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:
122 spin_unlock_irq(&die_lock);
125 panic("Fatal exception in interrupt");
130 printk(KERN_EMERG "Fatal exception: panic in 5 seconds\n");
131 set_current_state(TASK_UNINTERRUPTIBLE);
132 schedule_timeout(5 * HZ);
133 panic("Fatal exception");
141 _exception(int signr, siginfo_t *info, struct pt_regs *regs)
143 if (!user_mode(regs)) {
144 if (die("Exception in kernel mode", regs, signr))
148 force_sig_info(signr, info, current);
151 #ifdef CONFIG_PPC_PSERIES
152 /* Get the error information for errors coming through the
153 * FWNMI vectors. The pt_regs' r3 will be updated to reflect
154 * the actual r3 if possible, and a ptr to the error log entry
155 * will be returned if found.
157 static struct rtas_error_log *FWNMI_get_errinfo(struct pt_regs *regs)
159 unsigned long errdata = regs->gpr[3];
160 struct rtas_error_log *errhdr = NULL;
161 unsigned long *savep;
163 if ((errdata >= 0x7000 && errdata < 0x7fff0) ||
164 (errdata >= rtas.base && errdata < rtas.base + rtas.size - 16)) {
165 savep = __va(errdata);
166 regs->gpr[3] = savep[0]; /* restore original r3 */
167 errhdr = (struct rtas_error_log *)(savep + 1);
169 printk("FWNMI: corrupt r3\n");
174 /* Call this when done with the data returned by FWNMI_get_errinfo.
175 * It will release the saved data area for other CPUs in the
176 * partition to receive FWNMI errors.
178 static void FWNMI_release_errinfo(void)
180 int ret = rtas_call(rtas_token("ibm,nmi-interlock"), 0, 1, NULL);
182 printk("FWNMI: nmi-interlock failed: %d\n", ret);
187 SystemResetException(struct pt_regs *regs)
189 #ifdef CONFIG_PPC_PSERIES
191 struct rtas_error_log *errhdr = FWNMI_get_errinfo(regs);
193 /* XXX Should look at FWNMI information */
195 FWNMI_release_errinfo();
199 die("System Reset", regs, 0);
201 /* Must die if the interrupt is not recoverable */
202 if (!(regs->msr & MSR_RI))
203 panic("Unrecoverable System Reset");
205 /* What should we do here? We could issue a shutdown or hard reset. */
208 #ifdef CONFIG_PPC_PSERIES
210 * See if we can recover from a machine check exception.
211 * This is only called on power4 (or above) and only via
212 * the Firmware Non-Maskable Interrupts (fwnmi) handler
213 * which provides the error analysis for us.
215 * Return 1 if corrected (or delivered a signal).
216 * Return 0 if there is nothing we can do.
218 static int recover_mce(struct pt_regs *regs, struct rtas_error_log err)
222 if (err.disposition == DISP_FULLY_RECOVERED) {
223 /* Platform corrected itself */
225 } else if ((regs->msr & MSR_RI) &&
227 err.severity == SEVERITY_ERROR_SYNC &&
228 err.disposition == DISP_NOT_RECOVERED &&
229 err.target == TARGET_MEMORY &&
230 err.type == TYPE_ECC_UNCORR &&
231 !(current->pid == 0 || current->pid == 1)) {
232 /* Kill off a user process with an ECC error */
233 info.si_signo = SIGBUS;
235 /* XXX something better for ECC error? */
236 info.si_code = BUS_ADRERR;
237 info.si_addr = (void __user *)regs->nip;
238 printk(KERN_ERR "MCE: uncorrectable ecc error for pid %d\n",
240 _exception(SIGBUS, &info, regs);
248 * Handle a machine check.
250 * Note that on Power 4 and beyond Firmware Non-Maskable Interrupts (fwnmi)
251 * should be present. If so the handler which called us tells us if the
252 * error was recovered (never true if RI=0).
254 * On hardware prior to Power 4 these exceptions were asynchronous which
255 * means we can't tell exactly where it occurred and so we can't recover.
