Commit | Line | Data |
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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1da177e4 LT |
2 | /* |
3 | * linux/arch/arm/kernel/signal.c | |
4 | * | |
ab72b007 | 5 | * Copyright (C) 1995-2009 Russell King |
1da177e4 | 6 | */ |
1da177e4 | 7 | #include <linux/errno.h> |
48be69a0 | 8 | #include <linux/random.h> |
1da177e4 | 9 | #include <linux/signal.h> |
1da177e4 | 10 | #include <linux/personality.h> |
33fa9b13 | 11 | #include <linux/uaccess.h> |
733e5e4b | 12 | #include <linux/tracehook.h> |
c7edc9e3 | 13 | #include <linux/uprobes.h> |
e33f8d32 | 14 | #include <linux/syscalls.h> |
1da177e4 | 15 | |
ee90dabc | 16 | #include <asm/elf.h> |
1da177e4 | 17 | #include <asm/cacheflush.h> |
48be69a0 | 18 | #include <asm/traps.h> |
1da177e4 | 19 | #include <asm/unistd.h> |
82c6f5a5 | 20 | #include <asm/vfp.h> |
1da177e4 | 21 | |
5c165953 NP |
22 | #include "signal.h" |
23 | ||
24 | extern const unsigned long sigreturn_codes[17]; | |
1da177e4 | 25 | |
48be69a0 RK |
26 | static unsigned long signal_return_offset; |
27 | ||
3bec6ded | 28 | #ifdef CONFIG_CRUNCH |
65a5053b | 29 | static int preserve_crunch_context(struct crunch_sigframe __user *frame) |
3bec6ded LB |
30 | { |
31 | char kbuf[sizeof(*frame) + 8]; | |
32 | struct crunch_sigframe *kframe; | |
33 | ||
34 | /* the crunch context must be 64 bit aligned */ | |
35 | kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7); | |
36 | kframe->magic = CRUNCH_MAGIC; | |
37 | kframe->size = CRUNCH_STORAGE_SIZE; | |
38 | crunch_task_copy(current_thread_info(), &kframe->storage); | |
39 | return __copy_to_user(frame, kframe, sizeof(*frame)); | |
40 | } | |
41 | ||
ce184a0d | 42 | static int restore_crunch_context(char __user **auxp) |
3bec6ded | 43 | { |
ce184a0d DM |
44 | struct crunch_sigframe __user *frame = |
45 | (struct crunch_sigframe __user *)*auxp; | |
3bec6ded LB |
46 | char kbuf[sizeof(*frame) + 8]; |
47 | struct crunch_sigframe *kframe; | |
48 | ||
49 | /* the crunch context must be 64 bit aligned */ | |
50 | kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7); | |
51 | if (__copy_from_user(kframe, frame, sizeof(*frame))) | |
52 | return -1; | |
53 | if (kframe->magic != CRUNCH_MAGIC || | |
54 | kframe->size != CRUNCH_STORAGE_SIZE) | |
55 | return -1; | |
ce184a0d | 56 | *auxp += CRUNCH_STORAGE_SIZE; |
3bec6ded LB |
57 | crunch_task_restore(current_thread_info(), &kframe->storage); |
58 | return 0; | |
59 | } | |
60 | #endif | |
61 | ||
1da177e4 LT |
62 | #ifdef CONFIG_IWMMXT |
63 | ||
26958355 | 64 | static int preserve_iwmmxt_context(struct iwmmxt_sigframe __user *frame) |
1da177e4 | 65 | { |
69b04754 HD |
66 | char kbuf[sizeof(*frame) + 8]; |
67 | struct iwmmxt_sigframe *kframe; | |
ce184a0d | 68 | int err = 0; |
1da177e4 LT |
69 | |
70 | /* the iWMMXt context must be 64 bit aligned */ | |
69b04754 | 71 | kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7); |
ce184a0d DM |
72 | |
73 | if (test_thread_flag(TIF_USING_IWMMXT)) { | |
74 | kframe->magic = IWMMXT_MAGIC; | |
75 | kframe->size = IWMMXT_STORAGE_SIZE; | |
76 | iwmmxt_task_copy(current_thread_info(), &kframe->storage); | |
ce184a0d DM |
77 | } else { |
78 | /* | |
79 | * For bug-compatibility with older kernels, some space | |
80 | * has to be reserved for iWMMXt even if it's not used. | |
81 | * Set the magic and size appropriately so that properly | |
