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arm64: add abstractions for FPSIMD state manipulation
[deliverable/linux.git] / arch / arm64 / kernel / signal32.c
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/fpsimd.h>
27 #include <asm/signal32.h>
28 #include <asm/uaccess.h>
29 #include <asm/unistd32.h>
30
31 struct compat_sigcontext {
32 /* We always set these two fields to 0 */
33 compat_ulong_t trap_no;
34 compat_ulong_t error_code;
35
36 compat_ulong_t oldmask;
37 compat_ulong_t arm_r0;
38 compat_ulong_t arm_r1;
39 compat_ulong_t arm_r2;
40 compat_ulong_t arm_r3;
41 compat_ulong_t arm_r4;
42 compat_ulong_t arm_r5;
43 compat_ulong_t arm_r6;
44 compat_ulong_t arm_r7;
45 compat_ulong_t arm_r8;
46 compat_ulong_t arm_r9;
47 compat_ulong_t arm_r10;
48 compat_ulong_t arm_fp;
49 compat_ulong_t arm_ip;
50 compat_ulong_t arm_sp;
51 compat_ulong_t arm_lr;
52 compat_ulong_t arm_pc;
53 compat_ulong_t arm_cpsr;
54 compat_ulong_t fault_address;
55 };
56
57 struct compat_ucontext {
58 compat_ulong_t uc_flags;
59 compat_uptr_t uc_link;
60 compat_stack_t uc_stack;
61 struct compat_sigcontext uc_mcontext;
62 compat_sigset_t uc_sigmask;
63 int __unused[32 - (sizeof (compat_sigset_t) / sizeof (int))];
64 compat_ulong_t uc_regspace[128] __attribute__((__aligned__(8)));
65 };
66
67 struct compat_vfp_sigframe {
68 compat_ulong_t magic;
69 compat_ulong_t size;
70 struct compat_user_vfp {
71 compat_u64 fpregs[32];
72 compat_ulong_t fpscr;
73 } ufp;
74 struct compat_user_vfp_exc {
75 compat_ulong_t fpexc;
76 compat_ulong_t fpinst;
77 compat_ulong_t fpinst2;
78 } ufp_exc;
79 } __attribute__((__aligned__(8)));
80
81 #define VFP_MAGIC 0x56465001
82 #define VFP_STORAGE_SIZE sizeof(struct compat_vfp_sigframe)
83
84 struct compat_aux_sigframe {
85 struct compat_vfp_sigframe vfp;
86
87 /* Something that isn't a valid magic number for any coprocessor. */
88 unsigned long end_magic;
89 } __attribute__((__aligned__(8)));
90
91 struct compat_sigframe {
92 struct compat_ucontext uc;
93 compat_ulong_t retcode[2];
94 };
95
96 struct compat_rt_sigframe {
97 struct compat_siginfo info;
98 struct compat_sigframe sig;
99 };
100
101 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
102
103 static inline int put_sigset_t(compat_sigset_t __user *uset, sigset_t *set)
104 {
105 compat_sigset_t cset;
106
107 cset.sig[0] = set->sig[0] & 0xffffffffull;
108 cset.sig[1] = set->sig[0] >> 32;
109
110 return copy_to_user(uset, &cset, sizeof(*uset));
111 }
112
113 static inline int get_sigset_t(sigset_t *set,
114 const compat_sigset_t __user *uset)
115 {
116 compat_sigset_t s32;
117
118 if (copy_from_user(&s32, uset, sizeof(*uset)))
119 return -EFAULT;
120
121 set->sig[0] = s32.sig[0] | (((long)s32.sig[1]) << 32);
122 return 0;
123 }
124
125 int copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from)
126 {
127 int err;
128
129 if (!access_ok(VERIFY_WRITE, to, sizeof(*to)))
130 return -EFAULT;
131
132 /* If you change siginfo_t structure, please be sure
133 * this code is fixed accordingly.
134 * It should never copy any pad contained in the structure
135 * to avoid security leaks, but must copy the generic
136 * 3 ints plus the relevant union member.
137 * This routine must convert siginfo from 64bit to 32bit as well
138 * at the same time.
