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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * arch/sh/kernel/signal_64.c
4 *
5 * Copyright (C) 2000, 2001 Paolo Alberelli
6 * Copyright (C) 2003 - 2008 Paul Mundt
7 * Copyright (C) 2004 Richard Curnow
8 */
9#include <linux/rwsem.h>
10#include <linux/sched.h>
11#include <linux/mm.h>
12#include <linux/smp.h>
13#include <linux/kernel.h>
14#include <linux/signal.h>
15#include <linux/errno.h>
16#include <linux/wait.h>
17#include <linux/personality.h>
18#include <linux/ptrace.h>
19#include <linux/unistd.h>
20#include <linux/stddef.h>
21#include <linux/tracehook.h>
22#include <asm/ucontext.h>
23#include <linux/uaccess.h>
24#include <asm/pgtable.h>
25#include <asm/cacheflush.h>
26#include <asm/fpu.h>
27
28#define REG_RET 9
29#define REG_ARG1 2
30#define REG_ARG2 3
31#define REG_ARG3 4
32#define REG_SP 15
33#define REG_PR 18
34#define REF_REG_RET regs->regs[REG_RET]
35#define REF_REG_SP regs->regs[REG_SP]
36#define DEREF_REG_PR regs->regs[REG_PR]
37
38#define DEBUG_SIG 0
39
40static void
41handle_signal(struct ksignal *ksig, struct pt_regs *regs);
42
43static inline void
44handle_syscall_restart(struct pt_regs *regs, struct sigaction *sa)
45{
46 /* If we're not from a syscall, bail out */
47 if (regs->syscall_nr < 0)
48 return;
49
50 /* check for system call restart.. */
51 switch (regs->regs[REG_RET]) {
52 case -ERESTART_RESTARTBLOCK:
53 case -ERESTARTNOHAND:
54 no_system_call_restart:
55 regs->regs[REG_RET] = -EINTR;
56 break;
57
58 case -ERESTARTSYS:
59 if (!(sa->sa_flags & SA_RESTART))
60 goto no_system_call_restart;
61 /* fallthrough */
62 case -ERESTARTNOINTR:
63 /* Decode syscall # */
64 regs->regs[REG_RET] = regs->syscall_nr;
65 regs->pc -= 4;
66 break;
67 }
68}
69
70/*
71 * Note that 'init' is a special process: it doesn't get signals it doesn't
72 * want to handle. Thus you cannot kill init even with a SIGKILL even by
73 * mistake.
74 *
75 * Note that we go through the signals twice: once to check the signals that
76 * the kernel can handle, and then we build all the user-level signal handling
77 * stack-frames in one go after that.
78 */
79static void do_signal(struct pt_regs *regs)
80{
81 struct ksignal ksig;
82
83 /*
84 * We want the common case to go fast, which
85 * is why we may in certain cases get here from
86 * kernel mode. Just return without doing anything
87 * if so.
88 */
89 if (!user_mode(regs))
90 return;
91
92 if (get_signal(&ksig)) {
93 handle_syscall_restart(regs, &ksig.ka.sa);
94
95 /* Whee! Actually deliver the signal. */
96 handle_signal(&ksig, regs);
97 return;
98 }
99
100 /* Did we come from a system call? */
101 if (regs->syscall_nr >= 0) {
102 /* Restart the system call - no handlers present */
103 switch (regs->regs[REG_RET]) {
104 case -ERESTARTNOHAND:
105 case -ERESTARTSYS:
106 case -ERESTARTNOINTR:
107 /* Decode Syscall # */
108 regs->regs[REG_RET] = regs->syscall_nr;
109 regs->pc -= 4;
110 break;
111
112 case -ERESTART_RESTARTBLOCK:
113 regs->regs[REG_RET] = __NR_restart_syscall;
114 regs->pc -= 4;
115 break;
116 }
117 }
118
119 /* No signal to deliver -- put the saved sigmask back */
120 restore_saved_sigmask();
121}
122
123/*
124 * Do a signal return; undo the signal stack.
