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Linux 3.17-rc2
[linux/fpc-iii.git] / arch / arm64 / kernel / signal32.c
blob1b9ad02837cfcafd4ecbc87f3e10aafe504ac0de
1 /*
2 * Based on arch/arm/kernel/signal.c
3 *
4 * Copyright (C) 1995-2009 Russell King
5 * Copyright (C) 2012 ARM Ltd.
6 * Modified by Will Deacon <will.deacon@arm.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program. If not, see <http://www.gnu.org/licenses/>.
19 */
20
21 #include <linux/compat.h>
22 #include <linux/signal.h>
23 #include <linux/syscalls.h>
24 #include <linux/ratelimit.h>
25
26 #include <asm/esr.h>
27 #include <asm/fpsimd.h>
28 #include <asm/signal32.h>
29 #include <asm/uaccess.h>
30 #include <asm/unistd.h>
31
32 struct compat_sigcontext {
33 /* We always set these two fields to 0 */
34 compat_ulong_t trap_no;
35 compat_ulong_t error_code;
36
37 compat_ulong_t oldmask;
38 compat_ulong_t arm_r0;
39 compat_ulong_t arm_r1;
40 compat_ulong_t arm_r2;
41 compat_ulong_t arm_r3;
42 compat_ulong_t arm_r4;
43 compat_ulong_t arm_r5;
44 compat_ulong_t arm_r6;
45 compat_ulong_t arm_r7;
46 compat_ulong_t arm_r8;
47 compat_ulong_t arm_r9;
48 compat_ulong_t arm_r10;
49 compat_ulong_t arm_fp;
50 compat_ulong_t arm_ip;
51 compat_ulong_t arm_sp;
52 compat_ulong_t arm_lr;
53 compat_ulong_t arm_pc;
54 compat_ulong_t arm_cpsr;
55 compat_ulong_t fault_address;
56 };
57
58 struct compat_ucontext {
59 compat_ulong_t uc_flags;
60 compat_uptr_t uc_link;
61 compat_stack_t uc_stack;
62 struct compat_sigcontext uc_mcontext;
63 compat_sigset_t uc_sigmask;
64 int __unused[32 - (sizeof (compat_sigset_t) / sizeof (int))];
65 compat_ulong_t uc_regspace[128] __attribute__((__aligned__(8)));
66 };
67
68 struct compat_vfp_sigframe {
69 compat_ulong_t magic;
70 compat_ulong_t size;
71 struct compat_user_vfp {
72 compat_u64 fpregs[32];
73 compat_ulong_t fpscr;
74 } ufp;
75 struct compat_user_vfp_exc {
76 compat_ulong_t fpexc;
77 compat_ulong_t fpinst;
78 compat_ulong_t fpinst2;
79 } ufp_exc;
80 } __attribute__((__aligned__(8)));
81
82 #define VFP_MAGIC 0x56465001
83 #define VFP_STORAGE_SIZE sizeof(struct compat_vfp_sigframe)
84
85 #define FSR_WRITE_SHIFT (11)
86
87 struct compat_aux_sigframe {
88 struct compat_vfp_sigframe vfp;
89
90 /* Something that isn't a valid magic number for any coprocessor. */
91 unsigned long end_magic;
92 } __attribute__((__aligned__(8)));
93
94 struct compat_sigframe {
95 struct compat_ucontext uc;
96 compat_ulong_t retcode[2];
97 };
98
99 struct compat_rt_sigframe {
100 struct compat_siginfo info;
101 struct compat_sigframe sig;
102 };
103
104 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
105
106 static inline int put_sigset_t(compat_sigset_t __user *uset, sigset_t *set)
107 {
108 compat_sigset_t cset;
109
110 cset.sig[0] = set->sig[0] & 0xffffffffull;
111 cset.sig[1] = set->sig[0] >> 32;
112
113 return copy_to_user(uset, &cset, sizeof(*uset));
114 }
115
116 static inline int get_sigset_t(sigset_t *set,
117 const compat_sigset_t __user *uset)
118 {
119 compat_sigset_t s32;
120
121 if (copy_from_user(&s32, uset, sizeof(*uset)))
122 return -EFAULT;
123
124 set->sig[0] = s32.sig[0] | (((long)s32.sig[1]) << 32);
125 return 0;
126 }
127
128 int copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from)
129 {
130 int err;
131
132 if (!access_ok(VERIFY_WRITE, to, sizeof(*to)))
133 return -EFAULT;
134
135 /* If you change siginfo_t structure, please be sure
136 * this code is fixed accordingly.
