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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * fault.c: Page fault handlers for the Sparc.
4 *
5 * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
6 * Copyright (C) 1996 Eddie C. Dost (ecd@skynet.be)
7 * Copyright (C) 1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
8 */
9
10#include <asm/head.h>
11
12#include <linux/string.h>
13#include <linux/types.h>
14#include <linux/sched.h>
15#include <linux/ptrace.h>
16#include <linux/mman.h>
17#include <linux/threads.h>
18#include <linux/kernel.h>
19#include <linux/signal.h>
20#include <linux/mm.h>
21#include <linux/smp.h>
22#include <linux/perf_event.h>
23#include <linux/interrupt.h>
24#include <linux/kdebug.h>
25#include <linux/uaccess.h>
26#include <linux/extable.h>
27
28#include <asm/page.h>
29#include <asm/openprom.h>
30#include <asm/oplib.h>
31#include <asm/setup.h>
32#include <asm/smp.h>
33#include <asm/traps.h>
34
35#include "mm_32.h"
36
37int show_unhandled_signals = 1;
38
39static void __noreturn unhandled_fault(unsigned long address,
40 struct task_struct *tsk,
41 struct pt_regs *regs)
42{
43 if ((unsigned long) address < PAGE_SIZE) {
44 printk(KERN_ALERT
45 "Unable to handle kernel NULL pointer dereference\n");
46 } else {
47 printk(KERN_ALERT "Unable to handle kernel paging request at virtual address %08lx\n",
48 address);
49 }
50 printk(KERN_ALERT "tsk->{mm,active_mm}->context = %08lx\n",
51 (tsk->mm ? tsk->mm->context : tsk->active_mm->context));
52 printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %08lx\n",
53 (tsk->mm ? (unsigned long) tsk->mm->pgd :
54 (unsigned long) tsk->active_mm->pgd));
55 die_if_kernel("Oops", regs);
56}
57
58static inline void
59show_signal_msg(struct pt_regs *regs, int sig, int code,
60 unsigned long address, struct task_struct *tsk)
61{
62 if (!unhandled_signal(tsk, sig))
63 return;
64
65 if (!printk_ratelimit())
66 return;
67
68 printk("%s%s[%d]: segfault at %lx ip %px (rpc %px) sp %px error %x",
69 task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
70 tsk->comm, task_pid_nr(tsk), address,
71 (void *)regs->pc, (void *)regs->u_regs[UREG_I7],
72 (void *)regs->u_regs[UREG_FP], code);
73
74 print_vma_addr(KERN_CONT " in ", regs->pc);
75
76 printk(KERN_CONT "\n");
77}
78
79static void __do_fault_siginfo(int code, int sig, struct pt_regs *regs,
80 unsigned long addr)
81{
82 if (unlikely(show_unhandled_signals))
83 show_signal_msg(regs, sig, code,
84 addr, current);
85
86 force_sig_fault(sig, code, (void __user *) addr);
87}
88
89static unsigned long compute_si_addr(struct pt_regs *regs, int text_fault)
90{
91 unsigned int insn;
92
93 if (text_fault)
94 return regs->pc;
95
96 if (regs->psr & PSR_PS)
97 insn = *(unsigned int *) regs->pc;
98 else
99 __get_user(insn, (unsigned int *) regs->pc);
100
101 return safe_compute_effective_address(regs, insn);
102}
103
104static noinline void do_fault_siginfo(int code, int sig, struct pt_regs *regs,
105 int text_fault)
106{
107 unsigned long addr = compute_si_addr(regs, text_fault);
108
109 __do_fault_siginfo(code, sig, regs, addr);
110}
111
112asmlinkage void do_sparc_fault(struct pt_regs *regs, int text_fault, int write,
113 unsigned long address)
114{
115 struct vm_area_struct *vma;
116 struct task_struct *tsk = current;
117 struct mm_struct *mm = tsk->mm;
118 int from_user = !(regs->psr & PSR_PS);
119 int code;
120 vm_fault_t fault;
121 unsigned int flags = FAULT_FLAG_DEFAULT;
122
123 if (text_fault)
124 address = regs->pc;
125
126 /*
127 * We fault-in kernel-space virtual memory on-demand. The
128 * 'reference' page table is init_mm.pgd.
129 *
130 * NOTE! We MUST NOT take any locks for this case. We may
131 * be in an interrupt or a critical region, and should
132 * only copy the information from the master page table,
133 * nothing more.
