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
);
100 if (pgd_none(*pgdp
) || unlikely(pgd_bad(*pgdp
)))
102 pudp
= pud_offset(pgdp
, tpc
);
103 if (pud_none(*pudp
) || unlikely(pud_bad(*pudp
)))
106 /* This disables preemption for us as well. */
109 pmdp
= pmd_offset(pudp
, tpc
);
110 if (pmd_none(*pmdp
) || unlikely(pmd_bad(*pmdp
)))
113 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
114 if (pmd_trans_huge(*pmdp
)) {
115 if (pmd_trans_splitting(*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 %p (rpc %p) sp %p 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
,
178 if (fault_code
& FAULT_CODE_ITLB
) {
181 /* If we were able to probe the faulting instruction, use it
182 * to compute a precise fault address. Otherwise use the fault
183 * time provided address which may only have page granularity.
186 addr
= compute_effective_address(regs
, insn
, 0);
190 info
.si_addr
= (void __user
*) addr
;
193 if (unlikely(show_unhandled_signals
))
194 show_signal_msg(regs
, sig
, code
, addr
, current
);
196 force_sig_info(sig
, &info
, current
);
199 extern int handle_ldf_stq(u32
, struct pt_regs
*);
200 extern int handle_ld_nf(u32
, struct pt_regs
*);
202 static unsigned int get_fault_insn(struct pt_regs
*regs
, unsigned int insn
)
205 if (!regs
->tpc
|| (regs
->tpc
& 0x3))
207 if (regs
->tstate
& TSTATE_PRIV
) {
208 insn
= *(unsigned int *) regs
->tpc
;
210 insn
= get_user_insn(regs
->tpc
);
216 static void __kprobes
do_kernel_fault(struct pt_regs
*regs
, int si_code
,
217 int fault_code
, unsigned int insn
,
218 unsigned long address
)
220 unsigned char asi
= ASI_P
;
222 if ((!insn
) && (regs
->tstate
& TSTATE_PRIV
))
225 /* If user insn could be read (thus insn is zero), that
226 * is fine. We will just gun down the process with a signal
230 if (!(fault_code
& (FAULT_CODE_WRITE
|FAULT_CODE_ITLB
)) &&
231 (insn
& 0xc0800000) == 0xc0800000) {
233 asi
= (regs
->tstate
>> 24);
236 if ((asi
& 0xf2) == 0x82) {
237 if (insn
& 0x1000000) {
238 handle_ldf_stq(insn
, regs
);
240 /* This was a non-faulting load. Just clear the
241 * destination register(s) and continue with the next
244 handle_ld_nf(insn
, regs
);
250 /* Is this in ex_table? */
251 if (regs
->tstate
& TSTATE_PRIV
) {
252 const struct exception_table_entry
*entry
;
254 entry
= search_exception_tables(regs
->tpc
);
256 regs
->tpc
= entry
->fixup
;
257 regs
->tnpc
= regs
->tpc
+ 4;
261 /* The si_code was set to make clear whether
262 * this was a SEGV_MAPERR or SEGV_ACCERR fault.
