1 /*
2 * arch/sh/mm/tlb-flush_64.c
3 *
4 * Copyright (C) 2000, 2001 Paolo Alberelli
5 * Copyright (C) 2003 Richard Curnow (/proc/tlb, bug fixes)
6 * Copyright (C) 2003 Paul Mundt
7 *
8 * This file is subject to the terms and conditions of the GNU General Public
9 * License. See the file "COPYING" in the main directory of this archive
10 * for more details.
11 */
12 #include <linux/signal.h>
13 #include <linux/rwsem.h>
14 #include <linux/sched.h>
15 #include <linux/kernel.h>
16 #include <linux/errno.h>
17 #include <linux/string.h>
18 #include <linux/types.h>
19 #include <linux/ptrace.h>
20 #include <linux/mman.h>
21 #include <linux/mm.h>
22 #include <linux/smp.h>
23 #include <linux/interrupt.h>
24 #include <asm/system.h>
25 #include <asm/io.h>
26 #include <asm/tlb.h>
27 #include <asm/uaccess.h>
28 #include <asm/pgalloc.h>
29 #include <asm/mmu_context.h>
30
31 extern void die(const char *,struct pt_regs *,long);
32
33 #define PFLAG(val,flag) (( (val) & (flag) ) ? #flag : "" )
34 #define PPROT(flag) PFLAG(pgprot_val(prot),flag)
35
print_prots(pgprot_t prot)36 static inline void print_prots(pgprot_t prot)
37 {
38 printk("prot is 0x%08lx\n",pgprot_val(prot));
39
40 printk("%s %s %s %s %s\n",PPROT(_PAGE_SHARED),PPROT(_PAGE_READ),
41 PPROT(_PAGE_EXECUTE),PPROT(_PAGE_WRITE),PPROT(_PAGE_USER));
42 }
43
print_vma(struct vm_area_struct * vma)44 static inline void print_vma(struct vm_area_struct *vma)
45 {
46 printk("vma start 0x%08lx\n", vma->vm_start);
47 printk("vma end 0x%08lx\n", vma->vm_end);
48
49 print_prots(vma->vm_page_prot);
50 printk("vm_flags 0x%08lx\n", vma->vm_flags);
51 }
52
print_task(struct task_struct * tsk)53 static inline void print_task(struct task_struct *tsk)
54 {
55 printk("Task pid %d\n", task_pid_nr(tsk));
56 }
57
lookup_pte(struct mm_struct * mm,unsigned long address)58 static pte_t *lookup_pte(struct mm_struct *mm, unsigned long address)
59 {
60 pgd_t *dir;
61 pud_t *pud;
62 pmd_t *pmd;
63 pte_t *pte;
64 pte_t entry;
65
66 dir = pgd_offset(mm, address);
67 if (pgd_none(*dir))
68 return NULL;
69
70 pud = pud_offset(dir, address);
71 if (pud_none(*pud))
72 return NULL;
73
74 pmd = pmd_offset(pud, address);
75 if (pmd_none(*pmd))
76 return NULL;
77
78 pte = pte_offset_kernel(pmd, address);
79 entry = *pte;
80 if (pte_none(entry) || !pte_present(entry))
81 return NULL;
82
83 return pte;
84 }
85
86 /*
87 * This routine handles page faults. It determines the address,
88 * and the problem, and then passes it off to one of the appropriate
89 * routines.
90 */
do_page_fault(struct pt_regs * regs,unsigned long writeaccess,unsigned long textaccess,unsigned long address)91 asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long writeaccess,
92 unsigned long textaccess, unsigned long address)
93 {
94 struct task_struct *tsk;
95 struct mm_struct *mm;
96 struct vm_area_struct * vma;
97 const struct exception_table_entry *fixup;
98 pte_t *pte;
99 int fault;
100
101 /* SIM
102 * Note this is now called with interrupts still disabled
103 * This is to cope with being called for a missing IO port
104 * address with interrupts disabled. This should be fixed as
105 * soon as we have a better 'fast path' miss handler.
106 *
107 * Plus take care how you try and debug this stuff.
