if (!arch_spin_trylock(&die_lock)) {
		if (cpu == die_owner)
			/* nested oops. should stop eventually */;
		else
			arch_spin_lock(&die_lock);
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	}
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	die_nest_count++;
	die_owner = cpu;
	console_verbose();
	bust_spinlocks(1);
	if (machine_is(powermac))
		pmac_backlight_unblank();
	return flags;
}
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static void __kprobes oops_end(unsigned long flags, struct pt_regs *regs,
			       int signr)
{
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	bust_spinlocks(0);
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	die_owner = -1;
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	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
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	die_nest_count--;
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	oops_exit();
	printk("\n");
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	if (!die_nest_count)
		/* Nest count reaches zero, release the lock. */
		arch_spin_unlock(&die_lock);
	raw_local_irq_restore(flags);
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	crash_fadump(regs, "die oops");

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	/*
	 * A system reset (0x100) is a request to dump, so we always send
	 * it through the crashdump code.
	 */
	if (kexec_should_crash(current) || (TRAP(regs) == 0x100)) {
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		crash_kexec(regs);
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		/*
		 * We aren't the primary crash CPU. We need to send it
		 * to a holding pattern to avoid it ending up in the panic
		 * code.
		 */
		crash_kexec_secondary(regs);
	}
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	if (!signr)
		return;

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	/*
	 * While our oops output is serialised by a spinlock, output
	 * from panic() called below can race and corrupt it. If we
	 * know we are going to panic, delay for 1 second so we have a
	 * chance to get clean backtraces from all CPUs that are oopsing.
	 */
	if (in_interrupt() || panic_on_oops || !current->pid ||
	    is_global_init(current)) {
		mdelay(MSEC_PER_SEC);
	}

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	if (in_interrupt())
		panic("Fatal exception in interrupt");
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	if (panic_on_oops)
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		panic("Fatal exception");
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	do_exit(signr);
}
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static int __kprobes __die(const char *str, struct pt_regs *regs, long err)
{
	printk("Oops: %s, sig: %ld [#%d]\n", str, err, ++die_counter);
#ifdef CONFIG_PREEMPT
	printk("PREEMPT ");
#endif
#ifdef CONFIG_SMP
	printk("SMP NR_CPUS=%d ", NR_CPUS);
#endif
#ifdef CONFIG_DEBUG_PAGEALLOC
	printk("DEBUG_PAGEALLOC ");
#endif
#ifdef CONFIG_NUMA
	printk("NUMA ");
#endif
	printk("%s\n", ppc_md.name ? ppc_md.name : "");

	if (notify_die(DIE_OOPS, str, regs, err, 255, SIGSEGV) == NOTIFY_STOP)
		return 1;

	print_modules();
	show_regs(regs);
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	return 0;
}

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void die(const char *str, struct pt_regs *regs, long err)
{
	unsigned long flags = oops_begin(regs);

	if (__die(str, regs, err))
		err = 0;
	oops_end(flags, regs, err);
}

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void user_single_step_siginfo(struct task_struct *tsk,
				struct pt_regs *regs, siginfo_t *info)
{
	memset(info, 0, sizeof(*info));
	info->si_signo = SIGTRAP;
	info->si_code = TRAP_TRACE;
	info->si_addr = (void __user *)regs->nip;
}

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void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr)
{
	siginfo_t info;
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	const char fmt32[] = KERN_INFO "%s[%d]: unhandled signal %d " \
			"at %08lx nip %08lx lr %08lx code %x\n";
	const char fmt64[] = KERN_INFO "%s[%d]: unhandled signal %d " \
			"at %016lx nip %016lx lr %016lx code %x\n";
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	if (!user_mode(regs)) {
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		die("Exception in kernel mode", regs, signr);
		return;
	}

	if (show_unhandled_signals && unhandled_signal(current, signr)) {
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		printk_ratelimited(regs->msr & MSR_64BIT ? fmt64 : fmt32,
				   current->comm, current->pid, signr,
				   addr, regs->nip, regs->link, code);
	}
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	if (arch_irqs_disabled() && !arch_irq_disabled_regs(regs))
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		local_irq_enable();

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	current->thread.trap_nr = code;
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	memset(&info, 0, sizeof(info));
	info.si_signo = signr;
	info.si_code = code;
	info.si_addr = (void __user *) addr;
	force_sig_info(signr, &info, current);
}

#ifdef CONFIG_PPC64
void system_reset_exception(struct pt_regs *regs)
{
	/* See if any machine dependent calls */
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	if (ppc_md.system_reset_exception) {
		if (ppc_md.system_reset_exception(regs))
			return;
	}
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	die("System Reset", regs, SIGABRT);
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	/* Must die if the interrupt is not recoverable */
	if (!(regs->msr & MSR_RI))
		panic("Unrecoverable System Reset");

	/* What should we do here? We could issue a shutdown or hard reset. */
}
#endif

/*
 * I/O accesses can cause machine checks on powermacs.
 * Check if the NIP corresponds to the address of a sync
 * instruction for which there is an entry in the exception
 * table.
 * Note that the 601 only takes a machine check on TEA
 * (transfer error ack) signal assertion, and does not
 * set any of the top 16 bits of SRR1.
 *  -- paulus.
 */
static inline int check_io_access(struct pt_regs *regs)
{
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#ifdef CONFIG_PPC32
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	unsigned long msr = regs->msr;
	const struct exception_table_entry *entry;
	unsigned int *nip = (unsigned int *)regs->nip;

	if (((msr & 0xffff0000) == 0 || (msr & (0x80000 | 0x40000)))
	    && (entry = search_exception_tables(regs->nip)) != NULL) {
		/*
		 * Check that it's a sync instruction, or somewhere
		 * in the twi; isync; nop sequence that inb/inw/inl uses.
		 * As the address is in the exception table
		 * we should be able to read the instr there.
		 * For the debug message, we look at the preceding
		 * load or store.
		 */
		if (*nip == 0x60000000)		/* nop */
			nip -= 2;
		else if (*nip == 0x4c00012c)	/* isync */
			--nip;
		if (*nip == 0x7c0004ac || (*nip >> 26) == 3) {
			/* sync or twi */
			unsigned int rb;

