2 * fault.c: Page fault handlers for the Sparc.
4 * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
5 * Copyright (C) 1996 Eddie C. Dost (ecd@skynet.be)
6 * Copyright (C) 1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
11 #include <linux/string.h>
12 #include <linux/types.h>
13 #include <linux/sched.h>
14 #include <linux/ptrace.h>
15 #include <linux/mman.h>
16 #include <linux/threads.h>
17 #include <linux/kernel.h>
18 #include <linux/signal.h>
20 #include <linux/smp.h>
21 #include <linux/perf_event.h>
22 #include <linux/interrupt.h>
23 #include <linux/kdebug.h>
26 #include <asm/pgtable.h>
27 #include <asm/memreg.h>
28 #include <asm/openprom.h>
29 #include <asm/oplib.h>
31 #include <asm/traps.h>
32 #include <asm/uaccess.h>
34 extern int prom_node_root;
36 int show_unhandled_signals = 1;
38 /* At boot time we determine these two values necessary for setting
39 * up the segment maps and page table entries (pte's).
42 int num_segmaps, num_contexts;
45 /* various Virtual Address Cache parameters we find at boot time... */
47 int vac_size, vac_linesize, vac_do_hw_vac_flushes;
48 int vac_entries_per_context, vac_entries_per_segment;
49 int vac_entries_per_page;
51 /* Return how much physical memory we have. */
52 unsigned long probe_memory(void)
54 unsigned long total = 0;
57 for (i = 0; sp_banks[i].num_bytes; i++)
58 total += sp_banks[i].num_bytes;
63 extern void sun4c_complete_all_stores(void);
65 /* Whee, a level 15 NMI interrupt memory error. Let's have fun... */
66 asmlinkage void sparc_lvl15_nmi(struct pt_regs *regs, unsigned long serr,
67 unsigned long svaddr, unsigned long aerr,
70 sun4c_complete_all_stores();
71 printk("FAULT: NMI received\n");
72 printk("SREGS: Synchronous Error %08lx\n", serr);
73 printk(" Synchronous Vaddr %08lx\n", svaddr);
74 printk(" Asynchronous Error %08lx\n", aerr);
75 printk(" Asynchronous Vaddr %08lx\n", avaddr);
77 printk(" Memory Parity Error %08lx\n", *sun4c_memerr_reg);
78 printk("REGISTER DUMP:\n");
83 static void unhandled_fault(unsigned long, struct task_struct *,
84 struct pt_regs *) __attribute__ ((noreturn));
86 static void unhandled_fault(unsigned long address, struct task_struct *tsk,
89 if((unsigned long) address < PAGE_SIZE) {
91 "Unable to handle kernel NULL pointer dereference\n");
93 printk(KERN_ALERT "Unable to handle kernel paging request "
94 "at virtual address %08lx\n", address);
96 printk(KERN_ALERT "tsk->{mm,active_mm}->context = %08lx\n",
97 (tsk->mm ? tsk->mm->context : tsk->active_mm->context));
98 printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %08lx\n",
99 (tsk->mm ? (unsigned long) tsk->mm->pgd :
100 (unsigned long) tsk->active_mm->pgd));
101 die_if_kernel("Oops", regs);
104 asmlinkage int lookup_fault(unsigned long pc, unsigned long ret_pc,
105 unsigned long address)
112 i = search_extables_range(ret_pc, &g2);
115 /* load & store will be handled by fixup */
119 /* store will be handled by fixup, load will bump out */
120 /* for _to_ macros */
121 insn = *((unsigned int *) pc);
122 if ((insn >> 21) & 1)
127 /* load will be handled by fixup, store will bump out */
128 /* for _from_ macros */
129 insn = *((unsigned int *) pc);
130 if (!((insn >> 21) & 1) || ((insn>>19)&0x3f) == 15)
138 memset(®s, 0, sizeof (regs));
141 __asm__ __volatile__(
145 "nop\n" : "=r" (regs.psr));
146 unhandled_fault(address, current, ®s);
153 show_signal_msg(struct pt_regs *regs, int sig, int code,
154 unsigned long address, struct task_struct *tsk)
156 if (!unhandled_signal(tsk, sig))
159 if (!printk_ratelimit())
162 printk("%s%s[%d]: segfault at %lx ip %p (rpc %p) sp %p error %x",
163 task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
164 tsk->comm, task_pid_nr(tsk), address,
165 (void *)regs->pc, (void *)regs->u_regs[UREG_I7],
166 (void *)regs->u_regs[UREG_FP], code);
168 print_vma_addr(KERN_CONT " in ", regs->pc);
170 printk(KERN_CONT "\n");
173 static void __do_fault_siginfo(int code, int sig, struct pt_regs *regs,
181 info.si_addr = (void __user *) addr;
184 if (unlikely(show_unhandled_signals))
185 show_signal_msg(regs, sig, info.si_code,
188 force_sig_info (sig, &info, current);
191 extern unsigned long safe_compute_effective_address(struct pt_regs *,
194 static unsigned long compute_si_addr(struct pt_regs *regs, int text_fault)
201 if (regs->psr & PSR_PS) {
202 insn = *(unsigned int *) regs->pc;
204 __get_user(insn, (unsigned int *) regs->pc);
207 return safe_compute_effective_address(regs, insn);
210 static noinline void do_fault_siginfo(int code, int sig, struct pt_regs *regs,
213 unsigned long addr = compute_si_addr(regs, text_fault);
215 __do_fault_siginfo(code, sig, regs, addr);
218 asmlinkage void do_sparc_fault(struct pt_regs *regs, int text_fault, int write,
219 unsigned long address)
221 struct vm_area_struct *vma;
222 struct task_struct *tsk = current;
223 struct mm_struct *mm = tsk->mm;
226 int from_user = !(regs->psr & PSR_PS);
228 unsigned int flags = (FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |
229 (write ? FAULT_FLAG_WRITE : 0));
235 * We fault-in kernel-space virtual memory on-demand. The
236 * 'reference' page table is init_mm.pgd.
