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>
24 #include <asm/pgtable.h>
25 #include <asm/openprom.h>
26 #include <asm/oplib.h>
27 #include <asm/uaccess.h>
30 #include <asm/sections.h>
31 #include <asm/mmu_context.h>
34 static inline int notify_page_fault(struct pt_regs
*regs
)
38 /* kprobe_running() needs smp_processor_id() */
39 if (!user_mode(regs
)) {
41 if (kprobe_running() && kprobe_fault_handler(regs
, 0))
48 static inline int notify_page_fault(struct pt_regs
*regs
)
55 * To debug kernel to catch accesses to certain virtual/physical addresses.
56 * Mode = 0 selects physical watchpoints, mode = 1 selects virtual watchpoints.
57 * flags = VM_READ watches memread accesses, flags = VM_WRITE watches memwrite accesses.
58 * Caller passes in a 64bit aligned addr, with mask set to the bytes that need to be
59 * watched. This is only useful on a single cpu machine for now. After the watchpoint
60 * is detected, the process causing it will be killed, thus preventing an infinite loop.
62 void set_brkpt(unsigned long addr
, unsigned char mask
, int flags
, int mode
)
64 unsigned long lsubits
;
66 __asm__
__volatile__("ldxa [%%g0] %1, %0"
68 : "i" (ASI_LSU_CONTROL
));
69 lsubits
&= ~(LSU_CONTROL_PM
| LSU_CONTROL_VM
|
70 LSU_CONTROL_PR
| LSU_CONTROL_VR
|
71 LSU_CONTROL_PW
| LSU_CONTROL_VW
);
73 __asm__
__volatile__("stxa %0, [%1] %2\n\t"
76 : "r" (addr
), "r" (mode
? VIRT_WATCHPOINT
: PHYS_WATCHPOINT
),
79 lsubits
|= ((unsigned long)mask
<< (mode
? 25 : 33));
81 lsubits
|= (mode
? LSU_CONTROL_VR
: LSU_CONTROL_PR
);
83 lsubits
|= (mode
? LSU_CONTROL_VW
: LSU_CONTROL_PW
);
84 __asm__
__volatile__("stxa %0, [%%g0] %1\n\t"
87 : "r" (lsubits
), "i" (ASI_LSU_CONTROL
)
91 static void __kprobes
unhandled_fault(unsigned long address
,
92 struct task_struct
*tsk
,
95 if ((unsigned long) address
< PAGE_SIZE
) {
96 printk(KERN_ALERT
"Unable to handle kernel NULL "
97 "pointer dereference\n");
99 printk(KERN_ALERT
"Unable to handle kernel paging request "
100 "at virtual address %016lx\n", (unsigned long)address
);
102 printk(KERN_ALERT
"tsk->{mm,active_mm}->context = %016lx\n",
104 CTX_HWBITS(tsk
->mm
->context
) :
105 CTX_HWBITS(tsk
->active_mm
->context
)));
106 printk(KERN_ALERT
"tsk->{mm,active_mm}->pgd = %016lx\n",
107 (tsk
->mm
? (unsigned long) tsk
->mm
->pgd
:
108 (unsigned long) tsk
->active_mm
->pgd
));
109 die_if_kernel("Oops", regs
);
112 static void bad_kernel_pc(struct pt_regs
*regs
, unsigned long vaddr
)
114 printk(KERN_CRIT
"OOPS: Bogus kernel PC [%016lx] in fault handler\n",
116 printk(KERN_CRIT
"OOPS: RPC [%016lx]\n", regs
->u_regs
[15]);
117 printk("OOPS: RPC <%pS>\n", (void *) regs
->u_regs
[15]);
118 printk(KERN_CRIT
"OOPS: Fault was to vaddr[%lx]\n", vaddr
);
120 unhandled_fault(regs
->tpc
, current
, regs
);
124 * We now make sure that mmap_sem is held in all paths that call
125 * this. Additionally, to prevent kswapd from ripping ptes from
126 * under us, raise interrupts around the time that we look at the
127 * pte, kswapd will have to wait to get his smp ipi response from
128 * us. vmtruncate likewise. This saves us having to get pte lock.
