1 /* $Id: fault.c,v 1.59 2002/02/09 19:49:31 davem Exp $
2 * arch/sparc64/mm/fault.c: Page fault handlers for the 64-bit Sparc.
4 * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
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/smp_lock.h>
19 #include <linux/init.h>
20 #include <linux/interrupt.h>
21 #include <linux/kprobes.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/kdebug.h>
34 * To debug kernel to catch accesses to certain virtual/physical addresses.
35 * Mode = 0 selects physical watchpoints, mode = 1 selects virtual watchpoints.
36 * flags = VM_READ watches memread accesses, flags = VM_WRITE watches memwrite accesses.
37 * Caller passes in a 64bit aligned addr, with mask set to the bytes that need to be
38 * watched. This is only useful on a single cpu machine for now. After the watchpoint
39 * is detected, the process causing it will be killed, thus preventing an infinite loop.
41 void set_brkpt(unsigned long addr
, unsigned char mask
, int flags
, int mode
)
43 unsigned long lsubits
;
45 __asm__
__volatile__("ldxa [%%g0] %1, %0"
47 : "i" (ASI_LSU_CONTROL
));
48 lsubits
&= ~(LSU_CONTROL_PM
| LSU_CONTROL_VM
|
49 LSU_CONTROL_PR
| LSU_CONTROL_VR
|
50 LSU_CONTROL_PW
| LSU_CONTROL_VW
);
52 __asm__
__volatile__("stxa %0, [%1] %2\n\t"
55 : "r" (addr
), "r" (mode
? VIRT_WATCHPOINT
: PHYS_WATCHPOINT
),
58 lsubits
|= ((unsigned long)mask
<< (mode
? 25 : 33));
60 lsubits
|= (mode
? LSU_CONTROL_VR
: LSU_CONTROL_PR
);
62 lsubits
|= (mode
? LSU_CONTROL_VW
: LSU_CONTROL_PW
);
63 __asm__
__volatile__("stxa %0, [%%g0] %1\n\t"
66 : "r" (lsubits
), "i" (ASI_LSU_CONTROL
)
70 static void __kprobes
unhandled_fault(unsigned long address
,
71 struct task_struct
*tsk
,
74 if ((unsigned long) address
< PAGE_SIZE
) {
75 printk(KERN_ALERT
"Unable to handle kernel NULL "
76 "pointer dereference\n");
78 printk(KERN_ALERT
"Unable to handle kernel paging request "
79 "at virtual address %016lx\n", (unsigned long)address
);
81 printk(KERN_ALERT
"tsk->{mm,active_mm}->context = %016lx\n",
83 CTX_HWBITS(tsk
->mm
->context
) :
84 CTX_HWBITS(tsk
->active_mm
->context
)));
85 printk(KERN_ALERT
"tsk->{mm,active_mm}->pgd = %016lx\n",
86 (tsk
->mm
? (unsigned long) tsk
->mm
->pgd
:
87 (unsigned long) tsk
->active_mm
->pgd
));
88 if (notify_die(DIE_GPF
, "general protection fault", regs
,
89 0, 0, SIGSEGV
) == NOTIFY_STOP
)
91 die_if_kernel("Oops", regs
);
94 static void bad_kernel_pc(struct pt_regs
*regs
)
98 printk(KERN_CRIT
"OOPS: Bogus kernel PC [%016lx] in fault handler\n",
100 __asm__("mov %%sp, %0" : "=r" (ksp
));
101 show_stack(current
, ksp
);
102 unhandled_fault(regs
->tpc
, current
, regs
);
106 * We now make sure that mmap_sem is held in all paths that call
107 * this. Additionally, to prevent kswapd from ripping ptes from
108 * under us, raise interrupts around the time that we look at the
109 * pte, kswapd will have to wait to get his smp ipi response from
110 * us. vmtruncate likewise. This saves us having to get pte lock.
