2 * arch/sparc64/mm/fault.c: Page fault handlers for the 64-bit Sparc.
4 * Copyright (C) 1996, 2008 David S. Miller (davem@davemloft.net)
5 * Copyright (C) 1997, 1999 Jakub Jelinek (jj@ultra.linux.cz)
10 #include <linux/string.h>
11 #include <linux/types.h>
12 #include <linux/sched.h>
13 #include <linux/ptrace.h>
14 #include <linux/mman.h>
15 #include <linux/signal.h>
17 #include <linux/module.h>
18 #include <linux/init.h>
19 #include <linux/perf_event.h>
20 #include <linux/interrupt.h>
21 #include <linux/kprobes.h>
22 #include <linux/kdebug.h>
23 #include <linux/percpu.h>
24 #include <linux/context_tracking.h>
27 #include <asm/pgtable.h>
28 #include <asm/openprom.h>
29 #include <asm/oplib.h>
30 #include <asm/uaccess.h>
33 #include <asm/sections.h>
34 #include <asm/mmu_context.h>
36 int show_unhandled_signals = 1;
38 static inline __kprobes int notify_page_fault(struct pt_regs *regs)
42 /* kprobe_running() needs smp_processor_id() */
43 if (kprobes_built_in() && !user_mode(regs)) {
45 if (kprobe_running() && kprobe_fault_handler(regs, 0))
52 static void __kprobes unhandled_fault(unsigned long address,
53 struct task_struct *tsk,
56 if ((unsigned long) address < PAGE_SIZE) {
57 printk(KERN_ALERT "Unable to handle kernel NULL "
58 "pointer dereference\n");
60 printk(KERN_ALERT "Unable to handle kernel paging request "
61 "at virtual address %016lx\n", (unsigned long)address);
63 printk(KERN_ALERT "tsk->{mm,active_mm}->context = %016lx\n",
65 CTX_HWBITS(tsk->mm->context) :
66 CTX_HWBITS(tsk->active_mm->context)));
67 printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %016lx\n",
68 (tsk->mm ? (unsigned long) tsk->mm->pgd :
69 (unsigned long) tsk->active_mm->pgd));
70 die_if_kernel("Oops", regs);
73 static void __kprobes bad_kernel_pc(struct pt_regs *regs, unsigned long vaddr)
75 printk(KERN_CRIT "OOPS: Bogus kernel PC [%016lx] in fault handler\n",
77 printk(KERN_CRIT "OOPS: RPC [%016lx]\n", regs->u_regs[15]);
78 printk("OOPS: RPC <%pS>\n", (void *) regs->u_regs[15]);
79 printk(KERN_CRIT "OOPS: Fault was to vaddr[%lx]\n", vaddr);
81 unhandled_fault(regs->tpc, current, regs);
85 * We now make sure that mmap_sem is held in all paths that call
86 * this. Additionally, to prevent kswapd from ripping ptes from
87 * under us, raise interrupts around the time that we look at the
88 * pte, kswapd will have to wait to get his smp ipi response from
89 * us. vmtruncate likewise. This saves us having to get pte lock.
91 static unsigned int get_user_insn(unsigned long tpc)
93 pgd_t *pgdp = pgd_offset(current->mm, tpc);
103 pudp = pud_offset(pgdp, tpc);
106 pmdp = pmd_offset(pudp, tpc);
110 /* This disables preemption for us as well. */
111 __asm__ __volatile__("rdpr %%pstate, %0" : "=r" (pstate));
112 __asm__ __volatile__("wrpr %0, %1, %%pstate"
113 : : "r" (pstate), "i" (PSTATE_IE));
114 ptep = pte_offset_map(pmdp, tpc);
116 if (!pte_present(pte))
119 pa = (pte_pfn(pte) << PAGE_SHIFT);
120 pa += (tpc & ~PAGE_MASK);
122 /* Use phys bypass so we don't pollute dtlb/dcache. */
123 __asm__ __volatile__("lduwa [%1] %2, %0"
125 : "r" (pa), "i" (ASI_PHYS_USE_EC));
129 __asm__ __volatile__("wrpr %0, 0x0, %%pstate" : : "r" (pstate));
135 show_signal_msg(struct pt_regs *regs, int sig, int code,
136 unsigned long address, struct task_struct *tsk)
138 if (!unhandled_signal(tsk, sig))
141 if (!printk_ratelimit())
144 printk("%s%s[%d]: segfault at %lx ip %p (rpc %p) sp %p error %x",
145 task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
146 tsk->comm, task_pid_nr(tsk), address,
147 (void *)regs->tpc, (void *)regs->u_regs[UREG_I7],
148 (void *)regs->u_regs[UREG_FP], code);
150 print_vma_addr(KERN_CONT " in ", regs->tpc);
152 printk(KERN_CONT "\n");
155 static void do_fault_siginfo(int code, int sig, struct pt_regs *regs,
156 unsigned int insn, int fault_code)
164 if (fault_code & FAULT_CODE_ITLB)
167 addr = compute_effective_address(regs, insn, 0);
168 info.si_addr = (void __user *) addr;
