2 * fault.c: Page fault handlers for the Sparc.
4 * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
5 * Copyright (C) 1996 Eddie C. Dost (ecd@skynet.be)
6 * Copyright (C) 1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
11 #include <linux/string.h>
12 #include <linux/types.h>
13 #include <linux/sched.h>
14 #include <linux/ptrace.h>
15 #include <linux/mman.h>
16 #include <linux/threads.h>
17 #include <linux/kernel.h>
18 #include <linux/signal.h>
20 #include <linux/smp.h>
21 #include <linux/perf_event.h>
22 #include <linux/interrupt.h>
23 #include <linux/kdebug.h>
26 #include <asm/pgtable.h>
27 #include <asm/openprom.h>
28 #include <asm/oplib.h>
30 #include <asm/traps.h>
31 #include <asm/uaccess.h>
33 int show_unhandled_signals
= 1;
35 static void unhandled_fault(unsigned long, struct task_struct
*,
36 struct pt_regs
*) __attribute__ ((noreturn
));
38 static void __noreturn
unhandled_fault(unsigned long address
,
39 struct task_struct
*tsk
,
42 if ((unsigned long) address
< PAGE_SIZE
) {
44 "Unable to handle kernel NULL pointer dereference\n");
46 printk(KERN_ALERT
"Unable to handle kernel paging request at virtual address %08lx\n",
49 printk(KERN_ALERT
"tsk->{mm,active_mm}->context = %08lx\n",
50 (tsk
->mm
? tsk
->mm
->context
: tsk
->active_mm
->context
));
51 printk(KERN_ALERT
"tsk->{mm,active_mm}->pgd = %08lx\n",
52 (tsk
->mm
? (unsigned long) tsk
->mm
->pgd
:
53 (unsigned long) tsk
->active_mm
->pgd
));
54 die_if_kernel("Oops", regs
);
57 asmlinkage
int lookup_fault(unsigned long pc
, unsigned long ret_pc
,
58 unsigned long address
)
65 i
= search_extables_range(ret_pc
, &g2
);
68 /* load & store will be handled by fixup */
72 /* store will be handled by fixup, load will bump out */
74 insn
= *((unsigned int *) pc
);
80 /* load will be handled by fixup, store will bump out */
81 /* for _from_ macros */
82 insn
= *((unsigned int *) pc
);
83 if (!((insn
>> 21) & 1) || ((insn
>>19)&0x3f) == 15)
91 memset(®s
, 0, sizeof(regs
));
98 "nop\n" : "=r" (regs
.psr
));
99 unhandled_fault(address
, current
, ®s
);
106 show_signal_msg(struct pt_regs
*regs
, int sig
, int code
,
107 unsigned long address
, struct task_struct
*tsk
)
109 if (!unhandled_signal(tsk
, sig
))
112 if (!printk_ratelimit())
115 printk("%s%s[%d]: segfault at %lx ip %p (rpc %p) sp %p error %x",
116 task_pid_nr(tsk
) > 1 ? KERN_INFO
: KERN_EMERG
,
117 tsk
->comm
, task_pid_nr(tsk
), address
,
118 (void *)regs
->pc
, (void *)regs
->u_regs
[UREG_I7
],
119 (void *)regs
->u_regs
[UREG_FP
], code
);
121 print_vma_addr(KERN_CONT
" in ", regs
->pc
);
123 printk(KERN_CONT
"\n");
126 static void __do_fault_siginfo(int code
, int sig
, struct pt_regs
*regs
,
134 info
.si_addr
= (void __user
*) addr
;
137 if (unlikely(show_unhandled_signals
))
138 show_signal_msg(regs
, sig
, info
.si_code
,
141 force_sig_info (sig
, &info
, current
);
144 extern unsigned long safe_compute_effective_address(struct pt_regs
*,
147 static unsigned long compute_si_addr(struct pt_regs
*regs
, int text_fault
)
154 if (regs
->psr
& PSR_PS
)
155 insn
= *(unsigned int *) regs
->pc
;
157 __get_user(insn
, (unsigned int *) regs
->pc
);
159 return safe_compute_effective_address(regs
, insn
);
162 static noinline
void do_fault_siginfo(int code
, int sig
, struct pt_regs
*regs
,
165 unsigned long addr
= compute_si_addr(regs
, text_fault
);
167 __do_fault_siginfo(code
, sig
, regs
, addr
);
170 asmlinkage
void do_sparc_fault(struct pt_regs
*regs
, int text_fault
, int write
,
171 unsigned long address
)
173 struct vm_area_struct
*vma
;
174 struct task_struct
*tsk
= current
;
175 struct mm_struct
*mm
= tsk
->mm
;
178 int from_user
= !(regs
->psr
& PSR_PS
);
180 unsigned int flags
= FAULT_FLAG_ALLOW_RETRY
| FAULT_FLAG_KILLABLE
;
186 * We fault-in kernel-space virtual memory on-demand. The
187 * 'reference' page table is init_mm.pgd.