258 MachineCheckException(struct pt_regs *regs)
260 #ifdef CONFIG_PPC_PSERIES
261 struct rtas_error_log err, *errp;
264 errp = FWNMI_get_errinfo(regs);
267 FWNMI_release_errinfo(); /* frees errp */
268 if (errp && recover_mce(regs, err))
273 if (debugger_fault_handler(regs))
275 die("Machine check", regs, 0);
277 /* Must die if the interrupt is not recoverable */
278 if (!(regs->msr & MSR_RI))
279 panic("Unrecoverable Machine check");
283 UnknownException(struct pt_regs *regs)
287 printk("Bad trap at PC: %lx, SR: %lx, vector=%lx\n",
288 regs->nip, regs->msr, regs->trap);
290 info.si_signo = SIGTRAP;
294 _exception(SIGTRAP, &info, regs);
298 InstructionBreakpointException(struct pt_regs *regs)
302 if (debugger_iabr_match(regs))
304 info.si_signo = SIGTRAP;
306 info.si_code = TRAP_BRKPT;
307 info.si_addr = (void __user *)regs->nip;
308 _exception(SIGTRAP, &info, regs);
311 static void parse_fpe(struct pt_regs *regs)
316 flush_fp_to_thread(current);
318 fpscr = current->thread.fpscr;
320 /* Invalid operation */
321 if ((fpscr & FPSCR_VE) && (fpscr & FPSCR_VX))
322 info.si_code = FPE_FLTINV;
325 else if ((fpscr & FPSCR_OE) && (fpscr & FPSCR_OX))
326 info.si_code = FPE_FLTOVF;
329 else if ((fpscr & FPSCR_UE) && (fpscr & FPSCR_UX))
330 info.si_code = FPE_FLTUND;
333 else if ((fpscr & FPSCR_ZE) && (fpscr & FPSCR_ZX))
334 info.si_code = FPE_FLTDIV;
337 else if ((fpscr & FPSCR_XE) && (fpscr & FPSCR_XX))
338 info.si_code = FPE_FLTRES;
343 info.si_signo = SIGFPE;
345 info.si_addr = (void __user *)regs->nip;
346 _exception(SIGFPE, &info, regs);
350 * Look through the list of trap instructions that are used for BUG(),
351 * BUG_ON() and WARN_ON() and see if we hit one. At this point we know
352 * that the exception was caused by a trap instruction of some kind.
353 * Returns 1 if we should continue (i.e. it was a WARN_ON) or 0
356 extern struct bug_entry __start___bug_table[], __stop___bug_table[];
358 #ifndef CONFIG_MODULES
359 #define module_find_bug(x) NULL
362 static struct bug_entry *find_bug(unsigned long bugaddr)
364 struct bug_entry *bug;
366 for (bug = __start___bug_table; bug < __stop___bug_table; ++bug)
367 if (bugaddr == bug->bug_addr)
369 return module_find_bug(bugaddr);
373 check_bug_trap(struct pt_regs *regs)
375 struct bug_entry *bug;
378 if (regs->msr & MSR_PR)
379 return 0; /* not in kernel */
380 addr = regs->nip; /* address of trap instruction */
381 if (addr < PAGE_OFFSET)
383 bug = find_bug(regs->nip);
386 if (bug->line & BUG_WARNING_TRAP) {
387 /* this is a WARN_ON rather than BUG/BUG_ON */
388 printk(KERN_ERR "Badness in %s at %s:%d\n",
389 bug->function, bug->file,
390 (unsigned int)bug->line & ~BUG_WARNING_TRAP);
391 show_stack(current, (void *)regs->gpr[1]);
394 printk(KERN_CRIT "kernel BUG in %s at %s:%d!\n",
395 bug->function, bug->file, (unsigned int)bug->line);
400 ProgramCheckException(struct pt_regs *regs)
404 if (regs->msr & 0x100000) {
405 /* IEEE FP exception */
408 } else if (regs->msr & 0x40000) {
409 /* Privileged instruction */
411 info.si_signo = SIGILL;
413 info.si_code = ILL_PRVOPC;
414 info.si_addr = (void __user *)regs->nip;
415 _exception(SIGILL, &info, regs);
416 } else if (regs->msr & 0x20000) {
419 if (debugger_bpt(regs))
422 if (check_bug_trap(regs)) {
426 info.si_signo = SIGTRAP;
428 info.si_code = TRAP_BRKPT;
429 info.si_addr = (void __user *)regs->nip;
430 _exception(SIGTRAP, &info, regs);
432 /* Illegal instruction */
434 info.si_signo = SIGILL;
436 info.si_code = ILL_ILLTRP;
437 info.si_addr = (void __user *)regs->nip;
438 _exception(SIGILL, &info, regs);
442 void KernelFPUnavailableException(struct pt_regs *regs)
444 printk(KERN_EMERG "Unrecoverable FP Unavailable Exception "
445 "%lx at %lx\n", regs->trap, regs->nip);
446 die("Unrecoverable FP Unavailable Exception", regs, SIGABRT);
