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>
45 #ifdef CONFIG_DEBUGGER
46 int (*__debugger)(struct pt_regs *regs);
47 int (*__debugger_ipi)(struct pt_regs *regs);
48 int (*__debugger_bpt)(struct pt_regs *regs);
49 int (*__debugger_sstep)(struct pt_regs *regs);
50 int (*__debugger_iabr_match)(struct pt_regs *regs);
51 int (*__debugger_dabr_match)(struct pt_regs *regs);
52 int (*__debugger_fault_handler)(struct pt_regs *regs);
54 EXPORT_SYMBOL(__debugger);
55 EXPORT_SYMBOL(__debugger_ipi);
56 EXPORT_SYMBOL(__debugger_bpt);
57 EXPORT_SYMBOL(__debugger_sstep);
58 EXPORT_SYMBOL(__debugger_iabr_match);
59 EXPORT_SYMBOL(__debugger_dabr_match);
60 EXPORT_SYMBOL(__debugger_fault_handler);
63 struct notifier_block *ppc64_die_chain;
64 static DEFINE_SPINLOCK(die_notifier_lock);
66 int register_die_notifier(struct notifier_block *nb)
71 spin_lock_irqsave(&die_notifier_lock, flags);
72 err = notifier_chain_register(&ppc64_die_chain, nb);
73 spin_unlock_irqrestore(&die_notifier_lock, flags);
78 * Trap & Exception support
81 static DEFINE_SPINLOCK(die_lock);
83 int die(const char *str, struct pt_regs *regs, long err)
85 static int die_counter;
92 spin_lock_irq(&die_lock);
94 printk("Oops: %s, sig: %ld [#%d]\n", str, err, ++die_counter);
100 printk("SMP NR_CPUS=%d ", NR_CPUS);
103 #ifdef CONFIG_DEBUG_PAGEALLOC
104 printk("DEBUG_PAGEALLOC ");
111 switch(systemcfg->platform) {
112 case PLATFORM_PSERIES:
116 case PLATFORM_PSERIES_LPAR:
117 printk("PSERIES LPAR ");
120 case PLATFORM_ISERIES_LPAR:
121 printk("ISERIES LPAR ");
124 case PLATFORM_POWERMAC:
134 spin_unlock_irq(&die_lock);
137 panic("Fatal exception in interrupt");
140 printk(KERN_EMERG "Fatal exception: panic in 5 seconds\n");
142 panic("Fatal exception");
149 void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr)
153 if (!user_mode(regs)) {
154 if (die("Exception in kernel mode", regs, signr))
158 memset(&info, 0, sizeof(info));
159 info.si_signo = signr;
161 info.si_addr = (void __user *) addr;
162 force_sig_info(signr, &info, current);
165 void system_reset_exception(struct pt_regs *regs)
167 /* See if any machine dependent calls */
168 if (ppc_md.system_reset_exception)
169 ppc_md.system_reset_exception(regs);
171 die("System Reset", regs, 0);
173 /* Must die if the interrupt is not recoverable */
174 if (!(regs->msr & MSR_RI))
175 panic("Unrecoverable System Reset");
177 /* What should we do here? We could issue a shutdown or hard reset. */
180 void machine_check_exception(struct pt_regs *regs)
184 /* See if any machine dependent calls */
185 if (ppc_md.machine_check_exception)
186 recover = ppc_md.machine_check_exception(regs);
191 if (debugger_fault_handler(regs))
193 die("Machine check", regs, 0);
195 /* Must die if the interrupt is not recoverable */
196 if (!(regs->msr & MSR_RI))
197 panic("Unrecoverable Machine check");
200 void unknown_exception(struct pt_regs *regs)
202 printk("Bad trap at PC: %lx, SR: %lx, vector=%lx\n",
203 regs->nip, regs->msr, regs->trap);
205 _exception(SIGTRAP, regs, 0, 0);
208 void instruction_breakpoint_exception(struct pt_regs *regs)
210 if (notify_die(DIE_IABR_MATCH, "iabr_match", regs, 5,
211 5, SIGTRAP) == NOTIFY_STOP)
213 if (debugger_iabr_match(regs))
215 _exception(SIGTRAP, regs, TRAP_BRKPT, regs->nip);
218 void single_step_exception(struct pt_regs *regs)
220 regs->msr &= ~MSR_SE; /* Turn off 'trace' bit */
222 if (notify_die(DIE_SSTEP, "single_step", regs, 5,
223 5, SIGTRAP) == NOTIFY_STOP)
225 if (debugger_sstep(regs))
228 _exception(SIGTRAP, regs, TRAP_TRACE, regs->nip);
232 * After we have successfully emulated an instruction, we have to
233 * check if the instruction was being single-stepped, and if so,
234 * pretend we got a single-step exception. This was pointed out
235 * by Kumar Gala. -- paulus
237 static inline void emulate_single_step(struct pt_regs *regs)
239 if (regs->msr & MSR_SE)
240 single_step_exception(regs);
243 static void parse_fpe(struct pt_regs *regs)
248 flush_fp_to_thread(current);
250 fpscr = current->thread.fpscr;
252 /* Invalid operation */
253 if ((fpscr & FPSCR_VE) && (fpscr & FPSCR_VX))
257 else if ((fpscr & FPSCR_OE) && (fpscr & FPSCR_OX))
261 else if ((fpscr & FPSCR_UE) && (fpscr & FPSCR_UX))
265 else if ((fpscr & FPSCR_ZE) && (fpscr & FPSCR_ZX))
269 else if ((fpscr & FPSCR_XE) && (fpscr & FPSCR_XX))
272 _exception(SIGFPE, regs, code, regs->nip);
276 * Illegal instruction emulation support. Return non-zero if we can't
277 * emulate, or -EFAULT if the associated memory access caused an access
278 * fault. Return zero on success.
