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linux/arch/powerpc/kernel/traps.c
Scott Wood 5dd57a1308 [POWERPC] 8xx: Move softemu8xx.c from arch/ppc 
Previously, Soft_emulate_8xx was called with no implementation, resulting in
build failures whenever building 8xx without math emulation.  The
implementation is copied from arch/ppc to resolve this issue.

However, this sort of minimal emulation is not a very good idea other than
for compatibility with existing userspaces, as it's less efficient than
soft-float and can mislead users into believing they have soft-float.  Thus,
it is made a configurable option, off by default.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2007-10-04 11:02:54 -05:00

1119 lines
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/*
* 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@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>
#include <linux/ptrace.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/prctl.h>
#include <linux/delay.h>
#include <linux/kprobes.h>
#include <linux/kexec.h>
#include <linux/backlight.h>
#include <linux/bug.h>
#include <linux/kdebug.h>
#include <asm/pgtable.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/machdep.h>
#include <asm/rtas.h>
#include <asm/pmc.h>
#ifdef CONFIG_PPC32
#include <asm/reg.h>
#endif
#ifdef CONFIG_PMAC_BACKLIGHT
#include <asm/backlight.h>
#endif
#ifdef CONFIG_PPC64
#include <asm/firmware.h>
#include <asm/processor.h>
#endif
#include <asm/kexec.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
/*
* Trap & Exception support
*/
#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
int die(const char *str, struct pt_regs *regs, long err)
{
static struct {
spinlock_t lock;
u32 lock_owner;
int lock_owner_depth;
} die = {
.lock = __SPIN_LOCK_UNLOCKED(die.lock),
.lock_owner = -1,
.lock_owner_depth = 0
};
static int die_counter;
unsigned long flags;
if (debugger(regs))
return 1;
oops_enter();
if (die.lock_owner != raw_smp_processor_id()) {
console_verbose();
spin_lock_irqsave(&die.lock, flags);
die.lock_owner = smp_processor_id();
die.lock_owner_depth = 0;
bust_spinlocks(1);
if (machine_is(powermac))
pmac_backlight_unblank();
} else {
local_save_flags(flags);
}
if (++die.lock_owner_depth < 3) {
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 : "");
print_modules();
show_regs(regs);
} else {
printk("Recursive die() failure, output suppressed\n");
}
bust_spinlocks(0);
die.lock_owner = -1;
add_taint(TAINT_DIE);
spin_unlock_irqrestore(&die.lock, flags);
if (kexec_should_crash(current) ||
kexec_sr_activated(smp_processor_id()))
crash_kexec(regs);
crash_kexec_secondary(regs);
if (in_interrupt())
panic("Fatal exception in interrupt");
if (panic_on_oops)
panic("Fatal exception");
oops_exit();
do_exit(err);
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);
/*
* Init gets no signals that it doesn't have a handler for.
* That's all very well, but if it has caused a synchronous
* exception and we ignore the resulting signal, it will just
* generate the same exception over and over again and we get
* nowhere. Better to kill it and let the kernel panic.
*/
if (is_init(current)) {
__sighandler_t handler;
spin_lock_irq(&current->sighand->siglock);
handler = current->sighand->action[signr-1].sa.sa_handler;
spin_unlock_irq(&current->sighand->siglock);
if (handler == SIG_DFL) {
/* init has generated a synchronous exception
and it doesn't have a handler for the signal */
printk(KERN_CRIT "init has generated signal %d "
"but has no handler for it\n", signr);
do_exit(signr);
}
}
}
#ifdef CONFIG_PPC64
void system_reset_exception(struct pt_regs *regs)
{
/* See if any machine dependent calls */
if (ppc_md.system_reset_exception) {
if (ppc_md.system_reset_exception(regs))
return;
}
#ifdef CONFIG_KEXEC
cpu_set(smp_processor_id(), cpus_in_sr);
#endif
die("System Reset", regs, SIGABRT);
/*
* Some CPUs when released from the debugger will execute this path.
* These CPUs entered the debugger via a soft-reset. If the CPU was
* hung before entering the debugger it will return to the hung
* state when exiting this function. This causes a problem in
* kdump since the hung CPU(s) will not respond to the IPI sent
* from kdump. To prevent the problem we call crash_kexec_secondary()
* here. If a kdump had not been initiated or we exit the debugger
* with the "exit and recover" command (x) crash_kexec_secondary()
* will return after 5ms and the CPU returns to its previous state.
