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