2 * linux/arch/ppc64/kernel/traps.c
4 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
11 * Modified by Cort Dougan (cort@cs.nmt.edu)
12 * and Paul Mackerras (paulus@cs.anu.edu.au)
16 * This file handles the architecture-dependent parts of hardware exceptions
19 #include <linux/config.h>
20 #include <linux/errno.h>
21 #include <linux/sched.h>
22 #include <linux/kernel.h>
24 #include <linux/stddef.h>
25 #include <linux/unistd.h>
26 #include <linux/slab.h>
27 #include <linux/user.h>
28 #include <linux/a.out.h>
29 #include <linux/interrupt.h>
30 #include <linux/init.h>
31 #include <linux/module.h>
32 #include <linux/delay.h>
33 #include <asm/kdebug.h>
35 #include <asm/pgtable.h>
36 #include <asm/uaccess.h>
37 #include <asm/system.h>
39 #include <asm/processor.h>
40 #include <asm/ppcdebug.h>
42 #include <asm/systemcfg.h>
43 #include <asm/machdep.h>
46 #ifdef CONFIG_DEBUGGER
47 int (*__debugger)(struct pt_regs *regs);
48 int (*__debugger_ipi)(struct pt_regs *regs);
49 int (*__debugger_bpt)(struct pt_regs *regs);
50 int (*__debugger_sstep)(struct pt_regs *regs);
51 int (*__debugger_iabr_match)(struct pt_regs *regs);
52 int (*__debugger_dabr_match)(struct pt_regs *regs);
53 int (*__debugger_fault_handler)(struct pt_regs *regs);
55 EXPORT_SYMBOL(__debugger);
56 EXPORT_SYMBOL(__debugger_ipi);
57 EXPORT_SYMBOL(__debugger_bpt);
58 EXPORT_SYMBOL(__debugger_sstep);
59 EXPORT_SYMBOL(__debugger_iabr_match);
60 EXPORT_SYMBOL(__debugger_dabr_match);
61 EXPORT_SYMBOL(__debugger_fault_handler);
64 struct notifier_block *ppc64_die_chain;
65 static DEFINE_SPINLOCK(die_notifier_lock);
67 int register_die_notifier(struct notifier_block *nb)
72 spin_lock_irqsave(&die_notifier_lock, flags);
73 err = notifier_chain_register(&ppc64_die_chain, nb);
74 spin_unlock_irqrestore(&die_notifier_lock, flags);
79 * Trap & Exception support
82 static DEFINE_SPINLOCK(die_lock);
84 int die(const char *str, struct pt_regs *regs, long err)
86 static int die_counter;
93 spin_lock_irq(&die_lock);
95 printk("Oops: %s, sig: %ld [#%d]\n", str, err, ++die_counter);
101 printk("SMP NR_CPUS=%d ", NR_CPUS);
104 #ifdef CONFIG_DEBUG_PAGEALLOC
105 printk("DEBUG_PAGEALLOC ");
112 switch(systemcfg->platform) {
113 case PLATFORM_PSERIES:
117 case PLATFORM_PSERIES_LPAR:
118 printk("PSERIES LPAR ");
121 case PLATFORM_ISERIES_LPAR:
122 printk("ISERIES LPAR ");
125 case PLATFORM_POWERMAC:
135 spin_unlock_irq(&die_lock);
138 panic("Fatal exception in interrupt");
141 printk(KERN_EMERG "Fatal exception: panic in 5 seconds\n");
143 panic("Fatal exception");
150 void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr)
154 if (!user_mode(regs)) {
155 if (die("Exception in kernel mode", regs, signr))
159 memset(&info, 0, sizeof(info));
160 info.si_signo = signr;
162 info.si_addr = (void __user *) addr;
163 force_sig_info(signr, &info, current);
166 void system_reset_exception(struct pt_regs *regs)
168 /* See if any machine dependent calls */
169 if (ppc_md.system_reset_exception)
170 ppc_md.system_reset_exception(regs);
172 die("System Reset", regs, 0);
174 /* Must die if the interrupt is not recoverable */
175 if (!(regs->msr & MSR_RI))
176 panic("Unrecoverable System Reset");
178 /* What should we do here? We could issue a shutdown or hard reset. */
181 void machine_check_exception(struct pt_regs *regs)
185 /* See if any machine dependent calls */