112 static unsigned int get_user_insn(unsigned long tpc
)
114 pgd_t
*pgdp
= pgd_offset(current
->mm
, tpc
);
120 unsigned long pstate
;
124 pudp
= pud_offset(pgdp
, tpc
);
127 pmdp
= pmd_offset(pudp
, tpc
);
131 /* This disables preemption for us as well. */
132 __asm__
__volatile__("rdpr %%pstate, %0" : "=r" (pstate
));
133 __asm__
__volatile__("wrpr %0, %1, %%pstate"
134 : : "r" (pstate
), "i" (PSTATE_IE
));
135 ptep
= pte_offset_map(pmdp
, tpc
);
137 if (!pte_present(pte
))
140 pa
= (pte_pfn(pte
) << PAGE_SHIFT
);
141 pa
+= (tpc
& ~PAGE_MASK
);
143 /* Use phys bypass so we don't pollute dtlb/dcache. */
144 __asm__
__volatile__("lduwa [%1] %2, %0"
146 : "r" (pa
), "i" (ASI_PHYS_USE_EC
));
150 __asm__
__volatile__("wrpr %0, 0x0, %%pstate" : : "r" (pstate
));
155 extern unsigned long compute_effective_address(struct pt_regs
*, unsigned int, unsigned int);
157 static void do_fault_siginfo(int code
, int sig
, struct pt_regs
*regs
,
158 unsigned int insn
, int fault_code
)
165 if (fault_code
& FAULT_CODE_ITLB
)
166 info
.si_addr
= (void __user
*) regs
->tpc
;
168 info
.si_addr
= (void __user
*)
169 compute_effective_address(regs
, insn
, 0);
171 force_sig_info(sig
, &info
, current
);
174 extern int handle_ldf_stq(u32
, struct pt_regs
*);
175 extern int handle_ld_nf(u32
, struct pt_regs
*);
177 static unsigned int get_fault_insn(struct pt_regs
*regs
, unsigned int insn
)
180 if (!regs
->tpc
|| (regs
->tpc
& 0x3))
182 if (regs
->tstate
& TSTATE_PRIV
) {
183 insn
= *(unsigned int *) regs
->tpc
;
185 insn
= get_user_insn(regs
->tpc
);
191 static void do_kernel_fault(struct pt_regs
*regs
, int si_code
, int fault_code
,
192 unsigned int insn
, unsigned long address
)
194 unsigned char asi
= ASI_P
;
196 if ((!insn
) && (regs
->tstate
& TSTATE_PRIV
))
199 /* If user insn could be read (thus insn is zero), that
200 * is fine. We will just gun down the process with a signal
204 if (!(fault_code
& (FAULT_CODE_WRITE
|FAULT_CODE_ITLB
)) &&
205 (insn
& 0xc0800000) == 0xc0800000) {
207 asi
= (regs
->tstate
>> 24);
210 if ((asi
& 0xf2) == 0x82) {
211 if (insn
& 0x1000000) {
212 handle_ldf_stq(insn
, regs
);
214 /* This was a non-faulting load. Just clear the
215 * destination register(s) and continue with the next
218 handle_ld_nf(insn
, regs
);
224 /* Is this in ex_table? */
225 if (regs
->tstate
& TSTATE_PRIV
) {
226 const struct exception_table_entry
*entry
;
228 if (asi
== ASI_P
&& (insn
& 0xc0800000) == 0xc0800000) {
230 asi
= (regs
->tstate
>> 24);
235 /* Look in asi.h: All _S asis have LS bit set */
237 (entry
= search_exception_tables(regs
->tpc
))) {
238 regs
->tpc
= entry
->fixup
;
239 regs
->tnpc
= regs
->tpc
+ 4;
243 /* The si_code was set to make clear whether
244 * this was a SEGV_MAPERR or SEGV_ACCERR fault.
246 do_fault_siginfo(si_code
, SIGSEGV
, regs
, insn
, fault_code
);
251 unhandled_fault (address
, current
, regs
);
254 asmlinkage
void __kprobes
do_sparc64_fault(struct pt_regs
*regs
)
256 struct mm_struct
*mm
= current
->mm
;
257 struct vm_area_struct
*vma
;
258 unsigned int insn
= 0;
259 int si_code
, fault_code
;
260 unsigned long address
;
262 fault_code
= get_thread_fault_code();
264 if (notify_die(DIE_PAGE_FAULT
, "page_fault", regs
,
265 fault_code
, 0, SIGSEGV
) == NOTIFY_STOP
)
268 si_code
= SEGV_MAPERR
;
269 address
= current_thread_info()->fault_address
;
271 if ((fault_code
& FAULT_CODE_ITLB
) &&
272 (fault_code
& FAULT_CODE_DTLB
))
275 if (regs
->tstate
& TSTATE_PRIV
) {
276 unsigned long tpc
= regs
->tpc
;
278 /* Sanity check the PC. */
279 if ((tpc
>= KERNBASE
&& tpc
< (unsigned long) _etext
) ||
280 (tpc
>= MODULES_VADDR
&& tpc
< MODULES_END
)) {
281 /* Valid, no problems... */
289 * If we're in an interrupt or have no user
290 * context, we must not take the fault..
