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:
121 spin_unlock_irq(&die_lock);
124 panic("Fatal exception in interrupt");
129 printk(KERN_EMERG "Fatal exception: panic in 5 seconds\n");
130 set_current_state(TASK_UNINTERRUPTIBLE);
131 schedule_timeout(5 * HZ);
132 panic("Fatal exception");
140 _exception(int signr, struct pt_regs *regs, int code, unsigned long addr)
144 if (!user_mode(regs)) {
145 if (die("Exception in kernel mode", regs, signr))
149 memset(&info, 0, sizeof(info));
150 info.si_signo = signr;
152 info.si_addr = (void __user *) addr;
153 force_sig_info(signr, &info, current);
156 #ifdef CONFIG_PPC_PSERIES
157 /* Get the error information for errors coming through the
158 * FWNMI vectors. The pt_regs' r3 will be updated to reflect
159 * the actual r3 if possible, and a ptr to the error log entry
160 * will be returned if found.
162 static struct rtas_error_log *FWNMI_get_errinfo(struct pt_regs *regs)
164 unsigned long errdata = regs->gpr[3];
165 struct rtas_error_log *errhdr = NULL;
166 unsigned long *savep;
168 if ((errdata >= 0x7000 && errdata < 0x7fff0) ||
169 (errdata >= rtas.base && errdata < rtas.base + rtas.size - 16)) {
170 savep = __va(errdata);
171 regs->gpr[3] = savep[0]; /* restore original r3 */
172 errhdr = (struct rtas_error_log *)(savep + 1);
174 printk("FWNMI: corrupt r3\n");
179 /* Call this when done with the data returned by FWNMI_get_errinfo.
180 * It will release the saved data area for other CPUs in the
181 * partition to receive FWNMI errors.
183 static void FWNMI_release_errinfo(void)
185 int ret = rtas_call(rtas_token("ibm,nmi-interlock"), 0, 1, NULL);
187 printk("FWNMI: nmi-interlock failed: %d\n", ret);
192 SystemResetException(struct pt_regs *regs)
194 #ifdef CONFIG_PPC_PSERIES
196 struct rtas_error_log *errhdr = FWNMI_get_errinfo(regs);
198 /* XXX Should look at FWNMI information */
200 FWNMI_release_errinfo();
204 die("System Reset", regs, 0);
206 /* Must die if the interrupt is not recoverable */
207 if (!(regs->msr & MSR_RI))
208 panic("Unrecoverable System Reset");
210 /* What should we do here? We could issue a shutdown or hard reset. */
213 #ifdef CONFIG_PPC_PSERIES
215 * See if we can recover from a machine check exception.
216 * This is only called on power4 (or above) and only via
217 * the Firmware Non-Maskable Interrupts (fwnmi) handler
218 * which provides the error analysis for us.
220 * Return 1 if corrected (or delivered a signal).
221 * Return 0 if there is nothing we can do.
223 static int recover_mce(struct pt_regs *regs, struct rtas_error_log err)
225 if (err.disposition == RTAS_DISP_FULLY_RECOVERED) {
226 /* Platform corrected itself */
228 } else if ((regs->msr & MSR_RI) &&
230 err.severity == RTAS_SEVERITY_ERROR_SYNC &&
231 err.disposition == RTAS_DISP_NOT_RECOVERED &&
232 err.target == RTAS_TARGET_MEMORY &&
233 err.type == RTAS_TYPE_ECC_UNCORR &&
234 !(current->pid == 0 || current->pid == 1)) {
235 /* Kill off a user process with an ECC error */
236 printk(KERN_ERR "MCE: uncorrectable ecc error for pid %d\n",
238 /* XXX something better for ECC error? */
239 _exception(SIGBUS, regs, BUS_ADRERR, regs->nip);
247 * Handle a machine check.
249 * Note that on Power 4 and beyond Firmware Non-Maskable Interrupts (fwnmi)
250 * should be present. If so the handler which called us tells us if the
251 * error was recovered (never true if RI=0).
253 * On hardware prior to Power 4 these exceptions were asynchronous which
254 * means we can't tell exactly where it occurred and so we can't recover.