189 * NOTE! We MUST NOT take any locks for this case. We may
190 * be in an interrupt or a critical region, and should
191 * only copy the information from the master page table,
195 if (address
>= TASK_SIZE
)
199 * If we're in an interrupt or have no user
200 * context, we must not take the fault..
202 if (in_atomic() || !mm
)
205 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS
, 1, regs
, address
);
208 down_read(&mm
->mmap_sem
);
210 if (!from_user
&& address
>= PAGE_OFFSET
)
213 vma
= find_vma(mm
, address
);
216 if (vma
->vm_start
<= address
)
218 if (!(vma
->vm_flags
& VM_GROWSDOWN
))
220 if (expand_stack(vma
, address
))
223 * Ok, we have a good vm_area for this memory access, so
229 if (!(vma
->vm_flags
& VM_WRITE
))
232 /* Allow reads even for write-only mappings */
233 if (!(vma
->vm_flags
& (VM_READ
| VM_EXEC
)))
238 flags
|= FAULT_FLAG_USER
;
240 flags
|= FAULT_FLAG_WRITE
;
243 * If for any reason at all we couldn't handle the fault,
244 * make sure we exit gracefully rather than endlessly redo
247 fault
= handle_mm_fault(mm
, vma
, address
, flags
);
249 if ((fault
& VM_FAULT_RETRY
) && fatal_signal_pending(current
))
252 if (unlikely(fault
& VM_FAULT_ERROR
)) {
253 if (fault
& VM_FAULT_OOM
)
255 else if (fault
& VM_FAULT_SIGSEGV
)
257 else if (fault
& VM_FAULT_SIGBUS
)
262 if (flags
& FAULT_FLAG_ALLOW_RETRY
) {
263 if (fault
& VM_FAULT_MAJOR
) {
265 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ
,
269 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN
,
272 if (fault
& VM_FAULT_RETRY
) {
273 flags
&= ~FAULT_FLAG_ALLOW_RETRY
;
274 flags
|= FAULT_FLAG_TRIED
;
276 /* No need to up_read(&mm->mmap_sem) as we would
277 * have already released it in __lock_page_or_retry
285 up_read(&mm
->mmap_sem
);
289 * Something tried to access memory that isn't in our memory map..
290 * Fix it, but check if it's kernel or user first..
293 up_read(&mm
->mmap_sem
);
295 bad_area_nosemaphore
:
296 /* User mode accesses just cause a SIGSEGV */
298 do_fault_siginfo(code
, SIGSEGV
, regs
, text_fault
);
302 /* Is this in ex_table? */
304 g2
= regs
->u_regs
[UREG_G2
];
306 fixup
= search_extables_range(regs
->pc
, &g2
);
307 /* Values below 10 are reserved for other things */
309 extern const unsigned __memset_start
[];
310 extern const unsigned __memset_end
[];
311 extern const unsigned __csum_partial_copy_start
[];
312 extern const unsigned __csum_partial_copy_end
[];
314 #ifdef DEBUG_EXCEPTIONS
315 printk("Exception: PC<%08lx> faddr<%08lx>\n",
317 printk("EX_TABLE: insn<%08lx> fixup<%08x> g2<%08lx>\n",
318 regs
->pc
, fixup
, g2
);
320 if ((regs
->pc
>= (unsigned long)__memset_start
&&
321 regs
->pc
< (unsigned long)__memset_end
) ||
322 (regs
->pc
>= (unsigned long)__csum_partial_copy_start
&&
323 regs
->pc
< (unsigned long)__csum_partial_copy_end
)) {
324 regs
->u_regs
[UREG_I4
] = address
;
325 regs
->u_regs
[UREG_I5
] = regs
->pc
;
327 regs
->u_regs
[UREG_G2
] = g2
;
329 regs
->npc
= regs
->pc
+ 4;
334 unhandled_fault(address
, tsk
, regs
);
338 * We ran out of memory, or some other thing happened to us that made
339 * us unable to handle the page fault gracefully.