			--nip;
			rb = (*nip >> 11) & 0x1f;
			printk(KERN_DEBUG "%s bad port %lx at %p\n",
			       (*nip & 0x100)? "OUT to": "IN from",
			       regs->gpr[rb] - _IO_BASE, nip);
			regs->msr |= MSR_RI;
			regs->nip = entry->fixup;
			return 1;
		}
	}
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#endif /* CONFIG_PPC32 */
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	return 0;
}

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#ifdef CONFIG_PPC_ADV_DEBUG_REGS
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/* On 4xx, the reason for the machine check or program exception
   is in the ESR. */
#define get_reason(regs)	((regs)->dsisr)
#ifndef CONFIG_FSL_BOOKE
#define get_mc_reason(regs)	((regs)->dsisr)
#else
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#define get_mc_reason(regs)	(mfspr(SPRN_MCSR))
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#endif
#define REASON_FP		ESR_FP
#define REASON_ILLEGAL		(ESR_PIL | ESR_PUO)
#define REASON_PRIVILEGED	ESR_PPR
#define REASON_TRAP		ESR_PTR

/* single-step stuff */
#define single_stepping(regs)	(current->thread.dbcr0 & DBCR0_IC)
#define clear_single_step(regs)	(current->thread.dbcr0 &= ~DBCR0_IC)

#else
/* On non-4xx, the reason for the machine check or program
   exception is in the MSR. */
#define get_reason(regs)	((regs)->msr)
#define get_mc_reason(regs)	((regs)->msr)
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#define REASON_TM		0x200000
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#define REASON_FP		0x100000
#define REASON_ILLEGAL		0x80000
#define REASON_PRIVILEGED	0x40000
#define REASON_TRAP		0x20000

#define single_stepping(regs)	((regs)->msr & MSR_SE)
#define clear_single_step(regs)	((regs)->msr &= ~MSR_SE)
#endif

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#if defined(CONFIG_4xx)
int machine_check_4xx(struct pt_regs *regs)
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{
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	unsigned long reason = get_mc_reason(regs);
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	if (reason & ESR_IMCP) {
		printk("Instruction");
		mtspr(SPRN_ESR, reason & ~ESR_IMCP);
	} else
		printk("Data");
	printk(" machine check in kernel mode.\n");
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	return 0;
}

int machine_check_440A(struct pt_regs *regs)
{
	unsigned long reason = get_mc_reason(regs);

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	printk("Machine check in kernel mode.\n");
	if (reason & ESR_IMCP){
		printk("Instruction Synchronous Machine Check exception\n");
		mtspr(SPRN_ESR, reason & ~ESR_IMCP);
	}
	else {
		u32 mcsr = mfspr(SPRN_MCSR);
		if (mcsr & MCSR_IB)
			printk("Instruction Read PLB Error\n");
		if (mcsr & MCSR_DRB)
			printk("Data Read PLB Error\n");
		if (mcsr & MCSR_DWB)
			printk("Data Write PLB Error\n");
		if (mcsr & MCSR_TLBP)
			printk("TLB Parity Error\n");
		if (mcsr & MCSR_ICP){
			flush_instruction_cache();
			printk("I-Cache Parity Error\n");
		}
		if (mcsr & MCSR_DCSP)
			printk("D-Cache Search Parity Error\n");
		if (mcsr & MCSR_DCFP)
			printk("D-Cache Flush Parity Error\n");
		if (mcsr & MCSR_IMPE)
			printk("Machine Check exception is imprecise\n");

		/* Clear MCSR */
		mtspr(SPRN_MCSR, mcsr);
	}
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	return 0;
}
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int machine_check_47x(struct pt_regs *regs)
{
	unsigned long reason = get_mc_reason(regs);
	u32 mcsr;

	printk(KERN_ERR "Machine check in kernel mode.\n");
	if (reason & ESR_IMCP) {
		printk(KERN_ERR
		       "Instruction Synchronous Machine Check exception\n");
		mtspr(SPRN_ESR, reason & ~ESR_IMCP);
		return 0;
	}
	mcsr = mfspr(SPRN_MCSR);
	if (mcsr & MCSR_IB)
		printk(KERN_ERR "Instruction Read PLB Error\n");
	if (mcsr & MCSR_DRB)
		printk(KERN_ERR "Data Read PLB Error\n");
	if (mcsr & MCSR_DWB)
		printk(KERN_ERR "Data Write PLB Error\n");
	if (mcsr & MCSR_TLBP)
		printk(KERN_ERR "TLB Parity Error\n");
	if (mcsr & MCSR_ICP) {
		flush_instruction_cache();
		printk(KERN_ERR "I-Cache Parity Error\n");
	}
	if (mcsr & MCSR_DCSP)
		printk(KERN_ERR "D-Cache Search Parity Error\n");
	if (mcsr & PPC47x_MCSR_GPR)
		printk(KERN_ERR "GPR Parity Error\n");
	if (mcsr & PPC47x_MCSR_FPR)
		printk(KERN_ERR "FPR Parity Error\n");
	if (mcsr & PPC47x_MCSR_IPR)
		printk(KERN_ERR "Machine Check exception is imprecise\n");

	/* Clear MCSR */
	mtspr(SPRN_MCSR, mcsr);

	return 0;
}
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#elif defined(CONFIG_E500)
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int machine_check_e500mc(struct pt_regs *regs)
{
	unsigned long mcsr = mfspr(SPRN_MCSR);
	unsigned long reason = mcsr;
	int recoverable = 1;

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	if (reason & MCSR_LD) {
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		recoverable = fsl_rio_mcheck_exception(regs);
		if (recoverable == 1)
			goto silent_out;
	}

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	printk("Machine check in kernel mode.\n");
	printk("Caused by (from MCSR=%lx): ", reason);

	if (reason & MCSR_MCP)
		printk("Machine Check Signal\n");

	if (reason & MCSR_ICPERR) {
		printk("Instruction Cache Parity Error\n");

		/*
		 * This is recoverable by invalidating the i-cache.
		 */
		mtspr(SPRN_L1CSR1, mfspr(SPRN_L1CSR1) | L1CSR1_ICFI);
		while (mfspr(SPRN_L1CSR1) & L1CSR1_ICFI)
			;

