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/memreg.h>
28 #include <asm/openprom.h>
29 #include <asm/oplib.h>
31 #include <asm/traps.h>
32 #include <asm/uaccess.h>
34 extern int prom_node_root
;
36 int show_unhandled_signals
= 1;
38 /* At boot time we determine these two values necessary for setting
39 * up the segment maps and page table entries (pte's).
42 int num_segmaps
, num_contexts
;
45 /* various Virtual Address Cache parameters we find at boot time... */
47 int vac_size
, vac_linesize
, vac_do_hw_vac_flushes
;
48 int vac_entries_per_context
, vac_entries_per_segment
;
49 int vac_entries_per_page
;
51 /* Return how much physical memory we have. */
52 unsigned long probe_memory(void)
54 unsigned long total
= 0;
57 for (i
= 0; sp_banks
[i
].num_bytes
; i
++)
58 total
+= sp_banks
[i
].num_bytes
;
63 extern void sun4c_complete_all_stores(void);
65 /* Whee, a level 15 NMI interrupt memory error. Let's have fun... */
66 asmlinkage
void sparc_lvl15_nmi(struct pt_regs
*regs
, unsigned long serr
,
67 unsigned long svaddr
, unsigned long aerr
,
70 sun4c_complete_all_stores();
71 printk("FAULT: NMI received\n");
72 printk("SREGS: Synchronous Error %08lx\n", serr
);
73 printk(" Synchronous Vaddr %08lx\n", svaddr
);
74 printk(" Asynchronous Error %08lx\n", aerr
);
75 printk(" Asynchronous Vaddr %08lx\n", avaddr
);
77 printk(" Memory Parity Error %08lx\n", *sun4c_memerr_reg
);
78 printk("REGISTER DUMP:\n");
83 static void unhandled_fault(unsigned long, struct task_struct
*,
84 struct pt_regs
*) __attribute__ ((noreturn
));
86 static void unhandled_fault(unsigned long address
, struct task_struct
*tsk
,
89 if((unsigned long) address
< PAGE_SIZE
) {
91 "Unable to handle kernel NULL pointer dereference\n");
93 printk(KERN_ALERT
"Unable to handle kernel paging request "
94 "at virtual address %08lx\n", address
);
96 printk(KERN_ALERT
"tsk->{mm,active_mm}->context = %08lx\n",
97 (tsk
->mm
? tsk
->mm
->context
: tsk
->active_mm
->context
));
98 printk(KERN_ALERT
"tsk->{mm,active_mm}->pgd = %08lx\n",
99 (tsk
->mm
? (unsigned long) tsk
->mm
->pgd
:
100 (unsigned long) tsk
->active_mm
->pgd
));
101 die_if_kernel("Oops", regs
);
104 asmlinkage
int lookup_fault(unsigned long pc
, unsigned long ret_pc
,
105 unsigned long address
)
112 i
= search_extables_range(ret_pc
, &g2
);
115 /* load & store will be handled by fixup */
119 /* store will be handled by fixup, load will bump out */
120 /* for _to_ macros */
121 insn
= *((unsigned int *) pc
);
122 if ((insn
>> 21) & 1)
127 /* load will be handled by fixup, store will bump out */
128 /* for _from_ macros */
129 insn
= *((unsigned int *) pc
);
130 if (!((insn
>> 21) & 1) || ((insn
>>19)&0x3f) == 15)
138 memset(®s
, 0, sizeof (regs
));
141 __asm__
__volatile__(
145 "nop\n" : "=r" (regs
.psr
));
146 unhandled_fault(address
, current
, ®s
);
153 show_signal_msg(struct pt_regs
*regs
, int sig
, int code
,
154 unsigned long address
, struct task_struct
*tsk
)
156 if (!unhandled_signal(tsk
, sig
))
159 if (!printk_ratelimit())
162 printk("%s%s[%d]: segfault at %lx ip %p (rpc %p) sp %p error %x",