82 | * written userspace can skip it reliably: | |
83 | */ | |
73839798 JT |
84 | *kframe = (struct iwmmxt_sigframe) { |
85 | .magic = DUMMY_MAGIC, | |
86 | .size = IWMMXT_STORAGE_SIZE, | |
87 | }; | |
ce184a0d DM |
88 | } |
89 | ||
73839798 JT |
90 | err = __copy_to_user(frame, kframe, sizeof(*kframe)); |
91 | ||
ce184a0d | 92 | return err; |
1da177e4 LT |
93 | } |
94 | ||
ce184a0d | 95 | static int restore_iwmmxt_context(char __user **auxp) |
1da177e4 | 96 | { |
ce184a0d DM |
97 | struct iwmmxt_sigframe __user *frame = |
98 | (struct iwmmxt_sigframe __user *)*auxp; | |
69b04754 HD |
99 | char kbuf[sizeof(*frame) + 8]; |
100 | struct iwmmxt_sigframe *kframe; | |
101 | ||
102 | /* the iWMMXt context must be 64 bit aligned */ | |
103 | kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7); | |
104 | if (__copy_from_user(kframe, frame, sizeof(*frame))) | |
105 | return -1; | |
ce184a0d DM |
106 | |
107 | /* | |
108 | * For non-iWMMXt threads: a single iwmmxt_sigframe-sized dummy | |
109 | * block is discarded for compatibility with setup_sigframe() if | |
110 | * present, but we don't mandate its presence. If some other | |
111 | * magic is here, it's not for us: | |
112 | */ | |
113 | if (!test_thread_flag(TIF_USING_IWMMXT) && | |
114 | kframe->magic != DUMMY_MAGIC) | |
115 | return 0; | |
116 | ||
117 | if (kframe->size != IWMMXT_STORAGE_SIZE) | |
69b04754 | 118 | return -1; |
ce184a0d DM |
119 | |
120 | if (test_thread_flag(TIF_USING_IWMMXT)) { | |
121 | if (kframe->magic != IWMMXT_MAGIC) | |
122 | return -1; | |
123 | ||
124 | iwmmxt_task_restore(current_thread_info(), &kframe->storage); | |
125 | } | |
126 | ||
127 | *auxp += IWMMXT_STORAGE_SIZE; | |
69b04754 | 128 | return 0; |
1da177e4 LT |
129 | } |
130 | ||
131 | #endif | |
132 | ||
82c6f5a5 ID |
133 | #ifdef CONFIG_VFP |
134 | ||
135 | static int preserve_vfp_context(struct vfp_sigframe __user *frame) | |
136 | { | |
3aa2df6e | 137 | struct vfp_sigframe kframe; |
82c6f5a5 ID |
138 | int err = 0; |
139 | ||
3aa2df6e JT |
140 | memset(&kframe, 0, sizeof(kframe)); |
141 | kframe.magic = VFP_MAGIC; | |
142 | kframe.size = VFP_STORAGE_SIZE; | |
82c6f5a5 | 143 | |
3aa2df6e | 144 | err = vfp_preserve_user_clear_hwstate(&kframe.ufp, &kframe.ufp_exc); |
2498814f | 145 | if (err) |
3aa2df6e | 146 | return err; |
2498814f | 147 | |
3aa2df6e | 148 | return __copy_to_user(frame, &kframe, sizeof(kframe)); |
82c6f5a5 ID |
149 | } |
150 | ||
ce184a0d | 151 | static int restore_vfp_context(char __user **auxp) |
82c6f5a5 | 152 | { |
42019fc5 RK |
153 | struct vfp_sigframe frame; |
154 | int err; | |
82c6f5a5 | 155 | |
42019fc5 | 156 | err = __copy_from_user(&frame, *auxp, sizeof(frame)); |
82c6f5a5 | 157 | if (err) |
42019fc5 RK |
158 | return err; |
159 | ||
160 | if (frame.magic != VFP_MAGIC || frame.size != VFP_STORAGE_SIZE) | |
82c6f5a5 ID |
161 | return -EINVAL; |
162 | ||
42019fc5 RK |
163 | *auxp += sizeof(frame); |
164 | return vfp_restore_user_hwstate(&frame.ufp, &frame.ufp_exc); | |
82c6f5a5 ID |
165 | } |
166 | ||
167 | #endif | |
168 | ||
1da177e4 LT |
169 | /* |
170 | * Do a signal return; undo the signal stack. These are aligned to 64-bit. | |
171 | */ | |
1da177e4 | 172 | |
68071484 | 173 | static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf) |
1da177e4 | 174 | { |
c32cd419 | 175 | struct sigcontext context; |