		/*
		 * This will generally be accompanied by an instruction
		 * fetch error report -- only treat MCSR_IF as fatal
		 * if it wasn't due to an L1 parity error.
		 */
		reason &= ~MCSR_IF;
	}

	if (reason & MCSR_DCPERR_MC) {
		printk("Data Cache Parity Error\n");
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		/*
		 * In write shadow mode we auto-recover from the error, but it
		 * may still get logged and cause a machine check.  We should
		 * only treat the non-write shadow case as non-recoverable.
		 */
		if (!(mfspr(SPRN_L1CSR2) & L1CSR2_DCWS))
			recoverable = 0;
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	}

	if (reason & MCSR_L2MMU_MHIT) {
		printk("Hit on multiple TLB entries\n");
		recoverable = 0;
	}

	if (reason & MCSR_NMI)
		printk("Non-maskable interrupt\n");

	if (reason & MCSR_IF) {
		printk("Instruction Fetch Error Report\n");
		recoverable = 0;
	}

	if (reason & MCSR_LD) {
		printk("Load Error Report\n");
		recoverable = 0;
	}

	if (reason & MCSR_ST) {
		printk("Store Error Report\n");
		recoverable = 0;
	}

	if (reason & MCSR_LDG) {
		printk("Guarded Load Error Report\n");
		recoverable = 0;
	}

	if (reason & MCSR_TLBSYNC)
		printk("Simultaneous tlbsync operations\n");

	if (reason & MCSR_BSL2_ERR) {
		printk("Level 2 Cache Error\n");
		recoverable = 0;
	}

	if (reason & MCSR_MAV) {
		u64 addr;

		addr = mfspr(SPRN_MCAR);
		addr |= (u64)mfspr(SPRN_MCARU) << 32;

		printk("Machine Check %s Address: %#llx\n",
		       reason & MCSR_MEA ? "Effective" : "Physical", addr);
	}

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silent_out:
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	mtspr(SPRN_MCSR, mcsr);
	return mfspr(SPRN_MCSR) == 0 && recoverable;
}

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int machine_check_e500(struct pt_regs *regs)
{
	unsigned long reason = get_mc_reason(regs);

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	if (reason & MCSR_BUS_RBERR) {
		if (fsl_rio_mcheck_exception(regs))
			return 1;
	}

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	printk("Machine check in kernel mode.\n");
	printk("Caused by (from MCSR=%lx): ", reason);

	if (reason & MCSR_MCP)
		printk("Machine Check Signal\n");
	if (reason & MCSR_ICPERR)
		printk("Instruction Cache Parity Error\n");
	if (reason & MCSR_DCP_PERR)
		printk("Data Cache Push Parity Error\n");
	if (reason & MCSR_DCPERR)
		printk("Data Cache Parity Error\n");
	if (reason & MCSR_BUS_IAERR)
		printk("Bus - Instruction Address Error\n");
	if (reason & MCSR_BUS_RAERR)
		printk("Bus - Read Address Error\n");
	if (reason & MCSR_BUS_WAERR)
		printk("Bus - Write Address Error\n");
	if (reason & MCSR_BUS_IBERR)
		printk("Bus - Instruction Data Error\n");
	if (reason & MCSR_BUS_RBERR)
		printk("Bus - Read Data Bus Error\n");
	if (reason & MCSR_BUS_WBERR)
		printk("Bus - Read Data Bus Error\n");
	if (reason & MCSR_BUS_IPERR)
		printk("Bus - Instruction Parity Error\n");
	if (reason & MCSR_BUS_RPERR)
		printk("Bus - Read Parity Error\n");
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	return 0;
}
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int machine_check_generic(struct pt_regs *regs)
{
	return 0;
}
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#elif defined(CONFIG_E200)
int machine_check_e200(struct pt_regs *regs)
{
	unsigned long reason = get_mc_reason(regs);

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	printk("Machine check in kernel mode.\n");
	printk("Caused by (from MCSR=%lx): ", reason);

	if (reason & MCSR_MCP)
		printk("Machine Check Signal\n");
	if (reason & MCSR_CP_PERR)
		printk("Cache Push Parity Error\n");
	if (reason & MCSR_CPERR)
		printk("Cache Parity Error\n");
	if (reason & MCSR_EXCP_ERR)
		printk("ISI, ITLB, or Bus Error on first instruction fetch for an exception handler\n");
	if (reason & MCSR_BUS_IRERR)
		printk("Bus - Read Bus Error on instruction fetch\n");
	if (reason & MCSR_BUS_DRERR)
		printk("Bus - Read Bus Error on data load\n");
	if (reason & MCSR_BUS_WRERR)
		printk("Bus - Write Bus Error on buffered store or cache line push\n");
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	return 0;
}
#else
int machine_check_generic(struct pt_regs *regs)
{
	unsigned long reason = get_mc_reason(regs);

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	printk("Machine check in kernel mode.\n");
	printk("Caused by (from SRR1=%lx): ", reason);
	switch (reason & 0x601F0000) {
	case 0x80000:
		printk("Machine check signal\n");
		break;
	case 0:		/* for 601 */
	case 0x40000:
	case 0x140000:	/* 7450 MSS error and TEA */
		printk("Transfer error ack signal\n");
		break;
	case 0x20000:
		printk("Data parity error signal\n");
		break;
	case 0x10000:
		printk("Address parity error signal\n");
		break;
	case 0x20000000:
		printk("L1 Data Cache error\n");
		break;
	case 0x40000000:
		printk("L1 Instruction Cache error\n");
		break;
	case 0x00100000:
		printk("L2 data cache parity error\n");
		break;
	default:
		printk("Unknown values in msr\n");
	}
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	return 0;
}
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#endif /* everything else */
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void machine_check_exception(struct pt_regs *regs)
{
	int recover = 0;

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	__get_cpu_var(irq_stat).mce_exceptions++;

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	/* See if any machine dependent calls. In theory, we would want
	 * to call the CPU first, and call the ppc_md. one if the CPU
	 * one returns a positive number. However there is existing code
	 * that assumes the board gets a first chance, so let's keep it
	 * that way for now and fix things later. --BenH.
	 */
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	if (ppc_md.machine_check_exception)
		recover = ppc_md.machine_check_exception(regs);
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	else if (cur_cpu_spec->machine_check)
		recover = cur_cpu_spec->machine_check(regs);
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	if (recover > 0)
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		return;

