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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
35int show_unhandled_signals = 1;
36
37static 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
51static 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
72static 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 */
90static 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
126out:
127 pte_unmap(ptep);
128 __asm__ __volatile__("wrpr %0, 0x0, %%pstate" : : "r" (pstate));
129outret:
130 return insn;
131}
132
133static inline void
134show_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
154extern unsigned long compute_effective_address(struct pt_regs *, unsigned int, unsigned int);
155
156static 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
178extern int handle_ldf_stq(u32, struct pt_regs *);
179extern int handle_ld_nf(u32, struct pt_regs *);
180
181static 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
195static 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
247cannot_handle:
248 unhandled_fault (address, current, regs);
249}
250
251static 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
263static 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
275asmlinkage 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 }
370continue_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 */
396good_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 */
462bad_area:
463 insn = get_fault_insn(regs, insn);
464 up_read(&mm->mmap_sem);
465
466handle_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 */
474out_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
483intr_or_no_mm:
484 insn = get_fault_insn(regs, 0);
485 goto handle_kernel_fault;
486
487do_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}
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/extable.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#include <linux/context_tracking.h>
25#include <linux/uaccess.h>
26
27#include <asm/page.h>
28#include <asm/pgtable.h>
29#include <asm/openprom.h>
30#include <asm/oplib.h>
31#include <asm/asi.h>
32#include <asm/lsu.h>
33#include <asm/sections.h>
34#include <asm/mmu_context.h>
35#include <asm/setup.h>
36
37int show_unhandled_signals = 1;
38
39static inline __kprobes int notify_page_fault(struct pt_regs *regs)
40{
41 int ret = 0;
42
43 /* kprobe_running() needs smp_processor_id() */
44 if (kprobes_built_in() && !user_mode(regs)) {
45 preempt_disable();
46 if (kprobe_running() && kprobe_fault_handler(regs, 0))
47 ret = 1;
48 preempt_enable();
49 }
50 return ret;
51}
52
53static void __kprobes unhandled_fault(unsigned long address,
54 struct task_struct *tsk,
55 struct pt_regs *regs)
56{
57 if ((unsigned long) address < PAGE_SIZE) {
58 printk(KERN_ALERT "Unable to handle kernel NULL "
59 "pointer dereference\n");
60 } else {
61 printk(KERN_ALERT "Unable to handle kernel paging request "
62 "at virtual address %016lx\n", (unsigned long)address);
63 }
64 printk(KERN_ALERT "tsk->{mm,active_mm}->context = %016lx\n",
65 (tsk->mm ?
66 CTX_HWBITS(tsk->mm->context) :
67 CTX_HWBITS(tsk->active_mm->context)));
68 printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %016lx\n",
69 (tsk->mm ? (unsigned long) tsk->mm->pgd :
70 (unsigned long) tsk->active_mm->pgd));
71 die_if_kernel("Oops", regs);
72}
73
74static void __kprobes bad_kernel_pc(struct pt_regs *regs, unsigned long vaddr)
75{
76 printk(KERN_CRIT "OOPS: Bogus kernel PC [%016lx] in fault handler\n",
77 regs->tpc);
78 printk(KERN_CRIT "OOPS: RPC [%016lx]\n", regs->u_regs[15]);
79 printk("OOPS: RPC <%pS>\n", (void *) regs->u_regs[15]);
80 printk(KERN_CRIT "OOPS: Fault was to vaddr[%lx]\n", vaddr);
81 dump_stack();
82 unhandled_fault(regs->tpc, current, regs);
83}
84
85/*
86 * We now make sure that mmap_sem is held in all paths that call
87 * this. Additionally, to prevent kswapd from ripping ptes from
88 * under us, raise interrupts around the time that we look at the
89 * pte, kswapd will have to wait to get his smp ipi response from
90 * us. vmtruncate likewise. This saves us having to get pte lock.
