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mm: hugetlb: fix hugepage memory leak caused by wrong reserve count
[linux/fpc-iii.git] / arch / arm64 / kernel / signal32.c
blob71ef6dc89ae509cd299eab3f1959ffe4e8f96a33
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(from->si_int, &to->si_int);
158 break;
159 case __SI_POLL:
160 err |= __put_user(from->si_band, &to->si_band);
161 err |= __put_user(from->si_fd, &to->si_fd);
162 break;
163 case __SI_FAULT:
164 err |= __put_user((compat_uptr_t)(unsigned long)from->si_addr,
165 &to->si_addr);
166 #ifdef BUS_MCEERR_AO
167 /*
168 * Other callers might not initialize the si_lsb field,
169 * so check explicitely for the right codes here.
170 */
171 if (from->si_signo == SIGBUS &&
172 (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(from->si_int, &to->si_int);
188 break;
189 case __SI_SYS:
190 err |= __put_user((compat_uptr_t)(unsigned long)
191 from->si_call_addr, &to->si_call_addr);
192 err |= __put_user(from->si_syscall, &to->si_syscall);
193 err |= __put_user(from->si_arch, &to->si_arch);
194 break;
195 default: /* this is just in case for now ... */
196 err |= __put_user(from->si_pid, &to->si_pid);
197 err |= __put_user(from->si_uid, &to->si_uid);
198 break;
199 }
200 return err;
201 }
202
203 int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from)
204 {
205 if (copy_from_user(to, from, __ARCH_SI_PREAMBLE_SIZE) ||
206 copy_from_user(to->_sifields._pad,
207 from->_sifields._pad, SI_PAD_SIZE))
208 return -EFAULT;
209
210 return 0;
211 }
212
213 /*
214 * VFP save/restore code.
215 *
216 * We have to be careful with endianness, since the fpsimd context-switch
217 * code operates on 128-bit (Q) register values whereas the compat ABI
218 * uses an array of 64-bit (D) registers. Consequently, we need to swap
219 * the two halves of each Q register when running on a big-endian CPU.
220 */
221 union __fpsimd_vreg {
222 __uint128_t raw;
223 struct {
224 #ifdef __AARCH64EB__
225 u64 hi;
226 u64 lo;
227 #else
228 u64 lo;
229 u64 hi;
230 #endif
231 };
232 };
233
234 static int compat_preserve_vfp_context(struct compat_vfp_sigframe __user *frame)
235 {
236 struct fpsimd_state *fpsimd = &current->thread.fpsimd_state;
237 compat_ulong_t magic = VFP_MAGIC;
238 compat_ulong_t size = VFP_STORAGE_SIZE;
239 compat_ulong_t fpscr, fpexc;
240 int i, err = 0;
241
242 /*
243 * Save the hardware registers to the fpsimd_state structure.
244 * Note that this also saves V16-31, which aren't visible
245 * in AArch32.
246 */
247 fpsimd_preserve_current_state();
248
249 /* Place structure header on the stack */
250 __put_user_error(magic, &frame->magic, err);
251 __put_user_error(size, &frame->size, err);
252
253 /*
254 * Now copy the FP registers. Since the registers are packed,
255 * we can copy the prefix we want (V0-V15) as it is.
256 */
257 for (i = 0; i < ARRAY_SIZE(frame->ufp.fpregs); i += 2) {
258 union __fpsimd_vreg vreg = {
259 .raw = fpsimd->vregs[i >> 1],
260 };
261
262 __put_user_error(vreg.lo, &frame->ufp.fpregs[i], err);
263 __put_user_error(vreg.hi, &frame->ufp.fpregs[i + 1], err);
264 }
265
266 /* Create an AArch32 fpscr from the fpsr and the fpcr. */
267 fpscr = (fpsimd->fpsr & VFP_FPSCR_STAT_MASK) |
268 (fpsimd->fpcr & VFP_FPSCR_CTRL_MASK);
269 __put_user_error(fpscr, &frame->ufp.fpscr, err);
270
271 /*
272 * The exception register aren't available so we fake up a
273 * basic FPEXC and zero everything else.