134 */
135 code = SEGV_MAPERR;
136 if (address >= TASK_SIZE)
137 goto vmalloc_fault;
138
139 /*
140 * If we're in an interrupt or have no user
141 * context, we must not take the fault..
142 */
143 if (pagefault_disabled() || !mm)
144 goto no_context;
145
146 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
147
148retry:
149 mmap_read_lock(mm);
150
151 if (!from_user && address >= PAGE_OFFSET)
152 goto bad_area;
153
154 vma = find_vma(mm, address);
155 if (!vma)
156 goto bad_area;
157 if (vma->vm_start <= address)
158 goto good_area;
159 if (!(vma->vm_flags & VM_GROWSDOWN))
160 goto bad_area;
161 if (expand_stack(vma, address))
162 goto bad_area;
163 /*
164 * Ok, we have a good vm_area for this memory access, so
165 * we can handle it..
166 */
167good_area:
168 code = SEGV_ACCERR;
169 if (write) {
170 if (!(vma->vm_flags & VM_WRITE))
171 goto bad_area;
172 } else {
173 /* Allow reads even for write-only mappings */
174 if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
175 goto bad_area;
176 }
177
178 if (from_user)
179 flags |= FAULT_FLAG_USER;
180 if (write)
181 flags |= FAULT_FLAG_WRITE;
182
183 /*
184 * If for any reason at all we couldn't handle the fault,
185 * make sure we exit gracefully rather than endlessly redo
186 * the fault.
187 */
188 fault = handle_mm_fault(vma, address, flags, regs);
189
190 if (fault_signal_pending(fault, regs))
191 return;
192
193 /* The fault is fully completed (including releasing mmap lock) */
194 if (fault & VM_FAULT_COMPLETED)
195 return;
196
197 if (unlikely(fault & VM_FAULT_ERROR)) {
198 if (fault & VM_FAULT_OOM)
199 goto out_of_memory;
200 else if (fault & VM_FAULT_SIGSEGV)
201 goto bad_area;
202 else if (fault & VM_FAULT_SIGBUS)
203 goto do_sigbus;
204 BUG();
205 }
206
207 if (fault & VM_FAULT_RETRY) {
208 flags |= FAULT_FLAG_TRIED;
209
210 /* No need to mmap_read_unlock(mm) as we would
211 * have already released it in __lock_page_or_retry
212 * in mm/filemap.c.
213 */
214
215 goto retry;
216 }
217
218 mmap_read_unlock(mm);
219 return;
220
221 /*
222 * Something tried to access memory that isn't in our memory map..
223 * Fix it, but check if it's kernel or user first..
224 */
225bad_area:
226 mmap_read_unlock(mm);
227
228bad_area_nosemaphore:
229 /* User mode accesses just cause a SIGSEGV */
230 if (from_user) {
231 do_fault_siginfo(code, SIGSEGV, regs, text_fault);
232 return;
233 }
234
235 /* Is this in ex_table? */
236no_context:
237 if (!from_user) {
238 const struct exception_table_entry *entry;
239
240 entry = search_exception_tables(regs->pc);
241#ifdef DEBUG_EXCEPTIONS
242 printk("Exception: PC<%08lx> faddr<%08lx>\n",
243 regs->pc, address);
244 printk("EX_TABLE: insn<%08lx> fixup<%08x>\n",
245 regs->pc, entry->fixup);
246#endif
247 regs->pc = entry->fixup;
248 regs->npc = regs->pc + 4;
249 return;
250 }
251
252 unhandled_fault(address, tsk, regs);
253
254/*
255 * We ran out of memory, or some other thing happened to us that made
256 * us unable to handle the page fault gracefully.
257 */
258out_of_memory:
259 mmap_read_unlock(mm);
260 if (from_user) {
261 pagefault_out_of_memory();
262 return;
263 }
264 goto no_context;
265
266do_sigbus:
267 mmap_read_unlock(mm);
268 do_fault_siginfo(BUS_ADRERR, SIGBUS, regs, text_fault);
269 if (!from_user)
270 goto no_context;
271
272vmalloc_fault:
273 {
274 /*
275 * Synchronize this task's top level page-table
276 * with the 'reference' page table.
