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>
33 #include <asm/pgtable.h>
34 #include <asm/uaccess.h>
35 #include <asm/system.h>
37 #include <asm/processor.h>
38 #include <asm/ppcdebug.h>
41 #ifdef CONFIG_PPC_PSERIES
42 /* This is true if we are using the firmware NMI handler (typically LPAR) */
43 extern int fwnmi_active;
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);
65 * Trap & Exception support
68 static spinlock_t die_lock = SPIN_LOCK_UNLOCKED;
70 int die(const char *str, struct pt_regs *regs, long err)
72 static int die_counter;
79 spin_lock_irq(&die_lock);
81 printk("Oops: %s, sig: %ld [#%d]\n", str, err, ++die_counter);
87 printk("SMP NR_CPUS=%d ", NR_CPUS);
90 #ifdef CONFIG_DEBUG_PAGEALLOC
91 printk("DEBUG_PAGEALLOC ");
98 switch(systemcfg->platform) {
99 case PLATFORM_PSERIES:
103 case PLATFORM_PSERIES_LPAR:
104 printk("PSERIES LPAR ");
107 case PLATFORM_ISERIES_LPAR:
108 printk("ISERIES LPAR ");
111 case PLATFORM_POWERMAC:
120 spin_unlock_irq(&die_lock);
123 panic("Fatal exception in interrupt");
126 printk(KERN_EMERG "Fatal exception: panic in 5 seconds\n");
127 set_current_state(TASK_UNINTERRUPTIBLE);
128 schedule_timeout(5 * HZ);
129 panic("Fatal exception");
137 _exception(int signr, struct pt_regs *regs, int code, unsigned long addr)
141 if (!user_mode(regs)) {
142 if (die("Exception in kernel mode", regs, signr))
146 memset(&info, 0, sizeof(info));
147 info.si_signo = signr;
149 info.si_addr = (void __user *) addr;
150 force_sig_info(signr, &info, current);
153 #ifdef CONFIG_PPC_PSERIES
154 /* Get the error information for errors coming through the
155 * FWNMI vectors. The pt_regs' r3 will be updated to reflect
156 * the actual r3 if possible, and a ptr to the error log entry
157 * will be returned if found.
159 static struct rtas_error_log *FWNMI_get_errinfo(struct pt_regs *regs)
161 unsigned long errdata = regs->gpr[3];
162 struct rtas_error_log *errhdr = NULL;
163 unsigned long *savep;
165 if ((errdata >= 0x7000 && errdata < 0x7fff0) ||
166 (errdata >= rtas.base && errdata < rtas.base + rtas.size - 16)) {
167 savep = __va(errdata);
168 regs->gpr[3] = savep[0]; /* restore original r3 */
169 errhdr = (struct rtas_error_log *)(savep + 1);
171 printk("FWNMI: corrupt r3\n");
176 /* Call this when done with the data returned by FWNMI_get_errinfo.
177 * It will release the saved data area for other CPUs in the
178 * partition to receive FWNMI errors.
180 static void FWNMI_release_errinfo(void)
182 int ret = rtas_call(rtas_token("ibm,nmi-interlock"), 0, 1, NULL);
184 printk("FWNMI: nmi-interlock failed: %d\n", ret);
189 SystemResetException(struct pt_regs *regs)
191 #ifdef CONFIG_PPC_PSERIES
193 struct rtas_error_log *errhdr = FWNMI_get_errinfo(regs);
195 /* XXX Should look at FWNMI information */
197 FWNMI_release_errinfo();
201 die("System Reset", regs, 0);
203 /* Must die if the interrupt is not recoverable */
204 if (!(regs->msr & MSR_RI))
205 panic("Unrecoverable System Reset");
207 /* What should we do here? We could issue a shutdown or hard reset. */
210 #ifdef CONFIG_PPC_PSERIES
212 * See if we can recover from a machine check exception.