ce184a0d | 176 | char __user *aux; |
68071484 RK |
177 | sigset_t set; |
178 | int err; | |
179 | ||
180 | err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set)); | |
77097ae5 | 181 | if (err == 0) |
101d9b0d | 182 | set_current_blocked(&set); |
1da177e4 | 183 | |
c32cd419 RK |
184 | err |= __copy_from_user(&context, &sf->uc.uc_mcontext, sizeof(context)); |
185 | if (err == 0) { | |
186 | regs->ARM_r0 = context.arm_r0; | |
187 | regs->ARM_r1 = context.arm_r1; | |
188 | regs->ARM_r2 = context.arm_r2; | |
189 | regs->ARM_r3 = context.arm_r3; | |
190 | regs->ARM_r4 = context.arm_r4; | |
191 | regs->ARM_r5 = context.arm_r5; | |
192 | regs->ARM_r6 = context.arm_r6; | |
193 | regs->ARM_r7 = context.arm_r7; | |
194 | regs->ARM_r8 = context.arm_r8; | |
195 | regs->ARM_r9 = context.arm_r9; | |
196 | regs->ARM_r10 = context.arm_r10; | |
197 | regs->ARM_fp = context.arm_fp; | |
198 | regs->ARM_ip = context.arm_ip; | |
199 | regs->ARM_sp = context.arm_sp; | |
200 | regs->ARM_lr = context.arm_lr; | |
201 | regs->ARM_pc = context.arm_pc; | |
202 | regs->ARM_cpsr = context.arm_cpsr; | |
203 | } | |
1da177e4 LT |
204 | |
205 | err |= !valid_user_regs(regs); | |
206 | ||
ce184a0d | 207 | aux = (char __user *) sf->uc.uc_regspace; |
3bec6ded LB |
208 | #ifdef CONFIG_CRUNCH |
209 | if (err == 0) | |
ce184a0d | 210 | err |= restore_crunch_context(&aux); |
3bec6ded | 211 | #endif |
1da177e4 | 212 | #ifdef CONFIG_IWMMXT |
ce184a0d DM |
213 | if (err == 0) |
214 | err |= restore_iwmmxt_context(&aux); | |
1da177e4 LT |
215 | #endif |
216 | #ifdef CONFIG_VFP | |
82c6f5a5 | 217 | if (err == 0) |
ce184a0d | 218 | err |= restore_vfp_context(&aux); |
1da177e4 LT |
219 | #endif |
220 | ||
221 | return err; | |
222 | } | |
223 | ||
224 | asmlinkage int sys_sigreturn(struct pt_regs *regs) | |
225 | { | |
226 | struct sigframe __user *frame; | |
1da177e4 LT |
227 | |
228 | /* Always make any pending restarted system calls return -EINTR */ | |
f56141e3 | 229 | current->restart_block.fn = do_no_restart_syscall; |
1da177e4 LT |
230 | |
231 | /* | |
232 | * Since we stacked the signal on a 64-bit boundary, | |
233 | * then 'sp' should be word aligned here. If it's | |
234 | * not, then the user is trying to mess with us. | |
235 | */ | |
236 | if (regs->ARM_sp & 7) | |
237 | goto badframe; | |
238 | ||
239 | frame = (struct sigframe __user *)regs->ARM_sp; | |
240 | ||
96d4f267 | 241 | if (!access_ok(frame, sizeof (*frame))) |
1da177e4 | 242 | goto badframe; |
1da177e4 | 243 | |
68071484 | 244 | if (restore_sigframe(regs, frame)) |
1da177e4 LT |
245 | goto badframe; |
246 | ||
1da177e4 LT |
247 | return regs->ARM_r0; |
248 | ||
249 | badframe: | |
3cf5d076 | 250 | force_sig(SIGSEGV); |
1da177e4 LT |
251 | return 0; |
252 | } | |
253 | ||
254 | asmlinkage int sys_rt_sigreturn(struct pt_regs *regs) | |
255 | { | |
256 | struct rt_sigframe __user *frame; | |
1da177e4 LT |
257 | |
258 | /* Always make any pending restarted system calls return -EINTR */ | |
f56141e3 | 259 | current->restart_block.fn = do_no_restart_syscall; |
1da177e4 LT |
260 | |
261 | /* | |
262 | * Since we stacked the signal on a 64-bit boundary, | |
263 | * then 'sp' should be word aligned here. If it's | |
264 | * not, then the user is trying to mess with us. | |
265 | */ | |
266 | if (regs->ARM_sp & 7) | |
267 | goto badframe; | |
268 | ||