137 * It should never copy any pad contained in the structure
138 * to avoid security leaks, but must copy the generic
139 * 3 ints plus the relevant union member.
140 * This routine must convert siginfo from 64bit to 32bit as well
141 * at the same time.
142 */
143 err = __put_user(from->si_signo, &to->si_signo);
144 err |= __put_user(from->si_errno, &to->si_errno);
145 err |= __put_user((short)from->si_code, &to->si_code);
146 if (from->si_code < 0)
147 err |= __copy_to_user(&to->_sifields._pad, &from->_sifields._pad,
148 SI_PAD_SIZE);
149 else switch (from->si_code & __SI_MASK) {
150 case __SI_KILL:
151 err |= __put_user(from->si_pid, &to->si_pid);
152 err |= __put_user(from->si_uid, &to->si_uid);
153 break;
154 case __SI_TIMER:
155 err |= __put_user(from->si_tid, &to->si_tid);
156 err |= __put_user(from->si_overrun, &to->si_overrun);
157 err |= __put_user((compat_uptr_t)(unsigned long)from->si_ptr,
158 &to->si_ptr);
159 break;
160 case __SI_POLL:
161 err |= __put_user(from->si_band, &to->si_band);
162 err |= __put_user(from->si_fd, &to->si_fd);
163 break;
164 case __SI_FAULT:
165 err |= __put_user((compat_uptr_t)(unsigned long)from->si_addr,
166 &to->si_addr);
167 #ifdef BUS_MCEERR_AO
168 /*
169 * Other callers might not initialize the si_lsb field,
170 * so check explicitely for the right codes here.
171 */
172 if (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO)
173 err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb);
174 #endif
175 break;
176 case __SI_CHLD:
177 err |= __put_user(from->si_pid, &to->si_pid);
178 err |= __put_user(from->si_uid, &to->si_uid);
179 err |= __put_user(from->si_status, &to->si_status);
180 err |= __put_user(from->si_utime, &to->si_utime);
181 err |= __put_user(from->si_stime, &to->si_stime);
182 break;
183 case __SI_RT: /* This is not generated by the kernel as of now. */
184 case __SI_MESGQ: /* But this is */
185 err |= __put_user(from->si_pid, &to->si_pid);
186 err |= __put_user(from->si_uid, &to->si_uid);
187 err |= __put_user((compat_uptr_t)(unsigned long)from->si_ptr, &to->si_ptr);
188 break;
189 default: /* this is just in case for now ... */
190 err |= __put_user(from->si_pid, &to->si_pid);
191 err |= __put_user(from->si_uid, &to->si_uid);
192 break;
193 }
194 return err;
195 }
196
197 int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from)
198 {
199 memset(to, 0, sizeof *to);
200
201 if (copy_from_user(to, from, __ARCH_SI_PREAMBLE_SIZE) ||
202 copy_from_user(to->_sifields._pad,
203 from->_sifields._pad, SI_PAD_SIZE))
204 return -EFAULT;
205
206 return 0;
207 }
208
209 /*
210 * VFP save/restore code.
211 */
212 static int compat_preserve_vfp_context(struct compat_vfp_sigframe __user *frame)
213 {
214 struct fpsimd_state *fpsimd = &current->thread.fpsimd_state;
215 compat_ulong_t magic = VFP_MAGIC;
216 compat_ulong_t size = VFP_STORAGE_SIZE;
217 compat_ulong_t fpscr, fpexc;
218 int err = 0;
219
220 /*
221 * Save the hardware registers to the fpsimd_state structure.
222 * Note that this also saves V16-31, which aren't visible
223 * in AArch32.
224 */
225 fpsimd_preserve_current_state();
226
227 /* Place structure header on the stack */
228 __put_user_error(magic, &frame->magic, err);
229 __put_user_error(size, &frame->size, err);
230
231 /*
232 * Now copy the FP registers. Since the registers are packed,
233 * we can copy the prefix we want (V0-V15) as it is.
234 * FIXME: Won't work if big endian.
235 */
236 err |= __copy_to_user(&frame->ufp.fpregs, fpsimd->vregs,
237 sizeof(frame->ufp.fpregs));
238
239 /* Create an AArch32 fpscr from the fpsr and the fpcr. */
240 fpscr = (fpsimd->fpsr & VFP_FPSCR_STAT_MASK) |
241 (fpsimd->fpcr & VFP_FPSCR_CTRL_MASK);
242 __put_user_error(fpscr, &frame->ufp.fpscr, err);
243
244 /*
245 * The exception register aren't available so we fake up a
246 * basic FPEXC and zero everything else.