292 if (in_atomic() || !mm
)
295 if (test_thread_flag(TIF_32BIT
)) {
296 if (!(regs
->tstate
& TSTATE_PRIV
))
297 regs
->tpc
&= 0xffffffff;
298 address
&= 0xffffffff;
301 if (!down_read_trylock(&mm
->mmap_sem
)) {
302 if ((regs
->tstate
& TSTATE_PRIV
) &&
303 !search_exception_tables(regs
->tpc
)) {
304 insn
= get_fault_insn(regs
, insn
);
305 goto handle_kernel_fault
;
307 down_read(&mm
->mmap_sem
);
310 vma
= find_vma(mm
, address
);
314 /* Pure DTLB misses do not tell us whether the fault causing
315 * load/store/atomic was a write or not, it only says that there
316 * was no match. So in such a case we (carefully) read the
317 * instruction to try and figure this out. It's an optimization
318 * so it's ok if we can't do this.
320 * Special hack, window spill/fill knows the exact fault type.
323 (FAULT_CODE_DTLB
| FAULT_CODE_WRITE
| FAULT_CODE_WINFIXUP
)) == FAULT_CODE_DTLB
) &&
324 (vma
->vm_flags
& VM_WRITE
) != 0) {
325 insn
= get_fault_insn(regs
, 0);
328 if ((insn
& 0xc0200000) == 0xc0200000 &&
329 (insn
& 0x1780000) != 0x1680000) {
330 /* Don't bother updating thread struct value,
331 * because update_mmu_cache only cares which tlb
332 * the access came from.
334 fault_code
|= FAULT_CODE_WRITE
;
339 if (vma
->vm_start
<= address
)
341 if (!(vma
->vm_flags
& VM_GROWSDOWN
))
343 if (!(fault_code
& FAULT_CODE_WRITE
)) {
344 /* Non-faulting loads shouldn't expand stack. */
345 insn
= get_fault_insn(regs
, insn
);
346 if ((insn
& 0xc0800000) == 0xc0800000) {
350 asi
= (regs
->tstate
>> 24);
353 if ((asi
& 0xf2) == 0x82)
357 if (expand_stack(vma
, address
))
360 * Ok, we have a good vm_area for this memory access, so
364 si_code
= SEGV_ACCERR
;
366 /* If we took a ITLB miss on a non-executable page, catch
369 if ((fault_code
& FAULT_CODE_ITLB
) && !(vma
->vm_flags
& VM_EXEC
)) {
370 BUG_ON(address
!= regs
->tpc
);
371 BUG_ON(regs
->tstate
& TSTATE_PRIV
);
375 if (fault_code
& FAULT_CODE_WRITE
) {
376 if (!(vma
->vm_flags
& VM_WRITE
))
379 /* Spitfire has an icache which does not snoop
380 * processor stores. Later processors do...
382 if (tlb_type
== spitfire
&&
383 (vma
->vm_flags
& VM_EXEC
) != 0 &&
384 vma
->vm_file
!= NULL
)
385 set_thread_fault_code(fault_code
|
386 FAULT_CODE_BLKCOMMIT
);
388 /* Allow reads even for write-only mappings */
389 if (!(vma
->vm_flags
& (VM_READ
| VM_EXEC
)))
393 switch (handle_mm_fault(mm
, vma
, address
, (fault_code
& FAULT_CODE_WRITE
))) {
400 case VM_FAULT_SIGBUS
:
408 up_read(&mm
->mmap_sem
);
412 * Something tried to access memory that isn't in our memory map..
413 * Fix it, but check if it's kernel or user first..
416 insn
= get_fault_insn(regs
, insn
);
417 up_read(&mm
->mmap_sem
);
420 do_kernel_fault(regs
, si_code
, fault_code
, insn
, address
);
424 * We ran out of memory, or some other thing happened to us that made
425 * us unable to handle the page fault gracefully.
428 insn
= get_fault_insn(regs
, insn
);
429 up_read(&mm
->mmap_sem
);
430 printk("VM: killing process %s\n", current
->comm
);
431 if (!(regs
->tstate
& TSTATE_PRIV
))
433 goto handle_kernel_fault
;
436 insn
= get_fault_insn(regs
, 0);
437 goto handle_kernel_fault
;
440 insn
= get_fault_insn(regs
, insn
);
441 up_read(&mm
->mmap_sem
);
444 * Send a sigbus, regardless of whether we were in kernel
447 do_fault_siginfo(BUS_ADRERR
, SIGBUS
, regs
, insn
, fault_code
);
449 /* Kernel mode? Handle exceptions or die */
450 if (regs
->tstate
& TSTATE_PRIV
)
451 goto handle_kernel_fault
;
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