139 */
140 err = __put_user(from->si_signo, &to->si_signo);
141 err |= __put_user(from->si_errno, &to->si_errno);
142 err |= __put_user((short)from->si_code, &to->si_code);
143 if (from->si_code < 0)
144 err |= __copy_to_user(&to->_sifields._pad, &from->_sifields._pad,
145 SI_PAD_SIZE);
146 else switch (from->si_code & __SI_MASK) {
147 case __SI_KILL:
148 err |= __put_user(from->si_pid, &to->si_pid);
149 err |= __put_user(from->si_uid, &to->si_uid);
150 break;
151 case __SI_TIMER:
152 err |= __put_user(from->si_tid, &to->si_tid);
153 err |= __put_user(from->si_overrun, &to->si_overrun);
154 err |= __put_user((compat_uptr_t)(unsigned long)from->si_ptr,
155 &to->si_ptr);
156 break;
157 case __SI_POLL:
158 err |= __put_user(from->si_band, &to->si_band);
159 err |= __put_user(from->si_fd, &to->si_fd);
160 break;
161 case __SI_FAULT:
162 err |= __put_user((compat_uptr_t)(unsigned long)from->si_addr,
163 &to->si_addr);
164 #ifdef BUS_MCEERR_AO
165 /*
166 * Other callers might not initialize the si_lsb field,
167 * so check explicitely for the right codes here.
168 */
169 if (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO)
170 err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb);
171 #endif
172 break;
173 case __SI_CHLD:
174 err |= __put_user(from->si_pid, &to->si_pid);
175 err |= __put_user(from->si_uid, &to->si_uid);
176 err |= __put_user(from->si_status, &to->si_status);
177 err |= __put_user(from->si_utime, &to->si_utime);
178 err |= __put_user(from->si_stime, &to->si_stime);
179 break;
180 case __SI_RT: /* This is not generated by the kernel as of now. */
181 case __SI_MESGQ: /* But this is */
182 err |= __put_user(from->si_pid, &to->si_pid);
183 err |= __put_user(from->si_uid, &to->si_uid);
184 err |= __put_user((compat_uptr_t)(unsigned long)from->si_ptr, &to->si_ptr);
185 break;
186 default: /* this is just in case for now ... */
187 err |= __put_user(from->si_pid, &to->si_pid);
188 err |= __put_user(from->si_uid, &to->si_uid);
189 break;
190 }
191 return err;
192 }
193
194 int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from)
195 {
196 memset(to, 0, sizeof *to);
197
198 if (copy_from_user(to, from, __ARCH_SI_PREAMBLE_SIZE) ||
199 copy_from_user(to->_sifields._pad,
200 from->_sifields._pad, SI_PAD_SIZE))
201 return -EFAULT;
202
203 return 0;
204 }
205
206 /*
207 * VFP save/restore code.
208 */
209 static int compat_preserve_vfp_context(struct compat_vfp_sigframe __user *frame)
210 {
211 struct fpsimd_state *fpsimd = &current->thread.fpsimd_state;
212 compat_ulong_t magic = VFP_MAGIC;
213 compat_ulong_t size = VFP_STORAGE_SIZE;
214 compat_ulong_t fpscr, fpexc;
215 int err = 0;
216
217 /*
218 * Save the hardware registers to the fpsimd_state structure.
219 * Note that this also saves V16-31, which aren't visible
220 * in AArch32.
221 */
222 fpsimd_preserve_current_state();
223
224 /* Place structure header on the stack */
225 __put_user_error(magic, &frame->magic, err);
226 __put_user_error(size, &frame->size, err);
227
228 /*
229 * Now copy the FP registers. Since the registers are packed,
230 * we can copy the prefix we want (V0-V15) as it is.
231 * FIXME: Won't work if big endian.
232 */
233 err |= __copy_to_user(&frame->ufp.fpregs, fpsimd->vregs,
234 sizeof(frame->ufp.fpregs));
235
236 /* Create an AArch32 fpscr from the fpsr and the fpcr. */
237 fpscr = (fpsimd->fpsr & VFP_FPSCR_STAT_MASK) |
238 (fpsimd->fpcr & VFP_FPSCR_CTRL_MASK);
239 __put_user_error(fpscr, &frame->ufp.fpscr, err);
240
241 /*
242 * The exception register aren't available so we fake up a
243 * basic FPEXC and zero everything else.
