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Source at commit 0de2b2b3be81048189a32f7a3d3ba0ba9ec817b6 created 11 years 11 months ago. By Maarten ter Huurne, MIPS: JZ4740: Fixed value for round robin constant. | |
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1 | /* |
2 | * arch/sparc64/mm/fault.c: Page fault handlers for the 64-bit Sparc. |
3 | * |
4 | * Copyright (C) 1996, 2008 David S. Miller (davem@davemloft.net) |
5 | * Copyright (C) 1997, 1999 Jakub Jelinek (jj@ultra.linux.cz) |
6 | */ |
7 | |
8 | #include <asm/head.h> |
9 | |
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> |
16 | #include <linux/mm.h> |
17 | #include <linux/module.h> |
18 | #include <linux/init.h> |
19 | #include <linux/perf_event.h> |
20 | #include <linux/interrupt.h> |
21 | #include <linux/kprobes.h> |
22 | #include <linux/kdebug.h> |
23 | #include <linux/percpu.h> |
24 | |
25 | #include <asm/page.h> |
26 | #include <asm/pgtable.h> |
27 | #include <asm/openprom.h> |
28 | #include <asm/oplib.h> |
29 | #include <asm/uaccess.h> |
30 | #include <asm/asi.h> |
31 | #include <asm/lsu.h> |
32 | #include <asm/sections.h> |
33 | #include <asm/mmu_context.h> |
34 | |
35 | int show_unhandled_signals = 1; |
36 | |
37 | static inline __kprobes int notify_page_fault(struct pt_regs *regs) |
38 | { |
39 | int ret = 0; |
40 | |
41 | /* kprobe_running() needs smp_processor_id() */ |
42 | if (kprobes_built_in() && !user_mode(regs)) { |
43 | preempt_disable(); |
44 | if (kprobe_running() && kprobe_fault_handler(regs, 0)) |
45 | ret = 1; |
46 | preempt_enable(); |
47 | } |
48 | return ret; |
49 | } |
50 | |
51 | static void __kprobes unhandled_fault(unsigned long address, |
52 | struct task_struct *tsk, |
53 | struct pt_regs *regs) |
54 | { |
55 | if ((unsigned long) address < PAGE_SIZE) { |
56 | printk(KERN_ALERT "Unable to handle kernel NULL " |
57 | "pointer dereference\n"); |
58 | } else { |
59 | printk(KERN_ALERT "Unable to handle kernel paging request " |
60 | "at virtual address %016lx\n", (unsigned long)address); |
61 | } |
62 | printk(KERN_ALERT "tsk->{mm,active_mm}->context = %016lx\n", |
63 | (tsk->mm ? |
64 | CTX_HWBITS(tsk->mm->context) : |
65 | CTX_HWBITS(tsk->active_mm->context))); |
66 | printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %016lx\n", |
67 | (tsk->mm ? (unsigned long) tsk->mm->pgd : |
68 | (unsigned long) tsk->active_mm->pgd)); |
69 | die_if_kernel("Oops", regs); |
70 | } |
71 | |
72 | static void __kprobes bad_kernel_pc(struct pt_regs *regs, unsigned long vaddr) |
73 | { |
74 | printk(KERN_CRIT "OOPS: Bogus kernel PC [%016lx] in fault handler\n", |
75 | regs->tpc); |
76 | printk(KERN_CRIT "OOPS: RPC [%016lx]\n", regs->u_regs[15]); |
77 | printk("OOPS: RPC <%pS>\n", (void *) regs->u_regs[15]); |
78 | printk(KERN_CRIT "OOPS: Fault was to vaddr[%lx]\n", vaddr); |
79 | dump_stack(); |
80 | unhandled_fault(regs->tpc, current, regs); |
81 | } |
82 | |
83 | /* |
84 | * We now make sure that mmap_sem is held in all paths that call |
85 | * this. Additionally, to prevent kswapd from ripping ptes from |
86 | * under us, raise interrupts around the time that we look at the |
87 | * pte, kswapd will have to wait to get his smp ipi response from |
88 | * us. vmtruncate likewise. This saves us having to get pte lock. |