171 if (unlikely(show_unhandled_signals))
172 show_signal_msg(regs, sig, code, addr, current);
174 force_sig_info(sig, &info, current);
177 extern int handle_ldf_stq(u32, struct pt_regs *);
178 extern int handle_ld_nf(u32, struct pt_regs *);
180 static unsigned int get_fault_insn(struct pt_regs *regs, unsigned int insn)
183 if (!regs->tpc || (regs->tpc & 0x3))
185 if (regs->tstate & TSTATE_PRIV) {
186 insn = *(unsigned int *) regs->tpc;
188 insn = get_user_insn(regs->tpc);
194 static void __kprobes do_kernel_fault(struct pt_regs *regs, int si_code,
195 int fault_code, unsigned int insn,
196 unsigned long address)
198 unsigned char asi = ASI_P;
200 if ((!insn) && (regs->tstate & TSTATE_PRIV))
203 /* If user insn could be read (thus insn is zero), that
204 * is fine. We will just gun down the process with a signal
208 if (!(fault_code & (FAULT_CODE_WRITE|FAULT_CODE_ITLB)) &&
209 (insn & 0xc0800000) == 0xc0800000) {
211 asi = (regs->tstate >> 24);
214 if ((asi & 0xf2) == 0x82) {
215 if (insn & 0x1000000) {
216 handle_ldf_stq(insn, regs);
218 /* This was a non-faulting load. Just clear the
219 * destination register(s) and continue with the next
222 handle_ld_nf(insn, regs);
228 /* Is this in ex_table? */
229 if (regs->tstate & TSTATE_PRIV) {
230 const struct exception_table_entry *entry;
232 entry = search_exception_tables(regs->tpc);
234 regs->tpc = entry->fixup;
235 regs->tnpc = regs->tpc + 4;
239 /* The si_code was set to make clear whether
240 * this was a SEGV_MAPERR or SEGV_ACCERR fault.
242 do_fault_siginfo(si_code, SIGSEGV, regs, insn, fault_code);
247 unhandled_fault (address, current, regs);
250 static void noinline __kprobes bogus_32bit_fault_tpc(struct pt_regs *regs)
255 printk(KERN_ERR "FAULT[%s:%d]: 32-bit process reports "
256 "64-bit TPC [%lx]\n",
257 current->comm, current->pid,
262 static void noinline __kprobes bogus_32bit_fault_address(struct pt_regs *regs,
268 printk(KERN_ERR "FAULT[%s:%d]: 32-bit process "
269 "reports 64-bit fault address [%lx]\n",
270 current->comm, current->pid, addr);
274 asmlinkage void __kprobes do_sparc64_fault(struct pt_regs *regs)
276 enum ctx_state prev_state = exception_enter();
277 struct mm_struct *mm = current->mm;
278 struct vm_area_struct *vma;
279 unsigned int insn = 0;
280 int si_code, fault_code, fault;
281 unsigned long address, mm_rss;
282 unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
284 fault_code = get_thread_fault_code();
286 if (notify_page_fault(regs))
289 si_code = SEGV_MAPERR;
290 address = current_thread_info()->fault_address;
292 if ((fault_code & FAULT_CODE_ITLB) &&
293 (fault_code & FAULT_CODE_DTLB))
296 if (test_thread_flag(TIF_32BIT)) {
297 if (!(regs->tstate & TSTATE_PRIV)) {
298 if (unlikely((regs->tpc >> 32) != 0)) {
299 bogus_32bit_fault_tpc(regs);
303 if (unlikely((address >> 32) != 0)) {
304 bogus_32bit_fault_address(regs, address);
309 if (regs->tstate & TSTATE_PRIV) {
310 unsigned long tpc = regs->tpc;
312 /* Sanity check the PC. */
313 if ((tpc >= KERNBASE && tpc < (unsigned long) __init_end) ||
314 (tpc >= MODULES_VADDR && tpc < MODULES_END)) {
315 /* Valid, no problems... */
317 bad_kernel_pc(regs, address);
321 flags |= FAULT_FLAG_USER;
324 * If we're in an interrupt or have no user
325 * context, we must not take the fault..
327 if (in_atomic() || !mm)
330 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
332 if (!down_read_trylock(&mm->mmap_sem)) {
333 if ((regs->tstate & TSTATE_PRIV) &&
334 !search_exception_tables(regs->tpc)) {
335 insn = get_fault_insn(regs, insn);
336 goto handle_kernel_fault;
340 down_read(&mm->mmap_sem);
343 vma = find_vma(mm, address);
347 /* Pure DTLB misses do not tell us whether the fault causing
348 * load/store/atomic was a write or not, it only says that there
349 * was no match. So in such a case we (carefully) read the
350 * instruction to try and figure this out. It's an optimization
351 * so it's ok if we can't do this.
