1 /* $Id: fault.c,v 1.122 2001/11/17 07:19:26 davem Exp $
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/smp_lock.h>
22 #include <linux/interrupt.h>
23 #include <linux/module.h>
25 #include <asm/system.h>
26 #include <asm/segment.h>
28 #include <asm/pgtable.h>
29 #include <asm/memreg.h>
30 #include <asm/openprom.h>
31 #include <asm/oplib.h>
33 #include <asm/traps.h>
34 #include <asm/kdebug.h>
35 #include <asm/uaccess.h>
37 #define ELEMENTS(arr) (sizeof (arr)/sizeof (arr[0]))
39 extern int prom_node_root;
41 /* At boot time we determine these two values necessary for setting
42 * up the segment maps and page table entries (pte's).
45 int num_segmaps, num_contexts;
48 /* various Virtual Address Cache parameters we find at boot time... */
50 int vac_size, vac_linesize, vac_do_hw_vac_flushes;
51 int vac_entries_per_context, vac_entries_per_segment;
52 int vac_entries_per_page;
54 /* Nice, simple, prom library does all the sweating for us. ;) */
55 int prom_probe_memory (void)
57 register struct linux_mlist_v0 *mlist;
58 register unsigned long bytes, base_paddr, tally;
62 mlist= *prom_meminfo()->v0_available;
63 bytes = tally = mlist->num_bytes;
64 base_paddr = (unsigned long) mlist->start_adr;
66 sp_banks[0].base_addr = base_paddr;
67 sp_banks[0].num_bytes = bytes;
69 while (mlist->theres_more != (void *) 0){
71 mlist = mlist->theres_more;
72 bytes = mlist->num_bytes;
74 if (i > SPARC_PHYS_BANKS-1) {
75 printk ("The machine has more banks than "
76 "this kernel can support\n"
77 "Increase the SPARC_PHYS_BANKS "
78 "setting (currently %d)\n",
80 i = SPARC_PHYS_BANKS-1;
84 sp_banks[i].base_addr = (unsigned long) mlist->start_adr;
85 sp_banks[i].num_bytes = mlist->num_bytes;
89 sp_banks[i].base_addr = 0xdeadbeef;
90 sp_banks[i].num_bytes = 0;
92 /* Now mask all bank sizes on a page boundary, it is all we can
95 for(i=0; sp_banks[i].num_bytes != 0; i++)
96 sp_banks[i].num_bytes &= PAGE_MASK;
101 /* Traverse the memory lists in the prom to see how much physical we
109 total = prom_probe_memory();
111 /* Oh man, much nicer, keep the dirt in promlib. */
115 extern void sun4c_complete_all_stores(void);
117 /* Whee, a level 15 NMI interrupt memory error. Let's have fun... */
118 asmlinkage void sparc_lvl15_nmi(struct pt_regs *regs, unsigned long serr,
119 unsigned long svaddr, unsigned long aerr,
120 unsigned long avaddr)
122 sun4c_complete_all_stores();
123 printk("FAULT: NMI received\n");
124 printk("SREGS: Synchronous Error %08lx\n", serr);
125 printk(" Synchronous Vaddr %08lx\n", svaddr);
126 printk(" Asynchronous Error %08lx\n", aerr);
127 printk(" Asynchronous Vaddr %08lx\n", avaddr);
128 if (sun4c_memerr_reg)
129 printk(" Memory Parity Error %08lx\n", *sun4c_memerr_reg);
130 printk("REGISTER DUMP:\n");
135 static void unhandled_fault(unsigned long, struct task_struct *,
136 struct pt_regs *) __attribute__ ((noreturn));
138 static void unhandled_fault(unsigned long address, struct task_struct *tsk,
139 struct pt_regs *regs)
141 if((unsigned long) address < PAGE_SIZE) {
143 "Unable to handle kernel NULL pointer dereference\n");
145 printk(KERN_ALERT "Unable to handle kernel paging request "
146 "at virtual address %08lx\n", address);
148 printk(KERN_ALERT "tsk->{mm,active_mm}->context = %08lx\n",
149 (tsk->mm ? tsk->mm->context : tsk->active_mm->context));
150 printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %08lx\n",
151 (tsk->mm ? (unsigned long) tsk->mm->pgd :
152 (unsigned long) tsk->active_mm->pgd));
153 die_if_kernel("Oops", regs);
156 asmlinkage int lookup_fault(unsigned long pc, unsigned long ret_pc,
157 unsigned long address)
164 i = search_extables_range(ret_pc, &g2);
167 /* load & store will be handled by fixup */
171 /* store will be handled by fixup, load will bump out */
172 /* for _to_ macros */
173 insn = *((unsigned int *) pc);
174 if ((insn >> 21) & 1)
179 /* load will be handled by fixup, store will bump out */
180 /* for _from_ macros */
181 insn = *((unsigned int *) pc);
182 if (!((insn >> 21) & 1) || ((insn>>19)&0x3f) == 15)
190 memset(®s, 0, sizeof (regs));
193 __asm__ __volatile__(
197 "nop\n" : "=r" (regs.psr));
198 unhandled_fault(address, current, ®s);
204 asmlinkage void do_sparc_fault(struct pt_regs *regs, int text_fault, int write,
205 unsigned long address)
207 struct vm_area_struct *vma;
208 struct task_struct *tsk = current;
209 struct mm_struct *mm = tsk->mm;
213 int from_user = !(regs->psr & PSR_PS);
219 * We fault-in kernel-space virtual memory on-demand. The
220 * 'reference' page table is init_mm.pgd.