89 | */ |
90 | static unsigned int get_user_insn(unsigned long tpc) |
91 | { |
92 | pgd_t *pgdp = pgd_offset(current->mm, tpc); |
93 | pud_t *pudp; |
94 | pmd_t *pmdp; |
95 | pte_t *ptep, pte; |
96 | unsigned long pa; |
97 | u32 insn = 0; |
98 | unsigned long pstate; |
99 | |
100 | if (pgd_none(*pgdp)) |
101 | goto outret; |
102 | pudp = pud_offset(pgdp, tpc); |
103 | if (pud_none(*pudp)) |
104 | goto outret; |
105 | pmdp = pmd_offset(pudp, tpc); |
106 | if (pmd_none(*pmdp)) |
107 | goto outret; |
108 | |
109 | /* This disables preemption for us as well. */ |
110 | __asm__ __volatile__("rdpr %%pstate, %0" : "=r" (pstate)); |
111 | __asm__ __volatile__("wrpr %0, %1, %%pstate" |
112 | : : "r" (pstate), "i" (PSTATE_IE)); |
113 | ptep = pte_offset_map(pmdp, tpc); |
114 | pte = *ptep; |
115 | if (!pte_present(pte)) |
116 | goto out; |
117 | |
118 | pa = (pte_pfn(pte) << PAGE_SHIFT); |
119 | pa += (tpc & ~PAGE_MASK); |
120 | |
121 | /* Use phys bypass so we don't pollute dtlb/dcache. */ |
122 | __asm__ __volatile__("lduwa [%1] %2, %0" |
123 | : "=r" (insn) |
124 | : "r" (pa), "i" (ASI_PHYS_USE_EC)); |
125 | |
126 | out: |
127 | pte_unmap(ptep); |
128 | __asm__ __volatile__("wrpr %0, 0x0, %%pstate" : : "r" (pstate)); |
129 | outret: |
130 | return insn; |
131 | } |
132 | |
133 | static inline void |
134 | show_signal_msg(struct pt_regs *regs, int sig, int code, |
135 | unsigned long address, struct task_struct *tsk) |
136 | { |
137 | if (!unhandled_signal(tsk, sig)) |
138 | return; |
139 | |
140 | if (!printk_ratelimit()) |
141 | return; |
142 | |
143 | printk("%s%s[%d]: segfault at %lx ip %p (rpc %p) sp %p error %x", |
144 | task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG, |
145 | tsk->comm, task_pid_nr(tsk), address, |
146 | (void *)regs->tpc, (void *)regs->u_regs[UREG_I7], |
147 | (void *)regs->u_regs[UREG_FP], code); |
148 | |
149 | print_vma_addr(KERN_CONT " in ", regs->tpc); |
150 | |
151 | printk(KERN_CONT "\n"); |
152 | } |
153 | |
154 | extern unsigned long compute_effective_address(struct pt_regs *, unsigned int, unsigned int); |
155 | |
156 | static void do_fault_siginfo(int code, int sig, struct pt_regs *regs, |
157 | unsigned int insn, int fault_code) |
158 | { |
159 | unsigned long addr; |
160 | siginfo_t info; |
161 | |
162 | info.si_code = code; |
163 | info.si_signo = sig; |
164 | info.si_errno = 0; |
165 | if (fault_code & FAULT_CODE_ITLB) |
166 | addr = regs->tpc; |
167 | else |
168 | addr = compute_effective_address(regs, insn, 0); |
169 | info.si_addr = (void __user *) addr; |
170 | info.si_trapno = 0; |
171 | |
172 | if (unlikely(show_unhandled_signals)) |
173 | show_signal_msg(regs, sig, code, addr, current); |
174 | |
175 | force_sig_info(sig, &info, current); |
176 | } |
177 | |
178 | extern int handle_ldf_stq(u32, struct pt_regs *); |
179 | extern int handle_ld_nf(u32, struct pt_regs *); |
180 | |
181 | static unsigned int get_fault_insn(struct pt_regs *regs, unsigned int insn) |
182 | { |
183 | if (!insn) { |
184 | if (!regs->tpc || (regs->tpc & 0x3)) |
185 | return 0; |
186 | if (regs->tstate & TSTATE_PRIV) { |
187 | insn = *(unsigned int *) regs->tpc; |
188 | } else { |
189 | insn = get_user_insn(regs->tpc); |
190 | } |
191 | } |
192 | return insn; |