247 */
248 fpexc = (1 << 30);
249 __put_user_error(fpexc, &frame->ufp_exc.fpexc, err);
250 __put_user_error(0, &frame->ufp_exc.fpinst, err);
251 __put_user_error(0, &frame->ufp_exc.fpinst2, err);
252
253 return err ? -EFAULT : 0;
254 }
255
256 static int compat_restore_vfp_context(struct compat_vfp_sigframe __user *frame)
257 {
258 struct fpsimd_state fpsimd;
259 compat_ulong_t magic = VFP_MAGIC;
260 compat_ulong_t size = VFP_STORAGE_SIZE;
261 compat_ulong_t fpscr;
262 int err = 0;
263
264 __get_user_error(magic, &frame->magic, err);
265 __get_user_error(size, &frame->size, err);
266
267 if (err)
268 return -EFAULT;
269 if (magic != VFP_MAGIC || size != VFP_STORAGE_SIZE)
270 return -EINVAL;
271
272 /*
273 * Copy the FP registers into the start of the fpsimd_state.
274 * FIXME: Won't work if big endian.
275 */
276 err |= __copy_from_user(fpsimd.vregs, frame->ufp.fpregs,
277 sizeof(frame->ufp.fpregs));
278
279 /* Extract the fpsr and the fpcr from the fpscr */
280 __get_user_error(fpscr, &frame->ufp.fpscr, err);
281 fpsimd.fpsr = fpscr & VFP_FPSCR_STAT_MASK;
282 fpsimd.fpcr = fpscr & VFP_FPSCR_CTRL_MASK;
283
284 /*
285 * We don't need to touch the exception register, so
286 * reload the hardware state.
287 */
288 if (!err)
289 fpsimd_update_current_state(&fpsimd);
290
291 return err ? -EFAULT : 0;
292 }
293
294 static int compat_restore_sigframe(struct pt_regs *regs,
295 struct compat_sigframe __user *sf)
296 {
297 int err;
298 sigset_t set;
299 struct compat_aux_sigframe __user *aux;
300
301 err = get_sigset_t(&set, &sf->uc.uc_sigmask);
302 if (err == 0) {
303 sigdelsetmask(&set, ~_BLOCKABLE);
304 set_current_blocked(&set);
305 }
306
307 __get_user_error(regs->regs[0], &sf->uc.uc_mcontext.arm_r0, err);
308 __get_user_error(regs->regs[1], &sf->uc.uc_mcontext.arm_r1, err);
309 __get_user_error(regs->regs[2], &sf->uc.uc_mcontext.arm_r2, err);
310 __get_user_error(regs->regs[3], &sf->uc.uc_mcontext.arm_r3, err);
311 __get_user_error(regs->regs[4], &sf->uc.uc_mcontext.arm_r4, err);
312 __get_user_error(regs->regs[5], &sf->uc.uc_mcontext.arm_r5, err);
313 __get_user_error(regs->regs[6], &sf->uc.uc_mcontext.arm_r6, err);
314 __get_user_error(regs->regs[7], &sf->uc.uc_mcontext.arm_r7, err);
315 __get_user_error(regs->regs[8], &sf->uc.uc_mcontext.arm_r8, err);
316 __get_user_error(regs->regs[9], &sf->uc.uc_mcontext.arm_r9, err);
317 __get_user_error(regs->regs[10], &sf->uc.uc_mcontext.arm_r10, err);
318 __get_user_error(regs->regs[11], &sf->uc.uc_mcontext.arm_fp, err);
319 __get_user_error(regs->regs[12], &sf->uc.uc_mcontext.arm_ip, err);
320 __get_user_error(regs->compat_sp, &sf->uc.uc_mcontext.arm_sp, err);
321 __get_user_error(regs->compat_lr, &sf->uc.uc_mcontext.arm_lr, err);
322 __get_user_error(regs->pc, &sf->uc.uc_mcontext.arm_pc, err);
323 __get_user_error(regs->pstate, &sf->uc.uc_mcontext.arm_cpsr, err);
324
325 /*
326 * Avoid compat_sys_sigreturn() restarting.
327 */
328 regs->syscallno = ~0UL;
329
330 err |= !valid_user_regs(&regs->user_regs);
331
332 aux = (struct compat_aux_sigframe __user *) sf->uc.uc_regspace;
333 if (err == 0)
334 err |= compat_restore_vfp_context(&aux->vfp);
335
336 return err;
337 }
338
339 asmlinkage int compat_sys_sigreturn(struct pt_regs *regs)
340 {
341 struct compat_sigframe __user *frame;
342
343 /* Always make any pending restarted system calls return -EINTR */
344 current_thread_info()->restart_block.fn = do_no_restart_syscall;
345
346 /*
347 * Since we stacked the signal on a 64-bit boundary,
348 * then 'sp' should be word aligned here. If it's
349 * not, then the user is trying to mess with us.