274 */
275 fpexc = (1 << 30);
276 __put_user_error(fpexc, &frame->ufp_exc.fpexc, err);
277 __put_user_error(0, &frame->ufp_exc.fpinst, err);
278 __put_user_error(0, &frame->ufp_exc.fpinst2, err);
279
280 return err ? -EFAULT : 0;
281 }
282
283 static int compat_restore_vfp_context(struct compat_vfp_sigframe __user *frame)
284 {
285 struct fpsimd_state fpsimd;
286 compat_ulong_t magic = VFP_MAGIC;
287 compat_ulong_t size = VFP_STORAGE_SIZE;
288 compat_ulong_t fpscr;
289 int i, err = 0;
290
291 __get_user_error(magic, &frame->magic, err);
292 __get_user_error(size, &frame->size, err);
293
294 if (err)
295 return -EFAULT;
296 if (magic != VFP_MAGIC || size != VFP_STORAGE_SIZE)
297 return -EINVAL;
298
299 /* Copy the FP registers into the start of the fpsimd_state. */
300 for (i = 0; i < ARRAY_SIZE(frame->ufp.fpregs); i += 2) {
301 union __fpsimd_vreg vreg;
302
303 __get_user_error(vreg.lo, &frame->ufp.fpregs[i], err);
304 __get_user_error(vreg.hi, &frame->ufp.fpregs[i + 1], err);
305 fpsimd.vregs[i >> 1] = vreg.raw;
306 }
307
308 /* Extract the fpsr and the fpcr from the fpscr */
309 __get_user_error(fpscr, &frame->ufp.fpscr, err);
310 fpsimd.fpsr = fpscr & VFP_FPSCR_STAT_MASK;
311 fpsimd.fpcr = fpscr & VFP_FPSCR_CTRL_MASK;
312
313 /*
314 * We don't need to touch the exception register, so
315 * reload the hardware state.
316 */
317 if (!err)
318 fpsimd_update_current_state(&fpsimd);
319
320 return err ? -EFAULT : 0;
321 }
322
323 static int compat_restore_sigframe(struct pt_regs *regs,
324 struct compat_sigframe __user *sf)
325 {
326 int err;
327 sigset_t set;
328 struct compat_aux_sigframe __user *aux;
329
330 err = get_sigset_t(&set, &sf->uc.uc_sigmask);
331 if (err == 0) {
332 sigdelsetmask(&set, ~_BLOCKABLE);
333 set_current_blocked(&set);
334 }
335
336 __get_user_error(regs->regs[0], &sf->uc.uc_mcontext.arm_r0, err);
337 __get_user_error(regs->regs[1], &sf->uc.uc_mcontext.arm_r1, err);
338 __get_user_error(regs->regs[2], &sf->uc.uc_mcontext.arm_r2, err);
339 __get_user_error(regs->regs[3], &sf->uc.uc_mcontext.arm_r3, err);
340 __get_user_error(regs->regs[4], &sf->uc.uc_mcontext.arm_r4, err);
341 __get_user_error(regs->regs[5], &sf->uc.uc_mcontext.arm_r5, err);
342 __get_user_error(regs->regs[6], &sf->uc.uc_mcontext.arm_r6, err);
343 __get_user_error(regs->regs[7], &sf->uc.uc_mcontext.arm_r7, err);
344 __get_user_error(regs->regs[8], &sf->uc.uc_mcontext.arm_r8, err);
345 __get_user_error(regs->regs[9], &sf->uc.uc_mcontext.arm_r9, err);
346 __get_user_error(regs->regs[10], &sf->uc.uc_mcontext.arm_r10, err);
347 __get_user_error(regs->regs[11], &sf->uc.uc_mcontext.arm_fp, err);
348 __get_user_error(regs->regs[12], &sf->uc.uc_mcontext.arm_ip, err);
349 __get_user_error(regs->compat_sp, &sf->uc.uc_mcontext.arm_sp, err);
350 __get_user_error(regs->compat_lr, &sf->uc.uc_mcontext.arm_lr, err);
351 __get_user_error(regs->pc, &sf->uc.uc_mcontext.arm_pc, err);
352 __get_user_error(regs->pstate, &sf->uc.uc_mcontext.arm_cpsr, err);
353
354 /*
355 * Avoid compat_sys_sigreturn() restarting.
356 */
357 regs->syscallno = ~0UL;
358
359 err |= !valid_user_regs(&regs->user_regs);
360
361 aux = (struct compat_aux_sigframe __user *) sf->uc.uc_regspace;
362 if (err == 0)
363 err |= compat_restore_vfp_context(&aux->vfp);
364
365 return err;
366 }
367
368 asmlinkage int compat_sys_sigreturn(struct pt_regs *regs)
369 {
370 struct compat_sigframe __user *frame;
371
372 /* Always make any pending restarted system calls return -EINTR */
373 current->restart_block.fn = do_no_restart_syscall;
374
375 /*
376 * Since we stacked the signal on a 64-bit boundary,
377 * then 'sp' should be word aligned here. If it's
378 * not, then the user is trying to mess with us.
