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linux/arch/ppc64/kernel/traps.c

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