130 static unsigned int get_user_insn(unsigned long tpc
)
132 pgd_t
*pgdp
= pgd_offset(current
->mm
, tpc
);
138 unsigned long pstate
;
142 pudp
= pud_offset(pgdp
, tpc
);
145 pmdp
= pmd_offset(pudp
, tpc
);
149 /* This disables preemption for us as well. */
150 __asm__
__volatile__("rdpr %%pstate, %0" : "=r" (pstate
));
151 __asm__
__volatile__("wrpr %0, %1, %%pstate"
152 : : "r" (pstate
), "i" (PSTATE_IE
));
153 ptep
= pte_offset_map(pmdp
, tpc
);
155 if (!pte_present(pte
))
158 pa
= (pte_pfn(pte
) << PAGE_SHIFT
);
159 pa
+= (tpc
& ~PAGE_MASK
);
161 /* Use phys bypass so we don't pollute dtlb/dcache. */
162 __asm__
__volatile__("lduwa [%1] %2, %0"
164 : "r" (pa
), "i" (ASI_PHYS_USE_EC
));
168 __asm__
__volatile__("wrpr %0, 0x0, %%pstate" : : "r" (pstate
));
173 extern unsigned long compute_effective_address(struct pt_regs
*, unsigned int, unsigned int);
175 static void do_fault_siginfo(int code
, int sig
, struct pt_regs
*regs
,
176 unsigned int insn
, int fault_code
)
183 if (fault_code
& FAULT_CODE_ITLB
)
184 info
.si_addr
= (void __user
*) regs
->tpc
;
186 info
.si_addr
= (void __user
*)
187 compute_effective_address(regs
, insn
, 0);
189 force_sig_info(sig
, &info
, current
);
192 extern int handle_ldf_stq(u32
, struct pt_regs
*);
193 extern int handle_ld_nf(u32
, struct pt_regs
*);
195 static unsigned int get_fault_insn(struct pt_regs
*regs
, unsigned int insn
)
198 if (!regs
->tpc
|| (regs
->tpc
& 0x3))
200 if (regs
->tstate
& TSTATE_PRIV
) {
201 insn
= *(unsigned int *) regs
->tpc
;
203 insn
= get_user_insn(regs
->tpc
);
209 static void do_kernel_fault(struct pt_regs
*regs
, int si_code
, int fault_code
,
210 unsigned int insn
, unsigned long address
)
212 unsigned char asi
= ASI_P
;
214 if ((!insn
) && (regs
->tstate
& TSTATE_PRIV
))
217 /* If user insn could be read (thus insn is zero), that
218 * is fine. We will just gun down the process with a signal
222 if (!(fault_code
& (FAULT_CODE_WRITE
|FAULT_CODE_ITLB
)) &&
223 (insn
& 0xc0800000) == 0xc0800000) {
225 asi
= (regs
->tstate
>> 24);
228 if ((asi
& 0xf2) == 0x82) {
229 if (insn
& 0x1000000) {
230 handle_ldf_stq(insn
, regs
);
232 /* This was a non-faulting load. Just clear the
233 * destination register(s) and continue with the next
236 handle_ld_nf(insn
, regs
);
242 /* Is this in ex_table? */
243 if (regs
->tstate
& TSTATE_PRIV
) {
244 const struct exception_table_entry
*entry
;
246 entry
= search_exception_tables(regs
->tpc
);
248 regs
->tpc
= entry
->fixup
;
249 regs
->tnpc
= regs
->tpc
+ 4;
253 /* The si_code was set to make clear whether
254 * this was a SEGV_MAPERR or SEGV_ACCERR fault.
256 do_fault_siginfo(si_code
, SIGSEGV
, regs
, insn
, fault_code
);
261 unhandled_fault (address
, current
, regs
);
264 asmlinkage
void __kprobes
do_sparc64_fault(struct pt_regs
*regs
)
266 struct mm_struct
*mm
= current
->mm
;
267 struct vm_area_struct
*vma
;
268 unsigned int insn
= 0;
269 int si_code
, fault_code
, fault
;
270 unsigned long address
, mm_rss
;
272 fault_code
= get_thread_fault_code();
274 if (notify_page_fault(regs
))
277 si_code
= SEGV_MAPERR
;
278 address
= current_thread_info()->fault_address
;
280 if ((fault_code
& FAULT_CODE_ITLB
) &&
281 (fault_code
& FAULT_CODE_DTLB
))
284 if (regs
->tstate
& TSTATE_PRIV
) {
285 unsigned long tpc
= regs
->tpc
;
287 /* Sanity check the PC. */
288 if ((tpc
>= KERNBASE
&& tpc
< (unsigned long) __init_end
) ||
289 (tpc
>= MODULES_VADDR
&& tpc
< MODULES_END
)) {
290 /* Valid, no problems... */
292 bad_kernel_pc(regs
, address
);
298 * If we're in an interrupt or have no user
299 * context, we must not take the fault..
301 if (in_atomic() || !mm
)
304 if (test_thread_flag(TIF_32BIT
)) {
305 if (!(regs
->tstate
& TSTATE_PRIV
))
306 regs
->tpc
&= 0xffffffff;
307 address
&= 0xffffffff;
310 if (!down_read_trylock(&mm
->mmap_sem
)) {
311 if ((regs
->tstate
& TSTATE_PRIV
) &&
312 !search_exception_tables(regs
->tpc
)) {
313 insn
= get_fault_insn(regs
, insn
);
314 goto handle_kernel_fault
;
316 down_read(&mm
->mmap_sem
);
319 vma
= find_vma(mm
, address
);
323 /* Pure DTLB misses do not tell us whether the fault causing
324 * load/store/atomic was a write or not, it only says that there
325 * was no match. So in such a case we (carefully) read the
326 * instruction to try and figure this out. It's an optimization
327 * so it's ok if we can't do this.
