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/interrupt.h>
20 #include <linux/kprobes.h>
21 #include <linux/kdebug.h>
22 #include <linux/percpu.h>
25 #include <asm/pgtable.h>
26 #include <asm/openprom.h>
27 #include <asm/oplib.h>
28 #include <asm/uaccess.h>
31 #include <asm/sections.h>
32 #include <asm/mmu_context.h>
35 static inline int notify_page_fault(struct pt_regs
*regs
)
39 /* kprobe_running() needs smp_processor_id() */
40 if (!user_mode(regs
)) {
42 if (kprobe_running() && kprobe_fault_handler(regs
, 0))
49 static inline int notify_page_fault(struct pt_regs
*regs
)
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 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
);
102 unsigned long pstate
;
106 pudp
= pud_offset(pgdp
, tpc
);
109 pmdp
= pmd_offset(pudp
, tpc
);
113 /* This disables preemption for us as well. */
114 __asm__
__volatile__("rdpr %%pstate, %0" : "=r" (pstate
));
115 __asm__
__volatile__("wrpr %0, %1, %%pstate"
116 : : "r" (pstate
), "i" (PSTATE_IE
));
117 ptep
= pte_offset_map(pmdp
, tpc
);
119 if (!pte_present(pte
))
122 pa
= (pte_pfn(pte
) << PAGE_SHIFT
);
123 pa
+= (tpc
& ~PAGE_MASK
);
125 /* Use phys bypass so we don't pollute dtlb/dcache. */
126 __asm__
__volatile__("lduwa [%1] %2, %0"
128 : "r" (pa
), "i" (ASI_PHYS_USE_EC
));
132 __asm__
__volatile__("wrpr %0, 0x0, %%pstate" : : "r" (pstate
));
137 extern unsigned long compute_effective_address(struct pt_regs
*, unsigned int, unsigned int);
139 static void do_fault_siginfo(int code
, int sig
, struct pt_regs
*regs
,
140 unsigned int insn
, int fault_code
)
147 if (fault_code
& FAULT_CODE_ITLB
)
148 info
.si_addr
= (void __user
*) regs
->tpc
;
150 info
.si_addr
= (void __user
*)
151 compute_effective_address(regs
, insn
, 0);
153 force_sig_info(sig
, &info
, current
);
156 extern int handle_ldf_stq(u32
, struct pt_regs
*);
157 extern int handle_ld_nf(u32
, struct pt_regs
*);
159 static unsigned int get_fault_insn(struct pt_regs
*regs
, unsigned int insn
)
162 if (!regs
->tpc
|| (regs
->tpc
& 0x3))
164 if (regs
->tstate
& TSTATE_PRIV
) {
165 insn
= *(unsigned int *) regs
->tpc
;
167 insn
= get_user_insn(regs
->tpc
);
173 static void do_kernel_fault(struct pt_regs
*regs
, int si_code
, int fault_code
,
174 unsigned int insn
, unsigned long address
)
176 unsigned char asi
= ASI_P
;
178 if ((!insn
) && (regs
->tstate
& TSTATE_PRIV
))
181 /* If user insn could be read (thus insn is zero), that
182 * is fine. We will just gun down the process with a signal
186 if (!(fault_code
& (FAULT_CODE_WRITE
|FAULT_CODE_ITLB
)) &&
187 (insn
& 0xc0800000) == 0xc0800000) {
189 asi
= (regs
->tstate
>> 24);
192 if ((asi
& 0xf2) == 0x82) {
193 if (insn
& 0x1000000) {
194 handle_ldf_stq(insn
, regs
);
196 /* This was a non-faulting load. Just clear the
197 * destination register(s) and continue with the next
200 handle_ld_nf(insn
, regs
);
206 /* Is this in ex_table? */
207 if (regs
->tstate
& TSTATE_PRIV
) {
208 const struct exception_table_entry
*entry
;
210 entry
= search_exception_tables(regs
->tpc
);
212 regs
->tpc
= entry
->fixup
;
213 regs
->tnpc
= regs
->tpc
+ 4;
217 /* The si_code was set to make clear whether
218 * this was a SEGV_MAPERR or SEGV_ACCERR fault.
