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/openprom.h>
28 #include <asm/oplib.h>
29 #include <asm/setup.h>
31 #include <asm/traps.h>
32 #include <asm/uaccess.h>
36 int show_unhandled_signals = 1;
38 static void __noreturn unhandled_fault(unsigned long address,
39 struct task_struct *tsk,
42 if ((unsigned long) address < PAGE_SIZE) {
44 "Unable to handle kernel NULL pointer dereference\n");
46 printk(KERN_ALERT "Unable to handle kernel paging request at virtual address %08lx\n",
49 printk(KERN_ALERT "tsk->{mm,active_mm}->context = %08lx\n",
50 (tsk->mm ? tsk->mm->context : tsk->active_mm->context));
51 printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %08lx\n",
52 (tsk->mm ? (unsigned long) tsk->mm->pgd :
53 (unsigned long) tsk->active_mm->pgd));
54 die_if_kernel("Oops", regs);
57 asmlinkage int lookup_fault(unsigned long pc, unsigned long ret_pc,
58 unsigned long address)
65 i = search_extables_range(ret_pc, &g2);
68 /* load & store will be handled by fixup */
72 /* store will be handled by fixup, load will bump out */
74 insn = *((unsigned int *) pc);
80 /* load will be handled by fixup, store will bump out */
81 /* for _from_ macros */
82 insn = *((unsigned int *) pc);
83 if (!((insn >> 21) & 1) || ((insn>>19)&0x3f) == 15)
91 memset(®s, 0, sizeof(regs));
98 "nop\n" : "=r" (regs.psr));
99 unhandled_fault(address, current, ®s);
106 show_signal_msg(struct pt_regs *regs, int sig, int code,
107 unsigned long address, struct task_struct *tsk)
109 if (!unhandled_signal(tsk, sig))
112 if (!printk_ratelimit())
115 printk("%s%s[%d]: segfault at %lx ip %p (rpc %p) sp %p error %x",
116 task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
117 tsk->comm, task_pid_nr(tsk), address,
118 (void *)regs->pc, (void *)regs->u_regs[UREG_I7],
119 (void *)regs->u_regs[UREG_FP], code);
121 print_vma_addr(KERN_CONT " in ", regs->pc);
123 printk(KERN_CONT "\n");
126 static void __do_fault_siginfo(int code, int sig, struct pt_regs *regs,
134 info.si_addr = (void __user *) addr;
137 if (unlikely(show_unhandled_signals))
138 show_signal_msg(regs, sig, info.si_code,
141 force_sig_info (sig, &info, current);
144 static unsigned long compute_si_addr(struct pt_regs *regs, int text_fault)
151 if (regs->psr & PSR_PS)
152 insn = *(unsigned int *) regs->pc;
154 __get_user(insn, (unsigned int *) regs->pc);
156 return safe_compute_effective_address(regs, insn);
159 static noinline void do_fault_siginfo(int code, int sig, struct pt_regs *regs,
162 unsigned long addr = compute_si_addr(regs, text_fault);
164 __do_fault_siginfo(code, sig, regs, addr);
167 asmlinkage void do_sparc_fault(struct pt_regs *regs, int text_fault, int write,
168 unsigned long address)
170 struct vm_area_struct *vma;
171 struct task_struct *tsk = current;
172 struct mm_struct *mm = tsk->mm;
175 int from_user = !(regs->psr & PSR_PS);
177 unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
183 * We fault-in kernel-space virtual memory on-demand. The
184 * 'reference' page table is init_mm.pgd.
186 * NOTE! We MUST NOT take any locks for this case. We may
187 * be in an interrupt or a critical region, and should
188 * only copy the information from the master page table,
192 if (address >= TASK_SIZE)
196 * If we're in an interrupt or have no user
197 * context, we must not take the fault..
199 if (in_atomic() || !mm)
202 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
205 down_read(&mm->mmap_sem);
207 if (!from_user && address >= PAGE_OFFSET)
210 vma = find_vma(mm, address);
213 if (vma->vm_start <= address)
215 if (!(vma->vm_flags & VM_GROWSDOWN))
217 if (expand_stack(vma, address))
220 * Ok, we have a good vm_area for this memory access, so
226 if (!(vma->vm_flags & VM_WRITE))
229 /* Allow reads even for write-only mappings */
230 if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
235 flags |= FAULT_FLAG_USER;
237 flags |= FAULT_FLAG_WRITE;
240 * If for any reason at all we couldn't handle the fault,
241 * make sure we exit gracefully rather than endlessly redo
244 fault = handle_mm_fault(mm, vma, address, flags);
246 if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
249 if (unlikely(fault & VM_FAULT_ERROR)) {
250 if (fault & VM_FAULT_OOM)
252 else if (fault & VM_FAULT_SIGBUS)
257 if (flags & FAULT_FLAG_ALLOW_RETRY) {
258 if (fault & VM_FAULT_MAJOR) {
260 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ,
264 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN,
267 if (fault & VM_FAULT_RETRY) {
268 flags &= ~FAULT_FLAG_ALLOW_RETRY;
269 flags |= FAULT_FLAG_TRIED;
271 /* No need to up_read(&mm->mmap_sem) as we would
272 * have already released it in __lock_page_or_retry
280 up_read(&mm->mmap_sem);
284 * Something tried to access memory that isn't in our memory map..