244 */
245 fpexc = (1 << 30);
246 __put_user_error(fpexc, &frame->ufp_exc.fpexc, err);
247 __put_user_error(0, &frame->ufp_exc.fpinst, err);
248 __put_user_error(0, &frame->ufp_exc.fpinst2, err);
249
250 return err ? -EFAULT : 0;
251 }
252
253 static int compat_restore_vfp_context(struct compat_vfp_sigframe __user *frame)
254 {
255 struct fpsimd_state fpsimd;
256 compat_ulong_t magic = VFP_MAGIC;
257 compat_ulong_t size = VFP_STORAGE_SIZE;
258 compat_ulong_t fpscr;
259 int err = 0;
260
261 __get_user_error(magic, &frame->magic, err);
262 __get_user_error(size, &frame->size, err);
263
264 if (err)
265 return -EFAULT;
266 if (magic != VFP_MAGIC || size != VFP_STORAGE_SIZE)
267 return -EINVAL;
268
269 /*
270 * Copy the FP registers into the start of the fpsimd_state.
271 * FIXME: Won't work if big endian.
272 */
273 err |= __copy_from_user(fpsimd.vregs, frame->ufp.fpregs,
274 sizeof(frame->ufp.fpregs));
275
276 /* Extract the fpsr and the fpcr from the fpscr */
277 __get_user_error(fpscr, &frame->ufp.fpscr, err);
278 fpsimd.fpsr = fpscr & VFP_FPSCR_STAT_MASK;
279 fpsimd.fpcr = fpscr & VFP_FPSCR_CTRL_MASK;
280
281 /*
282 * We don't need to touch the exception register, so
283 * reload the hardware state.
284 */
285 if (!err)
286 fpsimd_update_current_state(&fpsimd);
287
288 return err ? -EFAULT : 0;
289 }
290
291 static int compat_restore_sigframe(struct pt_regs *regs,
292 struct compat_sigframe __user *sf)
293 {
294 int err;
295 sigset_t set;
296 struct compat_aux_sigframe __user *aux;
297
298 err = get_sigset_t(&set, &sf->uc.uc_sigmask);
299 if (err == 0) {
300 sigdelsetmask(&set, ~_BLOCKABLE);
301 set_current_blocked(&set);
302 }
303
304 __get_user_error(regs->regs[0], &sf->uc.uc_mcontext.arm_r0, err);
305 __get_user_error(regs->regs[1], &sf->uc.uc_mcontext.arm_r1, err);
306 __get_user_error(regs->regs[2], &sf->uc.uc_mcontext.arm_r2, err);
307 __get_user_error(regs->regs[3], &sf->uc.uc_mcontext.arm_r3, err);
308 __get_user_error(regs->regs[4], &sf->uc.uc_mcontext.arm_r4, err);
309 __get_user_error(regs->regs[5], &sf->uc.uc_mcontext.arm_r5, err);
310 __get_user_error(regs->regs[6], &sf->uc.uc_mcontext.arm_r6, err);
311 __get_user_error(regs->regs[7], &sf->uc.uc_mcontext.arm_r7, err);
312 __get_user_error(regs->regs[8], &sf->uc.uc_mcontext.arm_r8, err);
313 __get_user_error(regs->regs[9], &sf->uc.uc_mcontext.arm_r9, err);
314 __get_user_error(regs->regs[10], &sf->uc.uc_mcontext.arm_r10, err);
315 __get_user_error(regs->regs[11], &sf->uc.uc_mcontext.arm_fp, err);
316 __get_user_error(regs->regs[12], &sf->uc.uc_mcontext.arm_ip, err);
317 __get_user_error(regs->compat_sp, &sf->uc.uc_mcontext.arm_sp, err);
318 __get_user_error(regs->compat_lr, &sf->uc.uc_mcontext.arm_lr, err);
319 __get_user_error(regs->pc, &sf->uc.uc_mcontext.arm_pc, err);
320 __get_user_error(regs->pstate, &sf->uc.uc_mcontext.arm_cpsr, err);
321
322 /*
323 * Avoid compat_sys_sigreturn() restarting.
324 */
325 regs->syscallno = ~0UL;
326
327 err |= !valid_user_regs(&regs->user_regs);
328
329 aux = (struct compat_aux_sigframe __user *) sf->uc.uc_regspace;
330 if (err == 0)
331 err |= compat_restore_vfp_context(&aux->vfp);
332
333 return err;
334 }
335
336 asmlinkage int compat_sys_sigreturn(struct pt_regs *regs)
337 {
338 struct compat_sigframe __user *frame;
339
340 /* Always make any pending restarted system calls return -EINTR */
341 current_thread_info()->restart_block.fn = do_no_restart_syscall;
342
343 /*
344 * Since we stacked the signal on a 64-bit boundary,
345 * then 'sp' should be word aligned here. If it's
346 * not, then the user is trying to mess with us.