#if defined(CONFIG_8xx) && defined(CONFIG_PCI)
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	/* the qspan pci read routines can cause machine checks -- Cort
	 *
	 * yuck !!! that totally needs to go away ! There are better ways
	 * to deal with that than having a wart in the mcheck handler.
	 * -- BenH
	 */
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	bad_page_fault(regs, regs->dar, SIGBUS);
	return;
#endif

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	if (debugger_fault_handler(regs))
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		return;

	if (check_io_access(regs))
		return;

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	die("Machine check", regs, SIGBUS);
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	/* Must die if the interrupt is not recoverable */
	if (!(regs->msr & MSR_RI))
		panic("Unrecoverable Machine check");
}

void SMIException(struct pt_regs *regs)
{
	die("System Management Interrupt", regs, SIGABRT);
}

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void unknown_exception(struct pt_regs *regs)
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{
	printk("Bad trap at PC: %lx, SR: %lx, vector=%lx\n",
	       regs->nip, regs->msr, regs->trap);

	_exception(SIGTRAP, regs, 0, 0);
}

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void instruction_breakpoint_exception(struct pt_regs *regs)
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{
	if (notify_die(DIE_IABR_MATCH, "iabr_match", regs, 5,
					5, SIGTRAP) == NOTIFY_STOP)
		return;
	if (debugger_iabr_match(regs))
		return;
	_exception(SIGTRAP, regs, TRAP_BRKPT, regs->nip);
}

void RunModeException(struct pt_regs *regs)
{
	_exception(SIGTRAP, regs, 0, 0);
}

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void __kprobes single_step_exception(struct pt_regs *regs)
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{
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	clear_single_step(regs);
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	if (notify_die(DIE_SSTEP, "single_step", regs, 5,
					5, SIGTRAP) == NOTIFY_STOP)
		return;
	if (debugger_sstep(regs))
		return;

	_exception(SIGTRAP, regs, TRAP_TRACE, regs->nip);
}

/*
 * After we have successfully emulated an instruction, we have to
 * check if the instruction was being single-stepped, and if so,
 * pretend we got a single-step exception.  This was pointed out
 * by Kumar Gala.  -- paulus
 */
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static void emulate_single_step(struct pt_regs *regs)
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{
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	if (single_stepping(regs))
		single_step_exception(regs);
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}

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static inline int __parse_fpscr(unsigned long fpscr)
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{
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	int ret = 0;
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	/* Invalid operation */
	if ((fpscr & FPSCR_VE) && (fpscr & FPSCR_VX))
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		ret = FPE_FLTINV;
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	/* Overflow */
	else if ((fpscr & FPSCR_OE) && (fpscr & FPSCR_OX))
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		ret = FPE_FLTOVF;
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	/* Underflow */
	else if ((fpscr & FPSCR_UE) && (fpscr & FPSCR_UX))
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		ret = FPE_FLTUND;
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	/* Divide by zero */
	else if ((fpscr & FPSCR_ZE) && (fpscr & FPSCR_ZX))
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		ret = FPE_FLTDIV;
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	/* Inexact result */
	else if ((fpscr & FPSCR_XE) && (fpscr & FPSCR_XX))
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		ret = FPE_FLTRES;

	return ret;
}

static void parse_fpe(struct pt_regs *regs)
{
	int code = 0;

	flush_fp_to_thread(current);

	code = __parse_fpscr(current->thread.fpscr.val);
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	_exception(SIGFPE, regs, code, regs->nip);
}

/*
 * Illegal instruction emulation support.  Originally written to
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 * provide the PVR to user applications using the mfspr rd, PVR.
 * Return non-zero if we can't emulate, or -EFAULT if the associated
 * memory access caused an access fault.  Return zero on success.
 *
 * There are a couple of ways to do this, either "decode" the instruction
 * or directly match lots of bits.  In this case, matching lots of
 * bits is faster and easier.
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 *
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 */
static int emulate_string_inst(struct pt_regs *regs, u32 instword)
{
	u8 rT = (instword >> 21) & 0x1f;
	u8 rA = (instword >> 16) & 0x1f;
	u8 NB_RB = (instword >> 11) & 0x1f;
	u32 num_bytes;
	unsigned long EA;
	int pos = 0;

	/* Early out if we are an invalid form of lswx */
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	if ((instword & PPC_INST_STRING_MASK) == PPC_INST_LSWX)
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		if ((rT == rA) || (rT == NB_RB))
			return -EINVAL;

	EA = (rA == 0) ? 0 : regs->gpr[rA];

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	switch (instword & PPC_INST_STRING_MASK) {
		case PPC_INST_LSWX:
		case PPC_INST_STSWX:
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			EA += NB_RB;
			num_bytes = regs->xer & 0x7f;
			break;
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		case PPC_INST_LSWI:
		case PPC_INST_STSWI:
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			num_bytes = (NB_RB == 0) ? 32 : NB_RB;
			break;
		default:
			return -EINVAL;
	}

	while (num_bytes != 0)
	{
		u8 val;
		u32 shift = 8 * (3 - (pos & 0x3));

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		switch ((instword & PPC_INST_STRING_MASK)) {
			case PPC_INST_LSWX:
			case PPC_INST_LSWI:
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				if (get_user(val, (u8 __user *)EA))
					return -EFAULT;
				/* first time updating this reg,
				 * zero it out */
				if (pos == 0)
					regs->gpr[rT] = 0;
				regs->gpr[rT] |= val << shift;
				break;
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			case PPC_INST_STSWI:
			case PPC_INST_STSWX:
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				val = regs->gpr[rT] >> shift;
				if (put_user(val, (u8 __user *)EA))
					return -EFAULT;
				break;
		}
		/* move EA to next address */
		EA += 1;
		num_bytes--;

