1 // SPDX-License-Identifier: GPL-2.0
3 * arch/sparc64/mm/fault.c: Page fault handlers for the 64-bit Sparc.
5 * Copyright (C) 1996, 2008 David S. Miller (davem@davemloft.net)
6 * Copyright (C) 1997, 1999 Jakub Jelinek (jj@ultra.linux.cz)
11 #include <linux/string.h>
12 #include <linux/types.h>
13 #include <linux/sched.h>
14 #include <linux/sched/debug.h>
15 #include <linux/ptrace.h>
16 #include <linux/mman.h>
17 #include <linux/signal.h>
19 #include <linux/extable.h>
20 #include <linux/init.h>
21 #include <linux/perf_event.h>
22 #include <linux/interrupt.h>
23 #include <linux/kprobes.h>
24 #include <linux/kdebug.h>
25 #include <linux/percpu.h>
26 #include <linux/context_tracking.h>
27 #include <linux/uaccess.h>
30 #include <asm/pgtable.h>
31 #include <asm/openprom.h>
32 #include <asm/oplib.h>
35 #include <asm/sections.h>
36 #include <asm/mmu_context.h>
37 #include <asm/setup.h>
39 int show_unhandled_signals = 1;
41 static inline __kprobes int notify_page_fault(struct pt_regs *regs)
45 /* kprobe_running() needs smp_processor_id() */
46 if (kprobes_built_in() && !user_mode(regs)) {
48 if (kprobe_running() && kprobe_fault_handler(regs, 0))
55 static void __kprobes unhandled_fault(unsigned long address,
56 struct task_struct *tsk,
59 if ((unsigned long) address < PAGE_SIZE) {
60 printk(KERN_ALERT "Unable to handle kernel NULL "
61 "pointer dereference\n");
63 printk(KERN_ALERT "Unable to handle kernel paging request "
64 "at virtual address %016lx\n", (unsigned long)address);
66 printk(KERN_ALERT "tsk->{mm,active_mm}->context = %016lx\n",
68 CTX_HWBITS(tsk->mm->context) :
69 CTX_HWBITS(tsk->active_mm->context)));
70 printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %016lx\n",
71 (tsk->mm ? (unsigned long) tsk->mm->pgd :
72 (unsigned long) tsk->active_mm->pgd));
73 die_if_kernel("Oops", regs);
76 static void __kprobes bad_kernel_pc(struct pt_regs *regs, unsigned long vaddr)
78 printk(KERN_CRIT "OOPS: Bogus kernel PC [%016lx] in fault handler\n",
80 printk(KERN_CRIT "OOPS: RPC [%016lx]\n", regs->u_regs[15]);
81 printk("OOPS: RPC <%pS>\n", (void *) regs->u_regs[15]);
82 printk(KERN_CRIT "OOPS: Fault was to vaddr[%lx]\n", vaddr);
84 unhandled_fault(regs->tpc, current, regs);
88 * We now make sure that mmap_sem is held in all paths that call
89 * this. Additionally, to prevent kswapd from ripping ptes from
90 * under us, raise interrupts around the time that we look at the
91 * pte, kswapd will have to wait to get his smp ipi response from
92 * us. vmtruncate likewise. This saves us having to get pte lock.
94 static unsigned int get_user_insn(unsigned long tpc)
96 pgd_t *pgdp = pgd_offset(current->mm, tpc);
103 if (pgd_none(*pgdp) || unlikely(pgd_bad(*pgdp)))
105 pudp = pud_offset(pgdp, tpc);
106 if (pud_none(*pudp) || unlikely(pud_bad(*pudp)))
109 /* This disables preemption for us as well. */
112 pmdp = pmd_offset(pudp, tpc);
113 if (pmd_none(*pmdp) || unlikely(pmd_bad(*pmdp)))
116 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
117 if (is_hugetlb_pmd(*pmdp)) {
118 pa = pmd_pfn(*pmdp) << PAGE_SHIFT;
119 pa += tpc & ~HPAGE_MASK;
121 /* Use phys bypass so we don't pollute dtlb/dcache. */
122 __asm__ __volatile__("lduwa [%1] %2, %0"
124 : "r" (pa), "i" (ASI_PHYS_USE_EC));
128 ptep = pte_offset_map(pmdp, tpc);
130 if (pte_present(pte)) {
131 pa = (pte_pfn(pte) << PAGE_SHIFT);
132 pa += (tpc & ~PAGE_MASK);
134 /* Use phys bypass so we don't pollute dtlb/dcache. */
135 __asm__ __volatile__("lduwa [%1] %2, %0"
137 : "r" (pa), "i" (ASI_PHYS_USE_EC));
148 show_signal_msg(struct pt_regs *regs, int sig, int code,
149 unsigned long address, struct task_struct *tsk)
151 if (!unhandled_signal(tsk, sig))
154 if (!printk_ratelimit())
157 printk("%s%s[%d]: segfault at %lx ip %px (rpc %px) sp %px error %x",
158 task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
159 tsk->comm, task_pid_nr(tsk), address,
160 (void *)regs->tpc, (void *)regs->u_regs[UREG_I7],
161 (void *)regs->u_regs[UREG_FP], code);
163 print_vma_addr(KERN_CONT " in ", regs->tpc);
165 printk(KERN_CONT "\n");
168 static void do_fault_siginfo(int code, int sig, struct pt_regs *regs,
169 unsigned long fault_addr, unsigned int insn,
174 if (fault_code & FAULT_CODE_ITLB) {
177 /* If we were able to probe the faulting instruction, use it
178 * to compute a precise fault address. Otherwise use the fault
179 * time provided address which may only have page granularity.