193 | } |
194 | |
195 | static void __kprobes do_kernel_fault(struct pt_regs *regs, int si_code, |
196 | int fault_code, unsigned int insn, |
197 | unsigned long address) |
198 | { |
199 | unsigned char asi = ASI_P; |
200 | |
201 | if ((!insn) && (regs->tstate & TSTATE_PRIV)) |
202 | goto cannot_handle; |
203 | |
204 | /* If user insn could be read (thus insn is zero), that |
205 | * is fine. We will just gun down the process with a signal |
206 | * in that case. |
207 | */ |
208 | |
209 | if (!(fault_code & (FAULT_CODE_WRITE|FAULT_CODE_ITLB)) && |
210 | (insn & 0xc0800000) == 0xc0800000) { |
211 | if (insn & 0x2000) |
212 | asi = (regs->tstate >> 24); |
213 | else |
214 | asi = (insn >> 5); |
215 | if ((asi & 0xf2) == 0x82) { |
216 | if (insn & 0x1000000) { |
217 | handle_ldf_stq(insn, regs); |
218 | } else { |
219 | /* This was a non-faulting load. Just clear the |
220 | * destination register(s) and continue with the next |
221 | * instruction. -jj |
222 | */ |
223 | handle_ld_nf(insn, regs); |
224 | } |
225 | return; |
226 | } |
227 | } |
228 | |
229 | /* Is this in ex_table? */ |
230 | if (regs->tstate & TSTATE_PRIV) { |
231 | const struct exception_table_entry *entry; |
232 | |
233 | entry = search_exception_tables(regs->tpc); |
234 | if (entry) { |
235 | regs->tpc = entry->fixup; |
236 | regs->tnpc = regs->tpc + 4; |
237 | return; |
238 | } |
239 | } else { |
240 | /* The si_code was set to make clear whether |
241 | * this was a SEGV_MAPERR or SEGV_ACCERR fault. |
242 | */ |
243 | do_fault_siginfo(si_code, SIGSEGV, regs, insn, fault_code); |
244 | return; |
245 | } |
246 | |
247 | cannot_handle: |
248 | unhandled_fault (address, current, regs); |
249 | } |
250 | |
251 | static void noinline __kprobes bogus_32bit_fault_tpc(struct pt_regs *regs) |
252 | { |
253 | static int times; |
254 | |
255 | if (times++ < 10) |
256 | printk(KERN_ERR "FAULT[%s:%d]: 32-bit process reports " |
257 | "64-bit TPC [%lx]\n", |
258 | current->comm, current->pid, |
259 | regs->tpc); |
260 | show_regs(regs); |
261 | } |
262 | |
263 | static void noinline __kprobes bogus_32bit_fault_address(struct pt_regs *regs, |
264 | unsigned long addr) |
265 | { |
266 | static int times; |
267 | |
268 | if (times++ < 10) |
269 | printk(KERN_ERR "FAULT[%s:%d]: 32-bit process " |
270 | "reports 64-bit fault address [%lx]\n", |
271 | current->comm, current->pid, addr); |
272 | show_regs(regs); |
273 | } |
274 | |
275 | asmlinkage void __kprobes do_sparc64_fault(struct pt_regs *regs) |
276 | { |
277 | struct mm_struct *mm = current->mm; |
278 | struct vm_area_struct *vma; |
279 | unsigned int insn = 0; |
280 | int si_code, fault_code, fault; |
281 | unsigned long address, mm_rss; |
282 | |
283 | fault_code = get_thread_fault_code(); |
284 | |
285 | if (notify_page_fault(regs)) |
286 | return; |
287 | |
288 | si_code = SEGV_MAPERR; |
289 | address = current_thread_info()->fault_address; |
290 | |
291 | if ((fault_code & FAULT_CODE_ITLB) && |
292 | (fault_code & FAULT_CODE_DTLB)) |
293 | BUG(); |
294 | |
295 | if (test_thread_flag(TIF_32BIT)) { |
296 | if (!(regs->tstate & TSTATE_PRIV)) { |
297 | if (unlikely((regs->tpc >> 32) != 0)) { |
298 | bogus_32bit_fault_tpc(regs); |
299 | goto intr_or_no_mm; |
300 | } |
301 | } |