108 * For example, writing debug data to a port which you
109 * have just faulted on is not going to work.
110 */
111
112 tsk = current;
113 mm = tsk->mm;
114
115 /* Not an IO address, so reenable interrupts */
116 local_irq_enable();
117
118 /*
119 * If we're in an interrupt or have no user
120 * context, we must not take the fault..
121 */
122 if (in_atomic() || !mm)
123 goto no_context;
124
125 /* TLB misses upon some cache flushes get done under cli() */
126 down_read(&mm->mmap_sem);
127
128 vma = find_vma(mm, address);
129
130 if (!vma) {
131 #ifdef DEBUG_FAULT
132 print_task(tsk);
133 printk("%s:%d fault, address is 0x%08x PC %016Lx textaccess %d writeaccess %d\n",
134 __func__, __LINE__,
135 address,regs->pc,textaccess,writeaccess);
136 show_regs(regs);
137 #endif
138 goto bad_area;
139 }
140 if (vma->vm_start <= address) {
141 goto good_area;
142 }
143
144 if (!(vma->vm_flags & VM_GROWSDOWN)) {
145 #ifdef DEBUG_FAULT
146 print_task(tsk);
147 printk("%s:%d fault, address is 0x%08x PC %016Lx textaccess %d writeaccess %d\n",
148 __func__, __LINE__,
149 address,regs->pc,textaccess,writeaccess);
150 show_regs(regs);
151
152 print_vma(vma);
153 #endif
154 goto bad_area;
155 }
156 if (expand_stack(vma, address)) {
157 #ifdef DEBUG_FAULT
158 print_task(tsk);
159 printk("%s:%d fault, address is 0x%08x PC %016Lx textaccess %d writeaccess %d\n",
160 __func__, __LINE__,
161 address,regs->pc,textaccess,writeaccess);
162 show_regs(regs);
163 #endif
164 goto bad_area;
165 }
166 /*
167 * Ok, we have a good vm_area for this memory access, so
168 * we can handle it..
169 */
170 good_area:
171 if (textaccess) {
172 if (!(vma->vm_flags & VM_EXEC))
173 goto bad_area;
174 } else {
175 if (writeaccess) {
176 if (!(vma->vm_flags & VM_WRITE))
177 goto bad_area;
178 } else {
179 if (!(vma->vm_flags & VM_READ))
180 goto bad_area;
181 }
182 }
183
184 /*
185 * If for any reason at all we couldn't handle the fault,
186 * make sure we exit gracefully rather than endlessly redo
187 * the fault.
188 */
189 survive:
190 fault = handle_mm_fault(mm, vma, address, writeaccess);
191 if (unlikely(fault & VM_FAULT_ERROR)) {
192 if (fault & VM_FAULT_OOM)
193 goto out_of_memory;
194 else if (fault & VM_FAULT_SIGBUS)
195 goto do_sigbus;
196 BUG();
197 }
198 if (fault & VM_FAULT_MAJOR)
199 tsk->maj_flt++;
200 else
201 tsk->min_flt++;
202
203 /* If we get here, the page fault has been handled. Do the TLB refill
204 now from the newly-setup PTE, to avoid having to fault again right
205 away on the same instruction. */
206 pte = lookup_pte (mm, address);
207 if (!pte) {
208 /* From empirical evidence, we can get here, due to
209 !pte_present(pte). (e.g. if a swap-in occurs, and the page
210 is swapped back out again before the process that wanted it
211 gets rescheduled?) */
212 goto no_pte;
213 }
214
215 __do_tlb_refill(address, textaccess, pte);
216
217 no_pte:
218
219 up_read(&mm->mmap_sem);
220 return;
221
222 /*
223 * Something tried to access memory that isn't in our memory map..
224 * Fix it, but check if it's kernel or user first..