91 */
92static unsigned int get_user_insn(unsigned long tpc)
93{
94 pgd_t *pgdp = pgd_offset(current->mm, tpc);
95 pud_t *pudp;
96 pmd_t *pmdp;
97 pte_t *ptep, pte;
98 unsigned long pa;
99 u32 insn = 0;
100
101 if (pgd_none(*pgdp) || unlikely(pgd_bad(*pgdp)))
102 goto out;
103 pudp = pud_offset(pgdp, tpc);
104 if (pud_none(*pudp) || unlikely(pud_bad(*pudp)))
105 goto out;
106
107 /* This disables preemption for us as well. */
108 local_irq_disable();
109
110 pmdp = pmd_offset(pudp, tpc);
111 if (pmd_none(*pmdp) || unlikely(pmd_bad(*pmdp)))
112 goto out_irq_enable;
113
114#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
115 if (is_hugetlb_pmd(*pmdp)) {
116 pa = pmd_pfn(*pmdp) << PAGE_SHIFT;
117 pa += tpc & ~HPAGE_MASK;
118
119 /* Use phys bypass so we don't pollute dtlb/dcache. */
120 __asm__ __volatile__("lduwa [%1] %2, %0"
121 : "=r" (insn)
122 : "r" (pa), "i" (ASI_PHYS_USE_EC));
123 } else
124#endif
125 {
126 ptep = pte_offset_map(pmdp, tpc);
127 pte = *ptep;
128 if (pte_present(pte)) {
129 pa = (pte_pfn(pte) << PAGE_SHIFT);
130 pa += (tpc & ~PAGE_MASK);
131
132 /* Use phys bypass so we don't pollute dtlb/dcache. */
133 __asm__ __volatile__("lduwa [%1] %2, %0"
134 : "=r" (insn)
135 : "r" (pa), "i" (ASI_PHYS_USE_EC));
136 }
137 pte_unmap(ptep);
138 }
139out_irq_enable:
140 local_irq_enable();
141out:
142 return insn;
143}
144
145static inline void
146show_signal_msg(struct pt_regs *regs, int sig, int code,
147 unsigned long address, struct task_struct *tsk)
148{
149 if (!unhandled_signal(tsk, sig))
150 return;
151
152 if (!printk_ratelimit())
153 return;
154
155 printk("%s%s[%d]: segfault at %lx ip %p (rpc %p) sp %p error %x",
156 task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
157 tsk->comm, task_pid_nr(tsk), address,
158 (void *)regs->tpc, (void *)regs->u_regs[UREG_I7],
159 (void *)regs->u_regs[UREG_FP], code);
160
161 print_vma_addr(KERN_CONT " in ", regs->tpc);
162
163 printk(KERN_CONT "\n");
164}
165
166static void do_fault_siginfo(int code, int sig, struct pt_regs *regs,
167 unsigned long fault_addr, unsigned int insn,
168 int fault_code)
169{
170 unsigned long addr;
171 siginfo_t info;
172
173 info.si_code = code;
174 info.si_signo = sig;
175 info.si_errno = 0;
176 if (fault_code & FAULT_CODE_ITLB) {
177 addr = regs->tpc;
178 } else {
179 /* If we were able to probe the faulting instruction, use it
180 * to compute a precise fault address. Otherwise use the fault
181 * time provided address which may only have page granularity.
182 */
183 if (insn)
184 addr = compute_effective_address(regs, insn, 0);
185 else
186 addr = fault_addr;
187 }
188 info.si_addr = (void __user *) addr;
189 info.si_trapno = 0;
190
191 if (unlikely(show_unhandled_signals))
192 show_signal_msg(regs, sig, code, addr, current);
193
194 force_sig_info(sig, &info, current);
195}
196
197static unsigned int get_fault_insn(struct pt_regs *regs, unsigned int insn)
198{
199 if (!insn) {
200 if (!regs->tpc || (regs->tpc & 0x3))
201 return 0;
202 if (regs->tstate & TSTATE_PRIV) {
203 insn = *(unsigned int *) regs->tpc;
204 } else {
205 insn = get_user_insn(regs->tpc);
206 }
207 }
208 return insn;
209}
210
211static void __kprobes do_kernel_fault(struct pt_regs *regs, int si_code,
212 int fault_code, unsigned int insn,
213 unsigned long address)
214{
215 unsigned char asi = ASI_P;
216
217 if ((!insn) && (regs->tstate & TSTATE_PRIV))
218 goto cannot_handle;
219
220 /* If user insn could be read (thus insn is zero), that
221 * is fine. We will just gun down the process with a signal
222 * in that case.