302 | if (unlikely((address >> 32) != 0)) { |
303 | bogus_32bit_fault_address(regs, address); |
304 | goto intr_or_no_mm; |
305 | } |
306 | } |
307 | |
308 | if (regs->tstate & TSTATE_PRIV) { |
309 | unsigned long tpc = regs->tpc; |
310 | |
311 | /* Sanity check the PC. */ |
312 | if ((tpc >= KERNBASE && tpc < (unsigned long) __init_end) || |
313 | (tpc >= MODULES_VADDR && tpc < MODULES_END)) { |
314 | /* Valid, no problems... */ |
315 | } else { |
316 | bad_kernel_pc(regs, address); |
317 | return; |
318 | } |
319 | } |
320 | |
321 | /* |
322 | * If we're in an interrupt or have no user |
323 | * context, we must not take the fault.. |
324 | */ |
325 | if (in_atomic() || !mm) |
326 | goto intr_or_no_mm; |
327 | |
328 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); |
329 | |
330 | if (!down_read_trylock(&mm->mmap_sem)) { |
331 | if ((regs->tstate & TSTATE_PRIV) && |
332 | !search_exception_tables(regs->tpc)) { |
333 | insn = get_fault_insn(regs, insn); |
334 | goto handle_kernel_fault; |
335 | } |
336 | down_read(&mm->mmap_sem); |
337 | } |
338 | |
339 | vma = find_vma(mm, address); |
340 | if (!vma) |
341 | goto bad_area; |
342 | |
343 | /* Pure DTLB misses do not tell us whether the fault causing |
344 | * load/store/atomic was a write or not, it only says that there |
345 | * was no match. So in such a case we (carefully) read the |
346 | * instruction to try and figure this out. It's an optimization |
347 | * so it's ok if we can't do this. |
348 | * |
349 | * Special hack, window spill/fill knows the exact fault type. |
350 | */ |
351 | if (((fault_code & |
352 | (FAULT_CODE_DTLB | FAULT_CODE_WRITE | FAULT_CODE_WINFIXUP)) == FAULT_CODE_DTLB) && |
353 | (vma->vm_flags & VM_WRITE) != 0) { |
354 | insn = get_fault_insn(regs, 0); |
355 | if (!insn) |
356 | goto continue_fault; |
357 | /* All loads, stores and atomics have bits 30 and 31 both set |
358 | * in the instruction. Bit 21 is set in all stores, but we |
359 | * have to avoid prefetches which also have bit 21 set. |
360 | */ |
361 | if ((insn & 0xc0200000) == 0xc0200000 && |
362 | (insn & 0x01780000) != 0x01680000) { |
363 | /* Don't bother updating thread struct value, |
364 | * because update_mmu_cache only cares which tlb |
365 | * the access came from. |
366 | */ |
367 | fault_code |= FAULT_CODE_WRITE; |
368 | } |
369 | } |
370 | continue_fault: |
371 | |
372 | if (vma->vm_start <= address) |
373 | goto good_area; |
374 | if (!(vma->vm_flags & VM_GROWSDOWN)) |
375 | goto bad_area; |
376 | if (!(fault_code & FAULT_CODE_WRITE)) { |
377 | /* Non-faulting loads shouldn't expand stack. */ |
378 | insn = get_fault_insn(regs, insn); |
379 | if ((insn & 0xc0800000) == 0xc0800000) { |
380 | unsigned char asi; |
381 | |
382 | if (insn & 0x2000) |
383 | asi = (regs->tstate >> 24); |
384 | else |
385 | asi = (insn >> 5); |
386 | if ((asi & 0xf2) == 0x82) |
387 | goto bad_area; |
388 | } |
389 | } |
390 | if (expand_stack(vma, address)) |
391 | goto bad_area; |
392 | /* |
393 | * Ok, we have a good vm_area for this memory access, so |
394 | * we can handle it.. |
395 | */ |
396 | good_area: |
397 | si_code = SEGV_ACCERR; |
398 | |
399 | /* If we took a ITLB miss on a non-executable page, catch |
400 | * that here. |
401 | */ |
402 | if ((fault_code & FAULT_CODE_ITLB) && !(vma->vm_flags & VM_EXEC)) { |