449 void AltivecUnavailableException(struct pt_regs *regs)
451 #ifndef CONFIG_ALTIVEC
452 if (user_mode(regs)) {
453 /* A user program has executed an altivec instruction,
454 but this kernel doesn't support altivec. */
457 memset(&info, 0, sizeof(info));
458 info.si_signo = SIGILL;
459 info.si_code = ILL_ILLOPC;
460 info.si_addr = (void *) regs->nip;
461 _exception(SIGILL, &info, regs);
465 printk(KERN_EMERG "Unrecoverable VMX/Altivec Unavailable Exception "
466 "%lx at %lx\n", regs->trap, regs->nip);
467 die("Unrecoverable VMX/Altivec Unavailable Exception", regs, SIGABRT);
471 SingleStepException(struct pt_regs *regs)
475 regs->msr &= ~MSR_SE; /* Turn off 'trace' bit */
477 if (debugger_sstep(regs))
480 info.si_signo = SIGTRAP;
482 info.si_code = TRAP_TRACE;
483 info.si_addr = (void __user *)regs->nip;
484 _exception(SIGTRAP, &info, regs);
488 * After we have successfully emulated an instruction, we have to
489 * check if the instruction was being single-stepped, and if so,
490 * pretend we got a single-step exception. This was pointed out
491 * by Kumar Gala. -- paulus
493 static inline void emulate_single_step(struct pt_regs *regs)
495 if (regs->msr & MSR_SE)
496 SingleStepException(regs);
499 static void dummy_perf(struct pt_regs *regs)
503 void (*perf_irq)(struct pt_regs *) = dummy_perf;
506 PerformanceMonitorException(struct pt_regs *regs)
512 AlignmentException(struct pt_regs *regs)
517 fixed = fix_alignment(regs);
520 regs->nip += 4; /* skip over emulated instruction */
521 emulate_single_step(regs);
525 /* Operand address was bad */
526 if (fixed == -EFAULT) {
527 if (user_mode(regs)) {
528 info.si_signo = SIGSEGV;
530 info.si_code = SEGV_MAPERR;
531 info.si_addr = (void __user *)regs->dar;
532 force_sig_info(SIGSEGV, &info, current);
534 /* Search exception table */
535 bad_page_fault(regs, regs->dar, SIGSEGV);
541 info.si_signo = SIGBUS;
543 info.si_code = BUS_ADRALN;
544 info.si_addr = (void __user *)regs->nip;
545 _exception(SIGBUS, &info, regs);
548 #ifdef CONFIG_ALTIVEC
550 AltivecAssistException(struct pt_regs *regs)
555 if (!user_mode(regs)) {
556 printk(KERN_EMERG "VMX/Altivec assist exception in kernel mode"
557 " at %lx\n", regs->nip);
558 die("Kernel VMX/Altivec assist exception", regs, SIGILL);
561 flush_altivec_to_thread(current);
563 err = emulate_altivec(regs);
565 regs->nip += 4; /* skip emulated instruction */
566 emulate_single_step(regs);
570 if (err == -EFAULT) {
571 /* got an error reading the instruction */
572 info.si_signo = SIGSEGV;
574 info.si_code = SEGV_MAPERR;
575 info.si_addr = (void __user *) regs->nip;
576 force_sig_info(SIGSEGV, &info, current);
578 /* didn't recognize the instruction */
579 /* XXX quick hack for now: set the non-Java bit in the VSCR */
580 if (printk_ratelimit())
581 printk(KERN_ERR "Unrecognized altivec instruction "
582 "in %s at %lx\n", current->comm, regs->nip);
583 current->thread.vscr.u[3] |= 0x10000;
586 #endif /* CONFIG_ALTIVEC */
589 * We enter here if we get an unrecoverable exception, that is, one
590 * that happened at a point where the RI (recoverable interrupt) bit
591 * in the MSR is 0. This indicates that SRR0/1 are live, and that
592 * we therefore lost state by taking this exception.
594 void unrecoverable_exception(struct pt_regs *regs)
596 printk(KERN_EMERG "Unrecoverable exception %lx at %lx\n",
597 regs->trap, regs->nip);
598 die("Unrecoverable exception", regs, SIGABRT);
602 * We enter here if we discover during exception entry that we are
603 * running in supervisor mode with a userspace value in the stack pointer.
605 void kernel_bad_stack(struct pt_regs *regs)
607 printk(KERN_EMERG "Bad kernel stack pointer %lx at %lx\n",
608 regs->gpr[1], regs->nip);
609 die("Bad kernel stack pointer", regs, SIGABRT);
612 void __init trap_init(void)