182 addr = compute_effective_address(regs, insn, 0);
187 if (unlikely(show_unhandled_signals))
188 show_signal_msg(regs, sig, code, addr, current);
190 force_sig_fault(sig, code, (void __user *) addr, 0, current);
193 static unsigned int get_fault_insn(struct pt_regs *regs, unsigned int insn)
196 if (!regs->tpc || (regs->tpc & 0x3))
198 if (regs->tstate & TSTATE_PRIV) {
199 insn = *(unsigned int *) regs->tpc;
201 insn = get_user_insn(regs->tpc);
207 static void __kprobes do_kernel_fault(struct pt_regs *regs, int si_code,
208 int fault_code, unsigned int insn,
209 unsigned long address)
211 unsigned char asi = ASI_P;
213 if ((!insn) && (regs->tstate & TSTATE_PRIV))
216 /* If user insn could be read (thus insn is zero), that
217 * is fine. We will just gun down the process with a signal
221 if (!(fault_code & (FAULT_CODE_WRITE|FAULT_CODE_ITLB)) &&
222 (insn & 0xc0800000) == 0xc0800000) {
224 asi = (regs->tstate >> 24);
227 if ((asi & 0xf2) == 0x82) {
228 if (insn & 0x1000000) {
229 handle_ldf_stq(insn, regs);
231 /* This was a non-faulting load. Just clear the
232 * destination register(s) and continue with the next
235 handle_ld_nf(insn, regs);
241 /* Is this in ex_table? */
242 if (regs->tstate & TSTATE_PRIV) {
243 const struct exception_table_entry *entry;
245 entry = search_exception_tables(regs->tpc);
247 regs->tpc = entry->fixup;
248 regs->tnpc = regs->tpc + 4;
252 /* The si_code was set to make clear whether
253 * this was a SEGV_MAPERR or SEGV_ACCERR fault.
255 do_fault_siginfo(si_code, SIGSEGV, regs, address, insn, fault_code);
260 unhandled_fault (address, current, regs);
263 static void noinline __kprobes bogus_32bit_fault_tpc(struct pt_regs *regs)
268 printk(KERN_ERR "FAULT[%s:%d]: 32-bit process reports "
269 "64-bit TPC [%lx]\n",
270 current->comm, current->pid,
275 asmlinkage void __kprobes do_sparc64_fault(struct pt_regs *regs)
277 enum ctx_state prev_state = exception_enter();
278 struct mm_struct *mm = current->mm;
279 struct vm_area_struct *vma;
280 unsigned int insn = 0;
281 int si_code, fault_code;
283 unsigned long address, mm_rss;
284 unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
286 fault_code = get_thread_fault_code();
288 if (notify_page_fault(regs))
291 si_code = SEGV_MAPERR;
292 address = current_thread_info()->fault_address;
294 if ((fault_code & FAULT_CODE_ITLB) &&
295 (fault_code & FAULT_CODE_DTLB))
298 if (test_thread_flag(TIF_32BIT)) {
299 if (!(regs->tstate & TSTATE_PRIV)) {
300 if (unlikely((regs->tpc >> 32) != 0)) {
301 bogus_32bit_fault_tpc(regs);
305 if (unlikely((address >> 32) != 0))
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 (faulthandler_disabled() || !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 if (fault_code & FAULT_CODE_BAD_RA)
346 vma = find_vma(mm, address);
350 /* Pure DTLB misses do not tell us whether the fault causing
351 * load/store/atomic was a write or not, it only says that there
352 * was no match. So in such a case we (carefully) read the
353 * instruction to try and figure this out. It's an optimization
354 * so it's ok if we can't do this.
356 * Special hack, window spill/fill knows the exact fault type.
359 (FAULT_CODE_DTLB | FAULT_CODE_WRITE | FAULT_CODE_WINFIXUP)) == FAULT_CODE_DTLB) &&
360 (vma->vm_flags & VM_WRITE) != 0) {
361 insn = get_fault_insn(regs, 0);
364 /* All loads, stores and atomics have bits 30 and 31 both set
365 * in the instruction. Bit 21 is set in all stores, but we
366 * have to avoid prefetches which also have bit 21 set.