379 */
380 if (regs->compat_sp & 7)
381 goto badframe;
382
383 frame = (struct compat_sigframe __user *)regs->compat_sp;
384
385 if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
386 goto badframe;
387
388 if (compat_restore_sigframe(regs, frame))
389 goto badframe;
390
391 return regs->regs[0];
392
393 badframe:
394 if (show_unhandled_signals)
395 pr_info_ratelimited("%s[%d]: bad frame in %s: pc=%08llx sp=%08llx\n",
396 current->comm, task_pid_nr(current), __func__,
397 regs->pc, regs->compat_sp);
398 force_sig(SIGSEGV, current);
399 return 0;
400 }
401
402 asmlinkage int compat_sys_rt_sigreturn(struct pt_regs *regs)
403 {
404 struct compat_rt_sigframe __user *frame;
405
406 /* Always make any pending restarted system calls return -EINTR */
407 current->restart_block.fn = do_no_restart_syscall;
408
409 /*
410 * Since we stacked the signal on a 64-bit boundary,
411 * then 'sp' should be word aligned here. If it's
412 * not, then the user is trying to mess with us.
413 */
414 if (regs->compat_sp & 7)
415 goto badframe;
416
417 frame = (struct compat_rt_sigframe __user *)regs->compat_sp;
418
419 if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
420 goto badframe;
421
422 if (compat_restore_sigframe(regs, &frame->sig))
423 goto badframe;
424
425 if (compat_restore_altstack(&frame->sig.uc.uc_stack))
426 goto badframe;
427
428 return regs->regs[0];
429
430 badframe:
431 if (show_unhandled_signals)
432 pr_info_ratelimited("%s[%d]: bad frame in %s: pc=%08llx sp=%08llx\n",
433 current->comm, task_pid_nr(current), __func__,
434 regs->pc, regs->compat_sp);
435 force_sig(SIGSEGV, current);
436 return 0;
437 }
438
439 static void __user *compat_get_sigframe(struct ksignal *ksig,
440 struct pt_regs *regs,
441 int framesize)
442 {
443 compat_ulong_t sp = sigsp(regs->compat_sp, ksig);
444 void __user *frame;
445
446 /*
447 * ATPCS B01 mandates 8-byte alignment
448 */
449 frame = compat_ptr((compat_uptr_t)((sp - framesize) & ~7));
450
451 /*
452 * Check that we can actually write to the signal frame.
453 */
454 if (!access_ok(VERIFY_WRITE, frame, framesize))
455 frame = NULL;
456
457 return frame;
458 }
459
460 static void compat_setup_return(struct pt_regs *regs, struct k_sigaction *ka,
461 compat_ulong_t __user *rc, void __user *frame,
462 int usig)
463 {
464 compat_ulong_t handler = ptr_to_compat(ka->sa.sa_handler);
465 compat_ulong_t retcode;
466 compat_ulong_t spsr = regs->pstate & ~(PSR_f | COMPAT_PSR_E_BIT);
467 int thumb;
468
469 /* Check if the handler is written for ARM or Thumb */
470 thumb = handler & 1;
471
472 if (thumb)
473 spsr |= COMPAT_PSR_T_BIT;
474 else
475 spsr &= ~COMPAT_PSR_T_BIT;
476
477 /* The IT state must be cleared for both ARM and Thumb-2 */
478 spsr &= ~COMPAT_PSR_IT_MASK;
479
480 /* Restore the original endianness */
481 spsr |= COMPAT_PSR_ENDSTATE;
482
483 if (ka->sa.sa_flags & SA_RESTORER) {
484 retcode = ptr_to_compat(ka->sa.sa_restorer);
485 } else {
486 /* Set up sigreturn pointer */
487 unsigned int idx = thumb << 1;
488
489 if (ka->sa.sa_flags & SA_SIGINFO)
490 idx += 3;
491
492 retcode = AARCH32_VECTORS_BASE +
493 AARCH32_KERN_SIGRET_CODE_OFFSET +
494 (idx << 2) + thumb;
495 }
496
497 regs->regs[0] = usig;
498 regs->compat_sp = ptr_to_compat(frame);
499 regs->compat_lr = retcode;
500 regs->pc = handler;
501 regs->pstate = spsr;
502 }
503
504 static int compat_setup_sigframe(struct compat_sigframe __user *sf,
505 struct pt_regs *regs, sigset_t *set)
506 {
507 struct compat_aux_sigframe __user *aux;