213 * This is only called on power4 (or above) and only via
214 * the Firmware Non-Maskable Interrupts (fwnmi) handler
215 * which provides the error analysis for us.
217 * Return 1 if corrected (or delivered a signal).
218 * Return 0 if there is nothing we can do.
220 static int recover_mce(struct pt_regs *regs, struct rtas_error_log err)
222 if (err.disposition == RTAS_DISP_FULLY_RECOVERED) {
223 /* Platform corrected itself */
225 } else if ((regs->msr & MSR_RI) &&
227 err.severity == RTAS_SEVERITY_ERROR_SYNC &&
228 err.disposition == RTAS_DISP_NOT_RECOVERED &&
229 err.target == RTAS_TARGET_MEMORY &&
230 err.type == RTAS_TYPE_ECC_UNCORR &&
231 !(current->pid == 0 || current->pid == 1)) {
232 /* Kill off a user process with an ECC error */
233 printk(KERN_ERR "MCE: uncorrectable ecc error for pid %d\n",
235 /* XXX something better for ECC error? */
236 _exception(SIGBUS, regs, BUS_ADRERR, regs->nip);
244 * Handle a machine check.
246 * Note that on Power 4 and beyond Firmware Non-Maskable Interrupts (fwnmi)
247 * should be present. If so the handler which called us tells us if the
248 * error was recovered (never true if RI=0).
250 * On hardware prior to Power 4 these exceptions were asynchronous which
251 * means we can't tell exactly where it occurred and so we can't recover.
254 MachineCheckException(struct pt_regs *regs)
256 #ifdef CONFIG_PPC_PSERIES
257 struct rtas_error_log err, *errp;
260 errp = FWNMI_get_errinfo(regs);
263 FWNMI_release_errinfo(); /* frees errp */
264 if (errp && recover_mce(regs, err))
269 if (debugger_fault_handler(regs))
271 die("Machine check", regs, 0);
273 /* Must die if the interrupt is not recoverable */
274 if (!(regs->msr & MSR_RI))
275 panic("Unrecoverable Machine check");
279 UnknownException(struct pt_regs *regs)
281 printk("Bad trap at PC: %lx, SR: %lx, vector=%lx\n",
282 regs->nip, regs->msr, regs->trap);
284 _exception(SIGTRAP, regs, 0, 0);
288 InstructionBreakpointException(struct pt_regs *regs)
290 if (debugger_iabr_match(regs))
292 _exception(SIGTRAP, regs, TRAP_BRKPT, regs->nip);
296 SingleStepException(struct pt_regs *regs)
298 regs->msr &= ~MSR_SE; /* Turn off 'trace' bit */
300 if (debugger_sstep(regs))
303 _exception(SIGTRAP, regs, TRAP_TRACE, regs->nip);
307 * After we have successfully emulated an instruction, we have to
308 * check if the instruction was being single-stepped, and if so,
309 * pretend we got a single-step exception. This was pointed out
310 * by Kumar Gala. -- paulus
312 static inline void emulate_single_step(struct pt_regs *regs)
314 if (regs->msr & MSR_SE)
315 SingleStepException(regs);
318 static void parse_fpe(struct pt_regs *regs)
323 flush_fp_to_thread(current);
325 fpscr = current->thread.fpscr;
327 /* Invalid operation */
328 if ((fpscr & FPSCR_VE) && (fpscr & FPSCR_VX))
332 else if ((fpscr & FPSCR_OE) && (fpscr & FPSCR_OX))
336 else if ((fpscr & FPSCR_UE) && (fpscr & FPSCR_UX))
340 else if ((fpscr & FPSCR_ZE) && (fpscr & FPSCR_ZX))
344 else if ((fpscr & FPSCR_XE) && (fpscr & FPSCR_XX))
347 _exception(SIGFPE, regs, code, regs->nip);
351 * Illegal instruction emulation support. Return non-zero if we can't
352 * emulate, or -EFAULT if the associated memory access caused an access
353 * fault. Return zero on success.