125 */
126struct sigframe {
127 struct sigcontext sc;
128 unsigned long extramask[_NSIG_WORDS-1];
129 long long retcode[2];
130};
131
132struct rt_sigframe {
133 struct siginfo __user *pinfo;
134 void *puc;
135 struct siginfo info;
136 struct ucontext uc;
137 long long retcode[2];
138};
139
140#ifdef CONFIG_SH_FPU
141static inline int
142restore_sigcontext_fpu(struct pt_regs *regs, struct sigcontext __user *sc)
143{
144 int err = 0;
145 int fpvalid;
146
147 err |= __get_user (fpvalid, &sc->sc_fpvalid);
148 conditional_used_math(fpvalid);
149 if (! fpvalid)
150 return err;
151
152 if (current == last_task_used_math) {
153 last_task_used_math = NULL;
154 regs->sr |= SR_FD;
155 }
156
157 err |= __copy_from_user(¤t->thread.xstate->hardfpu, &sc->sc_fpregs[0],
158 (sizeof(long long) * 32) + (sizeof(int) * 1));
159
160 return err;
161}
162
163static inline int
164setup_sigcontext_fpu(struct pt_regs *regs, struct sigcontext __user *sc)
165{
166 int err = 0;
167 int fpvalid;
168
169 fpvalid = !!used_math();
170 err |= __put_user(fpvalid, &sc->sc_fpvalid);
171 if (! fpvalid)
172 return err;
173
174 if (current == last_task_used_math) {
175 enable_fpu();
176 save_fpu(current);
177 disable_fpu();
178 last_task_used_math = NULL;
179 regs->sr |= SR_FD;
180 }
181
182 err |= __copy_to_user(&sc->sc_fpregs[0], ¤t->thread.xstate->hardfpu,
183 (sizeof(long long) * 32) + (sizeof(int) * 1));
184 clear_used_math();
185
186 return err;
187}
188#else
189static inline int
190restore_sigcontext_fpu(struct pt_regs *regs, struct sigcontext __user *sc)
191{
192 return 0;
193}
194static inline int
195setup_sigcontext_fpu(struct pt_regs *regs, struct sigcontext __user *sc)
196{
197 return 0;
198}
199#endif
200
201static int
202restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, long long *r2_p)
203{
204 unsigned int err = 0;
205 unsigned long long current_sr, new_sr;
206#define SR_MASK 0xffff8cfd
207
208#define COPY(x) err |= __get_user(regs->x, &sc->sc_##x)
209
210 COPY(regs[0]); COPY(regs[1]); COPY(regs[2]); COPY(regs[3]);
211 COPY(regs[4]); COPY(regs[5]); COPY(regs[6]); COPY(regs[7]);
212 COPY(regs[8]); COPY(regs[9]); COPY(regs[10]); COPY(regs[11]);
213 COPY(regs[12]); COPY(regs[13]); COPY(regs[14]); COPY(regs[15]);
214 COPY(regs[16]); COPY(regs[17]); COPY(regs[18]); COPY(regs[19]);
215 COPY(regs[20]); COPY(regs[21]); COPY(regs[22]); COPY(regs[23]);
216 COPY(regs[24]); COPY(regs[25]); COPY(regs[26]); COPY(regs[27]);
217 COPY(regs[28]); COPY(regs[29]); COPY(regs[30]); COPY(regs[31]);
218 COPY(regs[32]); COPY(regs[33]); COPY(regs[34]); COPY(regs[35]);
219 COPY(regs[36]); COPY(regs[37]); COPY(regs[38]); COPY(regs[39]);
220 COPY(regs[40]); COPY(regs[41]); COPY(regs[42]); COPY(regs[43]);
221 COPY(regs[44]); COPY(regs[45]); COPY(regs[46]); COPY(regs[47]);
222 COPY(regs[48]); COPY(regs[49]); COPY(regs[50]); COPY(regs[51]);
223 COPY(regs[52]); COPY(regs[53]); COPY(regs[54]); COPY(regs[55]);
224 COPY(regs[56]); COPY(regs[57]); COPY(regs[58]); COPY(regs[59]);
225 COPY(regs[60]); COPY(regs[61]); COPY(regs[62]);
226 COPY(tregs[0]); COPY(tregs[1]); COPY(tregs[2]); COPY(tregs[3]);
227 COPY(tregs[4]); COPY(tregs[5]); COPY(tregs[6]); COPY(tregs[7]);
228
229 /* Prevent the signal handler manipulating SR in a way that can
230 crash the kernel. i.e. only allow S, Q, M, PR, SZ, FR to be
231 modified */
232 current_sr = regs->sr;
233 err |= __get_user(new_sr, &sc->sc_sr);
234 regs->sr &= SR_MASK;
235 regs->sr |= (new_sr & ~SR_MASK);
236
237 COPY(pc);
238
239#undef COPY
240
241 /* Must do this last in case it sets regs->sr.fd (i.e. after rest of sr
242 * has been restored above.) */
243 err |= restore_sigcontext_fpu(regs, sc);
