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>
35 #include <asm/setup.h>
37 int show_unhandled_signals
= 1;
39 static inline __kprobes
int notify_page_fault(struct pt_regs
*regs
)
43 /* kprobe_running() needs smp_processor_id() */
44 if (kprobes_built_in() && !user_mode(regs
)) {
46 if (kprobe_running() && kprobe_fault_handler(regs
, 0))
53 static void __kprobes
unhandled_fault(unsigned long address
,
54 struct task_struct
*tsk
,
57 if ((unsigned long) address
< PAGE_SIZE
) {
58 printk(KERN_ALERT
"Unable to handle kernel NULL "
59 "pointer dereference\n");
61 printk(KERN_ALERT
"Unable to handle kernel paging request "
62 "at virtual address %016lx\n", (unsigned long)address
);
64 printk(KERN_ALERT
"tsk->{mm,active_mm}->context = %016lx\n",
66 CTX_HWBITS(tsk
->mm
->context
) :
67 CTX_HWBITS(tsk
->active_mm
->context
)));
68 printk(KERN_ALERT
"tsk->{mm,active_mm}->pgd = %016lx\n",
69 (tsk
->mm
? (unsigned long) tsk
->mm
->pgd
:
70 (unsigned long) tsk
->active_mm
->pgd
));
71 die_if_kernel("Oops", regs
);
74 static void __kprobes
bad_kernel_pc(struct pt_regs
*regs
, unsigned long vaddr
)
76 printk(KERN_CRIT
"OOPS: Bogus kernel PC [%016lx] in fault handler\n",
78 printk(KERN_CRIT
"OOPS: RPC [%016lx]\n", regs
->u_regs
[15]);
79 printk("OOPS: RPC <%pS>\n", (void *) regs
->u_regs
[15]);
80 printk(KERN_CRIT
"OOPS: Fault was to vaddr[%lx]\n", vaddr
);
82 unhandled_fault(regs
->tpc
, current
, regs
);
86 * We now make sure that mmap_sem is held in all paths that call
87 * this. Additionally, to prevent kswapd from ripping ptes from
88 * under us, raise interrupts around the time that we look at the
89 * pte, kswapd will have to wait to get his smp ipi response from
90 * us. vmtruncate likewise. This saves us having to get pte lock.
92 static unsigned int get_user_insn(unsigned long tpc
)
94 pgd_t
*pgdp
= pgd_offset(current
->mm
, tpc
);
101 if (pgd_none(*pgdp
) || unlikely(pgd_bad(*pgdp
)))
103 pudp
= pud_offset(pgdp
, tpc
);
104 if (pud_none(*pudp
) || unlikely(pud_bad(*pudp
)))
107 /* This disables preemption for us as well. */
110 pmdp
= pmd_offset(pudp
, tpc
);
111 if (pmd_none(*pmdp
) || unlikely(pmd_bad(*pmdp
)))
114 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
115 if (pmd_trans_huge(*pmdp
)) {
116 if (pmd_trans_splitting(*pmdp
))
119 pa
= pmd_pfn(*pmdp
) << PAGE_SHIFT
;
120 pa
+= tpc
& ~HPAGE_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 ptep
= pte_offset_map(pmdp
, tpc
);
131 if (pte_present(pte
)) {
132 pa
= (pte_pfn(pte
) << PAGE_SHIFT
);
133 pa
+= (tpc
& ~PAGE_MASK
);
135 /* Use phys bypass so we don't pollute dtlb/dcache. */
136 __asm__
__volatile__("lduwa [%1] %2, %0"
138 : "r" (pa
), "i" (ASI_PHYS_USE_EC
));
149 show_signal_msg(struct pt_regs
*regs
, int sig
, int code
,
150 unsigned long address
, struct task_struct
*tsk
)
152 if (!unhandled_signal(tsk
, sig
))
155 if (!printk_ratelimit())
158 printk("%s%s[%d]: segfault at %lx ip %p (rpc %p) sp %p error %x",
159 task_pid_nr(tsk
) > 1 ? KERN_INFO
: KERN_EMERG
,
160 tsk
->comm
, task_pid_nr(tsk
), address
,
161 (void *)regs
->tpc
, (void *)regs
->u_regs
[UREG_I7
],
162 (void *)regs
->u_regs
[UREG_FP
], code
);
164 print_vma_addr(KERN_CONT
" in ", regs
->tpc
);
166 printk(KERN_CONT
"\n");
169 static void do_fault_siginfo(int code
, int sig
, struct pt_regs
*regs
,
170 unsigned long fault_addr
, unsigned int insn
,
179 if (fault_code
& FAULT_CODE_ITLB
) {
182 /* If we were able to probe the faulting instruction, use it
183 * to compute a precise fault address. Otherwise use the fault
184 * time provided address which may only have page granularity.