353 * Special hack, window spill/fill knows the exact fault type.
356 (FAULT_CODE_DTLB | FAULT_CODE_WRITE | FAULT_CODE_WINFIXUP)) == FAULT_CODE_DTLB) &&
357 (vma->vm_flags & VM_WRITE) != 0) {
358 insn = get_fault_insn(regs, 0);
361 /* All loads, stores and atomics have bits 30 and 31 both set
362 * in the instruction. Bit 21 is set in all stores, but we
363 * have to avoid prefetches which also have bit 21 set.
365 if ((insn & 0xc0200000) == 0xc0200000 &&
366 (insn & 0x01780000) != 0x01680000) {
367 /* Don't bother updating thread struct value,
368 * because update_mmu_cache only cares which tlb
369 * the access came from.
371 fault_code |= FAULT_CODE_WRITE;
376 if (vma->vm_start <= address)
378 if (!(vma->vm_flags & VM_GROWSDOWN))
380 if (!(fault_code & FAULT_CODE_WRITE)) {
381 /* Non-faulting loads shouldn't expand stack. */
382 insn = get_fault_insn(regs, insn);
383 if ((insn & 0xc0800000) == 0xc0800000) {
387 asi = (regs->tstate >> 24);
390 if ((asi & 0xf2) == 0x82)
394 if (expand_stack(vma, address))
397 * Ok, we have a good vm_area for this memory access, so
401 si_code = SEGV_ACCERR;
403 /* If we took a ITLB miss on a non-executable page, catch
406 if ((fault_code & FAULT_CODE_ITLB) && !(vma->vm_flags & VM_EXEC)) {
407 BUG_ON(address != regs->tpc);
408 BUG_ON(regs->tstate & TSTATE_PRIV);
412 if (fault_code & FAULT_CODE_WRITE) {
413 if (!(vma->vm_flags & VM_WRITE))
416 /* Spitfire has an icache which does not snoop
417 * processor stores. Later processors do...
419 if (tlb_type == spitfire &&
420 (vma->vm_flags & VM_EXEC) != 0 &&
421 vma->vm_file != NULL)
422 set_thread_fault_code(fault_code |
423 FAULT_CODE_BLKCOMMIT);
425 flags |= FAULT_FLAG_WRITE;
427 /* Allow reads even for write-only mappings */
428 if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
432 fault = handle_mm_fault(mm, vma, address, flags);
434 if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
437 if (unlikely(fault & VM_FAULT_ERROR)) {
438 if (fault & VM_FAULT_OOM)
440 else if (fault & VM_FAULT_SIGBUS)
445 if (flags & FAULT_FLAG_ALLOW_RETRY) {
446 if (fault & VM_FAULT_MAJOR) {
448 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ,
452 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN,
455 if (fault & VM_FAULT_RETRY) {
456 flags &= ~FAULT_FLAG_ALLOW_RETRY;
457 flags |= FAULT_FLAG_TRIED;
459 /* No need to up_read(&mm->mmap_sem) as we would
460 * have already released it in __lock_page_or_retry
467 up_read(&mm->mmap_sem);
469 mm_rss = get_mm_rss(mm);
470 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
471 mm_rss -= (mm->context.huge_pte_count * (HPAGE_SIZE / PAGE_SIZE));
473 if (unlikely(mm_rss >
474 mm->context.tsb_block[MM_TSB_BASE].tsb_rss_limit))
475 tsb_grow(mm, MM_TSB_BASE, mm_rss);
476 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
477 mm_rss = mm->context.huge_pte_count;
478 if (unlikely(mm_rss >
479 mm->context.tsb_block[MM_TSB_HUGE].tsb_rss_limit)) {
480 if (mm->context.tsb_block[MM_TSB_HUGE].tsb)
481 tsb_grow(mm, MM_TSB_HUGE, mm_rss);
488 exception_exit(prev_state);
492 * Something tried to access memory that isn't in our memory map..
493 * Fix it, but check if it's kernel or user first..
496 insn = get_fault_insn(regs, insn);
497 up_read(&mm->mmap_sem);
500 do_kernel_fault(regs, si_code, fault_code, insn, address);
504 * We ran out of memory, or some other thing happened to us that made
505 * us unable to handle the page fault gracefully.
508 insn = get_fault_insn(regs, insn);
509 up_read(&mm->mmap_sem);
510 if (!(regs->tstate & TSTATE_PRIV)) {
511 pagefault_out_of_memory();
514 goto handle_kernel_fault;
517 insn = get_fault_insn(regs, 0);
518 goto handle_kernel_fault;
521 insn = get_fault_insn(regs, insn);
522 up_read(&mm->mmap_sem);
525 * Send a sigbus, regardless of whether we were in kernel
528 do_fault_siginfo(BUS_ADRERR, SIGBUS, regs, insn, fault_code);
530 /* Kernel mode? Handle exceptions or die */
531 if (regs->tstate & TSTATE_PRIV)
532 goto handle_kernel_fault;