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563 lines
13 KiB
563 lines
13 KiB
/*
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* linux/arch/ppc64/kernel/traps.c
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*
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* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Modified by Cort Dougan (cort@cs.nmt.edu)
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* and Paul Mackerras (paulus@cs.anu.edu.au)
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*/
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/*
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* This file handles the architecture-dependent parts of hardware exceptions
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*/
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#include <linux/config.h>
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#include <linux/errno.h>
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/stddef.h>
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#include <linux/unistd.h>
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#include <linux/slab.h>
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#include <linux/user.h>
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#include <linux/a.out.h>
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#include <linux/interrupt.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/delay.h>
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#include <asm/kdebug.h>
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#include <asm/pgtable.h>
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#include <asm/uaccess.h>
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#include <asm/system.h>
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#include <asm/io.h>
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#include <asm/processor.h>
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#include <asm/ppcdebug.h>
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#include <asm/rtas.h>
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#include <asm/systemcfg.h>
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#include <asm/machdep.h>
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#include <asm/pmc.h>
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#ifdef CONFIG_DEBUGGER
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int (*__debugger)(struct pt_regs *regs);
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int (*__debugger_ipi)(struct pt_regs *regs);
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int (*__debugger_bpt)(struct pt_regs *regs);
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int (*__debugger_sstep)(struct pt_regs *regs);
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int (*__debugger_iabr_match)(struct pt_regs *regs);
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int (*__debugger_dabr_match)(struct pt_regs *regs);
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int (*__debugger_fault_handler)(struct pt_regs *regs);
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EXPORT_SYMBOL(__debugger);
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EXPORT_SYMBOL(__debugger_ipi);
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EXPORT_SYMBOL(__debugger_bpt);
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EXPORT_SYMBOL(__debugger_sstep);
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EXPORT_SYMBOL(__debugger_iabr_match);
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EXPORT_SYMBOL(__debugger_dabr_match);
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EXPORT_SYMBOL(__debugger_fault_handler);
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#endif
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struct notifier_block *ppc64_die_chain;
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static DEFINE_SPINLOCK(die_notifier_lock);
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int register_die_notifier(struct notifier_block *nb)
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{
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int err = 0;
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unsigned long flags;
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spin_lock_irqsave(&die_notifier_lock, flags);
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err = notifier_chain_register(&ppc64_die_chain, nb);
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spin_unlock_irqrestore(&die_notifier_lock, flags);
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return err;
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}
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/*
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* Trap & Exception support
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*/
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static DEFINE_SPINLOCK(die_lock);
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int die(const char *str, struct pt_regs *regs, long err)
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{
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static int die_counter;
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int nl = 0;
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if (debugger(regs))
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return 1;
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console_verbose();
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spin_lock_irq(&die_lock);
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bust_spinlocks(1);
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printk("Oops: %s, sig: %ld [#%d]\n", str, err, ++die_counter);
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#ifdef CONFIG_PREEMPT
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printk("PREEMPT ");
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nl = 1;
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#endif
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#ifdef CONFIG_SMP
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printk("SMP NR_CPUS=%d ", NR_CPUS);
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nl = 1;
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#endif
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#ifdef CONFIG_DEBUG_PAGEALLOC
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printk("DEBUG_PAGEALLOC ");
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nl = 1;
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#endif
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#ifdef CONFIG_NUMA
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printk("NUMA ");
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nl = 1;
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#endif
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switch(systemcfg->platform) {
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case PLATFORM_PSERIES:
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printk("PSERIES ");
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nl = 1;
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break;
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case PLATFORM_PSERIES_LPAR:
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printk("PSERIES LPAR ");
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nl = 1;
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break;
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case PLATFORM_ISERIES_LPAR:
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printk("ISERIES LPAR ");
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nl = 1;
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break;
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case PLATFORM_POWERMAC:
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printk("POWERMAC ");
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nl = 1;
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break;
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}
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if (nl)
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printk("\n");
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print_modules();
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show_regs(regs);
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bust_spinlocks(0);
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spin_unlock_irq(&die_lock);
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if (in_interrupt())
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panic("Fatal exception in interrupt");
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if (panic_on_oops) {
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printk(KERN_EMERG "Fatal exception: panic in 5 seconds\n");