281 #define INST_DCBA 0x7c0005ec
282 #define INST_DCBA_MASK 0x7c0007fe
284 #define INST_MCRXR 0x7c000400
285 #define INST_MCRXR_MASK 0x7c0007fe
287 static int emulate_instruction(struct pt_regs *regs)
289 unsigned int instword;
291 if (!user_mode(regs))
294 CHECK_FULL_REGS(regs);
296 if (get_user(instword, (unsigned int __user *)(regs->nip)))
299 /* Emulating the dcba insn is just a no-op. */
300 if ((instword & INST_DCBA_MASK) == INST_DCBA) {
305 "process %d (%s) uses obsolete 'dcba' insn\n",
306 current->pid, current->comm);
312 /* Emulate the mcrxr insn. */
313 if ((instword & INST_MCRXR_MASK) == INST_MCRXR) {
319 "process %d (%s) uses obsolete 'mcrxr' insn\n",
320 current->pid, current->comm);
324 shift = (instword >> 21) & 0x1c;
325 regs->ccr &= ~(0xf0000000 >> shift);
326 regs->ccr |= (regs->xer & 0xf0000000) >> shift;
327 regs->xer &= ~0xf0000000;
335 * Look through the list of trap instructions that are used for BUG(),
336 * BUG_ON() and WARN_ON() and see if we hit one. At this point we know
337 * that the exception was caused by a trap instruction of some kind.
338 * Returns 1 if we should continue (i.e. it was a WARN_ON) or 0
341 extern struct bug_entry __start___bug_table[], __stop___bug_table[];
343 #ifndef CONFIG_MODULES
344 #define module_find_bug(x) NULL
347 struct bug_entry *find_bug(unsigned long bugaddr)
349 struct bug_entry *bug;
351 for (bug = __start___bug_table; bug < __stop___bug_table; ++bug)
352 if (bugaddr == bug->bug_addr)
354 return module_find_bug(bugaddr);
358 check_bug_trap(struct pt_regs *regs)
360 struct bug_entry *bug;
363 if (regs->msr & MSR_PR)
364 return 0; /* not in kernel */
365 addr = regs->nip; /* address of trap instruction */
366 if (addr < PAGE_OFFSET)
368 bug = find_bug(regs->nip);
371 if (bug->line & BUG_WARNING_TRAP) {
372 /* this is a WARN_ON rather than BUG/BUG_ON */
373 printk(KERN_ERR "Badness in %s at %s:%d\n",
374 bug->function, bug->file,
375 (unsigned int)bug->line & ~BUG_WARNING_TRAP);
376 show_stack(current, (void *)regs->gpr[1]);
379 printk(KERN_CRIT "kernel BUG in %s at %s:%d!\n",
380 bug->function, bug->file, (unsigned int)bug->line);
384 void program_check_exception(struct pt_regs *regs)
386 if (debugger_fault_handler(regs))
389 if (regs->msr & 0x100000) {
390 /* IEEE FP exception */
393 } else if (regs->msr & 0x40000) {
394 /* Privileged instruction */
395 _exception(SIGILL, regs, ILL_PRVOPC, regs->nip);
397 } else if (regs->msr & 0x20000) {
400 if (notify_die(DIE_BPT, "breakpoint", regs, 5,
401 5, SIGTRAP) == NOTIFY_STOP)
403 if (debugger_bpt(regs))
406 if (check_bug_trap(regs)) {
410 _exception(SIGTRAP, regs, TRAP_BRKPT, regs->nip);
413 /* Illegal instruction; try to emulate it. */
414 switch (emulate_instruction(regs)) {
417 emulate_single_step(regs);
421 _exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
425 _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
431 void kernel_fp_unavailable_exception(struct pt_regs *regs)
433 printk(KERN_EMERG "Unrecoverable FP Unavailable Exception "
434 "%lx at %lx\n", regs->trap, regs->nip);
435 die("Unrecoverable FP Unavailable Exception", regs, SIGABRT);
438 void altivec_unavailable_exception(struct pt_regs *regs)
440 #ifndef CONFIG_ALTIVEC
441 if (user_mode(regs)) {
442 /* A user program has executed an altivec instruction,
443 but this kernel doesn't support altivec. */
444 _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
448 printk(KERN_EMERG "Unrecoverable VMX/Altivec Unavailable Exception "
449 "%lx at %lx\n", regs->trap, regs->nip);
450 die("Unrecoverable VMX/Altivec Unavailable Exception", regs, SIGABRT);
453 /* Ensure exceptions are disabled */
454 static void dummy_perf(struct pt_regs *regs)
456 unsigned int mmcr0 = mfspr(SPRN_MMCR0);
458 mmcr0 &= ~(MMCR0_PMXE|MMCR0_PMAO);
459 mtspr(SPRN_MMCR0, mmcr0);
462 void (*perf_irq)(struct pt_regs *) = dummy_perf;
464 EXPORT_SYMBOL(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)