		/* manage our position within the register */
		if (++pos == 4) {
			pos = 0;
			if (++rT == 32)
				rT = 0;
		}
	}

	return 0;
}

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static int emulate_popcntb_inst(struct pt_regs *regs, u32 instword)
{
	u32 ra,rs;
	unsigned long tmp;

	ra = (instword >> 16) & 0x1f;
	rs = (instword >> 21) & 0x1f;

	tmp = regs->gpr[rs];
	tmp = tmp - ((tmp >> 1) & 0x5555555555555555ULL);
	tmp = (tmp & 0x3333333333333333ULL) + ((tmp >> 2) & 0x3333333333333333ULL);
	tmp = (tmp + (tmp >> 4)) & 0x0f0f0f0f0f0f0f0fULL;
	regs->gpr[ra] = tmp;

	return 0;
}

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static int emulate_isel(struct pt_regs *regs, u32 instword)
{
	u8 rT = (instword >> 21) & 0x1f;
	u8 rA = (instword >> 16) & 0x1f;
	u8 rB = (instword >> 11) & 0x1f;
	u8 BC = (instword >> 6) & 0x1f;
	u8 bit;
	unsigned long tmp;

	tmp = (rA == 0) ? 0 : regs->gpr[rA];
	bit = (regs->ccr >> (31 - BC)) & 0x1;

	regs->gpr[rT] = bit ? tmp : regs->gpr[rB];

	return 0;
}

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static int emulate_instruction(struct pt_regs *regs)
{
	u32 instword;
	u32 rd;

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	if (!user_mode(regs) || (regs->msr & MSR_LE))
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		return -EINVAL;
	CHECK_FULL_REGS(regs);

	if (get_user(instword, (u32 __user *)(regs->nip)))
		return -EFAULT;

	/* Emulate the mfspr rD, PVR. */
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	if ((instword & PPC_INST_MFSPR_PVR_MASK) == PPC_INST_MFSPR_PVR) {
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		PPC_WARN_EMULATED(mfpvr, regs);
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		rd = (instword >> 21) & 0x1f;
		regs->gpr[rd] = mfspr(SPRN_PVR);
		return 0;
	}

	/* Emulating the dcba insn is just a no-op.  */
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	if ((instword & PPC_INST_DCBA_MASK) == PPC_INST_DCBA) {
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		PPC_WARN_EMULATED(dcba, regs);
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		return 0;
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	}
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	/* Emulate the mcrxr insn.  */
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	if ((instword & PPC_INST_MCRXR_MASK) == PPC_INST_MCRXR) {
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		int shift = (instword >> 21) & 0x1c;
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		unsigned long msk = 0xf0000000UL >> shift;

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		PPC_WARN_EMULATED(mcrxr, regs);
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		regs->ccr = (regs->ccr & ~msk) | ((regs->xer >> shift) & msk);
		regs->xer &= ~0xf0000000UL;
		return 0;
	}

	/* Emulate load/store string insn. */
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	if ((instword & PPC_INST_STRING_GEN_MASK) == PPC_INST_STRING) {
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		PPC_WARN_EMULATED(string, regs);
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		return emulate_string_inst(regs, instword);
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	}
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	/* Emulate the popcntb (Population Count Bytes) instruction. */
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	if ((instword & PPC_INST_POPCNTB_MASK) == PPC_INST_POPCNTB) {
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		PPC_WARN_EMULATED(popcntb, regs);
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		return emulate_popcntb_inst(regs, instword);
	}

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	/* Emulate isel (Integer Select) instruction */
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	if ((instword & PPC_INST_ISEL_MASK) == PPC_INST_ISEL) {
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		PPC_WARN_EMULATED(isel, regs);
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		return emulate_isel(regs, instword);
	}

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#ifdef CONFIG_PPC64
	/* Emulate the mfspr rD, DSCR. */
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	if ((((instword & PPC_INST_MFSPR_DSCR_USER_MASK) ==
		PPC_INST_MFSPR_DSCR_USER) ||
	     ((instword & PPC_INST_MFSPR_DSCR_MASK) ==
		PPC_INST_MFSPR_DSCR)) &&
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			cpu_has_feature(CPU_FTR_DSCR)) {
		PPC_WARN_EMULATED(mfdscr, regs);
		rd = (instword >> 21) & 0x1f;
		regs->gpr[rd] = mfspr(SPRN_DSCR);
		return 0;
	}
	/* Emulate the mtspr DSCR, rD. */
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	if ((((instword & PPC_INST_MTSPR_DSCR_USER_MASK) ==
		PPC_INST_MTSPR_DSCR_USER) ||
	     ((instword & PPC_INST_MTSPR_DSCR_MASK) ==
		PPC_INST_MTSPR_DSCR)) &&
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			cpu_has_feature(CPU_FTR_DSCR)) {
		PPC_WARN_EMULATED(mtdscr, regs);
		rd = (instword >> 21) & 0x1f;
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		current->thread.dscr = regs->gpr[rd];
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		current->thread.dscr_inherit = 1;
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		mtspr(SPRN_DSCR, current->thread.dscr);
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		return 0;
	}
#endif

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	return -EINVAL;
}

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int is_valid_bugaddr(unsigned long addr)
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{
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	return is_kernel_addr(addr);
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}

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void __kprobes program_check_exception(struct pt_regs *regs)
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{
	unsigned int reason = get_reason(regs);
	extern int do_mathemu(struct pt_regs *regs);

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	/* We can now get here via a FP Unavailable exception if the core
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	 * has no FPU, in that case the reason flags will be 0 */
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	if (reason & REASON_FP) {
		/* IEEE FP exception */
		parse_fpe(regs);
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		return;
	}
	if (reason & REASON_TRAP) {
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		/* Debugger is first in line to stop recursive faults in
		 * rcu_lock, notify_die, or atomic_notifier_call_chain */
		if (debugger_bpt(regs))
			return;