163 task_pid_nr(tsk
) > 1 ? KERN_INFO
: KERN_EMERG
,
164 tsk
->comm
, task_pid_nr(tsk
), address
,
165 (void *)regs
->pc
, (void *)regs
->u_regs
[UREG_I7
],
166 (void *)regs
->u_regs
[UREG_FP
], code
);
168 print_vma_addr(KERN_CONT
" in ", regs
->pc
);
170 printk(KERN_CONT
"\n");
173 static void __do_fault_siginfo(int code
, int sig
, struct pt_regs
*regs
,
181 info
.si_addr
= (void __user
*) addr
;
184 if (unlikely(show_unhandled_signals
))
185 show_signal_msg(regs
, sig
, info
.si_code
,
188 force_sig_info (sig
, &info
, current
);
191 extern unsigned long safe_compute_effective_address(struct pt_regs
*,
194 static unsigned long compute_si_addr(struct pt_regs
*regs
, int text_fault
)
201 if (regs
->psr
& PSR_PS
) {
202 insn
= *(unsigned int *) regs
->pc
;
204 __get_user(insn
, (unsigned int *) regs
->pc
);
207 return safe_compute_effective_address(regs
, insn
);
210 static noinline
void do_fault_siginfo(int code
, int sig
, struct pt_regs
*regs
,
213 unsigned long addr
= compute_si_addr(regs
, text_fault
);
215 __do_fault_siginfo(code
, sig
, regs
, addr
);
218 asmlinkage
void do_sparc_fault(struct pt_regs
*regs
, int text_fault
, int write
,
219 unsigned long address
)
221 struct vm_area_struct
*vma
;
222 struct task_struct
*tsk
= current
;
223 struct mm_struct
*mm
= tsk
->mm
;
226 int from_user
= !(regs
->psr
& PSR_PS
);
233 * We fault-in kernel-space virtual memory on-demand. The
234 * 'reference' page table is init_mm.pgd.
236 * NOTE! We MUST NOT take any locks for this case. We may
237 * be in an interrupt or a critical region, and should
238 * only copy the information from the master page table,
242 if (!ARCH_SUN4C
&& address
>= TASK_SIZE
)
246 * If we're in an interrupt or have no user
247 * context, we must not take the fault..
249 if (in_atomic() || !mm
)
252 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS
, 1, regs
, address
);
254 down_read(&mm
->mmap_sem
);
257 * The kernel referencing a bad kernel pointer can lock up
258 * a sun4c machine completely, so we must attempt recovery.
260 if(!from_user
&& address
>= PAGE_OFFSET
)
263 vma
= find_vma(mm
, address
);
266 if(vma
->vm_start
<= address
)
268 if(!(vma
->vm_flags
& VM_GROWSDOWN
))
270 if(expand_stack(vma
, address
))
273 * Ok, we have a good vm_area for this memory access, so
279 if(!(vma
->vm_flags
& VM_WRITE
))
282 /* Allow reads even for write-only mappings */
283 if(!(vma
->vm_flags
& (VM_READ
| VM_EXEC
)))
288 * If for any reason at all we couldn't handle the fault,
289 * make sure we exit gracefully rather than endlessly redo
292 fault
= handle_mm_fault(mm
, vma
, address
, write
? FAULT_FLAG_WRITE
: 0);
293 if (unlikely(fault
& VM_FAULT_ERROR
)) {
294 if (fault
& VM_FAULT_OOM
)
296 else if (fault
& VM_FAULT_SIGBUS
)
300 if (fault
& VM_FAULT_MAJOR
) {
302 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ
, 1, regs
, address
);
305 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN
, 1, regs
, address
);
307 up_read(&mm
->mmap_sem
);
311 * Something tried to access memory that isn't in our memory map..
312 * Fix it, but check if it's kernel or user first..