277 */
278 int offset = pgd_index(address);
279 pgd_t *pgd, *pgd_k;
280 p4d_t *p4d, *p4d_k;
281 pud_t *pud, *pud_k;
282 pmd_t *pmd, *pmd_k;
283
284 pgd = tsk->active_mm->pgd + offset;
285 pgd_k = init_mm.pgd + offset;
286
287 if (!pgd_present(*pgd)) {
288 if (!pgd_present(*pgd_k))
289 goto bad_area_nosemaphore;
290 pgd_val(*pgd) = pgd_val(*pgd_k);
291 return;
292 }
293
294 p4d = p4d_offset(pgd, address);
295 pud = pud_offset(p4d, address);
296 pmd = pmd_offset(pud, address);
297
298 p4d_k = p4d_offset(pgd_k, address);
299 pud_k = pud_offset(p4d_k, address);
300 pmd_k = pmd_offset(pud_k, address);
301
302 if (pmd_present(*pmd) || !pmd_present(*pmd_k))
303 goto bad_area_nosemaphore;
304
305 *pmd = *pmd_k;
306 return;
307 }
308}
309
310/* This always deals with user addresses. */
311static void force_user_fault(unsigned long address, int write)
312{
313 struct vm_area_struct *vma;
314 struct task_struct *tsk = current;
315 struct mm_struct *mm = tsk->mm;
316 unsigned int flags = FAULT_FLAG_USER;
317 int code;
318
319 code = SEGV_MAPERR;
320
321 mmap_read_lock(mm);
322 vma = find_vma(mm, address);
323 if (!vma)
324 goto bad_area;
325 if (vma->vm_start <= address)
326 goto good_area;
327 if (!(vma->vm_flags & VM_GROWSDOWN))
328 goto bad_area;
329 if (expand_stack(vma, address))
330 goto bad_area;
331good_area:
332 code = SEGV_ACCERR;
333 if (write) {
334 if (!(vma->vm_flags & VM_WRITE))
335 goto bad_area;
336 flags |= FAULT_FLAG_WRITE;
337 } else {
338 if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
339 goto bad_area;
340 }
341 switch (handle_mm_fault(vma, address, flags, NULL)) {
342 case VM_FAULT_SIGBUS:
343 case VM_FAULT_OOM:
344 goto do_sigbus;
345 }
346 mmap_read_unlock(mm);
347 return;
348bad_area:
349 mmap_read_unlock(mm);
350 __do_fault_siginfo(code, SIGSEGV, tsk->thread.kregs, address);
351 return;
352
353do_sigbus:
354 mmap_read_unlock(mm);
355 __do_fault_siginfo(BUS_ADRERR, SIGBUS, tsk->thread.kregs, address);
356}
357
358static void check_stack_aligned(unsigned long sp)
359{
360 if (sp & 0x7UL)
361 force_sig(SIGILL);
362}
363
364void window_overflow_fault(void)
365{
366 unsigned long sp;
367
368 sp = current_thread_info()->rwbuf_stkptrs[0];
369 if (((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
370 force_user_fault(sp + 0x38, 1);
371 force_user_fault(sp, 1);
372
373 check_stack_aligned(sp);
374}
375
376void window_underflow_fault(unsigned long sp)
377{
378 if (((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
379 force_user_fault(sp + 0x38, 0);
380 force_user_fault(sp, 0);
381
382 check_stack_aligned(sp);
383}
384
385void window_ret_fault(struct pt_regs *regs)
386{
387 unsigned long sp;
388
389 sp = regs->u_regs[UREG_FP];
390 if (((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
391 force_user_fault(sp + 0x38, 0);
392 force_user_fault(sp, 0);
393
394 check_stack_aligned(sp);
395}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * fault.c: Page fault handlers for the Sparc.