*/
crash_kexec_secondary(regs);
/* 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)
{
#ifdef CONFIG_PPC32
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;
}
}
#endif /* CONFIG_PPC32 */
return 0;
}
#if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
/* 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
#define get_mc_reason(regs) (mfspr(SPRN_MCSR) & MCSR_MASK)
#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)
#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
static int generic_machine_check_exception(struct pt_regs *regs)
{
unsigned long reason = get_mc_reason(regs);
#if defined(CONFIG_4xx) && !defined(CONFIG_440A)
if (reason & ESR_IMCP) {
printk("Instruction");
mtspr(SPRN_ESR, reason & ~ESR_IMCP);
} else
printk("Data");
printk(" machine check in kernel mode.\n");
#elif defined(CONFIG_440A)
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);
}
#elif defined (CONFIG_E500)
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");
#elif defined (CONFIG_E200)
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");
#else /* !CONFIG_4xx && !CONFIG_E500 && !CONFIG_E200 */
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");
}
#endif /* CONFIG_4xx */
return 0;
}
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);
else
recover = generic_machine_check_exception(regs);
if (recover)
return;
if (user_mode(regs)) {
regs->msr |= MSR_RI;
_exception(SIGBUS, regs, BUS_ADRERR, regs->nip);
return;
}
#if defined(CONFIG_8xx) && defined(CONFIG_PCI)
/* the qspan pci read routines can cause machine checks -- Cort */
bad_page_fault(regs, regs->dar, SIGBUS);
return;
#endif
if (debugger_fault_handler(regs)) {
regs->msr |= MSR_RI;
return;
}
if (check_io_access(regs))
return;
if (debugger_fault_handler(regs))
return;
die("Machine check", regs, SIGBUS);
/* 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);
}
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 RunModeException(struct pt_regs *regs)
{
_exception(SIGTRAP, regs, 0, 0);
}
void __kprobes single_step_exception(struct pt_regs *regs)
{
regs->msr &= ~(MSR_SE | MSR_BE); /* Turn off 'trace' bits */
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 void emulate_single_step(struct pt_regs *regs)
{
if (single_stepping(regs)) {
clear_single_step(regs);
_exception(SIGTRAP, regs, TRAP_TRACE, 0);
}
}
static inline int __parse_fpscr(unsigned long fpscr)
{
int ret = 0;
/* Invalid operation */
if ((fpscr & FPSCR_VE) && (fpscr & FPSCR_VX))
ret = FPE_FLTINV;
/* Overflow */
else if ((fpscr & FPSCR_OE) && (fpscr & FPSCR_OX))
ret = FPE_FLTOVF;
/* Underflow */
else if ((fpscr & FPSCR_UE) && (fpscr & FPSCR_UX))
ret = FPE_FLTUND;
/* Divide by zero */
else if ((fpscr & FPSCR_ZE) && (fpscr & FPSCR_ZX))
ret = FPE_FLTDIV;
/* Inexact result */
else if ((fpscr & FPSCR_XE) && (fpscr & FPSCR_XX))
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);
_exception(SIGFPE, regs, code, regs->nip);
}
/*
* Illegal instruction emulation support. Originally written to
* 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.