223 */
224
225 if (!(fault_code & (FAULT_CODE_WRITE|FAULT_CODE_ITLB)) &&
226 (insn & 0xc0800000) == 0xc0800000) {
227 if (insn & 0x2000)
228 asi = (regs->tstate >> 24);
229 else
230 asi = (insn >> 5);
231 if ((asi & 0xf2) == 0x82) {
232 if (insn & 0x1000000) {
233 handle_ldf_stq(insn, regs);
234 } else {
235 /* This was a non-faulting load. Just clear the
236 * destination register(s) and continue with the next
237 * instruction. -jj
238 */
239 handle_ld_nf(insn, regs);
240 }
241 return;
242 }
243 }
244
245 /* Is this in ex_table? */
246 if (regs->tstate & TSTATE_PRIV) {
247 const struct exception_table_entry *entry;
248
249 entry = search_exception_tables(regs->tpc);
250 if (entry) {
251 regs->tpc = entry->fixup;
252 regs->tnpc = regs->tpc + 4;
253 return;
254 }
255 } else {
256 /* The si_code was set to make clear whether
257 * this was a SEGV_MAPERR or SEGV_ACCERR fault.
258 */
259 do_fault_siginfo(si_code, SIGSEGV, regs, address, insn, fault_code);
260 return;
261 }
262
263cannot_handle:
264 unhandled_fault (address, current, regs);
265}
266
267static void noinline __kprobes bogus_32bit_fault_tpc(struct pt_regs *regs)
268{
269 static int times;
270
271 if (times++ < 10)
272 printk(KERN_ERR "FAULT[%s:%d]: 32-bit process reports "
273 "64-bit TPC [%lx]\n",
274 current->comm, current->pid,
275 regs->tpc);
276 show_regs(regs);
277}
278
279asmlinkage void __kprobes do_sparc64_fault(struct pt_regs *regs)
280{
281 enum ctx_state prev_state = exception_enter();
282 struct mm_struct *mm = current->mm;
283 struct vm_area_struct *vma;
284 unsigned int insn = 0;
285 int si_code, fault_code, fault;
286 unsigned long address, mm_rss;
287 unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
288
289 fault_code = get_thread_fault_code();
290
291 if (notify_page_fault(regs))
292 goto exit_exception;
293
294 si_code = SEGV_MAPERR;
295 address = current_thread_info()->fault_address;
296
297 if ((fault_code & FAULT_CODE_ITLB) &&
298 (fault_code & FAULT_CODE_DTLB))
299 BUG();
300
301 if (test_thread_flag(TIF_32BIT)) {
302 if (!(regs->tstate & TSTATE_PRIV)) {
303 if (unlikely((regs->tpc >> 32) != 0)) {
304 bogus_32bit_fault_tpc(regs);
305 goto intr_or_no_mm;
306 }
307 }
308 if (unlikely((address >> 32) != 0))
309 goto intr_or_no_mm;
310 }
311
312 if (regs->tstate & TSTATE_PRIV) {
313 unsigned long tpc = regs->tpc;
314
315 /* Sanity check the PC. */
316 if ((tpc >= KERNBASE && tpc < (unsigned long) __init_end) ||
317 (tpc >= MODULES_VADDR && tpc < MODULES_END)) {
318 /* Valid, no problems... */
319 } else {
320 bad_kernel_pc(regs, address);
321 goto exit_exception;
322 }
323 } else
324 flags |= FAULT_FLAG_USER;
325
326 /*
327 * If we're in an interrupt or have no user
328 * context, we must not take the fault..