342 up_read(&mm
->mmap_sem
);
344 pagefault_out_of_memory();
350 up_read(&mm
->mmap_sem
);
351 do_fault_siginfo(BUS_ADRERR
, SIGBUS
, regs
, text_fault
);
358 * Synchronize this task's top level page-table
359 * with the 'reference' page table.
361 int offset
= pgd_index(address
);
365 pgd
= tsk
->active_mm
->pgd
+ offset
;
366 pgd_k
= init_mm
.pgd
+ offset
;
368 if (!pgd_present(*pgd
)) {
369 if (!pgd_present(*pgd_k
))
370 goto bad_area_nosemaphore
;
371 pgd_val(*pgd
) = pgd_val(*pgd_k
);
375 pmd
= pmd_offset(pgd
, address
);
376 pmd_k
= pmd_offset(pgd_k
, address
);
378 if (pmd_present(*pmd
) || !pmd_present(*pmd_k
))
379 goto bad_area_nosemaphore
;
386 /* This always deals with user addresses. */
387 static void force_user_fault(unsigned long address
, int write
)
389 struct vm_area_struct
*vma
;
390 struct task_struct
*tsk
= current
;
391 struct mm_struct
*mm
= tsk
->mm
;
392 unsigned int flags
= FAULT_FLAG_USER
;
397 down_read(&mm
->mmap_sem
);
398 vma
= find_vma(mm
, address
);
401 if (vma
->vm_start
<= address
)
403 if (!(vma
->vm_flags
& VM_GROWSDOWN
))
405 if (expand_stack(vma
, address
))
410 if (!(vma
->vm_flags
& VM_WRITE
))
412 flags
|= FAULT_FLAG_WRITE
;
414 if (!(vma
->vm_flags
& (VM_READ
| VM_EXEC
)))
417 switch (handle_mm_fault(mm
, vma
, address
, flags
)) {
418 case VM_FAULT_SIGBUS
:
422 up_read(&mm
->mmap_sem
);
425 up_read(&mm
->mmap_sem
);
426 __do_fault_siginfo(code
, SIGSEGV
, tsk
->thread
.kregs
, address
);
430 up_read(&mm
->mmap_sem
);
431 __do_fault_siginfo(BUS_ADRERR
, SIGBUS
, tsk
->thread
.kregs
, address
);
434 static void check_stack_aligned(unsigned long sp
)
437 force_sig(SIGILL
, current
);
440 void window_overflow_fault(void)
444 sp
= current_thread_info()->rwbuf_stkptrs
[0];
445 if (((sp
+ 0x38) & PAGE_MASK
) != (sp
& PAGE_MASK
))
446 force_user_fault(sp
+ 0x38, 1);
447 force_user_fault(sp
, 1);
449 check_stack_aligned(sp
);
452 void window_underflow_fault(unsigned long sp
)
454 if (((sp
+ 0x38) & PAGE_MASK
) != (sp
& PAGE_MASK
))
455 force_user_fault(sp
+ 0x38, 0);
456 force_user_fault(sp
, 0);
458 check_stack_aligned(sp
);
461 void window_ret_fault(struct pt_regs
*regs
)
465 sp
= regs
->u_regs
[UREG_FP
];
466 if (((sp
+ 0x38) & PAGE_MASK
) != (sp
& PAGE_MASK
))
467 force_user_fault(sp
+ 0x38, 0);
468 force_user_fault(sp
, 0);
470 check_stack_aligned(sp
);