269 | frame = (struct rt_sigframe __user *)regs->ARM_sp; | |
270 | ||
96d4f267 | 271 | if (!access_ok(frame, sizeof (*frame))) |
1da177e4 | 272 | goto badframe; |
1da177e4 | 273 | |
68071484 | 274 | if (restore_sigframe(regs, &frame->sig)) |
1da177e4 LT |
275 | goto badframe; |
276 | ||
ec93ac86 | 277 | if (restore_altstack(&frame->sig.uc.uc_stack)) |
1da177e4 LT |
278 | goto badframe; |
279 | ||
1da177e4 LT |
280 | return regs->ARM_r0; |
281 | ||
282 | badframe: | |
3cf5d076 | 283 | force_sig(SIGSEGV); |
1da177e4 LT |
284 | return 0; |
285 | } | |
286 | ||
287 | static int | |
aca6ca10 | 288 | setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set) |
1da177e4 | 289 | { |
85fe0681 | 290 | struct aux_sigframe __user *aux; |
5ca451cf | 291 | struct sigcontext context; |
1da177e4 LT |
292 | int err = 0; |
293 | ||
5ca451cf JT |
294 | context = (struct sigcontext) { |
295 | .arm_r0 = regs->ARM_r0, | |
296 | .arm_r1 = regs->ARM_r1, | |
297 | .arm_r2 = regs->ARM_r2, | |
298 | .arm_r3 = regs->ARM_r3, | |
299 | .arm_r4 = regs->ARM_r4, | |
300 | .arm_r5 = regs->ARM_r5, | |
301 | .arm_r6 = regs->ARM_r6, | |
302 | .arm_r7 = regs->ARM_r7, | |
303 | .arm_r8 = regs->ARM_r8, | |
304 | .arm_r9 = regs->ARM_r9, | |
305 | .arm_r10 = regs->ARM_r10, | |
306 | .arm_fp = regs->ARM_fp, | |
307 | .arm_ip = regs->ARM_ip, | |
308 | .arm_sp = regs->ARM_sp, | |
309 | .arm_lr = regs->ARM_lr, | |
310 | .arm_pc = regs->ARM_pc, | |
311 | .arm_cpsr = regs->ARM_cpsr, | |
312 | ||
313 | .trap_no = current->thread.trap_no, | |
314 | .error_code = current->thread.error_code, | |
315 | .fault_address = current->thread.address, | |
316 | .oldmask = set->sig[0], | |
317 | }; | |
318 | ||
319 | err |= __copy_to_user(&sf->uc.uc_mcontext, &context, sizeof(context)); | |
aca6ca10 RK |
320 | |
321 | err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set)); | |
1da177e4 | 322 | |
85fe0681 | 323 | aux = (struct aux_sigframe __user *) sf->uc.uc_regspace; |
3bec6ded LB |
324 | #ifdef CONFIG_CRUNCH |
325 | if (err == 0) | |
326 | err |= preserve_crunch_context(&aux->crunch); | |
327 | #endif | |
1da177e4 | 328 | #ifdef CONFIG_IWMMXT |
ce184a0d | 329 | if (err == 0) |
1da177e4 LT |
330 | err |= preserve_iwmmxt_context(&aux->iwmmxt); |
331 | #endif | |
332 | #ifdef CONFIG_VFP | |
82c6f5a5 ID |
333 | if (err == 0) |
334 | err |= preserve_vfp_context(&aux->vfp); | |
1da177e4 | 335 | #endif |
18ea66bd | 336 | err |= __put_user(0, &aux->end_magic); |
1da177e4 LT |
337 | |
338 | return err; | |
339 | } | |
340 | ||
341 | static inline void __user * | |
7e243643 | 342 | get_sigframe(struct ksignal *ksig, struct pt_regs *regs, int framesize) |
1da177e4 | 343 | { |
7e243643 | 344 | unsigned long sp = sigsp(regs->ARM_sp, ksig); |
1da177e4 LT |
345 | void __user *frame; |
346 | ||
1da177e4 LT |
347 | /* |
348 | * ATPCS B01 mandates 8-byte alignment | |
349 | */ | |
350 | frame = (void __user *)((sp - framesize) & ~7); | |
351 | ||
352 | /* | |
353 | * Check that we can actually write to the signal frame. | |
354 | */ | |
96d4f267 | 355 | if (!access_ok(frame, framesize)) |
1da177e4 LT |
356 | frame = NULL; |
357 | ||
358 | return frame; | |
359 | } | |
360 | ||
361 | static int | |
7e243643 AV |
362 | setup_return(struct pt_regs *regs, struct ksignal *ksig, |
363 | unsigned long __user *rc, void __user *frame) | |
1da177e4 | 364 | { |