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ssleep(5);
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panic("Fatal exception");
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}
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do_exit(SIGSEGV);
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return 0;
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}
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void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr)
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{
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siginfo_t info;
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if (!user_mode(regs)) {
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if (die("Exception in kernel mode", regs, signr))
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return;
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}
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memset(&info, 0, sizeof(info));
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info.si_signo = signr;
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info.si_code = code;
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info.si_addr = (void __user *) addr;
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force_sig_info(signr, &info, current);
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}
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void system_reset_exception(struct pt_regs *regs)
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{
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/* See if any machine dependent calls */
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if (ppc_md.system_reset_exception)
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ppc_md.system_reset_exception(regs);
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die("System Reset", regs, 0);
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/* Must die if the interrupt is not recoverable */
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if (!(regs->msr & MSR_RI))
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panic("Unrecoverable System Reset");
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/* What should we do here? We could issue a shutdown or hard reset. */
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}
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void machine_check_exception(struct pt_regs *regs)
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{
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int recover = 0;
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/* See if any machine dependent calls */
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if (ppc_md.machine_check_exception)
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recover = ppc_md.machine_check_exception(regs);
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if (recover)
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return;
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if (debugger_fault_handler(regs))
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return;
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die("Machine check", regs, 0);
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/* Must die if the interrupt is not recoverable */
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if (!(regs->msr & MSR_RI))
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panic("Unrecoverable Machine check");
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}
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void unknown_exception(struct pt_regs *regs)
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{
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printk("Bad trap at PC: %lx, SR: %lx, vector=%lx\n",
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regs->nip, regs->msr, regs->trap);
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_exception(SIGTRAP, regs, 0, 0);
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}
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void instruction_breakpoint_exception(struct pt_regs *regs)
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{
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if (notify_die(DIE_IABR_MATCH, "iabr_match", regs, 5,
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5, SIGTRAP) == NOTIFY_STOP)
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return;
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if (debugger_iabr_match(regs))
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return;
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_exception(SIGTRAP, regs, TRAP_BRKPT, regs->nip);
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}
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void single_step_exception(struct pt_regs *regs)
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{
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regs->msr &= ~MSR_SE; /* Turn off 'trace' bit */
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if (notify_die(DIE_SSTEP, "single_step", regs, 5,
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5, SIGTRAP) == NOTIFY_STOP)
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return;
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if (debugger_sstep(regs))
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return;
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_exception(SIGTRAP, regs, TRAP_TRACE, regs->nip);
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}
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/*
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* After we have successfully emulated an instruction, we have to
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* check if the instruction was being single-stepped, and if so,
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* pretend we got a single-step exception. This was pointed out
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* by Kumar Gala. -- paulus
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*/
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static inline void emulate_single_step(struct pt_regs *regs)
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{
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if (regs->msr & MSR_SE)
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single_step_exception(regs);
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}
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static void parse_fpe(struct pt_regs *regs)
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{
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int code = 0;
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unsigned long fpscr;
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flush_fp_to_thread(current);
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fpscr = current->thread.fpscr;
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/* Invalid operation */
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if ((fpscr & FPSCR_VE) && (fpscr & FPSCR_VX))
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code = FPE_FLTINV;
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/* Overflow */
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else if ((fpscr & FPSCR_OE) && (fpscr & FPSCR_OX))
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code = FPE_FLTOVF;
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/* Underflow */
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else if ((fpscr & FPSCR_UE) && (fpscr & FPSCR_UX))
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code = FPE_FLTUND;
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/* Divide by zero */
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else if ((fpscr & FPSCR_ZE) && (fpscr & FPSCR_ZX))
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code = FPE_FLTDIV;
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/* Inexact result */
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else if ((fpscr & FPSCR_XE) && (fpscr & FPSCR_XX))
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code = FPE_FLTRES;
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_exception(SIGFPE, regs, code, regs->nip);
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}
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/*
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* Illegal instruction emulation support. Return non-zero if we can't
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* emulate, or -EFAULT if the associated memory access caused an access
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* fault. Return zero on success.