315 up_read(&mm
->mmap_sem
);
317 bad_area_nosemaphore
:
318 /* User mode accesses just cause a SIGSEGV */
320 do_fault_siginfo(code
, SIGSEGV
, regs
, text_fault
);
324 /* Is this in ex_table? */
326 g2
= regs
->u_regs
[UREG_G2
];
328 fixup
= search_extables_range(regs
->pc
, &g2
);
329 if (fixup
> 10) { /* Values below are reserved for other things */
330 extern const unsigned __memset_start
[];
331 extern const unsigned __memset_end
[];
332 extern const unsigned __csum_partial_copy_start
[];
333 extern const unsigned __csum_partial_copy_end
[];
335 #ifdef DEBUG_EXCEPTIONS
336 printk("Exception: PC<%08lx> faddr<%08lx>\n", regs
->pc
, address
);
337 printk("EX_TABLE: insn<%08lx> fixup<%08x> g2<%08lx>\n",
338 regs
->pc
, fixup
, g2
);
340 if ((regs
->pc
>= (unsigned long)__memset_start
&&
341 regs
->pc
< (unsigned long)__memset_end
) ||
342 (regs
->pc
>= (unsigned long)__csum_partial_copy_start
&&
343 regs
->pc
< (unsigned long)__csum_partial_copy_end
)) {
344 regs
->u_regs
[UREG_I4
] = address
;
345 regs
->u_regs
[UREG_I5
] = regs
->pc
;
347 regs
->u_regs
[UREG_G2
] = g2
;
349 regs
->npc
= regs
->pc
+ 4;
354 unhandled_fault (address
, tsk
, regs
);
358 * We ran out of memory, or some other thing happened to us that made
359 * us unable to handle the page fault gracefully.
362 up_read(&mm
->mmap_sem
);
364 pagefault_out_of_memory();
370 up_read(&mm
->mmap_sem
);
371 do_fault_siginfo(BUS_ADRERR
, SIGBUS
, regs
, text_fault
);
378 * Synchronize this task's top level page-table
379 * with the 'reference' page table.
381 int offset
= pgd_index(address
);
385 pgd
= tsk
->active_mm
->pgd
+ offset
;
386 pgd_k
= init_mm
.pgd
+ offset
;
388 if (!pgd_present(*pgd
)) {
389 if (!pgd_present(*pgd_k
))
390 goto bad_area_nosemaphore
;
391 pgd_val(*pgd
) = pgd_val(*pgd_k
);
395 pmd
= pmd_offset(pgd
, address
);
396 pmd_k
= pmd_offset(pgd_k
, address
);
398 if (pmd_present(*pmd
) || !pmd_present(*pmd_k
))
399 goto bad_area_nosemaphore
;
405 asmlinkage
void do_sun4c_fault(struct pt_regs
*regs
, int text_fault
, int write
,
406 unsigned long address
)
408 extern void sun4c_update_mmu_cache(struct vm_area_struct
*,
409 unsigned long,pte_t
*);
410 extern pte_t
*sun4c_pte_offset_kernel(pmd_t
*,unsigned long);
411 struct task_struct
*tsk
= current
;
412 struct mm_struct
*mm
= tsk
->mm
;
419 !(regs
->psr
& PSR_PS
)) {
420 unsigned int insn
, __user
*ip
;
422 ip
= (unsigned int __user
*)regs
->pc
;
423 if (!get_user(insn
, ip
)) {
424 if ((insn
& 0xc1680000) == 0xc0680000)
430 /* We are oopsing. */
431 do_sparc_fault(regs
, text_fault
, write
, address
);
432 BUG(); /* P3 Oops already, you bitch */
435 pgdp
= pgd_offset(mm
, address
);
436 ptep
= sun4c_pte_offset_kernel((pmd_t
*) pgdp
, address
);
438 if (pgd_val(*pgdp
)) {
440 if ((pte_val(*ptep
) & (_SUN4C_PAGE_WRITE
|_SUN4C_PAGE_PRESENT
))
441 == (_SUN4C_PAGE_WRITE
|_SUN4C_PAGE_PRESENT
)) {