187 addr
= compute_effective_address(regs
, insn
, 0);
191 info
.si_addr
= (void __user
*) addr
;
194 if (unlikely(show_unhandled_signals
))
195 show_signal_msg(regs
, sig
, code
, addr
, current
);
197 force_sig_info(sig
, &info
, current
);
200 static unsigned int get_fault_insn(struct pt_regs
*regs
, unsigned int insn
)
203 if (!regs
->tpc
|| (regs
->tpc
& 0x3))
205 if (regs
->tstate
& TSTATE_PRIV
) {
206 insn
= *(unsigned int *) regs
->tpc
;
208 insn
= get_user_insn(regs
->tpc
);
214 static void __kprobes
do_kernel_fault(struct pt_regs
*regs
, int si_code
,
215 int fault_code
, unsigned int insn
,
216 unsigned long address
)
218 unsigned char asi
= ASI_P
;
220 if ((!insn
) && (regs
->tstate
& TSTATE_PRIV
))
223 /* If user insn could be read (thus insn is zero), that
224 * is fine. We will just gun down the process with a signal
228 if (!(fault_code
& (FAULT_CODE_WRITE
|FAULT_CODE_ITLB
)) &&
229 (insn
& 0xc0800000) == 0xc0800000) {
231 asi
= (regs
->tstate
>> 24);
234 if ((asi
& 0xf2) == 0x82) {
235 if (insn
& 0x1000000) {
236 handle_ldf_stq(insn
, regs
);
238 /* This was a non-faulting load. Just clear the
239 * destination register(s) and continue with the next
242 handle_ld_nf(insn
, regs
);
248 /* Is this in ex_table? */
249 if (regs
->tstate
& TSTATE_PRIV
) {
250 const struct exception_table_entry
*entry
;
252 entry
= search_exception_tables(regs
->tpc
);
254 regs
->tpc
= entry
->fixup
;
255 regs
->tnpc
= regs
->tpc
+ 4;
259 /* The si_code was set to make clear whether
260 * this was a SEGV_MAPERR or SEGV_ACCERR fault.
262 do_fault_siginfo(si_code
, SIGSEGV
, regs
, address
, insn
, fault_code
);
267 unhandled_fault (address
, current
, regs
);
270 static void noinline __kprobes
bogus_32bit_fault_tpc(struct pt_regs
*regs
)
275 printk(KERN_ERR
"FAULT[%s:%d]: 32-bit process reports "
276 "64-bit TPC [%lx]\n",
277 current
->comm
, current
->pid
,
282 asmlinkage
void __kprobes
do_sparc64_fault(struct pt_regs
*regs
)
284 enum ctx_state prev_state
= exception_enter();
285 struct mm_struct
*mm
= current
->mm
;
286 struct vm_area_struct
*vma
;
287 unsigned int insn
= 0;
288 int si_code
, fault_code
, fault
;
289 unsigned long address
, mm_rss
;
290 unsigned int flags
= FAULT_FLAG_ALLOW_RETRY
| FAULT_FLAG_KILLABLE
;
292 fault_code
= get_thread_fault_code();
294 if (notify_page_fault(regs
))
297 si_code
= SEGV_MAPERR
;
298 address
= current_thread_info()->fault_address
;
300 if ((fault_code
& FAULT_CODE_ITLB
) &&
301 (fault_code
& FAULT_CODE_DTLB
))
304 if (test_thread_flag(TIF_32BIT
)) {
305 if (!(regs
->tstate
& TSTATE_PRIV
)) {
306 if (unlikely((regs
->tpc
>> 32) != 0)) {
307 bogus_32bit_fault_tpc(regs
);
311 if (unlikely((address
>> 32) != 0))
315 if (regs
->tstate
& TSTATE_PRIV
) {
316 unsigned long tpc
= regs
->tpc
;
318 /* Sanity check the PC. */
319 if ((tpc
>= KERNBASE
&& tpc
< (unsigned long) __init_end
) ||
320 (tpc
>= MODULES_VADDR
&& tpc
< MODULES_END
)) {
321 /* Valid, no problems... */
323 bad_kernel_pc(regs
, address
);
327 flags
|= FAULT_FLAG_USER
;
330 * If we're in an interrupt or have no user
331 * context, we must not take the fault..
333 if (in_atomic() || !mm
)
336 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS
, 1, regs
, address
);
338 if (!down_read_trylock(&mm
->mmap_sem
)) {
339 if ((regs
->tstate
& TSTATE_PRIV
) &&
340 !search_exception_tables(regs
->tpc
)) {
341 insn
= get_fault_insn(regs
, insn
);
342 goto handle_kernel_fault
;
346 down_read(&mm
->mmap_sem
);
349 vma
= find_vma(mm
, address
);
353 /* Pure DTLB misses do not tell us whether the fault causing
354 * load/store/atomic was a write or not, it only says that there
355 * was no match. So in such a case we (carefully) read the
356 * instruction to try and figure this out. It's an optimization
357 * so it's ok if we can't do this.