4 *
5 * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
6 * Copyright (C) 1996 Eddie C. Dost (ecd@skynet.be)
7 * Copyright (C) 1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
8 */
9
10#include <asm/head.h>
11
12#include <linux/string.h>
13#include <linux/types.h>
14#include <linux/sched.h>
15#include <linux/ptrace.h>
16#include <linux/mman.h>
17#include <linux/threads.h>
18#include <linux/kernel.h>
19#include <linux/signal.h>
20#include <linux/mm.h>
21#include <linux/smp.h>
22#include <linux/perf_event.h>
23#include <linux/interrupt.h>
24#include <linux/kdebug.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/setup.h>
32#include <asm/smp.h>
33#include <asm/traps.h>
34
35#include "mm_32.h"
36
37int show_unhandled_signals = 1;
38
39static void __noreturn unhandled_fault(unsigned long address,
40 struct task_struct *tsk,
41 struct pt_regs *regs)
42{
43 if ((unsigned long) address < PAGE_SIZE) {
44 printk(KERN_ALERT
45 "Unable to handle kernel NULL pointer dereference\n");
46 } else {
47 printk(KERN_ALERT "Unable to handle kernel paging request at virtual address %08lx\n",
48 address);
49 }
50 printk(KERN_ALERT "tsk->{mm,active_mm}->context = %08lx\n",
51 (tsk->mm ? tsk->mm->context : tsk->active_mm->context));
52 printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %08lx\n",
53 (tsk->mm ? (unsigned long) tsk->mm->pgd :
54 (unsigned long) tsk->active_mm->pgd));
55 die_if_kernel("Oops", regs);
56}
57
58asmlinkage int lookup_fault(unsigned long pc, unsigned long ret_pc,
59 unsigned long address)
60{
61 struct pt_regs regs;
62 unsigned long g2;
63 unsigned int insn;
64 int i;
65
66 i = search_extables_range(ret_pc, &g2);
67 switch (i) {
68 case 3:
69 /* load & store will be handled by fixup */
70 return 3;
71
72 case 1:
73 /* store will be handled by fixup, load will bump out */
74 /* for _to_ macros */
75 insn = *((unsigned int *) pc);
76 if ((insn >> 21) & 1)
77 return 1;
78 break;
79
80 case 2:
81 /* load will be handled by fixup, store will bump out */
82 /* for _from_ macros */
83 insn = *((unsigned int *) pc);
84 if (!((insn >> 21) & 1) || ((insn>>19)&0x3f) == 15)
85 return 2;
86 break;
87
88 default:
89 break;
90 }
91
92 memset(®s, 0, sizeof(regs));
93 regs.pc = pc;
94 regs.npc = pc + 4;
95 __asm__ __volatile__(
96 "rd %%psr, %0\n\t"
97 "nop\n\t"
98 "nop\n\t"
99 "nop\n" : "=r" (regs.psr));
100 unhandled_fault(address, current, ®s);
101
102 /* Not reached */
103 return 0;
104}
105
106static inline void
107show_signal_msg(struct pt_regs *regs, int sig, int code,
108 unsigned long address, struct task_struct *tsk)
109{
110 if (!unhandled_signal(tsk, sig))
111 return;
112
113 if (!printk_ratelimit())
114 return;
115
116 printk("%s%s[%d]: segfault at %lx ip %px (rpc %px) sp %px error %x",
117 task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
118 tsk->comm, task_pid_nr(tsk), address,
119 (void *)regs->pc, (void *)regs->u_regs[UREG_I7],
120 (void *)regs->u_regs[UREG_FP], code);
121
122 print_vma_addr(KERN_CONT " in ", regs->pc);
123
124 printk(KERN_CONT "\n");
125}
126
127static void __do_fault_siginfo(int code, int sig, struct pt_regs *regs,
128 unsigned long addr)
129{
130 siginfo_t info;
131
132 info.si_signo = sig;
133 info.si_code = code;
134 info.si_errno = 0;
135 info.si_addr = (void __user *) addr;
136 info.si_trapno = 0;
137
138 if (unlikely(show_unhandled_signals))
139 show_signal_msg(regs, sig, info.si_code,
140 addr, current);
141
142 force_sig_info (sig, &info, current);
143}
144
145static unsigned long compute_si_addr(struct pt_regs *regs, int text_fault)
146{
147 unsigned int insn;
148
149 if (text_fault)
150 return regs->pc;
151
152 if (regs->psr & PSR_PS)
153 insn = *(unsigned int *) regs->pc;
154 else
155 __get_user(insn, (unsigned int *) regs->pc);
156
157 return safe_compute_effective_address(regs, insn);
158}
159
160static noinline void do_fault_siginfo(int code, int sig, struct pt_regs *regs,
161 int text_fault)
162{
163 unsigned long addr = compute_si_addr(regs, text_fault);
164
165 __do_fault_siginfo(code, sig, regs, addr);
166}
167
168asmlinkage void do_sparc_fault(struct pt_regs *regs, int text_fault, int write,
169 unsigned long address)
170{
171 struct vm_area_struct *vma;
172 struct task_struct *tsk = current;
173 struct mm_struct *mm = tsk->mm;
174 unsigned int fixup;
175 unsigned long g2;
176 int from_user = !(regs->psr & PSR_PS);
177 int fault, code;
178 unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
179
180 if (text_fault)
181 address = regs->pc;
182
183 /*
184 * We fault-in kernel-space virtual memory on-demand. The
185 * 'reference' page table is init_mm.pgd.