350 */
351 if (regs->compat_sp & 7)
352 goto badframe;
353
354 frame = (struct compat_sigframe __user *)regs->compat_sp;
355
356 if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
357 goto badframe;
358
359 if (compat_restore_sigframe(regs, frame))
360 goto badframe;
361
362 return regs->regs[0];
363
364 badframe:
365 if (show_unhandled_signals)
366 pr_info_ratelimited("%s[%d]: bad frame in %s: pc=%08llx sp=%08llx\n",
367 current->comm, task_pid_nr(current), __func__,
368 regs->pc, regs->sp);
369 force_sig(SIGSEGV, current);
370 return 0;
371 }
372
373 asmlinkage int compat_sys_rt_sigreturn(struct pt_regs *regs)
374 {
375 struct compat_rt_sigframe __user *frame;
376
377 /* Always make any pending restarted system calls return -EINTR */
378 current_thread_info()->restart_block.fn = do_no_restart_syscall;
379
380 /*
381 * Since we stacked the signal on a 64-bit boundary,
382 * then 'sp' should be word aligned here. If it's
383 * not, then the user is trying to mess with us.
384 */
385 if (regs->compat_sp & 7)
386 goto badframe;
387
388 frame = (struct compat_rt_sigframe __user *)regs->compat_sp;
389
390 if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
391 goto badframe;
392
393 if (compat_restore_sigframe(regs, &frame->sig))
394 goto badframe;
395
396 if (compat_restore_altstack(&frame->sig.uc.uc_stack))
397 goto badframe;
398
399 return regs->regs[0];
400
401 badframe:
402 if (show_unhandled_signals)
403 pr_info_ratelimited("%s[%d]: bad frame in %s: pc=%08llx sp=%08llx\n",
404 current->comm, task_pid_nr(current), __func__,
405 regs->pc, regs->sp);
406 force_sig(SIGSEGV, current);
407 return 0;
408 }
409
410 static void __user *compat_get_sigframe(struct ksignal *ksig,
411 struct pt_regs *regs,
412 int framesize)
413 {
414 compat_ulong_t sp = sigsp(regs->compat_sp, ksig);
415 void __user *frame;
416
417 /*
418 * ATPCS B01 mandates 8-byte alignment
419 */
420 frame = compat_ptr((compat_uptr_t)((sp - framesize) & ~7));
421
422 /*
423 * Check that we can actually write to the signal frame.
424 */
425 if (!access_ok(VERIFY_WRITE, frame, framesize))
426 frame = NULL;
427
428 return frame;
429 }
430
431 static void compat_setup_return(struct pt_regs *regs, struct k_sigaction *ka,
432 compat_ulong_t __user *rc, void __user *frame,
433 int usig)
434 {
435 compat_ulong_t handler = ptr_to_compat(ka->sa.sa_handler);
436 compat_ulong_t retcode;
437 compat_ulong_t spsr = regs->pstate & ~PSR_f;
438 int thumb;
439
440 /* Check if the handler is written for ARM or Thumb */
441 thumb = handler & 1;
442
443 if (thumb)
444 spsr |= COMPAT_PSR_T_BIT;
445 else
446 spsr &= ~COMPAT_PSR_T_BIT;
447
448 /* The IT state must be cleared for both ARM and Thumb-2 */
449 spsr &= ~COMPAT_PSR_IT_MASK;
450
451 if (ka->sa.sa_flags & SA_RESTORER) {
452 retcode = ptr_to_compat(ka->sa.sa_restorer);
453 } else {
454 /* Set up sigreturn pointer */
455 unsigned int idx = thumb << 1;
456
457 if (ka->sa.sa_flags & SA_SIGINFO)
458 idx += 3;
459
460 retcode = AARCH32_VECTORS_BASE +
461 AARCH32_KERN_SIGRET_CODE_OFFSET +
462 (idx << 2) + thumb;
463 }
464
465 regs->regs[0] = usig;
466 regs->compat_sp = ptr_to_compat(frame);
467 regs->compat_lr = retcode;
468 regs->pc = handler;
469 regs->pstate = spsr;
470 }
471
472 static int compat_setup_sigframe(struct compat_sigframe __user *sf,
473 struct pt_regs *regs, sigset_t *set)
474 {
475 struct compat_aux_sigframe __user *aux;
476 int err = 0;
477