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		/* trap exception */
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		if (notify_die(DIE_BPT, "breakpoint", regs, 5, 5, SIGTRAP)
				== NOTIFY_STOP)
			return;
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		if (!(regs->msr & MSR_PR) &&  /* not user-mode */
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		    report_bug(regs->nip, regs) == BUG_TRAP_TYPE_WARN) {
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			regs->nip += 4;
			return;
		}
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		_exception(SIGTRAP, regs, TRAP_BRKPT, regs->nip);
		return;
	}
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#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
	if (reason & REASON_TM) {
		/* This is a TM "Bad Thing Exception" program check.
		 * This occurs when:
		 * -  An rfid/hrfid/mtmsrd attempts to cause an illegal
		 *    transition in TM states.
		 * -  A trechkpt is attempted when transactional.
		 * -  A treclaim is attempted when non transactional.
		 * -  A tend is illegally attempted.
		 * -  writing a TM SPR when transactional.
		 */
		if (!user_mode(regs) &&
		    report_bug(regs->nip, regs) == BUG_TRAP_TYPE_WARN) {
			regs->nip += 4;
			return;
		}
		/* If usermode caused this, it's done something illegal and
		 * gets a SIGILL slap on the wrist.  We call it an illegal
		 * operand to distinguish from the instruction just being bad
		 * (e.g. executing a 'tend' on a CPU without TM!); it's an
		 * illegal /placement/ of a valid instruction.
		 */
		if (user_mode(regs)) {
			_exception(SIGILL, regs, ILL_ILLOPN, regs->nip);
			return;
		} else {
			printk(KERN_EMERG "Unexpected TM Bad Thing exception "
			       "at %lx (msr 0x%x)\n", regs->nip, reason);
			die("Unrecoverable exception", regs, SIGABRT);
		}
	}
#endif
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	/* We restore the interrupt state now */
	if (!arch_irq_disabled_regs(regs))
		local_irq_enable();
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#ifdef CONFIG_MATH_EMULATION
	/* (reason & REASON_ILLEGAL) would be the obvious thing here,
	 * but there seems to be a hardware bug on the 405GP (RevD)
	 * that means ESR is sometimes set incorrectly - either to
	 * ESR_DST (!?) or 0.  In the process of chasing this with the
	 * hardware people - not sure if it can happen on any illegal
	 * instruction or only on FP instructions, whether there is a
Lucas De Marchi's avatar
Lucas De Marchi committed
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	 * pattern to occurrences etc. -dgibson 31/Mar/2003 */
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	switch (do_mathemu(regs)) {
	case 0:
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		emulate_single_step(regs);
		return;
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	case 1: {
			int code = 0;
			code = __parse_fpscr(current->thread.fpscr.val);
			_exception(SIGFPE, regs, code, regs->nip);
			return;
		}
	case -EFAULT:
		_exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
		return;
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	}
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	/* fall through on any other errors */
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#endif /* CONFIG_MATH_EMULATION */

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	/* Try to emulate it if we should. */
	if (reason & (REASON_ILLEGAL | REASON_PRIVILEGED)) {
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		switch (emulate_instruction(regs)) {
		case 0:
			regs->nip += 4;
			emulate_single_step(regs);
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			return;
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		case -EFAULT:
			_exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
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			return;
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		}
	}
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	if (reason & REASON_PRIVILEGED)
		_exception(SIGILL, regs, ILL_PRVOPC, regs->nip);
	else
		_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
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}

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void alignment_exception(struct pt_regs *regs)
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{
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	int sig, code, fixed = 0;
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	/* We restore the interrupt state now */
	if (!arch_irq_disabled_regs(regs))
		local_irq_enable();

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	/* we don't implement logging of alignment exceptions */
	if (!(current->thread.align_ctl & PR_UNALIGN_SIGBUS))
		fixed = fix_alignment(regs);
1130
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	if (fixed == 1) {
		regs->nip += 4;	/* skip over emulated instruction */
		emulate_single_step(regs);
		return;
	}

1137
	/* Operand address was bad */
1138
	if (fixed == -EFAULT) {
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		sig = SIGSEGV;
		code = SEGV_ACCERR;
	} else {
		sig = SIGBUS;
		code = BUS_ADRALN;
1144
	}
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	if (user_mode(regs))
		_exception(sig, regs, code, regs->dar);
	else
		bad_page_fault(regs, regs->dar, sig);
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}

void StackOverflow(struct pt_regs *regs)
{
	printk(KERN_CRIT "Kernel stack overflow in process %p, r1=%lx\n",
	       current, regs->gpr[1]);
	debugger(regs);
	show_regs(regs);
	panic("kernel stack overflow");
}

void nonrecoverable_exception(struct pt_regs *regs)
{
	printk(KERN_ERR "Non-recoverable exception at PC=%lx MSR=%lx\n",
	       regs->nip, regs->msr);
	debugger(regs);
	die("nonrecoverable exception", regs, SIGKILL);
}

void trace_syscall(struct pt_regs *regs)
{
	printk("Task: %p(%d), PC: %08lX/%08lX, Syscall: %3ld, Result: %s%ld    %s\n",
1171
	       current, task_pid_nr(current), regs->nip, regs->link, regs->gpr[0],
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	       regs->ccr&0x10000000?"Error=":"", regs->gpr[3], print_tainted());
}
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void kernel_fp_unavailable_exception(struct pt_regs *regs)
{
	printk(KERN_EMERG "Unrecoverable FP Unavailable Exception "
			  "%lx at %lx\n", regs->trap, regs->nip);
	die("Unrecoverable FP Unavailable Exception", regs, SIGABRT);
}

void altivec_unavailable_exception(struct pt_regs *regs)
{
	if (user_mode(regs)) {
		/* A user program has executed an altivec instruction,
		   but this kernel doesn't support altivec. */
		_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
		return;
	}
1190

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	printk(KERN_EMERG "Unrecoverable VMX/Altivec Unavailable Exception "
			"%lx at %lx\n", regs->trap, regs->nip);
	die("Unrecoverable VMX/Altivec Unavailable Exception", regs, SIGABRT);
}

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void vsx_unavailable_exception(struct pt_regs *regs)
{
	if (user_mode(regs)) {
		/* A user program has executed an vsx instruction,
		   but this kernel doesn't support vsx. */
		_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
		return;
	}

	printk(KERN_EMERG "Unrecoverable VSX Unavailable Exception "
			"%lx at %lx\n", regs->trap, regs->nip);
	die("Unrecoverable VSX Unavailable Exception", regs, SIGABRT);
}

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void tm_unavailable_exception(struct pt_regs *regs)
{
	/* We restore the interrupt state now */
	if (!arch_irq_disabled_regs(regs))
		local_irq_enable();

	/* Currently we never expect a TMU exception.  Catch
	 * this and kill the process!
	 */
	printk(KERN_EMERG "Unexpected TM unavailable exception at %lx "
	       "(msr %lx)\n",
	       regs->nip, regs->msr);

	if (user_mode(regs)) {
		_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
		return;
	}

	die("Unexpected TM unavailable exception", regs, SIGABRT);
}

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#ifdef CONFIG_PPC_TRANSACTIONAL_MEM

extern void do_load_up_fpu(struct pt_regs *regs);

void fp_unavailable_tm(struct pt_regs *regs)
{
	/* Note:  This does not handle any kind of FP laziness. */