244
245 regs->syscall_nr = -1; /* disable syscall checks */
246 err |= __get_user(*r2_p, &sc->sc_regs[REG_RET]);
247 return err;
248}
249
250asmlinkage int sys_sigreturn(unsigned long r2, unsigned long r3,
251 unsigned long r4, unsigned long r5,
252 unsigned long r6, unsigned long r7,
253 struct pt_regs * regs)
254{
255 struct sigframe __user *frame = (struct sigframe __user *) (long) REF_REG_SP;
256 sigset_t set;
257 long long ret;
258
259 /* Always make any pending restarted system calls return -EINTR */
260 current->restart_block.fn = do_no_restart_syscall;
261
262 if (!access_ok(frame, sizeof(*frame)))
263 goto badframe;
264
265 if (__get_user(set.sig[0], &frame->sc.oldmask)
266 || (_NSIG_WORDS > 1
267 && __copy_from_user(&set.sig[1], &frame->extramask,
268 sizeof(frame->extramask))))
269 goto badframe;
270
271 set_current_blocked(&set);
272
273 if (restore_sigcontext(regs, &frame->sc, &ret))
274 goto badframe;
275 regs->pc -= 4;
276
277 return (int) ret;
278
279badframe:
280 force_sig(SIGSEGV);
281 return 0;
282}
283
284asmlinkage int sys_rt_sigreturn(unsigned long r2, unsigned long r3,
285 unsigned long r4, unsigned long r5,
286 unsigned long r6, unsigned long r7,
287 struct pt_regs * regs)
288{
289 struct rt_sigframe __user *frame = (struct rt_sigframe __user *) (long) REF_REG_SP;
290 sigset_t set;
291 long long ret;
292
293 /* Always make any pending restarted system calls return -EINTR */
294 current->restart_block.fn = do_no_restart_syscall;
295
296 if (!access_ok(frame, sizeof(*frame)))
297 goto badframe;
298
299 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
300 goto badframe;
301
302 set_current_blocked(&set);
303
304 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ret))
305 goto badframe;
306 regs->pc -= 4;
307
308 if (restore_altstack(&frame->uc.uc_stack))
309 goto badframe;
310
311 return (int) ret;
312
313badframe:
314 force_sig(SIGSEGV);
315 return 0;
316}
317
318/*
319 * Set up a signal frame.
320 */
321static int
322setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
323 unsigned long mask)
324{
325 int err = 0;
326
327 /* Do this first, otherwise is this sets sr->fd, that value isn't preserved. */
328 err |= setup_sigcontext_fpu(regs, sc);
329
330#define COPY(x) err |= __put_user(regs->x, &sc->sc_##x)
331
332 COPY(regs[0]); COPY(regs[1]); COPY(regs[2]); COPY(regs[3]);
333 COPY(regs[4]); COPY(regs[5]); COPY(regs[6]); COPY(regs[7]);
334 COPY(regs[8]); COPY(regs[9]); COPY(regs[10]); COPY(regs[11]);
335 COPY(regs[12]); COPY(regs[13]); COPY(regs[14]); COPY(regs[15]);
336 COPY(regs[16]); COPY(regs[17]); COPY(regs[18]); COPY(regs[19]);
337 COPY(regs[20]); COPY(regs[21]); COPY(regs[22]); COPY(regs[23]);
338 COPY(regs[24]); COPY(regs[25]); COPY(regs[26]); COPY(regs[27]);
339 COPY(regs[28]); COPY(regs[29]); COPY(regs[30]); COPY(regs[31]);
340 COPY(regs[32]); COPY(regs[33]); COPY(regs[34]); COPY(regs[35]);
341 COPY(regs[36]); COPY(regs[37]); COPY(regs[38]); COPY(regs[39]);
342 COPY(regs[40]); COPY(regs[41]); COPY(regs[42]); COPY(regs[43]);
343 COPY(regs[44]); COPY(regs[45]); COPY(regs[46]); COPY(regs[47]);
344 COPY(regs[48]); COPY(regs[49]); COPY(regs[50]); COPY(regs[51]);
345 COPY(regs[52]); COPY(regs[53]); COPY(regs[54]); COPY(regs[55]);
346 COPY(regs[56]); COPY(regs[57]); COPY(regs[58]); COPY(regs[59]);
347 COPY(regs[60]); COPY(regs[61]); COPY(regs[62]);
348 COPY(tregs[0]); COPY(tregs[1]); COPY(tregs[2]); COPY(tregs[3]);
349 COPY(tregs[4]); COPY(tregs[5]); COPY(tregs[6]); COPY(tregs[7]);
350 COPY(sr); COPY(pc);
351
352#undef COPY
353
354 err |= __put_user(mask, &sc->oldmask);
355
356 return err;
357}
358
359/*
360 * Determine which stack to use..