508 int err = 0;
509
510 __put_user_error(regs->regs[0], &sf->uc.uc_mcontext.arm_r0, err);
511 __put_user_error(regs->regs[1], &sf->uc.uc_mcontext.arm_r1, err);
512 __put_user_error(regs->regs[2], &sf->uc.uc_mcontext.arm_r2, err);
513 __put_user_error(regs->regs[3], &sf->uc.uc_mcontext.arm_r3, err);
514 __put_user_error(regs->regs[4], &sf->uc.uc_mcontext.arm_r4, err);
515 __put_user_error(regs->regs[5], &sf->uc.uc_mcontext.arm_r5, err);
516 __put_user_error(regs->regs[6], &sf->uc.uc_mcontext.arm_r6, err);
517 __put_user_error(regs->regs[7], &sf->uc.uc_mcontext.arm_r7, err);
518 __put_user_error(regs->regs[8], &sf->uc.uc_mcontext.arm_r8, err);
519 __put_user_error(regs->regs[9], &sf->uc.uc_mcontext.arm_r9, err);
520 __put_user_error(regs->regs[10], &sf->uc.uc_mcontext.arm_r10, err);
521 __put_user_error(regs->regs[11], &sf->uc.uc_mcontext.arm_fp, err);
522 __put_user_error(regs->regs[12], &sf->uc.uc_mcontext.arm_ip, err);
523 __put_user_error(regs->compat_sp, &sf->uc.uc_mcontext.arm_sp, err);
524 __put_user_error(regs->compat_lr, &sf->uc.uc_mcontext.arm_lr, err);
525 __put_user_error(regs->pc, &sf->uc.uc_mcontext.arm_pc, err);
526 __put_user_error(regs->pstate, &sf->uc.uc_mcontext.arm_cpsr, err);
527
528 __put_user_error((compat_ulong_t)0, &sf->uc.uc_mcontext.trap_no, err);
529 /* set the compat FSR WnR */
530 __put_user_error(!!(current->thread.fault_code & ESR_ELx_WNR) <<
531 FSR_WRITE_SHIFT, &sf->uc.uc_mcontext.error_code, err);
532 __put_user_error(current->thread.fault_address, &sf->uc.uc_mcontext.fault_address, err);
533 __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err);
534
535 err |= put_sigset_t(&sf->uc.uc_sigmask, set);
536
537 aux = (struct compat_aux_sigframe __user *) sf->uc.uc_regspace;
538
539 if (err == 0)
540 err |= compat_preserve_vfp_context(&aux->vfp);
541 __put_user_error(0, &aux->end_magic, err);
542
543 return err;
544 }
545
546 /*
547 * 32-bit signal handling routines called from signal.c
548 */
549 int compat_setup_rt_frame(int usig, struct ksignal *ksig,
550 sigset_t *set, struct pt_regs *regs)
551 {
552 struct compat_rt_sigframe __user *frame;
553 int err = 0;
554
555 frame = compat_get_sigframe(ksig, regs, sizeof(*frame));
556
557 if (!frame)
558 return 1;
559
560 err |= copy_siginfo_to_user32(&frame->info, &ksig->info);
561
562 __put_user_error(0, &frame->sig.uc.uc_flags, err);
563 __put_user_error(0, &frame->sig.uc.uc_link, err);
564
565 err |= __compat_save_altstack(&frame->sig.uc.uc_stack, regs->compat_sp);
566
567 err |= compat_setup_sigframe(&frame->sig, regs, set);
568
569 if (err == 0) {
570 compat_setup_return(regs, &ksig->ka, frame->sig.retcode, frame, usig);
571 regs->regs[1] = (compat_ulong_t)(unsigned long)&frame->info;
572 regs->regs[2] = (compat_ulong_t)(unsigned long)&frame->sig.uc;
573 }
574
575 return err;
576 }
577
578 int compat_setup_frame(int usig, struct ksignal *ksig, sigset_t *set,
579 struct pt_regs *regs)
580 {
581 struct compat_sigframe __user *frame;
582 int err = 0;
583
584 frame = compat_get_sigframe(ksig, regs, sizeof(*frame));
585
586 if (!frame)
587 return 1;
588
589 __put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err);
590
591 err |= compat_setup_sigframe(frame, regs, set);
592 if (err == 0)
593 compat_setup_return(regs, &ksig->ka, frame->retcode, frame, usig);
594
595 return err;
596 }
597
598 void compat_setup_restart_syscall(struct pt_regs *regs)
599 {
600 regs->regs[7] = __NR_compat_restart_syscall;
601 }
Linux with added FPC-III support