356 #define INST_DCBA 0x7c0005ec
357 #define INST_DCBA_MASK 0x7c0007fe
359 #define INST_MCRXR 0x7c000400
360 #define INST_MCRXR_MASK 0x7c0007fe
362 static int emulate_instruction(struct pt_regs *regs)
364 unsigned int instword;
366 if (!user_mode(regs))
369 CHECK_FULL_REGS(regs);
371 if (get_user(instword, (unsigned int __user *)(regs->nip)))
374 /* Emulating the dcba insn is just a no-op. */
375 if ((instword & INST_DCBA_MASK) == INST_DCBA) {
380 "process %d (%s) uses obsolete 'dcba' insn\n",
381 current->pid, current->comm);
387 /* Emulate the mcrxr insn. */
388 if ((instword & INST_MCRXR_MASK) == INST_MCRXR) {
394 "process %d (%s) uses obsolete 'mcrxr' insn\n",
395 current->pid, current->comm);
399 shift = (instword >> 21) & 0x1c;
400 regs->ccr &= ~(0xf0000000 >> shift);
401 regs->ccr |= (regs->xer & 0xf0000000) >> shift;
402 regs->xer &= ~0xf0000000;
410 * Look through the list of trap instructions that are used for BUG(),
411 * BUG_ON() and WARN_ON() and see if we hit one. At this point we know
412 * that the exception was caused by a trap instruction of some kind.
413 * Returns 1 if we should continue (i.e. it was a WARN_ON) or 0
416 extern struct bug_entry __start___bug_table[], __stop___bug_table[];
418 #ifndef CONFIG_MODULES
419 #define module_find_bug(x) NULL
422 static struct bug_entry *find_bug(unsigned long bugaddr)
424 struct bug_entry *bug;
426 for (bug = __start___bug_table; bug < __stop___bug_table; ++bug)
427 if (bugaddr == bug->bug_addr)
429 return module_find_bug(bugaddr);
433 check_bug_trap(struct pt_regs *regs)
435 struct bug_entry *bug;
438 if (regs->msr & MSR_PR)
439 return 0; /* not in kernel */
440 addr = regs->nip; /* address of trap instruction */
441 if (addr < PAGE_OFFSET)
443 bug = find_bug(regs->nip);
446 if (bug->line & BUG_WARNING_TRAP) {
447 /* this is a WARN_ON rather than BUG/BUG_ON */
448 printk(KERN_ERR "Badness in %s at %s:%d\n",
449 bug->function, bug->file,
450 (unsigned int)bug->line & ~BUG_WARNING_TRAP);
451 show_stack(current, (void *)regs->gpr[1]);
454 printk(KERN_CRIT "kernel BUG in %s at %s:%d!\n",
455 bug->function, bug->file, (unsigned int)bug->line);
460 ProgramCheckException(struct pt_regs *regs)
462 if (regs->msr & 0x100000) {
463 /* IEEE FP exception */
466 } else if (regs->msr & 0x40000) {
467 /* Privileged instruction */
468 _exception(SIGILL, regs, ILL_PRVOPC, regs->nip);
470 } else if (regs->msr & 0x20000) {
473 if (debugger_bpt(regs))
476 if (check_bug_trap(regs)) {
480 _exception(SIGTRAP, regs, TRAP_BRKPT, regs->nip);
483 /* Illegal instruction; try to emulate it. */
484 switch (emulate_instruction(regs)) {
487 emulate_single_step(regs);
491 _exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
495 _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
501 void KernelFPUnavailableException(struct pt_regs *regs)
503 printk(KERN_EMERG "Unrecoverable FP Unavailable Exception "
504 "%lx at %lx\n", regs->trap, regs->nip);
505 die("Unrecoverable FP Unavailable Exception", regs, SIGABRT);
508 void AltivecUnavailableException(struct pt_regs *regs)