403 | BUG_ON(address != regs->tpc); |
404 | BUG_ON(regs->tstate & TSTATE_PRIV); |
405 | goto bad_area; |
406 | } |
407 | |
408 | if (fault_code & FAULT_CODE_WRITE) { |
409 | if (!(vma->vm_flags & VM_WRITE)) |
410 | goto bad_area; |
411 | |
412 | /* Spitfire has an icache which does not snoop |
413 | * processor stores. Later processors do... |
414 | */ |
415 | if (tlb_type == spitfire && |
416 | (vma->vm_flags & VM_EXEC) != 0 && |
417 | vma->vm_file != NULL) |
418 | set_thread_fault_code(fault_code | |
419 | FAULT_CODE_BLKCOMMIT); |
420 | } else { |
421 | /* Allow reads even for write-only mappings */ |
422 | if (!(vma->vm_flags & (VM_READ | VM_EXEC))) |
423 | goto bad_area; |
424 | } |
425 | |
426 | fault = handle_mm_fault(mm, vma, address, (fault_code & FAULT_CODE_WRITE) ? FAULT_FLAG_WRITE : 0); |
427 | if (unlikely(fault & VM_FAULT_ERROR)) { |
428 | if (fault & VM_FAULT_OOM) |
429 | goto out_of_memory; |
430 | else if (fault & VM_FAULT_SIGBUS) |
431 | goto do_sigbus; |
432 | BUG(); |
433 | } |
434 | if (fault & VM_FAULT_MAJOR) { |
435 | current->maj_flt++; |
436 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs, address); |
437 | } else { |
438 | current->min_flt++; |
439 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs, address); |
440 | } |
441 | up_read(&mm->mmap_sem); |
442 | |
443 | mm_rss = get_mm_rss(mm); |
444 | #ifdef CONFIG_HUGETLB_PAGE |
445 | mm_rss -= (mm->context.huge_pte_count * (HPAGE_SIZE / PAGE_SIZE)); |
446 | #endif |
447 | if (unlikely(mm_rss > |
448 | mm->context.tsb_block[MM_TSB_BASE].tsb_rss_limit)) |
449 | tsb_grow(mm, MM_TSB_BASE, mm_rss); |
450 | #ifdef CONFIG_HUGETLB_PAGE |
451 | mm_rss = mm->context.huge_pte_count; |
452 | if (unlikely(mm_rss > |
453 | mm->context.tsb_block[MM_TSB_HUGE].tsb_rss_limit)) |
454 | tsb_grow(mm, MM_TSB_HUGE, mm_rss); |
455 | #endif |
456 | return; |
457 | |
458 | /* |
459 | * Something tried to access memory that isn't in our memory map.. |
460 | * Fix it, but check if it's kernel or user first.. |
461 | */ |
462 | bad_area: |
463 | insn = get_fault_insn(regs, insn); |
464 | up_read(&mm->mmap_sem); |
465 | |
466 | handle_kernel_fault: |
467 | do_kernel_fault(regs, si_code, fault_code, insn, address); |
468 | return; |
469 | |
470 | /* |
471 | * We ran out of memory, or some other thing happened to us that made |
472 | * us unable to handle the page fault gracefully. |
473 | */ |
474 | out_of_memory: |
475 | insn = get_fault_insn(regs, insn); |
476 | up_read(&mm->mmap_sem); |
477 | if (!(regs->tstate & TSTATE_PRIV)) { |
478 | pagefault_out_of_memory(); |
479 | return; |
480 | } |
481 | goto handle_kernel_fault; |
482 | |
483 | intr_or_no_mm: |
484 | insn = get_fault_insn(regs, 0); |
485 | goto handle_kernel_fault; |
486 | |
487 | do_sigbus: |
488 | insn = get_fault_insn(regs, insn); |
489 | up_read(&mm->mmap_sem); |
490 | |
491 | /* |
492 | * Send a sigbus, regardless of whether we were in kernel |
493 | * or user mode. |
494 | */ |
495 | do_fault_siginfo(BUS_ADRERR, SIGBUS, regs, insn, fault_code); |
496 | |
497 | /* Kernel mode? Handle exceptions or die */ |
498 | if (regs->tstate & TSTATE_PRIV) |
499 | goto handle_kernel_fault; |
500 | } |
501 |
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