186 *
187 * NOTE! We MUST NOT take any locks for this case. We may
188 * be in an interrupt or a critical region, and should
189 * only copy the information from the master page table,
190 * nothing more.
191 */
192 code = SEGV_MAPERR;
193 if (address >= TASK_SIZE)
194 goto vmalloc_fault;
195
196 /*
197 * If we're in an interrupt or have no user
198 * context, we must not take the fault..
199 */
200 if (pagefault_disabled() || !mm)
201 goto no_context;
202
203 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
204
205retry:
206 down_read(&mm->mmap_sem);
207
208 if (!from_user && address >= PAGE_OFFSET)
209 goto bad_area;
210
211 vma = find_vma(mm, address);
212 if (!vma)
213 goto bad_area;
214 if (vma->vm_start <= address)
215 goto good_area;
216 if (!(vma->vm_flags & VM_GROWSDOWN))
217 goto bad_area;
218 if (expand_stack(vma, address))
219 goto bad_area;
220 /*
221 * Ok, we have a good vm_area for this memory access, so
222 * we can handle it..
223 */
224good_area:
225 code = SEGV_ACCERR;
226 if (write) {
227 if (!(vma->vm_flags & VM_WRITE))
228 goto bad_area;
229 } else {
230 /* Allow reads even for write-only mappings */
231 if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
232 goto bad_area;
233 }
234
235 if (from_user)
236 flags |= FAULT_FLAG_USER;
237 if (write)
238 flags |= FAULT_FLAG_WRITE;
239
240 /*
241 * If for any reason at all we couldn't handle the fault,
242 * make sure we exit gracefully rather than endlessly redo
243 * the fault.
244 */
245 fault = handle_mm_fault(vma, address, flags);
246
247 if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
248 return;
249
250 if (unlikely(fault & VM_FAULT_ERROR)) {
251 if (fault & VM_FAULT_OOM)
252 goto out_of_memory;
253 else if (fault & VM_FAULT_SIGSEGV)
254 goto bad_area;
255 else if (fault & VM_FAULT_SIGBUS)
256 goto do_sigbus;
257 BUG();
258 }
259
260 if (flags & FAULT_FLAG_ALLOW_RETRY) {
261 if (fault & VM_FAULT_MAJOR) {
262 current->maj_flt++;
263 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ,
264 1, regs, address);
265 } else {
266 current->min_flt++;
267 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN,
268 1, regs, address);
269 }
270 if (fault & VM_FAULT_RETRY) {
271 flags &= ~FAULT_FLAG_ALLOW_RETRY;
272 flags |= FAULT_FLAG_TRIED;
273
274 /* No need to up_read(&mm->mmap_sem) as we would
275 * have already released it in __lock_page_or_retry
276 * in mm/filemap.c.
277 */
278
279 goto retry;
280 }
281 }
282
283 up_read(&mm->mmap_sem);
284 return;
285
286 /*
287 * Something tried to access memory that isn't in our memory map..
288 * Fix it, but check if it's kernel or user first..
289 */
290bad_area:
291 up_read(&mm->mmap_sem);
292
293bad_area_nosemaphore:
294 /* User mode accesses just cause a SIGSEGV */
295 if (from_user) {
296 do_fault_siginfo(code, SIGSEGV, regs, text_fault);
297 return;
298 }
299
300 /* Is this in ex_table? */
301no_context:
302 g2 = regs->u_regs[UREG_G2];
303 if (!from_user) {
304 fixup = search_extables_range(regs->pc, &g2);
305 /* Values below 10 are reserved for other things */
306 if (fixup > 10) {
307 extern const unsigned int __memset_start[];
308 extern const unsigned int __memset_end[];
309 extern const unsigned int __csum_partial_copy_start[];
310 extern const unsigned int __csum_partial_copy_end[];
311
312#ifdef DEBUG_EXCEPTIONS
313 printk("Exception: PC<%08lx> faddr<%08lx>\n",
314 regs->pc, address);
315 printk("EX_TABLE: insn<%08lx> fixup<%08x> g2<%08lx>\n",
316 regs->pc, fixup, g2);
317#endif
318 if ((regs->pc >= (unsigned long)__memset_start &&
319 regs->pc < (unsigned long)__memset_end) ||
320 (regs->pc >= (unsigned long)__csum_partial_copy_start &&
321 regs->pc < (unsigned long)__csum_partial_copy_end)) {
322 regs->u_regs[UREG_I4] = address;
323 regs->u_regs[UREG_I5] = regs->pc;
324 }
325 regs->u_regs[UREG_G2] = g2;
326 regs->pc = fixup;
327 regs->npc = regs->pc + 4;
328 return;
329 }
330 }
331
332 unhandled_fault(address, tsk, regs);
333 do_exit(SIGKILL);
334
335/*
336 * We ran out of memory, or some other thing happened to us that made
337 * us unable to handle the page fault gracefully.