186 if (ppc_md.machine_check_exception)
187 recover = ppc_md.machine_check_exception(regs);
192 if (debugger_fault_handler(regs))
194 die("Machine check", regs, 0);
196 /* Must die if the interrupt is not recoverable */
197 if (!(regs->msr & MSR_RI))
198 panic("Unrecoverable Machine check");
201 void unknown_exception(struct pt_regs *regs)
203 printk("Bad trap at PC: %lx, SR: %lx, vector=%lx\n",
204 regs->nip, regs->msr, regs->trap);
206 _exception(SIGTRAP, regs, 0, 0);
209 void instruction_breakpoint_exception(struct pt_regs *regs)
211 if (notify_die(DIE_IABR_MATCH, "iabr_match", regs, 5,
212 5, SIGTRAP) == NOTIFY_STOP)
214 if (debugger_iabr_match(regs))
216 _exception(SIGTRAP, regs, TRAP_BRKPT, regs->nip);
219 void single_step_exception(struct pt_regs *regs)
221 regs->msr &= ~MSR_SE; /* Turn off 'trace' bit */
223 if (notify_die(DIE_SSTEP, "single_step", regs, 5,
224 5, SIGTRAP) == NOTIFY_STOP)
226 if (debugger_sstep(regs))
229 _exception(SIGTRAP, regs, TRAP_TRACE, regs->nip);
233 * After we have successfully emulated an instruction, we have to
234 * check if the instruction was being single-stepped, and if so,
235 * pretend we got a single-step exception. This was pointed out
236 * by Kumar Gala. -- paulus
238 static inline void emulate_single_step(struct pt_regs *regs)
240 if (regs->msr & MSR_SE)
241 single_step_exception(regs);
244 static void parse_fpe(struct pt_regs *regs)
249 flush_fp_to_thread(current);
251 fpscr = current->thread.fpscr;
253 /* Invalid operation */
254 if ((fpscr & FPSCR_VE) && (fpscr & FPSCR_VX))
258 else if ((fpscr & FPSCR_OE) && (fpscr & FPSCR_OX))
262 else if ((fpscr & FPSCR_UE) && (fpscr & FPSCR_UX))
266 else if ((fpscr & FPSCR_ZE) && (fpscr & FPSCR_ZX))
270 else if ((fpscr & FPSCR_XE) && (fpscr & FPSCR_XX))
273 _exception(SIGFPE, regs, code, regs->nip);
277 * Illegal instruction emulation support. Return non-zero if we can't
278 * emulate, or -EFAULT if the associated memory access caused an access
279 * fault. Return zero on success.
282 #define INST_MFSPR_PVR 0x7c1f42a6
283 #define INST_MFSPR_PVR_MASK 0xfc1fffff
285 #define INST_DCBA 0x7c0005ec
286 #define INST_DCBA_MASK 0x7c0007fe
288 #define INST_MCRXR 0x7c000400
289 #define INST_MCRXR_MASK 0x7c0007fe
291 static int emulate_instruction(struct pt_regs *regs)
293 unsigned int instword;
295 if (!user_mode(regs))
298 CHECK_FULL_REGS(regs);
300 if (get_user(instword, (unsigned int __user *)(regs->nip)))
303 /* Emulate the mfspr rD, PVR. */
304 if ((instword & INST_MFSPR_PVR_MASK) == INST_MFSPR_PVR) {
307 rd = (instword >> 21) & 0x1f;
308 regs->gpr[rd] = mfspr(SPRN_PVR);
312 /* Emulating the dcba insn is just a no-op. */
313 if ((instword & INST_DCBA_MASK) == INST_DCBA) {
318 "process %d (%s) uses obsolete 'dcba' insn\n",
319 current->pid, current->comm);
325 /* Emulate the mcrxr insn. */
326 if ((instword & INST_MCRXR_MASK) == INST_MCRXR) {
332 "process %d (%s) uses obsolete 'mcrxr' insn\n",
333 current->pid, current->comm);
337 shift = (instword >> 21) & 0x1c;
338 regs->ccr &= ~(0xf0000000 >> shift);
339 regs->ccr |= (regs->xer & 0xf0000000) >> shift;
340 regs->xer &= ~0xf0000000;
348 * Look through the list of trap instructions that are used for BUG(),
349 * BUG_ON() and WARN_ON() and see if we hit one. At this point we know
350 * that the exception was caused by a trap instruction of some kind.