329 * Special hack, window spill/fill knows the exact fault type.
332 (FAULT_CODE_DTLB
| FAULT_CODE_WRITE
| FAULT_CODE_WINFIXUP
)) == FAULT_CODE_DTLB
) &&
333 (vma
->vm_flags
& VM_WRITE
) != 0) {
334 insn
= get_fault_insn(regs
, 0);
337 /* All loads, stores and atomics have bits 30 and 31 both set
338 * in the instruction. Bit 21 is set in all stores, but we
339 * have to avoid prefetches which also have bit 21 set.
341 if ((insn
& 0xc0200000) == 0xc0200000 &&
342 (insn
& 0x01780000) != 0x01680000) {
343 /* Don't bother updating thread struct value,
344 * because update_mmu_cache only cares which tlb
345 * the access came from.
347 fault_code
|= FAULT_CODE_WRITE
;
352 if (vma
->vm_start
<= address
)
354 if (!(vma
->vm_flags
& VM_GROWSDOWN
))
356 if (!(fault_code
& FAULT_CODE_WRITE
)) {
357 /* Non-faulting loads shouldn't expand stack. */
358 insn
= get_fault_insn(regs
, insn
);
359 if ((insn
& 0xc0800000) == 0xc0800000) {
363 asi
= (regs
->tstate
>> 24);
366 if ((asi
& 0xf2) == 0x82)
370 if (expand_stack(vma
, address
))
373 * Ok, we have a good vm_area for this memory access, so
377 si_code
= SEGV_ACCERR
;
379 /* If we took a ITLB miss on a non-executable page, catch
382 if ((fault_code
& FAULT_CODE_ITLB
) && !(vma
->vm_flags
& VM_EXEC
)) {
383 BUG_ON(address
!= regs
->tpc
);
384 BUG_ON(regs
->tstate
& TSTATE_PRIV
);
388 if (fault_code
& FAULT_CODE_WRITE
) {
389 if (!(vma
->vm_flags
& VM_WRITE
))
392 /* Spitfire has an icache which does not snoop
393 * processor stores. Later processors do...
395 if (tlb_type
== spitfire
&&
396 (vma
->vm_flags
& VM_EXEC
) != 0 &&
397 vma
->vm_file
!= NULL
)
398 set_thread_fault_code(fault_code
|
399 FAULT_CODE_BLKCOMMIT
);
401 /* Allow reads even for write-only mappings */
402 if (!(vma
->vm_flags
& (VM_READ
| VM_EXEC
)))
406 fault
= handle_mm_fault(mm
, vma
, address
, (fault_code
& FAULT_CODE_WRITE
));
407 if (unlikely(fault
& VM_FAULT_ERROR
)) {
408 if (fault
& VM_FAULT_OOM
)
410 else if (fault
& VM_FAULT_SIGBUS
)
414 if (fault
& VM_FAULT_MAJOR
)
419 up_read(&mm
->mmap_sem
);
421 mm_rss
= get_mm_rss(mm
);
422 #ifdef CONFIG_HUGETLB_PAGE
423 mm_rss
-= (mm
->context
.huge_pte_count
* (HPAGE_SIZE
/ PAGE_SIZE
));
425 if (unlikely(mm_rss
>
426 mm
->context
.tsb_block
[MM_TSB_BASE
].tsb_rss_limit
))
427 tsb_grow(mm
, MM_TSB_BASE
, mm_rss
);
428 #ifdef CONFIG_HUGETLB_PAGE
429 mm_rss
= mm
->context
.huge_pte_count
;
430 if (unlikely(mm_rss
>
431 mm
->context
.tsb_block
[MM_TSB_HUGE
].tsb_rss_limit
))
432 tsb_grow(mm
, MM_TSB_HUGE
, mm_rss
);
437 * Something tried to access memory that isn't in our memory map..
438 * Fix it, but check if it's kernel or user first..
441 insn
= get_fault_insn(regs
, insn
);
442 up_read(&mm
->mmap_sem
);
445 do_kernel_fault(regs
, si_code
, fault_code
, insn
, address
);
449 * We ran out of memory, or some other thing happened to us that made
450 * us unable to handle the page fault gracefully.
453 insn
= get_fault_insn(regs
, insn
);
454 up_read(&mm
->mmap_sem
);
455 printk("VM: killing process %s\n", current
->comm
);
456 if (!(regs
->tstate
& TSTATE_PRIV
))
457 do_group_exit(SIGKILL
);
458 goto handle_kernel_fault
;
461 insn
= get_fault_insn(regs
, 0);
462 goto handle_kernel_fault
;
465 insn
= get_fault_insn(regs
, insn
);
466 up_read(&mm
->mmap_sem
);
469 * Send a sigbus, regardless of whether we were in kernel
472 do_fault_siginfo(BUS_ADRERR
, SIGBUS
, regs
, insn
, fault_code
);
474 /* Kernel mode? Handle exceptions or die */
475 if (regs
->tstate
& TSTATE_PRIV
)
476 goto handle_kernel_fault
;