7e243643 | 365 | unsigned long handler = (unsigned long)ksig->ka.sa.sa_handler; |
5c165953 | 366 | unsigned long handler_fdpic_GOT = 0; |
1da177e4 | 367 | unsigned long retcode; |
5c165953 | 368 | unsigned int idx, thumb = 0; |
53399053 | 369 | unsigned long cpsr = regs->ARM_cpsr & ~(PSR_f | PSR_E_BIT); |
5c165953 NP |
370 | bool fdpic = IS_ENABLED(CONFIG_BINFMT_ELF_FDPIC) && |
371 | (current->personality & FDPIC_FUNCPTRS); | |
372 | ||
373 | if (fdpic) { | |
374 | unsigned long __user *fdpic_func_desc = | |
375 | (unsigned long __user *)handler; | |
376 | if (__get_user(handler, &fdpic_func_desc[0]) || | |
377 | __get_user(handler_fdpic_GOT, &fdpic_func_desc[1])) | |
378 | return 1; | |
379 | } | |
53399053 RK |
380 | |
381 | cpsr |= PSR_ENDSTATE; | |
1da177e4 LT |
382 | |
383 | /* | |
384 | * Maybe we need to deliver a 32-bit signal to a 26-bit task. | |
385 | */ | |
7e243643 | 386 | if (ksig->ka.sa.sa_flags & SA_THIRTYTWO) |
1da177e4 LT |
387 | cpsr = (cpsr & ~MODE_MASK) | USR_MODE; |
388 | ||
389 | #ifdef CONFIG_ARM_THUMB | |
390 | if (elf_hwcap & HWCAP_THUMB) { | |
391 | /* | |
392 | * The LSB of the handler determines if we're going to | |
393 | * be using THUMB or ARM mode for this signal handler. | |
394 | */ | |
395 | thumb = handler & 1; | |
396 | ||
6ecf830e | 397 | /* |
9b55613f RK |
398 | * Clear the If-Then Thumb-2 execution state. ARM spec |
399 | * requires this to be all 000s in ARM mode. Snapdragon | |
400 | * S4/Krait misbehaves on a Thumb=>ARM signal transition | |
401 | * without this. | |
402 | * | |
403 | * We must do this whenever we are running on a Thumb-2 | |
404 | * capable CPU, which includes ARMv6T2. However, we elect | |
12fc7306 RK |
405 | * to always do this to simplify the code; this field is |
406 | * marked UNK/SBZP for older architectures. | |
6ecf830e P |
407 | */ |
408 | cpsr &= ~PSR_IT_MASK; | |
6ecf830e P |
409 | |
410 | if (thumb) { | |
411 | cpsr |= PSR_T_BIT; | |
d71e1352 | 412 | } else |
1da177e4 LT |
413 | cpsr &= ~PSR_T_BIT; |
414 | } | |
415 | #endif | |
416 | ||
7e243643 AV |
417 | if (ksig->ka.sa.sa_flags & SA_RESTORER) { |
418 | retcode = (unsigned long)ksig->ka.sa.sa_restorer; | |
5c165953 NP |
419 | if (fdpic) { |
420 | /* | |
421 | * We need code to load the function descriptor. | |
422 | * That code follows the standard sigreturn code | |
423 | * (6 words), and is made of 3 + 2 words for each | |
424 | * variant. The 4th copied word is the actual FD | |
425 | * address that the assembly code expects. | |
426 | */ | |
427 | idx = 6 + thumb * 3; | |
428 | if (ksig->ka.sa.sa_flags & SA_SIGINFO) | |
429 | idx += 5; | |
430 | if (__put_user(sigreturn_codes[idx], rc ) || | |
431 | __put_user(sigreturn_codes[idx+1], rc+1) || | |
432 | __put_user(sigreturn_codes[idx+2], rc+2) || | |
433 | __put_user(retcode, rc+3)) | |
434 | return 1; | |
435 | goto rc_finish; | |
436 | } | |
1da177e4 | 437 | } else { |
5c165953 | 438 | idx = thumb << 1; |
7e243643 | 439 | if (ksig->ka.sa.sa_flags & SA_SIGINFO) |
fcca538b | 440 | idx += 3; |
1da177e4 | 441 | |
9dfc28b6 JA |
442 | /* |
443 | * Put the sigreturn code on the stack no matter which return | |
444 | * mechanism we use in order to remain ABI compliant | |
445 | */ | |
fcca538b NP |
446 | if (__put_user(sigreturn_codes[idx], rc) || |
447 | __put_user(sigreturn_codes[idx+1], rc+1)) | |
1da177e4 LT |
448 | return 1; |
449 | ||