285 * Fix it, but check if it's kernel or user first..
288 up_read(&mm->mmap_sem);
290 bad_area_nosemaphore:
291 /* User mode accesses just cause a SIGSEGV */
293 do_fault_siginfo(code, SIGSEGV, regs, text_fault);
297 /* Is this in ex_table? */
299 g2 = regs->u_regs[UREG_G2];
301 fixup = search_extables_range(regs->pc, &g2);
302 /* Values below 10 are reserved for other things */
304 extern const unsigned __memset_start[];
305 extern const unsigned __memset_end[];
306 extern const unsigned __csum_partial_copy_start[];
307 extern const unsigned __csum_partial_copy_end[];
309 #ifdef DEBUG_EXCEPTIONS
310 printk("Exception: PC<%08lx> faddr<%08lx>\n",
312 printk("EX_TABLE: insn<%08lx> fixup<%08x> g2<%08lx>\n",
313 regs->pc, fixup, g2);
315 if ((regs->pc >= (unsigned long)__memset_start &&
316 regs->pc < (unsigned long)__memset_end) ||
317 (regs->pc >= (unsigned long)__csum_partial_copy_start &&
318 regs->pc < (unsigned long)__csum_partial_copy_end)) {
319 regs->u_regs[UREG_I4] = address;
320 regs->u_regs[UREG_I5] = regs->pc;
322 regs->u_regs[UREG_G2] = g2;
324 regs->npc = regs->pc + 4;
329 unhandled_fault(address, tsk, regs);
333 * We ran out of memory, or some other thing happened to us that made
334 * us unable to handle the page fault gracefully.
337 up_read(&mm->mmap_sem);
339 pagefault_out_of_memory();
345 up_read(&mm->mmap_sem);
346 do_fault_siginfo(BUS_ADRERR, SIGBUS, regs, text_fault);
353 * Synchronize this task's top level page-table
354 * with the 'reference' page table.
356 int offset = pgd_index(address);
360 pgd = tsk->active_mm->pgd + offset;
361 pgd_k = init_mm.pgd + offset;
363 if (!pgd_present(*pgd)) {
364 if (!pgd_present(*pgd_k))
365 goto bad_area_nosemaphore;
366 pgd_val(*pgd) = pgd_val(*pgd_k);
370 pmd = pmd_offset(pgd, address);
371 pmd_k = pmd_offset(pgd_k, address);
373 if (pmd_present(*pmd) || !pmd_present(*pmd_k))
374 goto bad_area_nosemaphore;
381 /* This always deals with user addresses. */
382 static void force_user_fault(unsigned long address, int write)
384 struct vm_area_struct *vma;
385 struct task_struct *tsk = current;
386 struct mm_struct *mm = tsk->mm;
387 unsigned int flags = FAULT_FLAG_USER;
392 down_read(&mm->mmap_sem);
393 vma = find_vma(mm, address);
396 if (vma->vm_start <= address)
398 if (!(vma->vm_flags & VM_GROWSDOWN))
400 if (expand_stack(vma, address))
405 if (!(vma->vm_flags & VM_WRITE))
407 flags |= FAULT_FLAG_WRITE;
409 if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
412 switch (handle_mm_fault(mm, vma, address, flags)) {
413 case VM_FAULT_SIGBUS:
417 up_read(&mm->mmap_sem);
420 up_read(&mm->mmap_sem);
421 __do_fault_siginfo(code, SIGSEGV, tsk->thread.kregs, address);
425 up_read(&mm->mmap_sem);
426 __do_fault_siginfo(BUS_ADRERR, SIGBUS, tsk->thread.kregs, address);
429 static void check_stack_aligned(unsigned long sp)
432 force_sig(SIGILL, current);
435 void window_overflow_fault(void)
439 sp = current_thread_info()->rwbuf_stkptrs[0];
440 if (((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
441 force_user_fault(sp + 0x38, 1);
442 force_user_fault(sp, 1);
444 check_stack_aligned(sp);
447 void window_underflow_fault(unsigned long sp)
449 if (((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
450 force_user_fault(sp + 0x38, 0);
451 force_user_fault(sp, 0);
453 check_stack_aligned(sp);
456 void window_ret_fault(struct pt_regs *regs)
460 sp = regs->u_regs[UREG_FP];
461 if (((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
462 force_user_fault(sp + 0x38, 0);
463 force_user_fault(sp, 0);
465 check_stack_aligned(sp);