444 *ptep
= __pte(pte_val(*ptep
) | _SUN4C_PAGE_ACCESSED
|
445 _SUN4C_PAGE_MODIFIED
|
449 local_irq_save(flags
);
450 if (sun4c_get_segmap(address
) != invalid_segment
) {
451 sun4c_put_pte(address
, pte_val(*ptep
));
452 local_irq_restore(flags
);
455 local_irq_restore(flags
);
458 if ((pte_val(*ptep
) & (_SUN4C_PAGE_READ
|_SUN4C_PAGE_PRESENT
))
459 == (_SUN4C_PAGE_READ
|_SUN4C_PAGE_PRESENT
)) {
462 *ptep
= __pte(pte_val(*ptep
) | _SUN4C_PAGE_ACCESSED
|
465 local_irq_save(flags
);
466 if (sun4c_get_segmap(address
) != invalid_segment
) {
467 sun4c_put_pte(address
, pte_val(*ptep
));
468 local_irq_restore(flags
);
471 local_irq_restore(flags
);
476 /* This conditional is 'interesting'. */
477 if (pgd_val(*pgdp
) && !(write
&& !(pte_val(*ptep
) & _SUN4C_PAGE_WRITE
))
478 && (pte_val(*ptep
) & _SUN4C_PAGE_VALID
))
479 /* Note: It is safe to not grab the MMAP semaphore here because
480 * we know that update_mmu_cache() will not sleep for
481 * any reason (at least not in the current implementation)
482 * and therefore there is no danger of another thread getting
483 * on the CPU and doing a shrink_mmap() on this vma.
485 sun4c_update_mmu_cache (find_vma(current
->mm
, address
), address
,
488 do_sparc_fault(regs
, text_fault
, write
, address
);
491 /* This always deals with user addresses. */
492 static void force_user_fault(unsigned long address
, int write
)
494 struct vm_area_struct
*vma
;
495 struct task_struct
*tsk
= current
;
496 struct mm_struct
*mm
= tsk
->mm
;
501 down_read(&mm
->mmap_sem
);
502 vma
= find_vma(mm
, address
);
505 if(vma
->vm_start
<= address
)
507 if(!(vma
->vm_flags
& VM_GROWSDOWN
))
509 if(expand_stack(vma
, address
))
514 if(!(vma
->vm_flags
& VM_WRITE
))
517 if(!(vma
->vm_flags
& (VM_READ
| VM_EXEC
)))
520 switch (handle_mm_fault(mm
, vma
, address
, write
? FAULT_FLAG_WRITE
: 0)) {
521 case VM_FAULT_SIGBUS
:
525 up_read(&mm
->mmap_sem
);
528 up_read(&mm
->mmap_sem
);
529 __do_fault_siginfo(code
, SIGSEGV
, tsk
->thread
.kregs
, address
);
533 up_read(&mm
->mmap_sem
);
534 __do_fault_siginfo(BUS_ADRERR
, SIGBUS
, tsk
->thread
.kregs
, address
);
537 static void check_stack_aligned(unsigned long sp
)
540 force_sig(SIGILL
, current
);
543 void window_overflow_fault(void)
547 sp
= current_thread_info()->rwbuf_stkptrs
[0];
548 if(((sp
+ 0x38) & PAGE_MASK
) != (sp
& PAGE_MASK
))
549 force_user_fault(sp
+ 0x38, 1);
550 force_user_fault(sp
, 1);
552 check_stack_aligned(sp
);
555 void window_underflow_fault(unsigned long sp
)
557 if(((sp
+ 0x38) & PAGE_MASK
) != (sp
& PAGE_MASK
))
558 force_user_fault(sp
+ 0x38, 0);
559 force_user_fault(sp
, 0);
561 check_stack_aligned(sp
);
564 void window_ret_fault(struct pt_regs
*regs
)
568 sp
= regs
->u_regs
[UREG_FP
];
569 if(((sp
+ 0x38) & PAGE_MASK
) != (sp
& PAGE_MASK
))
570 force_user_fault(sp
+ 0x38, 0);
571 force_user_fault(sp
, 0);
573 check_stack_aligned(sp
);