*
*/
#define INST_MFSPR_PVR 0x7c1f42a6
#define INST_MFSPR_PVR_MASK 0xfc1fffff
#define INST_DCBA 0x7c0005ec
#define INST_DCBA_MASK 0xfc0007fe
#define INST_MCRXR 0x7c000400
#define INST_MCRXR_MASK 0xfc0007fe
#define INST_STRING 0x7c00042a
#define INST_STRING_MASK 0xfc0007fe
#define INST_STRING_GEN_MASK 0xfc00067e
#define INST_LSWI 0x7c0004aa
#define INST_LSWX 0x7c00042a
#define INST_STSWI 0x7c0005aa
#define INST_STSWX 0x7c00052a
#define INST_POPCNTB 0x7c0000f4
#define INST_POPCNTB_MASK 0xfc0007fe
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 */
if ((instword & INST_STRING_MASK) == INST_LSWX)
if ((rT == rA) || (rT == NB_RB))
return -EINVAL;
EA = (rA == 0) ? 0 : regs->gpr[rA];
switch (instword & INST_STRING_MASK) {
case INST_LSWX:
case INST_STSWX:
EA += NB_RB;
num_bytes = regs->xer & 0x7f;
break;
case INST_LSWI:
case INST_STSWI:
num_bytes = (NB_RB == 0) ? 32 : NB_RB;
break;
default:
return -EINVAL;
}
while (num_bytes != 0)
{
u8 val;
u32 shift = 8 * (3 - (pos & 0x3));
switch ((instword & INST_STRING_MASK)) {
case INST_LSWX:
case INST_LSWI:
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;
case INST_STSWI:
case INST_STSWX:
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;
}
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;
}
static int emulate_instruction(struct pt_regs *regs)
{
u32 instword;
u32 rd;
if (!user_mode(regs) || (regs->msr & MSR_LE))
return -EINVAL;
CHECK_FULL_REGS(regs);
if (get_user(instword, (u32 __user *)(regs->nip)))
return -EFAULT;
/* Emulate the mfspr rD, PVR. */
if ((instword & INST_MFSPR_PVR_MASK) == INST_MFSPR_PVR) {
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)
return 0;
/* Emulate the mcrxr insn. */
if ((instword & INST_MCRXR_MASK) == INST_MCRXR) {
int shift = (instword >> 21) & 0x1c;
unsigned long msk = 0xf0000000UL >> shift;
regs->ccr = (regs->ccr & ~msk) | ((regs->xer >> shift) & msk);
regs->xer &= ~0xf0000000UL;
return 0;
}
/* Emulate load/store string insn. */
if ((instword & INST_STRING_GEN_MASK) == INST_STRING)
return emulate_string_inst(regs, instword);
/* Emulate the popcntb (Population Count Bytes) instruction. */
if ((instword & INST_POPCNTB_MASK) == INST_POPCNTB) {
return emulate_popcntb_inst(regs, instword);
}
return -EINVAL;
}
int is_valid_bugaddr(unsigned long addr)
{
return is_kernel_addr(addr);
}
void __kprobes program_check_exception(struct pt_regs *regs)
{
unsigned int reason = get_reason(regs);
extern int do_mathemu(struct pt_regs *regs);
/* We can now get here via a FP Unavailable exception if the core
* has no FPU, in that case the reason flags will be 0 */
if (reason & REASON_FP) {
/* IEEE FP exception */
parse_fpe(regs);
return;
}
if (reason & REASON_TRAP) {
/* trap exception */
if (notify_die(DIE_BPT, "breakpoint", regs, 5, 5, SIGTRAP)
== NOTIFY_STOP)
return;
if (debugger_bpt(regs))
return;
if (!(regs->msr & MSR_PR) && /* not user-mode */
report_bug(regs->nip, regs) == BUG_TRAP_TYPE_WARN) {
regs->nip += 4;
return;
}
_exception(SIGTRAP, regs, TRAP_BRKPT, regs->nip);
return;
}
local_irq_enable();
#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
* pattern to occurences etc. -dgibson 31/Mar/2003 */
switch (do_mathemu(regs)) {
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;
}
/* fall through on any other errors */
#endif /* CONFIG_MATH_EMULATION */
/* Try to emulate it if we should. */
if (reason & (REASON_ILLEGAL | REASON_PRIVILEGED)) {
switch (emulate_instruction(regs)) {
case 0:
regs->nip += 4;
emulate_single_step(regs);
return;
case -EFAULT:
_exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
return;
}
}
if (reason & REASON_PRIVILEGED)
_exception(SIGILL, regs, ILL_PRVOPC, regs->nip);
else
_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
}
void alignment_exception(struct pt_regs *regs)
{
int sig, code, fixed = 0;
/* we don't implement logging of alignment exceptions */
if (!(current->thread.align_ctl & PR_UNALIGN_SIGBUS))
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) {
sig = SIGSEGV;