359 * Special hack, window spill/fill knows the exact fault type.
362 (FAULT_CODE_DTLB
| FAULT_CODE_WRITE
| FAULT_CODE_WINFIXUP
)) == FAULT_CODE_DTLB
) &&
363 (vma
->vm_flags
& VM_WRITE
) != 0) {
364 insn
= get_fault_insn(regs
, 0);
367 /* All loads, stores and atomics have bits 30 and 31 both set
368 * in the instruction. Bit 21 is set in all stores, but we
369 * have to avoid prefetches which also have bit 21 set.
371 if ((insn
& 0xc0200000) == 0xc0200000 &&
372 (insn
& 0x01780000) != 0x01680000) {
373 /* Don't bother updating thread struct value,
374 * because update_mmu_cache only cares which tlb
375 * the access came from.
377 fault_code
|= FAULT_CODE_WRITE
;
382 if (vma
->vm_start
<= address
)
384 if (!(vma
->vm_flags
& VM_GROWSDOWN
))
386 if (!(fault_code
& FAULT_CODE_WRITE
)) {
387 /* Non-faulting loads shouldn't expand stack. */
388 insn
= get_fault_insn(regs
, insn
);
389 if ((insn
& 0xc0800000) == 0xc0800000) {
393 asi
= (regs
->tstate
>> 24);
396 if ((asi
& 0xf2) == 0x82)
400 if (expand_stack(vma
, address
))
403 * Ok, we have a good vm_area for this memory access, so
407 si_code
= SEGV_ACCERR
;
409 /* If we took a ITLB miss on a non-executable page, catch
412 if ((fault_code
& FAULT_CODE_ITLB
) && !(vma
->vm_flags
& VM_EXEC
)) {
413 BUG_ON(address
!= regs
->tpc
);
414 BUG_ON(regs
->tstate
& TSTATE_PRIV
);
418 if (fault_code
& FAULT_CODE_WRITE
) {
419 if (!(vma
->vm_flags
& VM_WRITE
))
422 /* Spitfire has an icache which does not snoop
423 * processor stores. Later processors do...
425 if (tlb_type
== spitfire
&&
426 (vma
->vm_flags
& VM_EXEC
) != 0 &&
427 vma
->vm_file
!= NULL
)
428 set_thread_fault_code(fault_code
|
429 FAULT_CODE_BLKCOMMIT
);
431 flags
|= FAULT_FLAG_WRITE
;
433 /* Allow reads even for write-only mappings */
434 if (!(vma
->vm_flags
& (VM_READ
| VM_EXEC
)))
438 fault
= handle_mm_fault(mm
, vma
, address
, flags
);
440 if ((fault
& VM_FAULT_RETRY
) && fatal_signal_pending(current
))
443 if (unlikely(fault
& VM_FAULT_ERROR
)) {
444 if (fault
& VM_FAULT_OOM
)
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_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
477 mm_rss
-= (mm
->context
.huge_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
.huge_pte_count
;
484 if (unlikely(mm_rss
>
485 mm
->context
.tsb_block
[MM_TSB_HUGE
].tsb_rss_limit
)) {
486 if (mm
->context
.tsb_block
[MM_TSB_HUGE
].tsb
)
487 tsb_grow(mm
, MM_TSB_HUGE
, mm_rss
);
494 exception_exit(prev_state
);
498 * Something tried to access memory that isn't in our memory map..
499 * Fix it, but check if it's kernel or user first..
502 insn
= get_fault_insn(regs
, insn
);
503 up_read(&mm
->mmap_sem
);
506 do_kernel_fault(regs
, si_code
, fault_code
, insn
, address
);
510 * We ran out of memory, or some other thing happened to us that made
511 * us unable to handle the page fault gracefully.
514 insn
= get_fault_insn(regs
, insn
);
515 up_read(&mm
->mmap_sem
);
516 if (!(regs
->tstate
& TSTATE_PRIV
)) {
517 pagefault_out_of_memory();
520 goto handle_kernel_fault
;
523 insn
= get_fault_insn(regs
, 0);
524 goto handle_kernel_fault
;
527 insn
= get_fault_insn(regs
, insn
);
528 up_read(&mm
->mmap_sem
);
531 * Send a sigbus, regardless of whether we were in kernel
534 do_fault_siginfo(BUS_ADRERR
, SIGBUS
, regs
, address
, insn
, fault_code
);
536 /* Kernel mode? Handle exceptions or die */
537 if (regs
->tstate
& TSTATE_PRIV
)
538 goto handle_kernel_fault
;