368 if ((insn & 0xc0200000) == 0xc0200000 &&
369 (insn & 0x01780000) != 0x01680000) {
370 /* Don't bother updating thread struct value,
371 * because update_mmu_cache only cares which tlb
372 * the access came from.
374 fault_code |= FAULT_CODE_WRITE;
379 if (vma->vm_start <= address)
381 if (!(vma->vm_flags & VM_GROWSDOWN))
383 if (!(fault_code & FAULT_CODE_WRITE)) {
384 /* Non-faulting loads shouldn't expand stack. */
385 insn = get_fault_insn(regs, insn);
386 if ((insn & 0xc0800000) == 0xc0800000) {
390 asi = (regs->tstate >> 24);
393 if ((asi & 0xf2) == 0x82)
397 if (expand_stack(vma, address))
400 * Ok, we have a good vm_area for this memory access, so
404 si_code = SEGV_ACCERR;
406 /* If we took a ITLB miss on a non-executable page, catch
409 if ((fault_code & FAULT_CODE_ITLB) && !(vma->vm_flags & VM_EXEC)) {
410 WARN(address != regs->tpc,
411 "address (%lx) != regs->tpc (%lx)\n", address, regs->tpc);
412 WARN_ON(regs->tstate & TSTATE_PRIV);
416 if (fault_code & FAULT_CODE_WRITE) {
417 if (!(vma->vm_flags & VM_WRITE))
420 /* Spitfire has an icache which does not snoop
421 * processor stores. Later processors do...
423 if (tlb_type == spitfire &&
424 (vma->vm_flags & VM_EXEC) != 0 &&
425 vma->vm_file != NULL)
426 set_thread_fault_code(fault_code |
427 FAULT_CODE_BLKCOMMIT);
429 flags |= FAULT_FLAG_WRITE;
431 /* Allow reads even for write-only mappings */
432 if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
436 fault = handle_mm_fault(vma, address, flags);
438 if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
441 if (unlikely(fault & VM_FAULT_ERROR)) {
442 if (fault & VM_FAULT_OOM)
444 else if (fault & VM_FAULT_SIGSEGV)
446 else if (fault & VM_FAULT_SIGBUS)
451 if (flags & FAULT_FLAG_ALLOW_RETRY) {
452 if (fault & VM_FAULT_MAJOR) {
454 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ,
458 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN,
461 if (fault & VM_FAULT_RETRY) {
462 flags &= ~FAULT_FLAG_ALLOW_RETRY;
463 flags |= FAULT_FLAG_TRIED;
465 /* No need to up_read(&mm->mmap_sem) as we would
466 * have already released it in __lock_page_or_retry
473 up_read(&mm->mmap_sem);
475 mm_rss = get_mm_rss(mm);
476 #if defined(CONFIG_TRANSPARENT_HUGEPAGE)
477 mm_rss -= (mm->context.thp_pte_count * (HPAGE_SIZE / PAGE_SIZE));
479 if (unlikely(mm_rss >
480 mm->context.tsb_block[MM_TSB_BASE].tsb_rss_limit))
481 tsb_grow(mm, MM_TSB_BASE, mm_rss);
482 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
483 mm_rss = mm->context.hugetlb_pte_count + mm->context.thp_pte_count;
484 mm_rss *= REAL_HPAGE_PER_HPAGE;
485 if (unlikely(mm_rss >
486 mm->context.tsb_block[MM_TSB_HUGE].tsb_rss_limit)) {
487 if (mm->context.tsb_block[MM_TSB_HUGE].tsb)
488 tsb_grow(mm, MM_TSB_HUGE, mm_rss);
495 exception_exit(prev_state);
499 * Something tried to access memory that isn't in our memory map..
500 * Fix it, but check if it's kernel or user first..
503 insn = get_fault_insn(regs, insn);
504 up_read(&mm->mmap_sem);
507 do_kernel_fault(regs, si_code, fault_code, insn, address);
511 * We ran out of memory, or some other thing happened to us that made
512 * us unable to handle the page fault gracefully.
515 insn = get_fault_insn(regs, insn);
516 up_read(&mm->mmap_sem);
517 if (!(regs->tstate & TSTATE_PRIV)) {
518 pagefault_out_of_memory();
521 goto handle_kernel_fault;
524 insn = get_fault_insn(regs, 0);
525 goto handle_kernel_fault;
528 insn = get_fault_insn(regs, insn);
529 up_read(&mm->mmap_sem);
532 * Send a sigbus, regardless of whether we were in kernel
535 do_fault_siginfo(BUS_ADRERR, SIGBUS, regs, address, insn, fault_code);
537 /* Kernel mode? Handle exceptions or die */
538 if (regs->tstate & TSTATE_PRIV)
539 goto handle_kernel_fault;