257 MachineCheckException(struct pt_regs *regs)
259 #ifdef CONFIG_PPC_PSERIES
260 struct rtas_error_log err, *errp;
263 errp = FWNMI_get_errinfo(regs);
266 FWNMI_release_errinfo(); /* frees errp */
267 if (errp && recover_mce(regs, err))
272 if (debugger_fault_handler(regs))
274 die("Machine check", regs, 0);
276 /* Must die if the interrupt is not recoverable */
277 if (!(regs->msr & MSR_RI))
278 panic("Unrecoverable Machine check");
282 UnknownException(struct pt_regs *regs)
284 printk("Bad trap at PC: %lx, SR: %lx, vector=%lx\n",
285 regs->nip, regs->msr, regs->trap);
287 _exception(SIGTRAP, regs, 0, 0);
291 InstructionBreakpointException(struct pt_regs *regs)
293 if (debugger_iabr_match(regs))
295 _exception(SIGTRAP, regs, TRAP_BRKPT, regs->nip);
299 SingleStepException(struct pt_regs *regs)
301 regs->msr &= ~MSR_SE; /* Turn off 'trace' bit */
303 if (debugger_sstep(regs))
306 _exception(SIGTRAP, regs, TRAP_TRACE, regs->nip);
310 * After we have successfully emulated an instruction, we have to
311 * check if the instruction was being single-stepped, and if so,
312 * pretend we got a single-step exception. This was pointed out
313 * by Kumar Gala. -- paulus
315 static inline void emulate_single_step(struct pt_regs *regs)
317 if (regs->msr & MSR_SE)
318 SingleStepException(regs);
321 static void parse_fpe(struct pt_regs *regs)
326 flush_fp_to_thread(current);
328 fpscr = current->thread.fpscr;
330 /* Invalid operation */
331 if ((fpscr & FPSCR_VE) && (fpscr & FPSCR_VX))
335 else if ((fpscr & FPSCR_OE) && (fpscr & FPSCR_OX))
339 else if ((fpscr & FPSCR_UE) && (fpscr & FPSCR_UX))
343 else if ((fpscr & FPSCR_ZE) && (fpscr & FPSCR_ZX))
347 else if ((fpscr & FPSCR_XE) && (fpscr & FPSCR_XX))
350 _exception(SIGFPE, regs, code, regs->nip);
354 * Illegal instruction emulation support. Return non-zero if we can't
355 * emulate, or -EFAULT if the associated memory access caused an access
356 * fault. Return zero on success.
359 #define INST_DCBA 0x7c0005ec
360 #define INST_DCBA_MASK 0x7c0007fe
362 #define INST_MCRXR 0x7c000400
363 #define INST_MCRXR_MASK 0x7c0007fe
365 static int emulate_instruction(struct pt_regs *regs)
367 unsigned int instword;
369 if (!user_mode(regs))
372 CHECK_FULL_REGS(regs);
374 if (get_user(instword, (unsigned int __user *)(regs->nip)))
377 /* Emulating the dcba insn is just a no-op. */
378 if ((instword & INST_DCBA_MASK) == INST_DCBA) {
383 "process %d (%s) uses obsolete 'dcba' insn\n",
384 current->pid, current->comm);
390 /* Emulate the mcrxr insn. */
391 if ((instword & INST_MCRXR_MASK) == INST_MCRXR) {
397 "process %d (%s) uses obsolete 'mcrxr' insn\n",
398 current->pid, current->comm);
402 shift = (instword >> 21) & 0x1c;
403 regs->ccr &= ~(0xf0000000 >> shift);
404 regs->ccr |= (regs->xer & 0xf0000000) >> shift;
405 regs->xer &= ~0xf0000000;
413 * Look through the list of trap instructions that are used for BUG(),
414 * BUG_ON() and WARN_ON() and see if we hit one. At this point we know
415 * that the exception was caused by a trap instruction of some kind.
416 * Returns 1 if we should continue (i.e. it was a WARN_ON) or 0
419 extern struct bug_entry __start___bug_table[], __stop___bug_table[];
421 #ifndef CONFIG_MODULES
422 #define module_find_bug(x) NULL
425 static struct bug_entry *find_bug(unsigned long bugaddr)
427 struct bug_entry *bug;
429 for (bug = __start___bug_table; bug < __stop___bug_table; ++bug)
430 if (bugaddr == bug->bug_addr)
432 return module_find_bug(bugaddr);
436 check_bug_trap(struct pt_regs *regs)
438 struct bug_entry *bug;
441 if (regs->msr & MSR_PR)
442 return 0; /* not in kernel */
443 addr = regs->nip; /* address of trap instruction */
444 if (addr < PAGE_OFFSET)
446 bug = find_bug(regs->nip);
449 if (bug->line & BUG_WARNING_TRAP) {
450 /* this is a WARN_ON rather than BUG/BUG_ON */
451 printk(KERN_ERR "Badness in %s at %s:%d\n",
452 bug->function, bug->file,
453 (unsigned int)bug->line & ~BUG_WARNING_TRAP);
454 show_stack(current, (void *)regs->gpr[1]);
457 printk(KERN_CRIT "kernel BUG in %s at %s:%d!\n",