5c165953 | 450 | rc_finish: |
8c0cc8a5 RK |
451 | #ifdef CONFIG_MMU |
452 | if (cpsr & MODE32_BIT) { | |
48be69a0 RK |
453 | struct mm_struct *mm = current->mm; |
454 | ||
e00d349e | 455 | /* |
48be69a0 RK |
456 | * 32-bit code can use the signal return page |
457 | * except when the MPU has protected the vectors | |
458 | * page from PL0 | |
e00d349e | 459 | */ |
48be69a0 RK |
460 | retcode = mm->context.sigpage + signal_return_offset + |
461 | (idx << 2) + thumb; | |
8c0cc8a5 RK |
462 | } else |
463 | #endif | |
464 | { | |
e00d349e RK |
465 | /* |
466 | * Ensure that the instruction cache sees | |
467 | * the return code written onto the stack. | |
468 | */ | |
469 | flush_icache_range((unsigned long)rc, | |
5c165953 | 470 | (unsigned long)(rc + 3)); |
e00d349e RK |
471 | |
472 | retcode = ((unsigned long)rc) + thumb; | |
473 | } | |
1da177e4 LT |
474 | } |
475 | ||
a4980448 | 476 | regs->ARM_r0 = ksig->sig; |
1da177e4 LT |
477 | regs->ARM_sp = (unsigned long)frame; |
478 | regs->ARM_lr = retcode; | |
479 | regs->ARM_pc = handler; | |
5c165953 NP |
480 | if (fdpic) |
481 | regs->ARM_r9 = handler_fdpic_GOT; | |
1da177e4 LT |
482 | regs->ARM_cpsr = cpsr; |
483 | ||
484 | return 0; | |
485 | } | |
486 | ||
487 | static int | |
7e243643 | 488 | setup_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs) |
1da177e4 | 489 | { |
7e243643 | 490 | struct sigframe __user *frame = get_sigframe(ksig, regs, sizeof(*frame)); |
1da177e4 LT |
491 | int err = 0; |
492 | ||
493 | if (!frame) | |
494 | return 1; | |
495 | ||
ca195cfe RK |
496 | /* |
497 | * Set uc.uc_flags to a value which sc.trap_no would never have. | |
498 | */ | |
18ea66bd | 499 | err = __put_user(0x5ac3c35a, &frame->uc.uc_flags); |
1da177e4 | 500 | |
aca6ca10 | 501 | err |= setup_sigframe(frame, regs, set); |
1da177e4 | 502 | if (err == 0) |
7e243643 | 503 | err = setup_return(regs, ksig, frame->retcode, frame); |
1da177e4 LT |
504 | |
505 | return err; | |
506 | } | |
507 | ||
508 | static int | |
7e243643 | 509 | setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs) |
1da177e4 | 510 | { |
7e243643 | 511 | struct rt_sigframe __user *frame = get_sigframe(ksig, regs, sizeof(*frame)); |
1da177e4 LT |
512 | int err = 0; |
513 | ||
514 | if (!frame) | |
515 | return 1; | |
516 | ||
7e243643 | 517 | err |= copy_siginfo_to_user(&frame->info, &ksig->info); |
1da177e4 | 518 | |
18ea66bd JT |
519 | err |= __put_user(0, &frame->sig.uc.uc_flags); |
520 | err |= __put_user(NULL, &frame->sig.uc.uc_link); | |
1da177e4 | 521 | |
ec93ac86 | 522 | err |= __save_altstack(&frame->sig.uc.uc_stack, regs->ARM_sp); |
aca6ca10 | 523 | err |= setup_sigframe(&frame->sig, regs, set); |
1da177e4 | 524 | if (err == 0) |
7e243643 | 525 | err = setup_return(regs, ksig, frame->sig.retcode, frame); |
1da177e4 LT |
526 | |
527 | if (err == 0) { | |
528 | /* | |
529 | * For realtime signals we must also set the second and third | |
530 | * arguments for the signal handler. | |
531 | * -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06 | |
532 | */ | |
533 | regs->ARM_r1 = (unsigned long)&frame->info; | |
cb3504e8 | 534 | regs->ARM_r2 = (unsigned long)&frame->sig.uc; |
1da177e4 LT |
535 | } |
536 | ||
537 | return err; | |
538 | } | |
539 | ||
1da177e4 LT |
540 | /* |
541 | * OK, we're invoking a handler | |
542 | */ | |
7e243643 | 543 | static void handle_signal(struct ksignal *ksig, struct pt_regs *regs) |