code = SEGV_ACCERR;
} else {
sig = SIGBUS;
code = BUS_ADRALN;
}
if (user_mode(regs))
_exception(sig, regs, code, regs->dar);
else
bad_page_fault(regs, regs->dar, sig);
}
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",
current, current->pid, regs->nip, regs->link, regs->gpr[0],
regs->ccr&0x10000000?"Error=":"", regs->gpr[3], print_tainted());
}
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);
}
void performance_monitor_exception(struct pt_regs *regs)
{
perf_irq(regs);
}
#ifdef CONFIG_8xx
void SoftwareEmulation(struct pt_regs *regs)
{
extern int do_mathemu(struct pt_regs *);
extern int Soft_emulate_8xx(struct pt_regs *);
#if defined(CONFIG_MATH_EMULATION) || defined(CONFIG_8XX_MINIMAL_FPEMU)
int errcode;
#endif
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);
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;
}
#elif defined(CONFIG_8XX_MINIMAL_FPEMU)
errcode = Soft_emulate_8xx(regs);
switch (errcode) {
case 0:
emulate_single_step(regs);
return;
case 1:
_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
return;
case -EFAULT:
_exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
return;
}
#else
_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
#endif
}
#endif /* CONFIG_8xx */
#if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
void DebugException(struct pt_regs *regs, unsigned long debug_status)
{
if (debug_status & DBSR_IC) { /* instruction completion */
regs->msr &= ~MSR_DE;
if (user_mode(regs)) {
current->thread.dbcr0 &= ~DBCR0_IC;
} else {
/* Disable instruction completion */
mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) & ~DBCR0_IC);
/* Clear the instruction completion event */
mtspr(SPRN_DBSR, DBSR_IC);
if (debugger_sstep(regs))
return;
}
_exception(SIGTRAP, regs, TRAP_TRACE, 0);
}
}
#endif /* CONFIG_4xx || CONFIG_BOOKE */
#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
void altivec_assist_exception(struct pt_regs *regs)
{
int err;
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 */
_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 */
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 */
#ifdef CONFIG_FSL_BOOKE
void CacheLockingException(struct pt_regs *regs, unsigned long address,
unsigned long error_code)
{
/* We treat cache locking instructions from the user
* as priv ops, in the future we could try to do
* something smarter
*/
if (error_code & (ESR_DLK|ESR_ILK))
_exception(SIGILL, regs, ILL_PRVOPC, regs->nip);
return;
}
#endif /* CONFIG_FSL_BOOKE */
#ifdef CONFIG_SPE
void SPEFloatingPointException(struct pt_regs *regs)
{
unsigned long spefscr;
int fpexc_mode;
int code = 0;
spefscr = current->thread.spefscr;
fpexc_mode = current->thread.fpexc_mode;
/* Hardware does not neccessarily set sticky
* underflow/overflow/invalid flags */
if ((spefscr & SPEFSCR_FOVF) && (fpexc_mode & PR_FP_EXC_OVF)) {
code = FPE_FLTOVF;
spefscr |= SPEFSCR_FOVFS;
}
else if ((spefscr & SPEFSCR_FUNF) && (fpexc_mode & PR_FP_EXC_UND)) {
code = FPE_FLTUND;
spefscr |= SPEFSCR_FUNFS;
}
else if ((spefscr & SPEFSCR_FDBZ) && (fpexc_mode & PR_FP_EXC_DIV))
code = FPE_FLTDIV;
else if ((spefscr & SPEFSCR_FINV) && (fpexc_mode & PR_FP_EXC_INV)) {
code = FPE_FLTINV;
spefscr |= SPEFSCR_FINVS;
}
else if ((spefscr & (SPEFSCR_FG | SPEFSCR_FX)) && (fpexc_mode & PR_FP_EXC_RES))
code = FPE_FLTRES;
current->thread.spefscr = spefscr;
_exception(SIGFPE, regs, code, regs->nip);
return;
}
#endif
/*
* 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);
}
#ifdef CONFIG_BOOKE_WDT
/*
* Default handler for a Watchdog exception,
* spins until a reboot occurs
*/
void __attribute__ ((weak)) WatchdogHandler(struct pt_regs *regs)
{
/* Generic WatchdogHandler, implement your own */
mtspr(SPRN_TCR, mfspr(SPRN_TCR)&(~TCR_WIE));
return;
}
void WatchdogException(struct pt_regs *regs)
{
printk (KERN_EMERG "PowerPC Book-E Watchdog Exception\n");
WatchdogHandler(regs);
}
#endif
/*
* 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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