351 * Returns 1 if we should continue (i.e. it was a WARN_ON) or 0
354 extern struct bug_entry __start___bug_table[], __stop___bug_table[];
356 #ifndef CONFIG_MODULES
357 #define module_find_bug(x) NULL
360 struct bug_entry *find_bug(unsigned long bugaddr)
362 struct bug_entry *bug;
364 for (bug = __start___bug_table; bug < __stop___bug_table; ++bug)
365 if (bugaddr == bug->bug_addr)
367 return module_find_bug(bugaddr);
371 check_bug_trap(struct pt_regs *regs)
373 struct bug_entry *bug;
376 if (regs->msr & MSR_PR)
377 return 0; /* not in kernel */
378 addr = regs->nip; /* address of trap instruction */
379 if (addr < PAGE_OFFSET)
381 bug = find_bug(regs->nip);
384 if (bug->line & BUG_WARNING_TRAP) {
385 /* this is a WARN_ON rather than BUG/BUG_ON */
386 printk(KERN_ERR "Badness in %s at %s:%d\n",
387 bug->function, bug->file,
388 (unsigned int)bug->line & ~BUG_WARNING_TRAP);
389 show_stack(current, (void *)regs->gpr[1]);
392 printk(KERN_CRIT "kernel BUG in %s at %s:%d!\n",
393 bug->function, bug->file, (unsigned int)bug->line);
397 void program_check_exception(struct pt_regs *regs)
399 if (debugger_fault_handler(regs))
402 if (regs->msr & 0x100000) {
403 /* IEEE FP exception */
405 } else if (regs->msr & 0x20000) {
408 if (notify_die(DIE_BPT, "breakpoint", regs, 5,
409 5, SIGTRAP) == NOTIFY_STOP)
411 if (debugger_bpt(regs))
414 if (check_bug_trap(regs)) {
418 _exception(SIGTRAP, regs, TRAP_BRKPT, regs->nip);
421 /* Privileged or illegal instruction; try to emulate it. */
422 switch (emulate_instruction(regs)) {
425 emulate_single_step(regs);
429 _exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
433 if (regs->msr & 0x40000)
435 _exception(SIGILL, regs, ILL_PRVOPC, regs->nip);
438 _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
444 void kernel_fp_unavailable_exception(struct pt_regs *regs)
446 printk(KERN_EMERG "Unrecoverable FP Unavailable Exception "
447 "%lx at %lx\n", regs->trap, regs->nip);
448 die("Unrecoverable FP Unavailable Exception", regs, SIGABRT);
451 void altivec_unavailable_exception(struct pt_regs *regs)
453 if (user_mode(regs)) {
454 /* A user program has executed an altivec instruction,
455 but this kernel doesn't support altivec. */
456 _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
459 printk(KERN_EMERG "Unrecoverable VMX/Altivec Unavailable Exception "
460 "%lx at %lx\n", regs->trap, regs->nip);
461 die("Unrecoverable VMX/Altivec Unavailable Exception", regs, SIGABRT);
464 extern perf_irq_t perf_irq;
466 void performance_monitor_exception(struct pt_regs *regs)
471 void alignment_exception(struct pt_regs *regs)
475 fixed = fix_alignment(regs);
478 regs->nip += 4; /* skip over emulated instruction */
479 emulate_single_step(regs);
483 /* Operand address was bad */
484 if (fixed == -EFAULT) {
485 if (user_mode(regs)) {
486 _exception(SIGSEGV, regs, SEGV_MAPERR, regs->dar);
488 /* Search exception table */
489 bad_page_fault(regs, regs->dar, SIGSEGV);
495 _exception(SIGBUS, regs, BUS_ADRALN, regs->nip);
498 #ifdef CONFIG_ALTIVEC
499 void altivec_assist_exception(struct pt_regs *regs)
504 if (!user_mode(regs)) {
505 printk(KERN_EMERG "VMX/Altivec assist exception in kernel mode"
506 " at %lx\n", regs->nip);
507 die("Kernel VMX/Altivec assist exception", regs, SIGILL);
510 flush_altivec_to_thread(current);
512 err = emulate_altivec(regs);
514 regs->nip += 4; /* skip emulated instruction */
515 emulate_single_step(regs);
519 if (err == -EFAULT) {
520 /* got an error reading the instruction */
521 info.si_signo = SIGSEGV;
523 info.si_code = SEGV_MAPERR;
524 info.si_addr = (void __user *) regs->nip;
525 force_sig_info(SIGSEGV, &info, current);
527 /* didn't recognize the instruction */
528 /* XXX quick hack for now: set the non-Java bit in the VSCR */
529 if (printk_ratelimit())
530 printk(KERN_ERR "Unrecognized altivec instruction "
531 "in %s at %lx\n", current->comm, regs->nip);
532 current->thread.vscr.u[3] |= 0x10000;
535 #endif /* CONFIG_ALTIVEC */
538 * We enter here if we get an unrecoverable exception, that is, one
539 * that happened at a point where the RI (recoverable interrupt) bit
540 * in the MSR is 0. This indicates that SRR0/1 are live, and that
541 * we therefore lost state by taking this exception.
543 void unrecoverable_exception(struct pt_regs *regs)
545 printk(KERN_EMERG "Unrecoverable exception %lx at %lx\n",
546 regs->trap, regs->nip);
547 die("Unrecoverable exception", regs, SIGABRT);
551 * We enter here if we discover during exception entry that we are
552 * running in supervisor mode with a userspace value in the stack pointer.
554 void kernel_bad_stack(struct pt_regs *regs)
556 printk(KERN_EMERG "Bad kernel stack pointer %lx at %lx\n",
557 regs->gpr[1], regs->nip);
558 die("Bad kernel stack pointer", regs, SIGABRT);
561 void __init trap_init(void)