222 * NOTE! We MUST NOT take any locks for this case. We may
223 * be in an interrupt or a critical region, and should
224 * only copy the information from the master page table,
227 if (!ARCH_SUN4C_SUN4 && address >= TASK_SIZE)
230 info.si_code = SEGV_MAPERR;
233 * If we're in an interrupt or have no user
234 * context, we must not take the fault..
236 if (in_atomic() || !mm)
239 down_read(&mm->mmap_sem);
242 * The kernel referencing a bad kernel pointer can lock up
243 * a sun4c machine completely, so we must attempt recovery.
245 if(!from_user && address >= PAGE_OFFSET)
248 vma = find_vma(mm, address);
251 if(vma->vm_start <= address)
253 if(!(vma->vm_flags & VM_GROWSDOWN))
255 if(expand_stack(vma, address))
258 * Ok, we have a good vm_area for this memory access, so
262 info.si_code = SEGV_ACCERR;
264 if(!(vma->vm_flags & VM_WRITE))
267 /* Allow reads even for write-only mappings */
268 if(!(vma->vm_flags & (VM_READ | VM_EXEC)))
273 * If for any reason at all we couldn't handle the fault,
274 * make sure we exit gracefully rather than endlessly redo
277 switch (handle_mm_fault(mm, vma, address, write)) {
289 up_read(&mm->mmap_sem);
293 * Something tried to access memory that isn't in our memory map..
294 * Fix it, but check if it's kernel or user first..
297 up_read(&mm->mmap_sem);
299 bad_area_nosemaphore:
300 /* User mode accesses just cause a SIGSEGV */
303 printk("Fault whee %s [%d]: segfaults at %08lx pc=%08lx\n",
304 tsk->comm, tsk->pid, address, regs->pc);
306 info.si_signo = SIGSEGV;
308 /* info.si_code set above to make clear whether
309 this was a SEGV_MAPERR or SEGV_ACCERR fault. */
310 info.si_addr = (void *)address;
312 force_sig_info (SIGSEGV, &info, tsk);
316 /* Is this in ex_table? */
318 g2 = regs->u_regs[UREG_G2];
319 if (!from_user && (fixup = search_extables_range(regs->pc, &g2))) {
320 if (fixup > 10) { /* Values below are reserved for other things */
321 extern const unsigned __memset_start[];
322 extern const unsigned __memset_end[];
323 extern const unsigned __csum_partial_copy_start[];
324 extern const unsigned __csum_partial_copy_end[];
326 #ifdef DEBUG_EXCEPTIONS
327 printk("Exception: PC<%08lx> faddr<%08lx>\n", regs->pc, address);
328 printk("EX_TABLE: insn<%08lx> fixup<%08x> g2<%08lx>\n",
329 regs->pc, fixup, g2);
331 if ((regs->pc >= (unsigned long)__memset_start &&
332 regs->pc < (unsigned long)__memset_end) ||
333 (regs->pc >= (unsigned long)__csum_partial_copy_start &&
334 regs->pc < (unsigned long)__csum_partial_copy_end)) {
335 regs->u_regs[UREG_I4] = address;
336 regs->u_regs[UREG_I5] = regs->pc;
338 regs->u_regs[UREG_G2] = g2;
340 regs->npc = regs->pc + 4;
345 unhandled_fault (address, tsk, regs);
349 * We ran out of memory, or some other thing happened to us that made
350 * us unable to handle the page fault gracefully.
353 up_read(&mm->mmap_sem);
354 printk("VM: killing process %s\n", tsk->comm);
360 up_read(&mm->mmap_sem);
361 info.si_signo = SIGBUS;
363 info.si_code = BUS_ADRERR;
364 info.si_addr = (void *)address;
366 force_sig_info (SIGBUS, &info, tsk);
373 * Synchronize this task's top level page-table
374 * with the 'reference' page table.