361 */
362static inline void __user *
363get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
364{
365 if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! sas_ss_flags(sp))
366 sp = current->sas_ss_sp + current->sas_ss_size;
367
368 return (void __user *)((sp - frame_size) & -8ul);
369}
370
371void sa_default_restorer(void); /* See comments below */
372void sa_default_rt_restorer(void); /* See comments below */
373
374static int setup_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
375{
376 struct sigframe __user *frame;
377 int err = 0, sig = ksig->sig;
378 int signal;
379
380 frame = get_sigframe(&ksig->ka, regs->regs[REG_SP], sizeof(*frame));
381
382 if (!access_ok(frame, sizeof(*frame)))
383 return -EFAULT;
384
385 err |= setup_sigcontext(&frame->sc, regs, set->sig[0]);
386
387 /* Give up earlier as i386, in case */
388 if (err)
389 return -EFAULT;
390
391 if (_NSIG_WORDS > 1) {
392 err |= __copy_to_user(frame->extramask, &set->sig[1],
393 sizeof(frame->extramask)); }
394
395 /* Give up earlier as i386, in case */
396 if (err)
397 return -EFAULT;
398
399 /* Set up to return from userspace. If provided, use a stub
400 already in userspace. */
401 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
402 /*
403 * On SH5 all edited pointers are subject to NEFF
404 */
405 DEREF_REG_PR = neff_sign_extend((unsigned long)
406 ksig->ka->sa.sa_restorer | 0x1);
407 } else {
408 /*
409 * Different approach on SH5.
410 * . Endianness independent asm code gets placed in entry.S .
411 * This is limited to four ASM instructions corresponding
412 * to two long longs in size.
413 * . err checking is done on the else branch only
414 * . flush_icache_range() is called upon __put_user() only
415 * . all edited pointers are subject to NEFF
416 * . being code, linker turns ShMedia bit on, always
417 * dereference index -1.
418 */
419 DEREF_REG_PR = neff_sign_extend((unsigned long)
420 frame->retcode | 0x01);
421
422 if (__copy_to_user(frame->retcode,
423 (void *)((unsigned long)sa_default_restorer & (~1)), 16) != 0)
424 return -EFAULT;
425
426 /* Cohere the trampoline with the I-cache. */
427 flush_cache_sigtramp(DEREF_REG_PR-1);
428 }
429
430 /*
431 * Set up registers for signal handler.
432 * All edited pointers are subject to NEFF.
433 */
434 regs->regs[REG_SP] = neff_sign_extend((unsigned long)frame);
435 regs->regs[REG_ARG1] = sig; /* Arg for signal handler */
436
437 /* FIXME:
438 The glibc profiling support for SH-5 needs to be passed a sigcontext
439 so it can retrieve the PC. At some point during 2003 the glibc
440 support was changed to receive the sigcontext through the 2nd
441 argument, but there are still versions of libc.so in use that use
442 the 3rd argument. Until libc.so is stabilised, pass the sigcontext
443 through both 2nd and 3rd arguments.