478 __put_user_error(regs->regs[0], &sf->uc.uc_mcontext.arm_r0, err);
479 __put_user_error(regs->regs[1], &sf->uc.uc_mcontext.arm_r1, err);
480 __put_user_error(regs->regs[2], &sf->uc.uc_mcontext.arm_r2, err);
481 __put_user_error(regs->regs[3], &sf->uc.uc_mcontext.arm_r3, err);
482 __put_user_error(regs->regs[4], &sf->uc.uc_mcontext.arm_r4, err);
483 __put_user_error(regs->regs[5], &sf->uc.uc_mcontext.arm_r5, err);
484 __put_user_error(regs->regs[6], &sf->uc.uc_mcontext.arm_r6, err);
485 __put_user_error(regs->regs[7], &sf->uc.uc_mcontext.arm_r7, err);
486 __put_user_error(regs->regs[8], &sf->uc.uc_mcontext.arm_r8, err);
487 __put_user_error(regs->regs[9], &sf->uc.uc_mcontext.arm_r9, err);
488 __put_user_error(regs->regs[10], &sf->uc.uc_mcontext.arm_r10, err);
489 __put_user_error(regs->regs[11], &sf->uc.uc_mcontext.arm_fp, err);
490 __put_user_error(regs->regs[12], &sf->uc.uc_mcontext.arm_ip, err);
491 __put_user_error(regs->compat_sp, &sf->uc.uc_mcontext.arm_sp, err);
492 __put_user_error(regs->compat_lr, &sf->uc.uc_mcontext.arm_lr, err);
493 __put_user_error(regs->pc, &sf->uc.uc_mcontext.arm_pc, err);
494 __put_user_error(regs->pstate, &sf->uc.uc_mcontext.arm_cpsr, err);
495
496 __put_user_error((compat_ulong_t)0, &sf->uc.uc_mcontext.trap_no, err);
497 /* set the compat FSR WnR */
498 __put_user_error(!!(current->thread.fault_code & ESR_EL1_WRITE) <<
499 FSR_WRITE_SHIFT, &sf->uc.uc_mcontext.error_code, err);
500 __put_user_error(current->thread.fault_address, &sf->uc.uc_mcontext.fault_address, err);
501 __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err);
502
503 err |= put_sigset_t(&sf->uc.uc_sigmask, set);
504
505 aux = (struct compat_aux_sigframe __user *) sf->uc.uc_regspace;
506
507 if (err == 0)
508 err |= compat_preserve_vfp_context(&aux->vfp);
509 __put_user_error(0, &aux->end_magic, err);
510
511 return err;
512 }
513
514 /*
515 * 32-bit signal handling routines called from signal.c
516 */
517 int compat_setup_rt_frame(int usig, struct ksignal *ksig,
518 sigset_t *set, struct pt_regs *regs)
519 {
520 struct compat_rt_sigframe __user *frame;
521 int err = 0;
522
523 frame = compat_get_sigframe(ksig, regs, sizeof(*frame));
524
525 if (!frame)
526 return 1;
527
528 err |= copy_siginfo_to_user32(&frame->info, &ksig->info);
529
530 __put_user_error(0, &frame->sig.uc.uc_flags, err);
531 __put_user_error(0, &frame->sig.uc.uc_link, err);
532
533 err |= __compat_save_altstack(&frame->sig.uc.uc_stack, regs->compat_sp);
534
535 err |= compat_setup_sigframe(&frame->sig, regs, set);
536
537 if (err == 0) {
538 compat_setup_return(regs, &ksig->ka, frame->sig.retcode, frame, usig);
539 regs->regs[1] = (compat_ulong_t)(unsigned long)&frame->info;
540 regs->regs[2] = (compat_ulong_t)(unsigned long)&frame->sig.uc;
541 }
542
543 return err;
544 }
545
546 int compat_setup_frame(int usig, struct ksignal *ksig, sigset_t *set,
547 struct pt_regs *regs)
548 {
549 struct compat_sigframe __user *frame;
550 int err = 0;
551
552 frame = compat_get_sigframe(ksig, regs, sizeof(*frame));
553
554 if (!frame)
555 return 1;
556
557 __put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err);
558
559 err |= compat_setup_sigframe(frame, regs, set);
560 if (err == 0)
561 compat_setup_return(regs, &ksig->ka, frame->retcode, frame, usig);
562
563 return err;
564 }
565
566 void compat_setup_restart_syscall(struct pt_regs *regs)
567 {
568 regs->regs[7] = __NR_compat_restart_syscall;
569 }
Linux with added FPC-III support