1da177e4 | 544 | { |
b7f9a11a | 545 | sigset_t *oldset = sigmask_to_save(); |
1da177e4 LT |
546 | int ret; |
547 | ||
9800b9dc | 548 | /* |
bff9504b | 549 | * Perform fixup for the pre-signal frame. |
9800b9dc | 550 | */ |
784e0300 | 551 | rseq_signal_deliver(ksig, regs); |
9800b9dc | 552 | |
1da177e4 LT |
553 | /* |
554 | * Set up the stack frame | |
555 | */ | |
7e243643 AV |
556 | if (ksig->ka.sa.sa_flags & SA_SIGINFO) |
557 | ret = setup_rt_frame(ksig, oldset, regs); | |
1da177e4 | 558 | else |
7e243643 | 559 | ret = setup_frame(ksig, oldset, regs); |
1da177e4 LT |
560 | |
561 | /* | |
562 | * Check that the resulting registers are actually sane. | |
563 | */ | |
564 | ret |= !valid_user_regs(regs); | |
565 | ||
7e243643 | 566 | signal_setup_done(ret, ksig, 0); |
1da177e4 LT |
567 | } |
568 | ||
569 | /* | |
570 | * Note that 'init' is a special process: it doesn't get signals it doesn't | |
571 | * want to handle. Thus you cannot kill init even with a SIGKILL even by | |
572 | * mistake. | |
573 | * | |
574 | * Note that we go through the signals twice: once to check the signals that | |
575 | * the kernel can handle, and then we build all the user-level signal handling | |
576 | * stack-frames in one go after that. | |
577 | */ | |
81783786 | 578 | static int do_signal(struct pt_regs *regs, int syscall) |
1da177e4 | 579 | { |
2af68df0 | 580 | unsigned int retval = 0, continue_addr = 0, restart_addr = 0; |
7e243643 | 581 | struct ksignal ksig; |
81783786 | 582 | int restart = 0; |
1da177e4 | 583 | |
2af68df0 AB |
584 | /* |
585 | * If we were from a system call, check for system call restarting... | |
586 | */ | |
587 | if (syscall) { | |
588 | continue_addr = regs->ARM_pc; | |
589 | restart_addr = continue_addr - (thumb_mode(regs) ? 2 : 4); | |
590 | retval = regs->ARM_r0; | |
591 | ||
592 | /* | |
593 | * Prepare for system call restart. We do this here so that a | |
594 | * debugger will see the already changed PSW. | |
595 | */ | |
596 | switch (retval) { | |
81783786 | 597 | case -ERESTART_RESTARTBLOCK: |
66285217 | 598 | restart -= 2; |
df561f66 | 599 | fallthrough; |
2af68df0 AB |
600 | case -ERESTARTNOHAND: |
601 | case -ERESTARTSYS: | |
602 | case -ERESTARTNOINTR: | |
81783786 | 603 | restart++; |
2af68df0 AB |
604 | regs->ARM_r0 = regs->ARM_ORIG_r0; |
605 | regs->ARM_pc = restart_addr; | |
606 | break; | |
2af68df0 AB |
607 | } |
608 | } | |
609 | ||
2af68df0 AB |
610 | /* |
611 | * Get the signal to deliver. When running under ptrace, at this | |
612 | * point the debugger may change all our registers ... | |
613 | */ | |
81783786 AV |
614 | /* |
615 | * Depending on the signal settings we may need to revert the | |
616 | * decision to restart the system call. But skip this if a | |
617 | * debugger has chosen to restart at a different PC. | |
618 | */ | |
7e243643 AV |
619 | if (get_signal(&ksig)) { |
620 | /* handler */ | |
621 | if (unlikely(restart) && regs->ARM_pc == restart_addr) { | |
ad82cc08 WD |
622 | if (retval == -ERESTARTNOHAND || |
623 | retval == -ERESTART_RESTARTBLOCK | |
2af68df0 | 624 | || (retval == -ERESTARTSYS |
7e243643 | 625 | && !(ksig.ka.sa.sa_flags & SA_RESTART))) { |
2af68df0 AB |
626 | regs->ARM_r0 = -EINTR; |
627 | regs->ARM_pc = continue_addr; | |
628 | } | |
629 | } | |
7e243643 AV |
630 | handle_signal(&ksig, regs); |