220 do_fault_siginfo(si_code
, SIGSEGV
, regs
, insn
, fault_code
);
225 unhandled_fault (address
, current
, regs
);
228 asmlinkage
void __kprobes
do_sparc64_fault(struct pt_regs
*regs
)
230 struct mm_struct
*mm
= current
->mm
;
231 struct vm_area_struct
*vma
;
232 unsigned int insn
= 0;
233 int si_code
, fault_code
, fault
;
234 unsigned long address
, mm_rss
;
236 fault_code
= get_thread_fault_code();
238 if (notify_page_fault(regs
))
241 si_code
= SEGV_MAPERR
;
242 address
= current_thread_info()->fault_address
;
244 if ((fault_code
& FAULT_CODE_ITLB
) &&
245 (fault_code
& FAULT_CODE_DTLB
))
248 if (test_thread_flag(TIF_32BIT
)) {
249 if (!(regs
->tstate
& TSTATE_PRIV
))
250 regs
->tpc
&= 0xffffffff;
251 address
&= 0xffffffff;
254 if (regs
->tstate
& TSTATE_PRIV
) {
255 unsigned long eaddr
, tpc
= regs
->tpc
;
257 /* Sanity check the PC. */
258 if ((tpc
>= KERNBASE
&& tpc
< (unsigned long) __init_end
) ||
259 (tpc
>= MODULES_VADDR
&& tpc
< MODULES_END
)) {
260 /* Valid, no problems... */
262 bad_kernel_pc(regs
, address
);
266 insn
= get_fault_insn(regs
, insn
);
267 eaddr
= compute_effective_address(regs
, insn
, 0);
268 if (WARN_ON_ONCE((eaddr
& PAGE_MASK
) != (address
& PAGE_MASK
))){
269 printk(KERN_ERR
"FAULT: Mismatch kernel fault "
270 "address: addr[%lx] eaddr[%lx] TPC[%lx]\n",
271 address
, eaddr
, tpc
);
273 goto handle_kernel_fault
;
278 * If we're in an interrupt or have no user
279 * context, we must not take the fault..
281 if (in_atomic() || !mm
)
284 if (!down_read_trylock(&mm
->mmap_sem
)) {
285 if ((regs
->tstate
& TSTATE_PRIV
) &&
286 !search_exception_tables(regs
->tpc
)) {
287 insn
= get_fault_insn(regs
, insn
);
288 goto handle_kernel_fault
;
290 down_read(&mm
->mmap_sem
);
293 vma
= find_vma(mm
, address
);
297 /* Pure DTLB misses do not tell us whether the fault causing
298 * load/store/atomic was a write or not, it only says that there
299 * was no match. So in such a case we (carefully) read the
300 * instruction to try and figure this out. It's an optimization
301 * so it's ok if we can't do this.
303 * Special hack, window spill/fill knows the exact fault type.
306 (FAULT_CODE_DTLB
| FAULT_CODE_WRITE
| FAULT_CODE_WINFIXUP
)) == FAULT_CODE_DTLB
) &&
307 (vma
->vm_flags
& VM_WRITE
) != 0) {
308 insn
= get_fault_insn(regs
, 0);
311 /* All loads, stores and atomics have bits 30 and 31 both set
312 * in the instruction. Bit 21 is set in all stores, but we
313 * have to avoid prefetches which also have bit 21 set.
315 if ((insn
& 0xc0200000) == 0xc0200000 &&
316 (insn
& 0x01780000) != 0x01680000) {
317 /* Don't bother updating thread struct value,
318 * because update_mmu_cache only cares which tlb
319 * the access came from.