	TM_DEBUG("FP Unavailable trap whilst transactional at 0x%lx, MSR=%lx\n",
		 regs->nip, regs->msr);
	tm_enable();

        /* We can only have got here if the task started using FP after
         * beginning the transaction.  So, the transactional regs are just a
         * copy of the checkpointed ones.  But, we still need to recheckpoint
         * as we're enabling FP for the process; it will return, abort the
         * transaction, and probably retry but now with FP enabled.  So the
         * checkpointed FP registers need to be loaded.
	 */
	tm_reclaim(&current->thread, current->thread.regs->msr,
		   TM_CAUSE_FAC_UNAV);
	/* Reclaim didn't save out any FPRs to transact_fprs. */

	/* Enable FP for the task: */
	regs->msr |= (MSR_FP | current->thread.fpexc_mode);

	/* This loads and recheckpoints the FP registers from
	 * thread.fpr[].  They will remain in registers after the
	 * checkpoint so we don't need to reload them after.
	 */
	tm_recheckpoint(&current->thread, regs->msr);
}

#ifdef CONFIG_ALTIVEC
extern void do_load_up_altivec(struct pt_regs *regs);

void altivec_unavailable_tm(struct pt_regs *regs)
{
	/* See the comments in fp_unavailable_tm().  This function operates
	 * the same way.
	 */

	TM_DEBUG("Vector Unavailable trap whilst transactional at 0x%lx,"
		 "MSR=%lx\n",
		 regs->nip, regs->msr);
	tm_enable();
	tm_reclaim(&current->thread, current->thread.regs->msr,
		   TM_CAUSE_FAC_UNAV);
	regs->msr |= MSR_VEC;
	tm_recheckpoint(&current->thread, regs->msr);
	current->thread.used_vr = 1;
}
#endif

#ifdef CONFIG_VSX
void vsx_unavailable_tm(struct pt_regs *regs)
{
	/* See the comments in fp_unavailable_tm().  This works similarly,
	 * though we're loading both FP and VEC registers in here.
	 *
	 * If FP isn't in use, load FP regs.  If VEC isn't in use, load VEC
	 * regs.  Either way, set MSR_VSX.
	 */

	TM_DEBUG("VSX Unavailable trap whilst transactional at 0x%lx,"
		 "MSR=%lx\n",
		 regs->nip, regs->msr);

	tm_enable();
	/* This reclaims FP and/or VR regs if they're already enabled */
	tm_reclaim(&current->thread, current->thread.regs->msr,
		   TM_CAUSE_FAC_UNAV);

	regs->msr |= MSR_VEC | MSR_FP | current->thread.fpexc_mode |
		MSR_VSX;
	/* This loads & recheckpoints FP and VRs. */
	tm_recheckpoint(&current->thread, regs->msr);
	current->thread.used_vsr = 1;
}
#endif
#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */

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void performance_monitor_exception(struct pt_regs *regs)
{
1315
1316
	__get_cpu_var(irq_stat).pmu_irqs++;

1317
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1319
	perf_irq(regs);
}

1320
#ifdef CONFIG_8xx
1321
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1324
void SoftwareEmulation(struct pt_regs *regs)
{
	extern int do_mathemu(struct pt_regs *);
	extern int Soft_emulate_8xx(struct pt_regs *);
1325
#if defined(CONFIG_MATH_EMULATION) || defined(CONFIG_8XX_MINIMAL_FPEMU)
1326
	int errcode;
1327
#endif
1328
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1331
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1334
1335
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1337

	CHECK_FULL_REGS(regs);

	if (!user_mode(regs)) {
		debugger(regs);
		die("Kernel Mode Software FPU Emulation", regs, SIGFPE);
	}

#ifdef CONFIG_MATH_EMULATION
	errcode = do_mathemu(regs);
1338
	if (errcode >= 0)
1339
		PPC_WARN_EMULATED(math, regs);
1340
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1358

	switch (errcode) {
	case 0:
		emulate_single_step(regs);
		return;
	case 1: {
			int code = 0;
			code = __parse_fpscr(current->thread.fpscr.val);
			_exception(SIGFPE, regs, code, regs->nip);
			return;
		}
	case -EFAULT:
		_exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
		return;
	default:
		_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
		return;
	}

1359
#elif defined(CONFIG_8XX_MINIMAL_FPEMU)
1360
	errcode = Soft_emulate_8xx(regs);
1361
	if (errcode >= 0)
1362
		PPC_WARN_EMULATED(8xx, regs);
1363

1364
1365
	switch (errcode) {
	case 0:
1366
		emulate_single_step(regs);
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1374
		return;
	case 1:
		_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
		return;
	case -EFAULT:
		_exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
		return;
	}
1375
1376
#else
	_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
1377
#endif
1378
}
1379
#endif /* CONFIG_8xx */
1380