376 int offset = pgd_index(address);
380 pgd = tsk->active_mm->pgd + offset;
381 pgd_k = init_mm.pgd + offset;
383 if (!pgd_present(*pgd)) {
384 if (!pgd_present(*pgd_k))
385 goto bad_area_nosemaphore;
386 pgd_val(*pgd) = pgd_val(*pgd_k);
390 pmd = pmd_offset(pgd, address);
391 pmd_k = pmd_offset(pgd_k, address);
393 if (pmd_present(*pmd) || !pmd_present(*pmd_k))
394 goto bad_area_nosemaphore;
400 asmlinkage void do_sun4c_fault(struct pt_regs *regs, int text_fault, int write,
401 unsigned long address)
403 extern void sun4c_update_mmu_cache(struct vm_area_struct *,
404 unsigned long,pte_t);
405 extern pte_t *sun4c_pte_offset_kernel(pmd_t *,unsigned long);
406 struct task_struct *tsk = current;
407 struct mm_struct *mm = tsk->mm;
414 !(regs->psr & PSR_PS)) {
415 unsigned int insn, __user *ip;
417 ip = (unsigned int __user *)regs->pc;
418 if (!get_user(insn, ip)) {
419 if ((insn & 0xc1680000) == 0xc0680000)
425 /* We are oopsing. */
426 do_sparc_fault(regs, text_fault, write, address);
427 BUG(); /* P3 Oops already, you bitch */
430 pgdp = pgd_offset(mm, address);
431 ptep = sun4c_pte_offset_kernel((pmd_t *) pgdp, address);
433 if (pgd_val(*pgdp)) {
435 if ((pte_val(*ptep) & (_SUN4C_PAGE_WRITE|_SUN4C_PAGE_PRESENT))
436 == (_SUN4C_PAGE_WRITE|_SUN4C_PAGE_PRESENT)) {
439 *ptep = __pte(pte_val(*ptep) | _SUN4C_PAGE_ACCESSED |
440 _SUN4C_PAGE_MODIFIED |
444 local_irq_save(flags);
445 if (sun4c_get_segmap(address) != invalid_segment) {
446 sun4c_put_pte(address, pte_val(*ptep));
447 local_irq_restore(flags);
450 local_irq_restore(flags);
453 if ((pte_val(*ptep) & (_SUN4C_PAGE_READ|_SUN4C_PAGE_PRESENT))
454 == (_SUN4C_PAGE_READ|_SUN4C_PAGE_PRESENT)) {
457 *ptep = __pte(pte_val(*ptep) | _SUN4C_PAGE_ACCESSED |
460 local_irq_save(flags);
461 if (sun4c_get_segmap(address) != invalid_segment) {
462 sun4c_put_pte(address, pte_val(*ptep));
463 local_irq_restore(flags);
466 local_irq_restore(flags);
471 /* This conditional is 'interesting'. */
472 if (pgd_val(*pgdp) && !(write && !(pte_val(*ptep) & _SUN4C_PAGE_WRITE))
473 && (pte_val(*ptep) & _SUN4C_PAGE_VALID))
474 /* Note: It is safe to not grab the MMAP semaphore here because
475 * we know that update_mmu_cache() will not sleep for
476 * any reason (at least not in the current implementation)
477 * and therefore there is no danger of another thread getting
478 * on the CPU and doing a shrink_mmap() on this vma.
480 sun4c_update_mmu_cache (find_vma(current->mm, address), address,
483 do_sparc_fault(regs, text_fault, write, address);
486 /* This always deals with user addresses. */
487 inline void force_user_fault(unsigned long address, int write)
489 struct vm_area_struct *vma;
490 struct task_struct *tsk = current;
491 struct mm_struct *mm = tsk->mm;
494 info.si_code = SEGV_MAPERR;
497 printk("wf<pid=%d,wr=%d,addr=%08lx>\n",
498 tsk->pid, write, address);
500 down_read(&mm->mmap_sem);
501 vma = find_vma(mm, address);
504 if(vma->vm_start <= address)
506 if(!(vma->vm_flags & VM_GROWSDOWN))
508 if(expand_stack(vma, address))
511 info.si_code = SEGV_ACCERR;
513 if(!(vma->vm_flags & VM_WRITE))
516 if(!(vma->vm_flags & (VM_READ | VM_EXEC)))
519 if (!handle_mm_fault(mm, vma, address, write))
521 up_read(&mm->mmap_sem);
524 up_read(&mm->mmap_sem);
526 printk("Window whee %s [%d]: segfaults at %08lx\n",
527 tsk->comm, tsk->pid, address);
529 info.si_signo = SIGSEGV;
531 /* info.si_code set above to make clear whether
532 this was a SEGV_MAPERR or SEGV_ACCERR fault. */
533 info.si_addr = (void *)address;
535 force_sig_info (SIGSEGV, &info, tsk);
539 up_read(&mm->mmap_sem);
540 info.si_signo = SIGBUS;
542 info.si_code = BUS_ADRERR;
543 info.si_addr = (void *)address;
545 force_sig_info (SIGBUS, &info, tsk);
548 void window_overflow_fault(void)
552 sp = current_thread_info()->rwbuf_stkptrs[0];
553 if(((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
554 force_user_fault(sp + 0x38, 1);
555 force_user_fault(sp, 1);
558 void window_underflow_fault(unsigned long sp)
560 if(((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
561 force_user_fault(sp + 0x38, 0);
562 force_user_fault(sp, 0);
565 void window_ret_fault(struct pt_regs *regs)
569 sp = regs->u_regs[UREG_FP];
570 if(((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
571 force_user_fault(sp + 0x38, 0);
572 force_user_fault(sp, 0);