631 | } else { | |
632 | /* no handler */ | |
633 | restore_saved_sigmask(); | |
634 | if (unlikely(restart) && regs->ARM_pc == restart_addr) { | |
635 | regs->ARM_pc = continue_addr; | |
636 | return restart; | |
637 | } | |
1da177e4 | 638 | } |
7e243643 | 639 | return 0; |
1da177e4 LT |
640 | } |
641 | ||
81783786 | 642 | asmlinkage int |
0a267fa6 | 643 | do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall) |
1da177e4 | 644 | { |
3302cadd RK |
645 | /* |
646 | * The assembly code enters us with IRQs off, but it hasn't | |
647 | * informed the tracing code of that for efficiency reasons. | |
648 | * Update the trace code with the current status. | |
649 | */ | |
650 | trace_hardirqs_off(); | |
0a267fa6 AV |
651 | do { |
652 | if (likely(thread_flags & _TIF_NEED_RESCHED)) { | |
653 | schedule(); | |
654 | } else { | |
655 | if (unlikely(!user_mode(regs))) | |
81783786 | 656 | return 0; |
0a267fa6 AV |
657 | local_irq_enable(); |
658 | if (thread_flags & _TIF_SIGPENDING) { | |
66285217 AV |
659 | int restart = do_signal(regs, syscall); |
660 | if (unlikely(restart)) { | |
81783786 AV |
661 | /* |
662 | * Restart without handlers. | |
663 | * Deal with it without leaving | |
664 | * the kernel space. | |
665 | */ | |
66285217 | 666 | return restart; |
81783786 | 667 | } |
0a267fa6 | 668 | syscall = 0; |
c7edc9e3 | 669 | } else if (thread_flags & _TIF_UPROBE) { |
c7edc9e3 | 670 | uprobe_notify_resume(regs); |
0a267fa6 AV |
671 | } else { |
672 | clear_thread_flag(TIF_NOTIFY_RESUME); | |
673 | tracehook_notify_resume(regs); | |
784e0300 | 674 | rseq_handle_notify_resume(NULL, regs); |
0a267fa6 AV |
675 | } |
676 | } | |
677 | local_irq_disable(); | |
678 | thread_flags = current_thread_info()->flags; | |
679 | } while (thread_flags & _TIF_WORK_MASK); | |
81783786 | 680 | return 0; |
1da177e4 | 681 | } |
48be69a0 | 682 | |
48be69a0 RK |
683 | struct page *get_signal_page(void) |
684 | { | |
e0d40756 RK |
685 | unsigned long ptr; |
686 | unsigned offset; | |
687 | struct page *page; | |
688 | void *addr; | |
48be69a0 | 689 | |
e0d40756 | 690 | page = alloc_pages(GFP_KERNEL, 0); |
48be69a0 | 691 | |
e0d40756 RK |
692 | if (!page) |
693 | return NULL; | |
48be69a0 | 694 | |
e0d40756 | 695 | addr = page_address(page); |
48be69a0 | 696 | |
e0d40756 RK |
697 | /* Give the signal return code some randomness */ |
698 | offset = 0x200 + (get_random_int() & 0x7fc); | |
699 | signal_return_offset = offset; | |
48be69a0 | 700 | |
e0d40756 RK |
701 | /* |
702 | * Copy signal return handlers into the vector page, and | |
703 | * set sigreturn to be a pointer to these. | |
704 | */ | |
705 | memcpy(addr + offset, sigreturn_codes, sizeof(sigreturn_codes)); | |
48be69a0 | 706 | |
e0d40756 RK |
707 | ptr = (unsigned long)addr + offset; |
708 | flush_icache_range(ptr, ptr + sizeof(sigreturn_codes)); | |
48be69a0 | 709 | |
e0d40756 | 710 | return page; |
48be69a0 | 711 | } |
e33f8d32 TG |
712 | |
713 | /* Defer to generic check */ | |
714 | asmlinkage void addr_limit_check_failed(void) | |
715 | { | |
bfe00c5b | 716 | #ifdef CONFIG_MMU |
e33f8d32 | 717 | addr_limit_user_check(); |
bfe00c5b | 718 | #endif |
e33f8d32 | 719 | } |
b74406f3 MD |
720 | |
721 | #ifdef CONFIG_DEBUG_RSEQ | |
722 | asmlinkage void do_rseq_syscall(struct pt_regs *regs) | |
723 | { | |
724 | rseq_syscall(regs); | |
725 | } | |
726 | #endif |