321 fault_code
|= FAULT_CODE_WRITE
;
326 if (vma
->vm_start
<= address
)
328 if (!(vma
->vm_flags
& VM_GROWSDOWN
))
330 if (!(fault_code
& FAULT_CODE_WRITE
)) {
331 /* Non-faulting loads shouldn't expand stack. */
332 insn
= get_fault_insn(regs
, insn
);
333 if ((insn
& 0xc0800000) == 0xc0800000) {
337 asi
= (regs
->tstate
>> 24);
340 if ((asi
& 0xf2) == 0x82)
344 if (expand_stack(vma
, address
))
347 * Ok, we have a good vm_area for this memory access, so
351 si_code
= SEGV_ACCERR
;
353 /* If we took a ITLB miss on a non-executable page, catch
356 if ((fault_code
& FAULT_CODE_ITLB
) && !(vma
->vm_flags
& VM_EXEC
)) {
357 BUG_ON(address
!= regs
->tpc
);
358 BUG_ON(regs
->tstate
& TSTATE_PRIV
);
362 if (fault_code
& FAULT_CODE_WRITE
) {
363 if (!(vma
->vm_flags
& VM_WRITE
))
366 /* Spitfire has an icache which does not snoop
367 * processor stores. Later processors do...
369 if (tlb_type
== spitfire
&&
370 (vma
->vm_flags
& VM_EXEC
) != 0 &&
371 vma
->vm_file
!= NULL
)
372 set_thread_fault_code(fault_code
|
373 FAULT_CODE_BLKCOMMIT
);
375 /* Allow reads even for write-only mappings */
376 if (!(vma
->vm_flags
& (VM_READ
| VM_EXEC
)))
380 fault
= handle_mm_fault(mm
, vma
, address
, (fault_code
& FAULT_CODE_WRITE
));
381 if (unlikely(fault
& VM_FAULT_ERROR
)) {
382 if (fault
& VM_FAULT_OOM
)
384 else if (fault
& VM_FAULT_SIGBUS
)
388 if (fault
& VM_FAULT_MAJOR
)
393 up_read(&mm
->mmap_sem
);
395 mm_rss
= get_mm_rss(mm
);
396 #ifdef CONFIG_HUGETLB_PAGE
397 mm_rss
-= (mm
->context
.huge_pte_count
* (HPAGE_SIZE
/ PAGE_SIZE
));
399 if (unlikely(mm_rss
>
400 mm
->context
.tsb_block
[MM_TSB_BASE
].tsb_rss_limit
))
401 tsb_grow(mm
, MM_TSB_BASE
, mm_rss
);
402 #ifdef CONFIG_HUGETLB_PAGE
403 mm_rss
= mm
->context
.huge_pte_count
;
404 if (unlikely(mm_rss
>
405 mm
->context
.tsb_block
[MM_TSB_HUGE
].tsb_rss_limit
))
406 tsb_grow(mm
, MM_TSB_HUGE
, mm_rss
);
411 * Something tried to access memory that isn't in our memory map..
412 * Fix it, but check if it's kernel or user first..
415 insn
= get_fault_insn(regs
, insn
);
416 up_read(&mm
->mmap_sem
);
419 do_kernel_fault(regs
, si_code
, fault_code
, insn
, address
);
423 * We ran out of memory, or some other thing happened to us that made
424 * us unable to handle the page fault gracefully.
427 insn
= get_fault_insn(regs
, insn
);
428 up_read(&mm
->mmap_sem
);
429 printk("VM: killing process %s\n", current
->comm
);
430 if (!(regs
->tstate
& TSTATE_PRIV
))
431 do_group_exit(SIGKILL
);
432 goto handle_kernel_fault
;
435 insn
= get_fault_insn(regs
, 0);
436 goto handle_kernel_fault
;
439 insn
= get_fault_insn(regs
, insn
);
440 up_read(&mm
->mmap_sem
);
443 * Send a sigbus, regardless of whether we were in kernel
446 do_fault_siginfo(BUS_ADRERR
, SIGBUS
, regs
, insn
, fault_code
);
448 /* Kernel mode? Handle exceptions or die */
449 if (regs
->tstate
& TSTATE_PRIV
)
450 goto handle_kernel_fault
;