338 */
339out_of_memory:
340 up_read(&mm->mmap_sem);
341 if (from_user) {
342 pagefault_out_of_memory();
343 return;
344 }
345 goto no_context;
346
347do_sigbus:
348 up_read(&mm->mmap_sem);
349 do_fault_siginfo(BUS_ADRERR, SIGBUS, regs, text_fault);
350 if (!from_user)
351 goto no_context;
352
353vmalloc_fault:
354 {
355 /*
356 * Synchronize this task's top level page-table
357 * with the 'reference' page table.
358 */
359 int offset = pgd_index(address);
360 pgd_t *pgd, *pgd_k;
361 pmd_t *pmd, *pmd_k;
362
363 pgd = tsk->active_mm->pgd + offset;
364 pgd_k = init_mm.pgd + offset;
365
366 if (!pgd_present(*pgd)) {
367 if (!pgd_present(*pgd_k))
368 goto bad_area_nosemaphore;
369 pgd_val(*pgd) = pgd_val(*pgd_k);
370 return;
371 }
372
373 pmd = pmd_offset(pgd, address);
374 pmd_k = pmd_offset(pgd_k, address);
375
376 if (pmd_present(*pmd) || !pmd_present(*pmd_k))
377 goto bad_area_nosemaphore;
378
379 *pmd = *pmd_k;
380 return;
381 }
382}
383
384/* This always deals with user addresses. */
385static void force_user_fault(unsigned long address, int write)
386{
387 struct vm_area_struct *vma;
388 struct task_struct *tsk = current;
389 struct mm_struct *mm = tsk->mm;
390 unsigned int flags = FAULT_FLAG_USER;
391 int code;
392
393 code = SEGV_MAPERR;
394
395 down_read(&mm->mmap_sem);
396 vma = find_vma(mm, address);
397 if (!vma)
398 goto bad_area;
399 if (vma->vm_start <= address)
400 goto good_area;
401 if (!(vma->vm_flags & VM_GROWSDOWN))
402 goto bad_area;
403 if (expand_stack(vma, address))
404 goto bad_area;
405good_area:
406 code = SEGV_ACCERR;
407 if (write) {
408 if (!(vma->vm_flags & VM_WRITE))
409 goto bad_area;
410 flags |= FAULT_FLAG_WRITE;
411 } else {
412 if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
413 goto bad_area;
414 }
415 switch (handle_mm_fault(vma, address, flags)) {
416 case VM_FAULT_SIGBUS:
417 case VM_FAULT_OOM:
418 goto do_sigbus;
419 }
420 up_read(&mm->mmap_sem);
421 return;
422bad_area:
423 up_read(&mm->mmap_sem);
424 __do_fault_siginfo(code, SIGSEGV, tsk->thread.kregs, address);
425 return;
426
427do_sigbus:
428 up_read(&mm->mmap_sem);
429 __do_fault_siginfo(BUS_ADRERR, SIGBUS, tsk->thread.kregs, address);
430}
431
432static void check_stack_aligned(unsigned long sp)
433{
434 if (sp & 0x7UL)
435 force_sig(SIGILL, current);
436}
437
438void window_overflow_fault(void)
439{
440 unsigned long sp;
441
442 sp = current_thread_info()->rwbuf_stkptrs[0];
443 if (((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
444 force_user_fault(sp + 0x38, 1);
445 force_user_fault(sp, 1);
446
447 check_stack_aligned(sp);
448}
449
450void window_underflow_fault(unsigned long sp)
451{
452 if (((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
453 force_user_fault(sp + 0x38, 0);
454 force_user_fault(sp, 0);
455
456 check_stack_aligned(sp);
457}
458
459void window_ret_fault(struct pt_regs *regs)
460{
461 unsigned long sp;
462
463 sp = regs->u_regs[UREG_FP];
464 if (((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
465 force_user_fault(sp + 0x38, 0);
466 force_user_fault(sp, 0);
467
468 check_stack_aligned(sp);
469}