238 * NOTE! We MUST NOT take any locks for this case. We may
239 * be in an interrupt or a critical region, and should
240 * only copy the information from the master page table,
244 if (!ARCH_SUN4C && address >= TASK_SIZE)
248 * If we're in an interrupt or have no user
249 * context, we must not take the fault..
251 if (in_atomic() || !mm)
254 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
257 down_read(&mm->mmap_sem);
260 * The kernel referencing a bad kernel pointer can lock up
261 * a sun4c machine completely, so we must attempt recovery.
263 if(!from_user && address >= PAGE_OFFSET)
266 vma = find_vma(mm, address);
269 if(vma->vm_start <= address)
271 if(!(vma->vm_flags & VM_GROWSDOWN))
273 if(expand_stack(vma, address))
276 * Ok, we have a good vm_area for this memory access, so
282 if(!(vma->vm_flags & VM_WRITE))
285 /* Allow reads even for write-only mappings */
286 if(!(vma->vm_flags & (VM_READ | VM_EXEC)))
291 * If for any reason at all we couldn't handle the fault,
292 * make sure we exit gracefully rather than endlessly redo
295 fault = handle_mm_fault(mm, vma, address, flags);
297 if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
300 if (unlikely(fault & VM_FAULT_ERROR)) {
301 if (fault & VM_FAULT_OOM)
303 else if (fault & VM_FAULT_SIGBUS)
308 if (flags & FAULT_FLAG_ALLOW_RETRY) {
309 if (fault & VM_FAULT_MAJOR) {
311 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ,
315 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN,
318 if (fault & VM_FAULT_RETRY) {
319 flags &= ~FAULT_FLAG_ALLOW_RETRY;
321 /* No need to up_read(&mm->mmap_sem) as we would
322 * have already released it in __lock_page_or_retry
330 up_read(&mm->mmap_sem);
334 * Something tried to access memory that isn't in our memory map..
335 * Fix it, but check if it's kernel or user first..
338 up_read(&mm->mmap_sem);
340 bad_area_nosemaphore:
341 /* User mode accesses just cause a SIGSEGV */
343 do_fault_siginfo(code, SIGSEGV, regs, text_fault);
347 /* Is this in ex_table? */
349 g2 = regs->u_regs[UREG_G2];
351 fixup = search_extables_range(regs->pc, &g2);
352 if (fixup > 10) { /* Values below are reserved for other things */
353 extern const unsigned __memset_start[];
354 extern const unsigned __memset_end[];
355 extern const unsigned __csum_partial_copy_start[];
356 extern const unsigned __csum_partial_copy_end[];
358 #ifdef DEBUG_EXCEPTIONS
359 printk("Exception: PC<%08lx> faddr<%08lx>\n", regs->pc, address);
360 printk("EX_TABLE: insn<%08lx> fixup<%08x> g2<%08lx>\n",
361 regs->pc, fixup, g2);
363 if ((regs->pc >= (unsigned long)__memset_start &&
364 regs->pc < (unsigned long)__memset_end) ||
365 (regs->pc >= (unsigned long)__csum_partial_copy_start &&
366 regs->pc < (unsigned long)__csum_partial_copy_end)) {
367 regs->u_regs[UREG_I4] = address;
368 regs->u_regs[UREG_I5] = regs->pc;
370 regs->u_regs[UREG_G2] = g2;
372 regs->npc = regs->pc + 4;
377 unhandled_fault (address, tsk, regs);
381 * We ran out of memory, or some other thing happened to us that made
382 * us unable to handle the page fault gracefully.
385 up_read(&mm->mmap_sem);
387 pagefault_out_of_memory();
393 up_read(&mm->mmap_sem);
394 do_fault_siginfo(BUS_ADRERR, SIGBUS, regs, text_fault);
401 * Synchronize this task's top level page-table
402 * with the 'reference' page table.