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*/
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#define INST_MFSPR_PVR 0x7c1f42a6
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#define INST_MFSPR_PVR_MASK 0xfc1fffff
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#define INST_DCBA 0x7c0005ec
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#define INST_DCBA_MASK 0x7c0007fe
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#define INST_MCRXR 0x7c000400
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#define INST_MCRXR_MASK 0x7c0007fe
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static int emulate_instruction(struct pt_regs *regs)
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{
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unsigned int instword;
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if (!user_mode(regs))
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return -EINVAL;
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CHECK_FULL_REGS(regs);
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if (get_user(instword, (unsigned int __user *)(regs->nip)))
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return -EFAULT;
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/* Emulate the mfspr rD, PVR. */
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if ((instword & INST_MFSPR_PVR_MASK) == INST_MFSPR_PVR) {
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unsigned int rd;
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rd = (instword >> 21) & 0x1f;
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regs->gpr[rd] = mfspr(SPRN_PVR);
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return 0;
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}
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/* Emulating the dcba insn is just a no-op. */
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if ((instword & INST_DCBA_MASK) == INST_DCBA) {
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static int warned;
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if (!warned) {
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printk(KERN_WARNING
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"process %d (%s) uses obsolete 'dcba' insn\n",
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current->pid, current->comm);
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warned = 1;
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}
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return 0;
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}
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/* Emulate the mcrxr insn. */
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if ((instword & INST_MCRXR_MASK) == INST_MCRXR) {
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static int warned;
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unsigned int shift;
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if (!warned) {
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printk(KERN_WARNING
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"process %d (%s) uses obsolete 'mcrxr' insn\n",
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current->pid, current->comm);
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warned = 1;
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}
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shift = (instword >> 21) & 0x1c;
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regs->ccr &= ~(0xf0000000 >> shift);
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regs->ccr |= (regs->xer & 0xf0000000) >> shift;
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regs->xer &= ~0xf0000000;
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return 0;
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}
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return -EINVAL;
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}
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/*
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* Look through the list of trap instructions that are used for BUG(),
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* BUG_ON() and WARN_ON() and see if we hit one. At this point we know
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* that the exception was caused by a trap instruction of some kind.
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* Returns 1 if we should continue (i.e. it was a WARN_ON) or 0
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* otherwise.
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*/
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extern struct bug_entry __start___bug_table[], __stop___bug_table[];
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#ifndef CONFIG_MODULES
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#define module_find_bug(x) NULL
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#endif
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struct bug_entry *find_bug(unsigned long bugaddr)
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{
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struct bug_entry *bug;
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for (bug = __start___bug_table; bug < __stop___bug_table; ++bug)
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if (bugaddr == bug->bug_addr)
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return bug;
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return module_find_bug(bugaddr);
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}
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static int
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check_bug_trap(struct pt_regs *regs)
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{
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struct bug_entry *bug;
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unsigned long addr;
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if (regs->msr & MSR_PR)
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return 0; /* not in kernel */
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addr = regs->nip; /* address of trap instruction */
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if (addr < PAGE_OFFSET)
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return 0;
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bug = find_bug(regs->nip);
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if (bug == NULL)
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return 0;
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if (bug->line & BUG_WARNING_TRAP) {
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/* this is a WARN_ON rather than BUG/BUG_ON */
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printk(KERN_ERR "Badness in %s at %s:%d\n",
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bug->function, bug->file,
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(unsigned int)bug->line & ~BUG_WARNING_TRAP);
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show_stack(current, (void *)regs->gpr[1]);
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return 1;
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}
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printk(KERN_CRIT "kernel BUG in %s at %s:%d!\n",
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bug->function, bug->file, (unsigned int)bug->line);
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return 0;
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}
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void program_check_exception(struct pt_regs *regs)
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{
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if (debugger_fault_handler(regs))
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return;
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if (regs->msr & 0x100000) {
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/* IEEE FP exception */
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parse_fpe(regs);
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} else if (regs->msr & 0x20000) {
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/* trap exception */
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if (notify_die(DIE_BPT, "breakpoint", regs, 5,
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5, SIGTRAP) == NOTIFY_STOP)
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return;
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if (debugger_bpt(regs))
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return;
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if (check_bug_trap(regs)) {
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regs->nip += 4;
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return;
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}