444 */
445
446 regs->regs[REG_ARG2] = (unsigned long long)(unsigned long)(signed long)&frame->sc;
447 regs->regs[REG_ARG3] = (unsigned long long)(unsigned long)(signed long)&frame->sc;
448
449 regs->pc = neff_sign_extend((unsigned long)ksig->ka.sa.sa_handler);
450
451 /* Broken %016Lx */
452 pr_debug("SIG deliver (#%d,%s:%d): sp=%p pc=%08Lx%08Lx link=%08Lx%08Lx\n",
453 sig, current->comm, current->pid, frame,
454 regs->pc >> 32, regs->pc & 0xffffffff,
455 DEREF_REG_PR >> 32, DEREF_REG_PR & 0xffffffff);
456
457 return 0;
458}
459
460static int setup_rt_frame(struct ksignal *kig, sigset_t *set,
461 struct pt_regs *regs)
462{
463 struct rt_sigframe __user *frame;
464 int err = 0, sig = ksig->sig;
465
466 frame = get_sigframe(&ksig->ka, regs->regs[REG_SP], sizeof(*frame));
467
468 if (!access_ok(frame, sizeof(*frame)))
469 return -EFAULT;
470
471 err |= __put_user(&frame->info, &frame->pinfo);
472 err |= __put_user(&frame->uc, &frame->puc);
473 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
474
475 /* Give up earlier as i386, in case */
476 if (err)
477 return -EFAULT;
478
479 /* Create the ucontext. */
480 err |= __put_user(0, &frame->uc.uc_flags);
481 err |= __put_user(0, &frame->uc.uc_link);
482 err |= __save_altstack(&frame->uc.uc_stack, regs->regs[REG_SP]);
483 err |= setup_sigcontext(&frame->uc.uc_mcontext,
484 regs, set->sig[0]);
485 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
486
487 /* Give up earlier as i386, in case */
488 if (err)
489 return -EFAULT;
490
491 /* Set up to return from userspace. If provided, use a stub
492 already in userspace. */
493 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
494 /*
495 * On SH5 all edited pointers are subject to NEFF
496 */
497 DEREF_REG_PR = neff_sign_extend((unsigned long)
498 ksig->ka.sa.sa_restorer | 0x1);
499 } else {
500 /*
501 * Different approach on SH5.
502 * . Endianness independent asm code gets placed in entry.S .
503 * This is limited to four ASM instructions corresponding
504 * to two long longs in size.
505 * . err checking is done on the else branch only
506 * . flush_icache_range() is called upon __put_user() only
507 * . all edited pointers are subject to NEFF
508 * . being code, linker turns ShMedia bit on, always
509 * dereference index -1.
510 */
511 DEREF_REG_PR = neff_sign_extend((unsigned long)
512 frame->retcode | 0x01);
513
514 if (__copy_to_user(frame->retcode,
515 (void *)((unsigned long)sa_default_rt_restorer & (~1)), 16) != 0)
516 return -EFAULT;
517
518 /* Cohere the trampoline with the I-cache. */
519 flush_icache_range(DEREF_REG_PR-1, DEREF_REG_PR-1+15);
520 }
521
522 /*
523 * Set up registers for signal handler.
524 * All edited pointers are subject to NEFF.
525 */
526 regs->regs[REG_SP] = neff_sign_extend((unsigned long)frame);
527 regs->regs[REG_ARG1] = sig; /* Arg for signal handler */
528 regs->regs[REG_ARG2] = (unsigned long long)(unsigned long)(signed long)&frame->info;
529 regs->regs[REG_ARG3] = (unsigned long long)(unsigned long)(signed long)&frame->uc.uc_mcontext;
530 regs->pc = neff_sign_extend((unsigned long)ksig->ka.sa.sa_handler);
531
532 pr_debug("SIG deliver (#%d,%s:%d): sp=%p pc=%08Lx%08Lx link=%08Lx%08Lx\n",
533 sig, current->comm, current->pid, frame,
534 regs->pc >> 32, regs->pc & 0xffffffff,
535 DEREF_REG_PR >> 32, DEREF_REG_PR & 0xffffffff);
536
537 return 0;
538}
539
540/*
541 * OK, we're invoking a handler
542 */
543static void
544handle_signal(struct ksignal *ksig, struct pt_regs *regs)
545{
546 sigset_t *oldset = sigmask_to_save();
547 int ret;
548
549 /* Set up the stack frame */
550 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
551 ret = setup_rt_frame(ksig, oldset, regs);
552 else
553 ret = setup_frame(ksig, oldset, regs);
554
555 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
556}
557
558asmlinkage void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags)
559{
560 if (thread_info_flags & _TIF_SIGPENDING)
561 do_signal(regs);
562
563 if (thread_info_flags & _TIF_NOTIFY_RESUME) {
564 clear_thread_flag(TIF_NOTIFY_RESUME);
565 tracehook_notify_resume(regs);
566 }
567}