225 */
226 bad_area:
227 #ifdef DEBUG_FAULT
228 printk("fault:bad area\n");
229 #endif
230 up_read(&mm->mmap_sem);
231
232 if (user_mode(regs)) {
233 static int count=0;
234 siginfo_t info;
235 if (count < 4) {
236 /* This is really to help debug faults when starting
237 * usermode, so only need a few */
238 count++;
239 printk("user mode bad_area address=%08lx pid=%d (%s) pc=%08lx\n",
240 address, task_pid_nr(current), current->comm,
241 (unsigned long) regs->pc);
242 #if 0
243 show_regs(regs);
244 #endif
245 }
246 if (is_global_init(tsk)) {
247 panic("INIT had user mode bad_area\n");
248 }
249 tsk->thread.address = address;
250 tsk->thread.error_code = writeaccess;
251 info.si_signo = SIGSEGV;
252 info.si_errno = 0;
253 info.si_addr = (void *) address;
254 force_sig_info(SIGSEGV, &info, tsk);
255 return;
256 }
257
258 no_context:
259 #ifdef DEBUG_FAULT
260 printk("fault:No context\n");
261 #endif
262 /* Are we prepared to handle this kernel fault? */
263 fixup = search_exception_tables(regs->pc);
264 if (fixup) {
265 regs->pc = fixup->fixup;
266 return;
267 }
268
269 /*
270 * Oops. The kernel tried to access some bad page. We'll have to
271 * terminate things with extreme prejudice.
272 *
273 */
274 if (address < PAGE_SIZE)
275 printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference");
276 else
277 printk(KERN_ALERT "Unable to handle kernel paging request");
278 printk(" at virtual address %08lx\n", address);
279 printk(KERN_ALERT "pc = %08Lx%08Lx\n", regs->pc >> 32, regs->pc & 0xffffffff);
280 die("Oops", regs, writeaccess);
281 do_exit(SIGKILL);
282
283 /*
284 * We ran out of memory, or some other thing happened to us that made
285 * us unable to handle the page fault gracefully.
286 */
287 out_of_memory:
288 if (is_global_init(current)) {
289 panic("INIT out of memory\n");
290 yield();
291 goto survive;
292 }
293 printk("fault:Out of memory\n");
294 up_read(&mm->mmap_sem);
295 if (is_global_init(current)) {
296 yield();
297 down_read(&mm->mmap_sem);
298 goto survive;
299 }
300 printk("VM: killing process %s\n", tsk->comm);
301 if (user_mode(regs))
302 do_group_exit(SIGKILL);
303 goto no_context;
304
305 do_sigbus:
306 printk("fault:Do sigbus\n");
307 up_read(&mm->mmap_sem);
308
309 /*
310 * Send a sigbus, regardless of whether we were in kernel
311 * or user mode.
312 */
313 tsk->thread.address = address;
314 tsk->thread.error_code = writeaccess;
315 tsk->thread.trap_no = 14;
316 force_sig(SIGBUS, tsk);
317
318 /* Kernel mode? Handle exceptions or die */
319 if (!user_mode(regs))
320 goto no_context;
321 }
322
update_mmu_cache(struct vm_area_struct * vma,unsigned long address,pte_t pte)323 void update_mmu_cache(struct vm_area_struct * vma,
324 unsigned long address, pte_t pte)
325 {
326 /*
327 * This appears to get called once for every pte entry that gets
328 * established => I don't think it's efficient to try refilling the
329 * TLBs with the pages - some may not get accessed even. Also, for
330 * executable pages, it is impossible to determine reliably here which
331 * TLB they should be mapped into (or both even).
332 *
333 * So, just do nothing here and handle faults on demand. In the
334 * TLBMISS handling case, the refill is now done anyway after the pte
335 * has been fixed up, so that deals with most useful cases.
336 */
337 }
338
local_flush_tlb_one(unsigned long asid,unsigned long page)339 void local_flush_tlb_one(unsigned long asid, unsigned long page)
340 {
341 unsigned long long match, pteh=0, lpage;
342 unsigned long tlb;
343
344 /*
345 * Sign-extend based on neff.