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_exception(SIGTRAP, regs, TRAP_BRKPT, regs->nip);
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} else {
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/* Privileged or illegal instruction; try to emulate it. */
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switch (emulate_instruction(regs)) {
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case 0:
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regs->nip += 4;
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emulate_single_step(regs);
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break;
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case -EFAULT:
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_exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
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break;
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default:
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if (regs->msr & 0x40000)
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/* priveleged */
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_exception(SIGILL, regs, ILL_PRVOPC, regs->nip);
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else
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/* illegal */
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_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
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break;
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}
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}
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}
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void kernel_fp_unavailable_exception(struct pt_regs *regs)
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{
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printk(KERN_EMERG "Unrecoverable FP Unavailable Exception "
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"%lx at %lx\n", regs->trap, regs->nip);
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die("Unrecoverable FP Unavailable Exception", regs, SIGABRT);
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}
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void altivec_unavailable_exception(struct pt_regs *regs)
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{
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if (user_mode(regs)) {
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/* A user program has executed an altivec instruction,
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but this kernel doesn't support altivec. */
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_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
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return;
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}
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printk(KERN_EMERG "Unrecoverable VMX/Altivec Unavailable Exception "
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"%lx at %lx\n", regs->trap, regs->nip);
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die("Unrecoverable VMX/Altivec Unavailable Exception", regs, SIGABRT);
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}
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extern perf_irq_t perf_irq;
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void performance_monitor_exception(struct pt_regs *regs)
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{
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perf_irq(regs);
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}
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void alignment_exception(struct pt_regs *regs)
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{
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int fixed;
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fixed = fix_alignment(regs);
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if (fixed == 1) {
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regs->nip += 4; /* skip over emulated instruction */
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emulate_single_step(regs);
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return;
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}
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/* Operand address was bad */
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if (fixed == -EFAULT) {
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if (user_mode(regs)) {
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_exception(SIGSEGV, regs, SEGV_MAPERR, regs->dar);
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} else {
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/* Search exception table */
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bad_page_fault(regs, regs->dar, SIGSEGV);
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}
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return;
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}
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_exception(SIGBUS, regs, BUS_ADRALN, regs->nip);
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}
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#ifdef CONFIG_ALTIVEC
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void altivec_assist_exception(struct pt_regs *regs)
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{
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int err;
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siginfo_t info;
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if (!user_mode(regs)) {
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printk(KERN_EMERG "VMX/Altivec assist exception in kernel mode"
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" at %lx\n", regs->nip);
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die("Kernel VMX/Altivec assist exception", regs, SIGILL);
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}
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flush_altivec_to_thread(current);
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err = emulate_altivec(regs);
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if (err == 0) {
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regs->nip += 4; /* skip emulated instruction */
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emulate_single_step(regs);
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return;
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}
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if (err == -EFAULT) {
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/* got an error reading the instruction */
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info.si_signo = SIGSEGV;
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info.si_errno = 0;
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info.si_code = SEGV_MAPERR;
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info.si_addr = (void __user *) regs->nip;
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force_sig_info(SIGSEGV, &info, current);
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} else {
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/* didn't recognize the instruction */
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/* XXX quick hack for now: set the non-Java bit in the VSCR */
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if (printk_ratelimit())
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printk(KERN_ERR "Unrecognized altivec instruction "
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"in %s at %lx\n", current->comm, regs->nip);
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current->thread.vscr.u[3] |= 0x10000;
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}
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}
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#endif /* CONFIG_ALTIVEC */
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/*
|
|
* We enter here if we get an unrecoverable exception, that is, one
|
|
* that happened at a point where the RI (recoverable interrupt) bit
|
|
* in the MSR is 0. This indicates that SRR0/1 are live, and that
|
|
* we therefore lost state by taking this exception.
|
|
*/
|
|
void unrecoverable_exception(struct pt_regs *regs)
|
|
{
|
|
printk(KERN_EMERG "Unrecoverable exception %lx at %lx\n",
|
|
regs->trap, regs->nip);
|
|
die("Unrecoverable exception", regs, SIGABRT);
|
|
}
|
|
|
|
/*
|
|
* We enter here if we discover during exception entry that we are
|
|
* running in supervisor mode with a userspace value in the stack pointer.
|
|
*/
|
|
void kernel_bad_stack(struct pt_regs *regs)
|
|
{
|
|
printk(KERN_EMERG "Bad kernel stack pointer %lx at %lx\n",
|
|
regs->gpr[1], regs->nip);
|
|
die("Bad kernel stack pointer", regs, SIGABRT);
|
|
}
|
|
|
|
void __init trap_init(void)
|
|
{
|
|
}
|
|
|