1381
#ifdef CONFIG_PPC_ADV_DEBUG_REGS
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static void handle_debug(struct pt_regs *regs, unsigned long debug_status)
{
	int changed = 0;
	/*
	 * Determine the cause of the debug event, clear the
	 * event flags and send a trap to the handler. Torez
	 */
	if (debug_status & (DBSR_DAC1R | DBSR_DAC1W)) {
		dbcr_dac(current) &= ~(DBCR_DAC1R | DBCR_DAC1W);
#ifdef CONFIG_PPC_ADV_DEBUG_DAC_RANGE
		current->thread.dbcr2 &= ~DBCR2_DAC12MODE;
#endif
		do_send_trap(regs, mfspr(SPRN_DAC1), debug_status, TRAP_HWBKPT,
			     5);
		changed |= 0x01;
	}  else if (debug_status & (DBSR_DAC2R | DBSR_DAC2W)) {
		dbcr_dac(current) &= ~(DBCR_DAC2R | DBCR_DAC2W);
		do_send_trap(regs, mfspr(SPRN_DAC2), debug_status, TRAP_HWBKPT,
			     6);
		changed |= 0x01;
	}  else if (debug_status & DBSR_IAC1) {
		current->thread.dbcr0 &= ~DBCR0_IAC1;
		dbcr_iac_range(current) &= ~DBCR_IAC12MODE;
		do_send_trap(regs, mfspr(SPRN_IAC1), debug_status, TRAP_HWBKPT,
			     1);
		changed |= 0x01;
	}  else if (debug_status & DBSR_IAC2) {
		current->thread.dbcr0 &= ~DBCR0_IAC2;
		do_send_trap(regs, mfspr(SPRN_IAC2), debug_status, TRAP_HWBKPT,
			     2);
		changed |= 0x01;
	}  else if (debug_status & DBSR_IAC3) {
		current->thread.dbcr0 &= ~DBCR0_IAC3;
		dbcr_iac_range(current) &= ~DBCR_IAC34MODE;
		do_send_trap(regs, mfspr(SPRN_IAC3), debug_status, TRAP_HWBKPT,
			     3);
		changed |= 0x01;
	}  else if (debug_status & DBSR_IAC4) {
		current->thread.dbcr0 &= ~DBCR0_IAC4;
		do_send_trap(regs, mfspr(SPRN_IAC4), debug_status, TRAP_HWBKPT,
			     4);
		changed |= 0x01;
	}
	/*
	 * At the point this routine was called, the MSR(DE) was turned off.
	 * Check all other debug flags and see if that bit needs to be turned
	 * back on or not.
	 */
	if (DBCR_ACTIVE_EVENTS(current->thread.dbcr0, current->thread.dbcr1))
		regs->msr |= MSR_DE;
	else
		/* Make sure the IDM flag is off */
		current->thread.dbcr0 &= ~DBCR0_IDM;

	if (changed & 0x01)
		mtspr(SPRN_DBCR0, current->thread.dbcr0);
}
1439

1440
void __kprobes DebugException(struct pt_regs *regs, unsigned long debug_status)
1441
{
1442
1443
	current->thread.dbsr = debug_status;

1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
	/* Hack alert: On BookE, Branch Taken stops on the branch itself, while
	 * on server, it stops on the target of the branch. In order to simulate
	 * the server behaviour, we thus restart right away with a single step
	 * instead of stopping here when hitting a BT
	 */
	if (debug_status & DBSR_BT) {
		regs->msr &= ~MSR_DE;

		/* Disable BT */
		mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) & ~DBCR0_BT);
		/* Clear the BT event */
		mtspr(SPRN_DBSR, DBSR_BT);

		/* Do the single step trick only when coming from userspace */
		if (user_mode(regs)) {
			current->thread.dbcr0 &= ~DBCR0_BT;
			current->thread.dbcr0 |= DBCR0_IDM | DBCR0_IC;
			regs->msr |= MSR_DE;
			return;
		}

		if (notify_die(DIE_SSTEP, "block_step", regs, 5,
			       5, SIGTRAP) == NOTIFY_STOP) {
			return;
		}
		if (debugger_sstep(regs))
			return;
	} else if (debug_status & DBSR_IC) { 	/* Instruction complete */
1472
		regs->msr &= ~MSR_DE;
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486

		/* Disable instruction completion */
		mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) & ~DBCR0_IC);
		/* Clear the instruction completion event */
		mtspr(SPRN_DBSR, DBSR_IC);

		if (notify_die(DIE_SSTEP, "single_step", regs, 5,
			       5, SIGTRAP) == NOTIFY_STOP) {
			return;
		}

		if (debugger_sstep(regs))
			return;

1487
		if (user_mode(regs)) {
1488
1489
1490
1491
1492
1493
1494
			current->thread.dbcr0 &= ~DBCR0_IC;
			if (DBCR_ACTIVE_EVENTS(current->thread.dbcr0,
					       current->thread.dbcr1))
				regs->msr |= MSR_DE;
			else
				/* Make sure the IDM bit is off */
				current->thread.dbcr0 &= ~DBCR0_IDM;
1495
		}
1496
1497
1498
1499

		_exception(SIGTRAP, regs, TRAP_TRACE, regs->nip);
	} else
		handle_debug(regs, debug_status);
1500
}
1501
#endif /* CONFIG_PPC_ADV_DEBUG_REGS */
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511

#if !defined(CONFIG_TAU_INT)
void TAUException(struct pt_regs *regs)
{
	printk("TAU trap at PC: %lx, MSR: %lx, vector=%lx    %s\n",
	       regs->nip, regs->msr, regs->trap, print_tainted());
}
#endif /* CONFIG_INT_TAU */

#ifdef CONFIG_ALTIVEC
1512
void altivec_assist_exception(struct pt_regs *regs)
1513
1514
1515
1516
1517
1518
{
	int err;

	if (!user_mode(regs)) {
		printk(KERN_EMERG "VMX/Altivec assist exception in kernel mode"
		       " at %lx\n", regs->nip);
1519
		die("Kernel VMX/Altivec assist exception", regs, SIGILL);
1520
1521
	}

1522
1523
	flush_altivec_to_thread(current);

1524
	PPC_WARN_EMULATED(altivec, regs);
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
	err = emulate_altivec(regs);
	if (err == 0) {
		regs->nip += 4;		/* skip emulated instruction */
		emulate_single_step(regs);
		return;
	}

	if (err == -EFAULT) {
		/* got an error reading the instruction */
		_exception(SIGSEGV, regs, SEGV_ACCERR, regs->nip);
	} else {
		/* didn't recognize the instruction */
		/* XXX quick hack for now: set the non-Java bit in the VSCR */
1538
1539
		printk_ratelimited(KERN_ERR "Unrecognized altivec instruction "
				   "in %s at %lx\n", current->comm, regs->nip);
1540
1541
1542
1543
1544
		current->thread.vscr.u[3] |= 0x10000;
	}
}
#endif /* CONFIG_ALTIVEC */

1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
#ifdef CONFIG_VSX
void vsx_assist_exception(struct pt_regs *regs)
{
	if (!user_mode(regs)) {
		printk(KERN_EMERG "VSX assist exception in kernel mode"
		       " at %lx\n", regs->nip);
		die("Kernel VSX assist exception", regs, SIGILL);
	}

	flush_vsx_to_thread(current);
	printk(KERN_INFO "VSX assist not supported at %lx\n