329 */
330 if (faulthandler_disabled() || !mm)
331 goto intr_or_no_mm;
332
333 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
334
335 if (!down_read_trylock(&mm->mmap_sem)) {
336 if ((regs->tstate & TSTATE_PRIV) &&
337 !search_exception_tables(regs->tpc)) {
338 insn = get_fault_insn(regs, insn);
339 goto handle_kernel_fault;
340 }
341
342retry:
343 down_read(&mm->mmap_sem);
344 }
345
346 if (fault_code & FAULT_CODE_BAD_RA)
347 goto do_sigbus;
348
349 vma = find_vma(mm, address);
350 if (!vma)
351 goto bad_area;
352
353 /* Pure DTLB misses do not tell us whether the fault causing
354 * load/store/atomic was a write or not, it only says that there
355 * was no match. So in such a case we (carefully) read the
356 * instruction to try and figure this out. It's an optimization
357 * so it's ok if we can't do this.
358 *
359 * Special hack, window spill/fill knows the exact fault type.
360 */
361 if (((fault_code &
362 (FAULT_CODE_DTLB | FAULT_CODE_WRITE | FAULT_CODE_WINFIXUP)) == FAULT_CODE_DTLB) &&
363 (vma->vm_flags & VM_WRITE) != 0) {
364 insn = get_fault_insn(regs, 0);
365 if (!insn)
366 goto continue_fault;
367 /* All loads, stores and atomics have bits 30 and 31 both set
368 * in the instruction. Bit 21 is set in all stores, but we
369 * have to avoid prefetches which also have bit 21 set.
370 */
371 if ((insn & 0xc0200000) == 0xc0200000 &&
372 (insn & 0x01780000) != 0x01680000) {
373 /* Don't bother updating thread struct value,
374 * because update_mmu_cache only cares which tlb
375 * the access came from.
376 */
377 fault_code |= FAULT_CODE_WRITE;
378 }
379 }
380continue_fault:
381
382 if (vma->vm_start <= address)
383 goto good_area;
384 if (!(vma->vm_flags & VM_GROWSDOWN))
385 goto bad_area;
386 if (!(fault_code & FAULT_CODE_WRITE)) {
387 /* Non-faulting loads shouldn't expand stack. */
388 insn = get_fault_insn(regs, insn);
389 if ((insn & 0xc0800000) == 0xc0800000) {
390 unsigned char asi;
391
392 if (insn & 0x2000)
393 asi = (regs->tstate >> 24);
394 else
395 asi = (insn >> 5);
396 if ((asi & 0xf2) == 0x82)
397 goto bad_area;
398 }
399 }
400 if (expand_stack(vma, address))
401 goto bad_area;
402 /*
403 * Ok, we have a good vm_area for this memory access, so
404 * we can handle it..
405 */
406good_area:
407 si_code = SEGV_ACCERR;
408
409 /* If we took a ITLB miss on a non-executable page, catch
410 * that here.
411 */
412 if ((fault_code & FAULT_CODE_ITLB) && !(vma->vm_flags & VM_EXEC)) {
413 WARN(address != regs->tpc,
414 "address (%lx) != regs->tpc (%lx)\n", address, regs->tpc);
415 WARN_ON(regs->tstate & TSTATE_PRIV);
416 goto bad_area;
417 }
418
419 if (fault_code & FAULT_CODE_WRITE) {
420 if (!(vma->vm_flags & VM_WRITE))
421 goto bad_area;
422
423 /* Spitfire has an icache which does not snoop
424 * processor stores. Later processors do...