458 bug->function, bug->file, (unsigned int)bug->line);
463 ProgramCheckException(struct pt_regs *regs)
465 if (regs->msr & 0x100000) {
466 /* IEEE FP exception */
469 } else if (regs->msr & 0x40000) {
470 /* Privileged instruction */
471 _exception(SIGILL, regs, ILL_PRVOPC, regs->nip);
473 } else if (regs->msr & 0x20000) {
476 if (debugger_bpt(regs))
479 if (check_bug_trap(regs)) {
483 _exception(SIGTRAP, regs, TRAP_BRKPT, regs->nip);
486 /* Illegal instruction; try to emulate it. */
487 switch (emulate_instruction(regs)) {
490 emulate_single_step(regs);
494 _exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
498 _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
504 void KernelFPUnavailableException(struct pt_regs *regs)
506 printk(KERN_EMERG "Unrecoverable FP Unavailable Exception "
507 "%lx at %lx\n", regs->trap, regs->nip);
508 die("Unrecoverable FP Unavailable Exception", regs, SIGABRT);
511 void AltivecUnavailableException(struct pt_regs *regs)
513 #ifndef CONFIG_ALTIVEC
514 if (user_mode(regs)) {
515 /* A user program has executed an altivec instruction,
516 but this kernel doesn't support altivec. */
517 _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
521 printk(KERN_EMERG "Unrecoverable VMX/Altivec Unavailable Exception "
522 "%lx at %lx\n", regs->trap, regs->nip);
523 die("Unrecoverable VMX/Altivec Unavailable Exception", regs, SIGABRT);
526 /* Ensure exceptions are disabled */
527 #define MMCR0_PMXE (1UL << (31 - 5))
528 #define MMCR0_PMAO (1UL << (31 - 24))
530 static void dummy_perf(struct pt_regs *regs)
532 unsigned int mmcr0 = mfspr(SPRN_MMCR0);
534 mmcr0 &= ~(MMCR0_PMXE|MMCR0_PMAO);
535 mtspr(SPRN_MMCR0, mmcr0);
538 void (*perf_irq)(struct pt_regs *) = dummy_perf;
540 EXPORT_SYMBOL(perf_irq);
543 PerformanceMonitorException(struct pt_regs *regs)
549 AlignmentException(struct pt_regs *regs)
553 fixed = fix_alignment(regs);
556 regs->nip += 4; /* skip over emulated instruction */
557 emulate_single_step(regs);
561 /* Operand address was bad */
562 if (fixed == -EFAULT) {
563 if (user_mode(regs)) {
564 _exception(SIGSEGV, regs, SEGV_MAPERR, regs->dar);
566 /* Search exception table */
567 bad_page_fault(regs, regs->dar, SIGSEGV);
573 _exception(SIGBUS, regs, BUS_ADRALN, regs->nip);
576 #ifdef CONFIG_ALTIVEC
578 AltivecAssistException(struct pt_regs *regs)
583 if (!user_mode(regs)) {
584 printk(KERN_EMERG "VMX/Altivec assist exception in kernel mode"
585 " at %lx\n", regs->nip);
586 die("Kernel VMX/Altivec assist exception", regs, SIGILL);
589 flush_altivec_to_thread(current);
591 err = emulate_altivec(regs);
593 regs->nip += 4; /* skip emulated instruction */
594 emulate_single_step(regs);
598 if (err == -EFAULT) {
599 /* got an error reading the instruction */
600 info.si_signo = SIGSEGV;
602 info.si_code = SEGV_MAPERR;
603 info.si_addr = (void __user *) regs->nip;
604 force_sig_info(SIGSEGV, &info, current);
606 /* didn't recognize the instruction */
607 /* XXX quick hack for now: set the non-Java bit in the VSCR */
608 if (printk_ratelimit())
609 printk(KERN_ERR "Unrecognized altivec instruction "
610 "in %s at %lx\n", current->comm, regs->nip);
611 current->thread.vscr.u[3] |= 0x10000;
614 #endif /* CONFIG_ALTIVEC */
617 * We enter here if we get an unrecoverable exception, that is, one
618 * that happened at a point where the RI (recoverable interrupt) bit
619 * in the MSR is 0. This indicates that SRR0/1 are live, and that
620 * we therefore lost state by taking this exception.
622 void unrecoverable_exception(struct pt_regs *regs)
624 printk(KERN_EMERG "Unrecoverable exception %lx at %lx\n",
625 regs->trap, regs->nip);
626 die("Unrecoverable exception", regs, SIGABRT);
630 * We enter here if we discover during exception entry that we are
631 * running in supervisor mode with a userspace value in the stack pointer.
633 void kernel_bad_stack(struct pt_regs *regs)
635 printk(KERN_EMERG "Bad kernel stack pointer %lx at %lx\n",
636 regs->gpr[1], regs->nip);
637 die("Bad kernel stack pointer", regs, SIGABRT);
640 void __init trap_init(void)