404 int offset = pgd_index(address);
408 pgd = tsk->active_mm->pgd + offset;
409 pgd_k = init_mm.pgd + offset;
411 if (!pgd_present(*pgd)) {
412 if (!pgd_present(*pgd_k))
413 goto bad_area_nosemaphore;
414 pgd_val(*pgd) = pgd_val(*pgd_k);
418 pmd = pmd_offset(pgd, address);
419 pmd_k = pmd_offset(pgd_k, address);
421 if (pmd_present(*pmd) || !pmd_present(*pmd_k))
422 goto bad_area_nosemaphore;
428 asmlinkage void do_sun4c_fault(struct pt_regs *regs, int text_fault, int write,
429 unsigned long address)
431 extern void sun4c_update_mmu_cache(struct vm_area_struct *,
432 unsigned long,pte_t *);
433 extern pte_t *sun4c_pte_offset_kernel(pmd_t *,unsigned long);
434 struct task_struct *tsk = current;
435 struct mm_struct *mm = tsk->mm;
442 !(regs->psr & PSR_PS)) {
443 unsigned int insn, __user *ip;
445 ip = (unsigned int __user *)regs->pc;
446 if (!get_user(insn, ip)) {
447 if ((insn & 0xc1680000) == 0xc0680000)
453 /* We are oopsing. */
454 do_sparc_fault(regs, text_fault, write, address);
455 BUG(); /* P3 Oops already, you bitch */
458 pgdp = pgd_offset(mm, address);
459 ptep = sun4c_pte_offset_kernel((pmd_t *) pgdp, address);
461 if (pgd_val(*pgdp)) {
463 if ((pte_val(*ptep) & (_SUN4C_PAGE_WRITE|_SUN4C_PAGE_PRESENT))
464 == (_SUN4C_PAGE_WRITE|_SUN4C_PAGE_PRESENT)) {
467 *ptep = __pte(pte_val(*ptep) | _SUN4C_PAGE_ACCESSED |
468 _SUN4C_PAGE_MODIFIED |
472 local_irq_save(flags);
473 if (sun4c_get_segmap(address) != invalid_segment) {
474 sun4c_put_pte(address, pte_val(*ptep));
475 local_irq_restore(flags);
478 local_irq_restore(flags);
481 if ((pte_val(*ptep) & (_SUN4C_PAGE_READ|_SUN4C_PAGE_PRESENT))
482 == (_SUN4C_PAGE_READ|_SUN4C_PAGE_PRESENT)) {
485 *ptep = __pte(pte_val(*ptep) | _SUN4C_PAGE_ACCESSED |
488 local_irq_save(flags);
489 if (sun4c_get_segmap(address) != invalid_segment) {
490 sun4c_put_pte(address, pte_val(*ptep));
491 local_irq_restore(flags);
494 local_irq_restore(flags);
499 /* This conditional is 'interesting'. */
500 if (pgd_val(*pgdp) && !(write && !(pte_val(*ptep) & _SUN4C_PAGE_WRITE))
501 && (pte_val(*ptep) & _SUN4C_PAGE_VALID))
502 /* Note: It is safe to not grab the MMAP semaphore here because
503 * we know that update_mmu_cache() will not sleep for
504 * any reason (at least not in the current implementation)
505 * and therefore there is no danger of another thread getting
506 * on the CPU and doing a shrink_mmap() on this vma.
508 sun4c_update_mmu_cache (find_vma(current->mm, address), address,
511 do_sparc_fault(regs, text_fault, write, address);
514 /* This always deals with user addresses. */
515 static void force_user_fault(unsigned long address, int write)
517 struct vm_area_struct *vma;
518 struct task_struct *tsk = current;
519 struct mm_struct *mm = tsk->mm;
524 down_read(&mm->mmap_sem);
525 vma = find_vma(mm, address);
528 if(vma->vm_start <= address)
530 if(!(vma->vm_flags & VM_GROWSDOWN))
532 if(expand_stack(vma, address))
537 if(!(vma->vm_flags & VM_WRITE))
540 if(!(vma->vm_flags & (VM_READ | VM_EXEC)))
543 switch (handle_mm_fault(mm, vma, address, write ? FAULT_FLAG_WRITE : 0)) {
544 case VM_FAULT_SIGBUS:
548 up_read(&mm->mmap_sem);
551 up_read(&mm->mmap_sem);
552 __do_fault_siginfo(code, SIGSEGV, tsk->thread.kregs, address);
556 up_read(&mm->mmap_sem);
557 __do_fault_siginfo(BUS_ADRERR, SIGBUS, tsk->thread.kregs, address);
560 static void check_stack_aligned(unsigned long sp)
563 force_sig(SIGILL, current);
566 void window_overflow_fault(void)
570 sp = current_thread_info()->rwbuf_stkptrs[0];
571 if(((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
572 force_user_fault(sp + 0x38, 1);
573 force_user_fault(sp, 1);
575 check_stack_aligned(sp);
578 void window_underflow_fault(unsigned long sp)
580 if(((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
581 force_user_fault(sp + 0x38, 0);
582 force_user_fault(sp, 0);
584 check_stack_aligned(sp);
587 void window_ret_fault(struct pt_regs *regs)
591 sp = regs->u_regs[UREG_FP];
592 if(((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
593 force_user_fault(sp + 0x38, 0);
594 force_user_fault(sp, 0);
596 check_stack_aligned(sp);