425 */
426 if (tlb_type == spitfire &&
427 (vma->vm_flags & VM_EXEC) != 0 &&
428 vma->vm_file != NULL)
429 set_thread_fault_code(fault_code |
430 FAULT_CODE_BLKCOMMIT);
431
432 flags |= FAULT_FLAG_WRITE;
433 } else {
434 /* Allow reads even for write-only mappings */
435 if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
436 goto bad_area;
437 }
438
439 fault = handle_mm_fault(vma, address, flags);
440
441 if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
442 goto exit_exception;
443
444 if (unlikely(fault & VM_FAULT_ERROR)) {
445 if (fault & VM_FAULT_OOM)
446 goto out_of_memory;
447 else if (fault & VM_FAULT_SIGSEGV)
448 goto bad_area;
449 else if (fault & VM_FAULT_SIGBUS)
450 goto do_sigbus;
451 BUG();
452 }
453
454 if (flags & FAULT_FLAG_ALLOW_RETRY) {
455 if (fault & VM_FAULT_MAJOR) {
456 current->maj_flt++;
457 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ,
458 1, regs, address);
459 } else {
460 current->min_flt++;
461 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN,
462 1, regs, address);
463 }
464 if (fault & VM_FAULT_RETRY) {
465 flags &= ~FAULT_FLAG_ALLOW_RETRY;
466 flags |= FAULT_FLAG_TRIED;
467
468 /* No need to up_read(&mm->mmap_sem) as we would
469 * have already released it in __lock_page_or_retry
470 * in mm/filemap.c.
471 */
472
473 goto retry;
474 }
475 }
476 up_read(&mm->mmap_sem);
477
478 mm_rss = get_mm_rss(mm);
479#if defined(CONFIG_TRANSPARENT_HUGEPAGE)
480 mm_rss -= (mm->context.thp_pte_count * (HPAGE_SIZE / PAGE_SIZE));
481#endif
482 if (unlikely(mm_rss >
483 mm->context.tsb_block[MM_TSB_BASE].tsb_rss_limit))
484 tsb_grow(mm, MM_TSB_BASE, mm_rss);
485#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
486 mm_rss = mm->context.hugetlb_pte_count + mm->context.thp_pte_count;
487 mm_rss *= REAL_HPAGE_PER_HPAGE;
488 if (unlikely(mm_rss >
489 mm->context.tsb_block[MM_TSB_HUGE].tsb_rss_limit)) {
490 if (mm->context.tsb_block[MM_TSB_HUGE].tsb)
491 tsb_grow(mm, MM_TSB_HUGE, mm_rss);
492 else
493 hugetlb_setup(regs);
494
495 }
496#endif
497exit_exception:
498 exception_exit(prev_state);
499 return;
500
501 /*
502 * Something tried to access memory that isn't in our memory map..
503 * Fix it, but check if it's kernel or user first..
504 */
505bad_area:
506 insn = get_fault_insn(regs, insn);
507 up_read(&mm->mmap_sem);
508
509handle_kernel_fault:
510 do_kernel_fault(regs, si_code, fault_code, insn, address);
511 goto exit_exception;
512
513/*
514 * We ran out of memory, or some other thing happened to us that made
515 * us unable to handle the page fault gracefully.
516 */
517out_of_memory:
518 insn = get_fault_insn(regs, insn);
519 up_read(&mm->mmap_sem);
520 if (!(regs->tstate & TSTATE_PRIV)) {
521 pagefault_out_of_memory();
522 goto exit_exception;
523 }
524 goto handle_kernel_fault;
525
526intr_or_no_mm:
527 insn = get_fault_insn(regs, 0);
528 goto handle_kernel_fault;
529
530do_sigbus:
531 insn = get_fault_insn(regs, insn);
532 up_read(&mm->mmap_sem);
533
534 /*
535 * Send a sigbus, regardless of whether we were in kernel
536 * or user mode.
537 */
538 do_fault_siginfo(BUS_ADRERR, SIGBUS, regs, address, insn, fault_code);
539
540 /* Kernel mode? Handle exceptions or die */
541 if (regs->tstate & TSTATE_PRIV)
542 goto handle_kernel_fault;
543}