510 #ifndef CONFIG_ALTIVEC
511 if (user_mode(regs)) {
512 /* A user program has executed an altivec instruction,
513 but this kernel doesn't support altivec. */
514 _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
518 printk(KERN_EMERG "Unrecoverable VMX/Altivec Unavailable Exception "
519 "%lx at %lx\n", regs->trap, regs->nip);
520 die("Unrecoverable VMX/Altivec Unavailable Exception", regs, SIGABRT);
523 /* Ensure exceptions are disabled */
524 #define MMCR0_PMXE (1UL << (31 - 5))
525 #define MMCR0_PMAO (1UL << (31 - 24))
527 static void dummy_perf(struct pt_regs *regs)
529 unsigned int mmcr0 = mfspr(SPRN_MMCR0);
531 mmcr0 &= ~(MMCR0_PMXE|MMCR0_PMAO);
532 mtspr(SPRN_MMCR0, mmcr0);
535 void (*perf_irq)(struct pt_regs *) = dummy_perf;
537 EXPORT_SYMBOL(perf_irq);
540 PerformanceMonitorException(struct pt_regs *regs)
546 AlignmentException(struct pt_regs *regs)
550 fixed = fix_alignment(regs);
553 regs->nip += 4; /* skip over emulated instruction */
554 emulate_single_step(regs);
558 /* Operand address was bad */
559 if (fixed == -EFAULT) {
560 if (user_mode(regs)) {
561 _exception(SIGSEGV, regs, SEGV_MAPERR, regs->dar);
563 /* Search exception table */
564 bad_page_fault(regs, regs->dar, SIGSEGV);
570 _exception(SIGBUS, regs, BUS_ADRALN, regs->nip);
573 #ifdef CONFIG_ALTIVEC
575 AltivecAssistException(struct pt_regs *regs)
580 if (!user_mode(regs)) {
581 printk(KERN_EMERG "VMX/Altivec assist exception in kernel mode"
582 " at %lx\n", regs->nip);
583 die("Kernel VMX/Altivec assist exception", regs, SIGILL);
586 flush_altivec_to_thread(current);
588 err = emulate_altivec(regs);
590 regs->nip += 4; /* skip emulated instruction */
591 emulate_single_step(regs);
595 if (err == -EFAULT) {
596 /* got an error reading the instruction */
597 info.si_signo = SIGSEGV;
599 info.si_code = SEGV_MAPERR;
600 info.si_addr = (void __user *) regs->nip;
601 force_sig_info(SIGSEGV, &info, current);
603 /* didn't recognize the instruction */
604 /* XXX quick hack for now: set the non-Java bit in the VSCR */
605 if (printk_ratelimit())
606 printk(KERN_ERR "Unrecognized altivec instruction "
607 "in %s at %lx\n", current->comm, regs->nip);
608 current->thread.vscr.u[3] |= 0x10000;
611 #endif /* CONFIG_ALTIVEC */
614 * We enter here if we get an unrecoverable exception, that is, one
615 * that happened at a point where the RI (recoverable interrupt) bit
616 * in the MSR is 0. This indicates that SRR0/1 are live, and that
617 * we therefore lost state by taking this exception.
619 void unrecoverable_exception(struct pt_regs *regs)
621 printk(KERN_EMERG "Unrecoverable exception %lx at %lx\n",
622 regs->trap, regs->nip);
623 die("Unrecoverable exception", regs, SIGABRT);
627 * We enter here if we discover during exception entry that we are
628 * running in supervisor mode with a userspace value in the stack pointer.
630 void kernel_bad_stack(struct pt_regs *regs)
632 printk(KERN_EMERG "Bad kernel stack pointer %lx at %lx\n",
633 regs->gpr[1], regs->nip);
634 die("Bad kernel stack pointer", regs, SIGABRT);
637 void __init trap_init(void)