264 do_fault_siginfo(si_code
, SIGSEGV
, regs
, address
, insn
, fault_code
);
269 unhandled_fault (address
, current
, regs
);
272 static void noinline __kprobes
bogus_32bit_fault_tpc(struct pt_regs
*regs
)
277 printk(KERN_ERR
"FAULT[%s:%d]: 32-bit process reports "
278 "64-bit TPC [%lx]\n",
279 current
->comm
, current
->pid
,
284 static void noinline __kprobes
bogus_32bit_fault_address(struct pt_regs
*regs
,
290 printk(KERN_ERR
"FAULT[%s:%d]: 32-bit process "
291 "reports 64-bit fault address [%lx]\n",
292 current
->comm
, current
->pid
, addr
);
296 asmlinkage
void __kprobes
do_sparc64_fault(struct pt_regs
*regs
)
298 enum ctx_state prev_state
= exception_enter();
299 struct mm_struct
*mm
= current
->mm
;
300 struct vm_area_struct
*vma
;
301 unsigned int insn
= 0;
302 int si_code
, fault_code
, fault
;
303 unsigned long address
, mm_rss
;
304 unsigned int flags
= FAULT_FLAG_ALLOW_RETRY
| FAULT_FLAG_KILLABLE
;
306 fault_code
= get_thread_fault_code();
308 if (notify_page_fault(regs
))
311 si_code
= SEGV_MAPERR
;
312 address
= current_thread_info()->fault_address
;
314 if ((fault_code
& FAULT_CODE_ITLB
) &&
315 (fault_code
& FAULT_CODE_DTLB
))
318 if (test_thread_flag(TIF_32BIT
)) {
319 if (!(regs
->tstate
& TSTATE_PRIV
)) {
320 if (unlikely((regs
->tpc
>> 32) != 0)) {
321 bogus_32bit_fault_tpc(regs
);
325 if (unlikely((address
>> 32) != 0)) {
326 bogus_32bit_fault_address(regs
, address
);
331 if (regs
->tstate
& TSTATE_PRIV
) {
332 unsigned long tpc
= regs
->tpc
;
334 /* Sanity check the PC. */
335 if ((tpc
>= KERNBASE
&& tpc
< (unsigned long) __init_end
) ||
336 (tpc
>= MODULES_VADDR
&& tpc
< MODULES_END
)) {
337 /* Valid, no problems... */
339 bad_kernel_pc(regs
, address
);
343 flags
|= FAULT_FLAG_USER
;
346 * If we're in an interrupt or have no user
347 * context, we must not take the fault..
349 if (in_atomic() || !mm
)
352 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS
, 1, regs
, address
);
354 if (!down_read_trylock(&mm
->mmap_sem
)) {
355 if ((regs
->tstate
& TSTATE_PRIV
) &&
356 !search_exception_tables(regs
->tpc
)) {
357 insn
= get_fault_insn(regs
, insn
);
358 goto handle_kernel_fault
;
362 down_read(&mm
->mmap_sem
);
365 vma
= find_vma(mm
, address
);
369 /* Pure DTLB misses do not tell us whether the fault causing
370 * load/store/atomic was a write or not, it only says that there
371 * was no match. So in such a case we (carefully) read the
372 * instruction to try and figure this out. It's an optimization
373 * so it's ok if we can't do this.
375 * Special hack, window spill/fill knows the exact fault type.
378 (FAULT_CODE_DTLB
| FAULT_CODE_WRITE
| FAULT_CODE_WINFIXUP
)) == FAULT_CODE_DTLB
) &&
379 (vma
->vm_flags
& VM_WRITE
) != 0) {
380 insn
= get_fault_insn(regs
, 0);
383 /* All loads, stores and atomics have bits 30 and 31 both set
384 * in the instruction. Bit 21 is set in all stores, but we
385 * have to avoid prefetches which also have bit 21 set.
387 if ((insn
& 0xc0200000) == 0xc0200000 &&
388 (insn
& 0x01780000) != 0x01680000) {
389 /* Don't bother updating thread struct value,
390 * because update_mmu_cache only cares which tlb
391 * the access came from.
393 fault_code
|= FAULT_CODE_WRITE
;
398 if (vma
->vm_start
<= address
)
400 if (!(vma
->vm_flags
& VM_GROWSDOWN
))
402 if (!(fault_code
& FAULT_CODE_WRITE
)) {
403 /* Non-faulting loads shouldn't expand stack. */
404 insn
= get_fault_insn(regs
, insn
);
405 if ((insn
& 0xc0800000) == 0xc0800000) {
409 asi
= (regs
->tstate
>> 24);
412 if ((asi
& 0xf2) == 0x82)
416 if (expand_stack(vma
, address
))
419 * Ok, we have a good vm_area for this memory access, so
423 si_code
= SEGV_ACCERR
;
425 /* If we took a ITLB miss on a non-executable page, catch
428 if ((fault_code
& FAULT_CODE_ITLB
) && !(vma
->vm_flags
& VM_EXEC
)) {
429 BUG_ON(address
!= regs
->tpc
);
430 BUG_ON(regs
->tstate
& TSTATE_PRIV
);
434 if (fault_code
& FAULT_CODE_WRITE
) {
435 if (!(vma
->vm_flags
& VM_WRITE
))
438 /* Spitfire has an icache which does not snoop
439 * processor stores. Later processors do...