346 */
347 lpage = (page & NEFF_SIGN) ? (page | NEFF_MASK) : page;
348 match = (asid << PTEH_ASID_SHIFT) | PTEH_VALID;
349 match |= lpage;
350
351 for_each_itlb_entry(tlb) {
352 asm volatile ("getcfg %1, 0, %0"
353 : "=r" (pteh)
354 : "r" (tlb) );
355
356 if (pteh == match) {
357 __flush_tlb_slot(tlb);
358 break;
359 }
360 }
361
362 for_each_dtlb_entry(tlb) {
363 asm volatile ("getcfg %1, 0, %0"
364 : "=r" (pteh)
365 : "r" (tlb) );
366
367 if (pteh == match) {
368 __flush_tlb_slot(tlb);
369 break;
370 }
371
372 }
373 }
374
local_flush_tlb_page(struct vm_area_struct * vma,unsigned long page)375 void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
376 {
377 unsigned long flags;
378
379 if (vma->vm_mm) {
380 page &= PAGE_MASK;
381 local_irq_save(flags);
382 local_flush_tlb_one(get_asid(), page);
383 local_irq_restore(flags);
384 }
385 }
386
local_flush_tlb_range(struct vm_area_struct * vma,unsigned long start,unsigned long end)387 void local_flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
388 unsigned long end)
389 {
390 unsigned long flags;
391 unsigned long long match, pteh=0, pteh_epn, pteh_low;
392 unsigned long tlb;
393 unsigned int cpu = smp_processor_id();
394 struct mm_struct *mm;
395
396 mm = vma->vm_mm;
397 if (cpu_context(cpu, mm) == NO_CONTEXT)
398 return;
399
400 local_irq_save(flags);
401
402 start &= PAGE_MASK;
403 end &= PAGE_MASK;
404
405 match = (cpu_asid(cpu, mm) << PTEH_ASID_SHIFT) | PTEH_VALID;
406
407 /* Flush ITLB */
408 for_each_itlb_entry(tlb) {
409 asm volatile ("getcfg %1, 0, %0"
410 : "=r" (pteh)
411 : "r" (tlb) );
412
413 pteh_epn = pteh & PAGE_MASK;
414 pteh_low = pteh & ~PAGE_MASK;
415
416 if (pteh_low == match && pteh_epn >= start && pteh_epn <= end)
417 __flush_tlb_slot(tlb);
418 }
419
420 /* Flush DTLB */
421 for_each_dtlb_entry(tlb) {
422 asm volatile ("getcfg %1, 0, %0"
423 : "=r" (pteh)
424 : "r" (tlb) );
425
426 pteh_epn = pteh & PAGE_MASK;
427 pteh_low = pteh & ~PAGE_MASK;
428
429 if (pteh_low == match && pteh_epn >= start && pteh_epn <= end)
430 __flush_tlb_slot(tlb);
431 }
432
433 local_irq_restore(flags);
434 }
435
local_flush_tlb_mm(struct mm_struct * mm)436 void local_flush_tlb_mm(struct mm_struct *mm)
437 {
438 unsigned long flags;
439 unsigned int cpu = smp_processor_id();
440
441 if (cpu_context(cpu, mm) == NO_CONTEXT)
442 return;
443
444 local_irq_save(flags);
445
446 cpu_context(cpu, mm) = NO_CONTEXT;
447 if (mm == current->mm)
448 activate_context(mm, cpu);
449
450 local_irq_restore(flags);
451 }
452
local_flush_tlb_all(void)453 void local_flush_tlb_all(void)
454 {
455 /* Invalidate all, including shared pages, excluding fixed TLBs */
456 unsigned long flags, tlb;
457
458 local_irq_save(flags);
459
460 /* Flush each ITLB entry */
461 for_each_itlb_entry(tlb)
462 __flush_tlb_slot(tlb);
463
464 /* Flush each DTLB entry */
465 for_each_dtlb_entry(tlb)
466 __flush_tlb_slot(tlb);
467
468 local_irq_restore(flags);
469 }
470
local_flush_tlb_kernel_range(unsigned long start,unsigned long end)471 void local_flush_tlb_kernel_range(unsigned long start, unsigned long end)
472 {
473 /* FIXME: Optimize this later.. */
474 flush_tlb_all();
475 }
476