347 */
348 if (regs->compat_sp & 7)
349 goto badframe;
350
351 frame = (struct compat_sigframe __user *)regs->compat_sp;
352
353 if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
354 goto badframe;
355
356 if (compat_restore_sigframe(regs, frame))
357 goto badframe;
358
359 return regs->regs[0];
360
361 badframe:
362 if (show_unhandled_signals)
363 pr_info_ratelimited("%s[%d]: bad frame in %s: pc=%08llx sp=%08llx\n",
364 current->comm, task_pid_nr(current), __func__,
365 regs->pc, regs->sp);
366 force_sig(SIGSEGV, current);
367 return 0;
368 }
369
370 asmlinkage int compat_sys_rt_sigreturn(struct pt_regs *regs)
371 {
372 struct compat_rt_sigframe __user *frame;
373
374 /* Always make any pending restarted system calls return -EINTR */
375 current_thread_info()->restart_block.fn = do_no_restart_syscall;
376
377 /*
378 * Since we stacked the signal on a 64-bit boundary,
379 * then 'sp' should be word aligned here. If it's
380 * not, then the user is trying to mess with us.
381 */
382 if (regs->compat_sp & 7)
383 goto badframe;
384
385 frame = (struct compat_rt_sigframe __user *)regs->compat_sp;
386
387 if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
388 goto badframe;
389
390 if (compat_restore_sigframe(regs, &frame->sig))
391 goto badframe;
392
393 if (compat_restore_altstack(&frame->sig.uc.uc_stack))
394 goto badframe;
395
396 return regs->regs[0];
397
398 badframe:
399 if (show_unhandled_signals)
400 pr_info_ratelimited("%s[%d]: bad frame in %s: pc=%08llx sp=%08llx\n",
401 current->comm, task_pid_nr(current), __func__,
402 regs->pc, regs->sp);
403 force_sig(SIGSEGV, current);
404 return 0;
405 }
406
407 static void __user *compat_get_sigframe(struct k_sigaction *ka,
408 struct pt_regs *regs,
409 int framesize)
410 {
411 compat_ulong_t sp = regs->compat_sp;
412 void __user *frame;
413
414 /*
415 * This is the X/Open sanctioned signal stack switching.
416 */
417 if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp))
418 sp = current->sas_ss_sp + current->sas_ss_size;
419
420 /*
421 * ATPCS B01 mandates 8-byte alignment
422 */
423 frame = compat_ptr((compat_uptr_t)((sp - framesize) & ~7));
424
425 /*
426 * Check that we can actually write to the signal frame.
427 */
428 if (!access_ok(VERIFY_WRITE, frame, framesize))
429 frame = NULL;
430
431 return frame;
432 }
433
434 static void compat_setup_return(struct pt_regs *regs, struct k_sigaction *ka,
435 compat_ulong_t __user *rc, void __user *frame,
436 int usig)
437 {
438 compat_ulong_t handler = ptr_to_compat(ka->sa.sa_handler);
439 compat_ulong_t retcode;
440 compat_ulong_t spsr = regs->pstate & ~PSR_f;
441 int thumb;
442
443 /* Check if the handler is written for ARM or Thumb */
444 thumb = handler & 1;
445
446 if (thumb)
447 spsr |= COMPAT_PSR_T_BIT;
448 else
449 spsr &= ~COMPAT_PSR_T_BIT;
450
451 /* The IT state must be cleared for both ARM and Thumb-2 */
452 spsr &= ~COMPAT_PSR_IT_MASK;
453
454 if (ka->sa.sa_flags & SA_RESTORER) {
455 retcode = ptr_to_compat(ka->sa.sa_restorer);
456 } else {
457 /* Set up sigreturn pointer */
458 unsigned int idx = thumb << 1;
459
460 if (ka->sa.sa_flags & SA_SIGINFO)
461 idx += 3;
462
463 retcode = AARCH32_VECTORS_BASE +
464 AARCH32_KERN_SIGRET_CODE_OFFSET +
465 (idx << 2) + thumb;
466 }
467
468 regs->regs[0] = usig;
469 regs->compat_sp = ptr_to_compat(frame);
470 regs->compat_lr = retcode;
471 regs->pc = handler;
472 regs->pstate = spsr;
473 }
474
475 static int compat_setup_sigframe(struct compat_sigframe __user *sf,
476 struct pt_regs *regs, sigset_t *set)