441 if (tlb_type
== spitfire
&&
442 (vma
->vm_flags
& VM_EXEC
) != 0 &&
443 vma
->vm_file
!= NULL
)
444 set_thread_fault_code(fault_code
|
445 FAULT_CODE_BLKCOMMIT
);
447 flags
|= FAULT_FLAG_WRITE
;
449 /* Allow reads even for write-only mappings */
450 if (!(vma
->vm_flags
& (VM_READ
| VM_EXEC
)))
454 fault
= handle_mm_fault(mm
, vma
, address
, flags
);
456 if ((fault
& VM_FAULT_RETRY
) && fatal_signal_pending(current
))
459 if (unlikely(fault
& VM_FAULT_ERROR
)) {
460 if (fault
& VM_FAULT_OOM
)
462 else if (fault
& VM_FAULT_SIGBUS
)
467 if (flags
& FAULT_FLAG_ALLOW_RETRY
) {
468 if (fault
& VM_FAULT_MAJOR
) {
470 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ
,
474 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN
,
477 if (fault
& VM_FAULT_RETRY
) {
478 flags
&= ~FAULT_FLAG_ALLOW_RETRY
;
479 flags
|= FAULT_FLAG_TRIED
;
481 /* No need to up_read(&mm->mmap_sem) as we would
482 * have already released it in __lock_page_or_retry
489 up_read(&mm
->mmap_sem
);
491 mm_rss
= get_mm_rss(mm
);
492 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
493 mm_rss
-= (mm
->context
.huge_pte_count
* (HPAGE_SIZE
/ PAGE_SIZE
));
495 if (unlikely(mm_rss
>
496 mm
->context
.tsb_block
[MM_TSB_BASE
].tsb_rss_limit
))
497 tsb_grow(mm
, MM_TSB_BASE
, mm_rss
);
498 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
499 mm_rss
= mm
->context
.huge_pte_count
;
500 if (unlikely(mm_rss
>
501 mm
->context
.tsb_block
[MM_TSB_HUGE
].tsb_rss_limit
)) {
502 if (mm
->context
.tsb_block
[MM_TSB_HUGE
].tsb
)
503 tsb_grow(mm
, MM_TSB_HUGE
, mm_rss
);
510 exception_exit(prev_state
);
514 * Something tried to access memory that isn't in our memory map..
515 * Fix it, but check if it's kernel or user first..
518 insn
= get_fault_insn(regs
, insn
);
519 up_read(&mm
->mmap_sem
);
522 do_kernel_fault(regs
, si_code
, fault_code
, insn
, address
);
526 * We ran out of memory, or some other thing happened to us that made
527 * us unable to handle the page fault gracefully.
530 insn
= get_fault_insn(regs
, insn
);
531 up_read(&mm
->mmap_sem
);
532 if (!(regs
->tstate
& TSTATE_PRIV
)) {
533 pagefault_out_of_memory();
536 goto handle_kernel_fault
;
539 insn
= get_fault_insn(regs
, 0);
540 goto handle_kernel_fault
;
543 insn
= get_fault_insn(regs
, insn
);
544 up_read(&mm
->mmap_sem
);
547 * Send a sigbus, regardless of whether we were in kernel
550 do_fault_siginfo(BUS_ADRERR
, SIGBUS
, regs
, address
, insn
, fault_code
);
552 /* Kernel mode? Handle exceptions or die */
553 if (regs
->tstate
& TSTATE_PRIV
)
554 goto handle_kernel_fault
;