477 {
478 struct compat_aux_sigframe __user *aux;
479 int err = 0;
480
481 __put_user_error(regs->regs[0], &sf->uc.uc_mcontext.arm_r0, err);
482 __put_user_error(regs->regs[1], &sf->uc.uc_mcontext.arm_r1, err);
483 __put_user_error(regs->regs[2], &sf->uc.uc_mcontext.arm_r2, err);
484 __put_user_error(regs->regs[3], &sf->uc.uc_mcontext.arm_r3, err);
485 __put_user_error(regs->regs[4], &sf->uc.uc_mcontext.arm_r4, err);
486 __put_user_error(regs->regs[5], &sf->uc.uc_mcontext.arm_r5, err);
487 __put_user_error(regs->regs[6], &sf->uc.uc_mcontext.arm_r6, err);
488 __put_user_error(regs->regs[7], &sf->uc.uc_mcontext.arm_r7, err);
489 __put_user_error(regs->regs[8], &sf->uc.uc_mcontext.arm_r8, err);
490 __put_user_error(regs->regs[9], &sf->uc.uc_mcontext.arm_r9, err);
491 __put_user_error(regs->regs[10], &sf->uc.uc_mcontext.arm_r10, err);
492 __put_user_error(regs->regs[11], &sf->uc.uc_mcontext.arm_fp, err);
493 __put_user_error(regs->regs[12], &sf->uc.uc_mcontext.arm_ip, err);
494 __put_user_error(regs->compat_sp, &sf->uc.uc_mcontext.arm_sp, err);
495 __put_user_error(regs->compat_lr, &sf->uc.uc_mcontext.arm_lr, err);
496 __put_user_error(regs->pc, &sf->uc.uc_mcontext.arm_pc, err);
497 __put_user_error(regs->pstate, &sf->uc.uc_mcontext.arm_cpsr, err);
498
499 __put_user_error((compat_ulong_t)0, &sf->uc.uc_mcontext.trap_no, err);
500 __put_user_error((compat_ulong_t)0, &sf->uc.uc_mcontext.error_code, err);
501 __put_user_error(current->thread.fault_address, &sf->uc.uc_mcontext.fault_address, err);
502 __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err);
503
504 err |= put_sigset_t(&sf->uc.uc_sigmask, set);
505
506 aux = (struct compat_aux_sigframe __user *) sf->uc.uc_regspace;
507
508 if (err == 0)
509 err |= compat_preserve_vfp_context(&aux->vfp);
510 __put_user_error(0, &aux->end_magic, err);
511
512 return err;
513 }
514
515 /*
516 * 32-bit signal handling routines called from signal.c
517 */
518 int compat_setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info,
519 sigset_t *set, struct pt_regs *regs)
520 {
521 struct compat_rt_sigframe __user *frame;
522 int err = 0;
523
524 frame = compat_get_sigframe(ka, regs, sizeof(*frame));
525
526 if (!frame)
527 return 1;
528
529 err |= copy_siginfo_to_user32(&frame->info, info);
530
531 __put_user_error(0, &frame->sig.uc.uc_flags, err);
532 __put_user_error(0, &frame->sig.uc.uc_link, err);
533
534 err |= __compat_save_altstack(&frame->sig.uc.uc_stack, regs->compat_sp);
535
536 err |= compat_setup_sigframe(&frame->sig, regs, set);
537
538 if (err == 0) {
539 compat_setup_return(regs, ka, frame->sig.retcode, frame, usig);
540 regs->regs[1] = (compat_ulong_t)(unsigned long)&frame->info;
541 regs->regs[2] = (compat_ulong_t)(unsigned long)&frame->sig.uc;
542 }
543
544 return err;
545 }
546
547 int compat_setup_frame(int usig, struct k_sigaction *ka, sigset_t *set,
548 struct pt_regs *regs)
549 {
550 struct compat_sigframe __user *frame;
551 int err = 0;
552
553 frame = compat_get_sigframe(ka, regs, sizeof(*frame));
554
555 if (!frame)
556 return 1;
557
558 __put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err);
559
560 err |= compat_setup_sigframe(frame, regs, set);
561 if (err == 0)
562 compat_setup_return(regs, ka, frame->retcode, frame, usig);
563
564 return err;
565 }
566
567 void compat_setup_restart_syscall(struct pt_regs *regs)
568 {
569 regs->regs[7] = __NR_compat_restart_syscall;
570 }
Linux kernel - Deliverables
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