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Linux 5.8-rc4
[linux/fpc-iii.git] / arch / sparc / kernel / signal_32.c
blob3b005b6c3e0fd9b43cfb5bd00666971483552006
1 // SPDX-License-Identifier: GPL-2.0
2 /* linux/arch/sparc/kernel/signal.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
6 * Copyright (C) 1996 Miguel de Icaza (miguel@nuclecu.unam.mx)
7 * Copyright (C) 1997 Eddie C. Dost (ecd@skynet.be)
8 */
9
10 #include <linux/sched.h>
11 #include <linux/kernel.h>
12 #include <linux/signal.h>
13 #include <linux/errno.h>
14 #include <linux/wait.h>
15 #include <linux/ptrace.h>
16 #include <linux/unistd.h>
17 #include <linux/mm.h>
18 #include <linux/tty.h>
19 #include <linux/smp.h>
20 #include <linux/binfmts.h> /* do_coredum */
21 #include <linux/bitops.h>
22 #include <linux/tracehook.h>
23
24 #include <linux/uaccess.h>
25 #include <asm/ptrace.h>
26 #include <asm/pgalloc.h>
27 #include <asm/cacheflush.h> /* flush_sig_insns */
28 #include <asm/switch_to.h>
29
30 #include "sigutil.h"
31 #include "kernel.h"
32
33 extern void fpsave(unsigned long *fpregs, unsigned long *fsr,
34 void *fpqueue, unsigned long *fpqdepth);
35 extern void fpload(unsigned long *fpregs, unsigned long *fsr);
36
37 struct signal_frame {
38 struct sparc_stackf ss;
39 __siginfo32_t info;
40 __siginfo_fpu_t __user *fpu_save;
41 unsigned long insns[2] __attribute__ ((aligned (8)));
42 unsigned int extramask[_NSIG_WORDS - 1];
43 unsigned int extra_size; /* Should be 0 */
44 __siginfo_rwin_t __user *rwin_save;
45 } __attribute__((aligned(8)));
46
47 struct rt_signal_frame {
48 struct sparc_stackf ss;
49 siginfo_t info;
50 struct pt_regs regs;
51 sigset_t mask;
52 __siginfo_fpu_t __user *fpu_save;
53 unsigned int insns[2];
54 stack_t stack;
55 unsigned int extra_size; /* Should be 0 */
56 __siginfo_rwin_t __user *rwin_save;
57 } __attribute__((aligned(8)));
58
59 /* Align macros */
60 #define SF_ALIGNEDSZ (((sizeof(struct signal_frame) + 7) & (~7)))
61 #define RT_ALIGNEDSZ (((sizeof(struct rt_signal_frame) + 7) & (~7)))
62
63 /* Checks if the fp is valid. We always build signal frames which are
64 * 16-byte aligned, therefore we can always enforce that the restore
65 * frame has that property as well.
66 */
67 static inline bool invalid_frame_pointer(void __user *fp, int fplen)
68 {
69 if ((((unsigned long) fp) & 15) || !__access_ok((unsigned long)fp, fplen))
70 return true;
71
72 return false;
73 }
74
75 asmlinkage void do_sigreturn(struct pt_regs *regs)
76 {
77 unsigned long up_psr, pc, npc, ufp;
78 struct signal_frame __user *sf;
79 sigset_t set;
80 __siginfo_fpu_t __user *fpu_save;
81 __siginfo_rwin_t __user *rwin_save;
82 int err;
83
84 /* Always make any pending restarted system calls return -EINTR */
85 current->restart_block.fn = do_no_restart_syscall;
86
87 synchronize_user_stack();
88
89 sf = (struct signal_frame __user *) regs->u_regs[UREG_FP];
90
91 /* 1. Make sure we are not getting garbage from the user */
92 if (invalid_frame_pointer(sf, sizeof(*sf)))
93 goto segv_and_exit;
94
95 if (get_user(ufp, &sf->info.si_regs.u_regs[UREG_FP]))
96 goto segv_and_exit;
97
98 if (ufp & 0x7)
99 goto segv_and_exit;
100
101 err = __get_user(pc, &sf->info.si_regs.pc);
102 err |= __get_user(npc, &sf->info.si_regs.npc);
103
104 if ((pc | npc) & 3)
105 goto segv_and_exit;
106
107 /* 2. Restore the state */
108 up_psr = regs->psr;
109 err |= __copy_from_user(regs, &sf->info.si_regs, sizeof(struct pt_regs));
110
111 /* User can only change condition codes and FPU enabling in %psr. */
112 regs->psr = (up_psr & ~(PSR_ICC | PSR_EF))
113 | (regs->psr & (PSR_ICC | PSR_EF));
114
115 /* Prevent syscall restart. */
116 pt_regs_clear_syscall(regs);
117
118 err |= __get_user(fpu_save, &sf->fpu_save);
119 if (fpu_save)
120 err |= restore_fpu_state(regs, fpu_save);
121 err |= __get_user(rwin_save, &sf->rwin_save);
122 if (rwin_save)
123 err |= restore_rwin_state(rwin_save);
124
125 /* This is pretty much atomic, no amount locking would prevent
126 * the races which exist anyways.
127 */
128 err |= __get_user(set.sig[0], &sf->info.si_mask);
129 err |= __copy_from_user(&set.sig[1], &sf->extramask,
130 (_NSIG_WORDS-1) * sizeof(unsigned int));
131
132 if (err)
133 goto segv_and_exit;
134
135 set_current_blocked(&set);
136 return;
137
138 segv_and_exit:
139 force_sig(SIGSEGV);
140 }
141
142 asmlinkage void do_rt_sigreturn(struct pt_regs *regs)
143 {
144 struct rt_signal_frame __user *sf;
145 unsigned int psr, pc, npc, ufp;
146 __siginfo_fpu_t __user *fpu_save;
147 __siginfo_rwin_t __user *rwin_save;
148 sigset_t set;
149 int err;
150
151 synchronize_user_stack();
152 sf = (struct rt_signal_frame __user *) regs->u_regs[UREG_FP];
153 if (invalid_frame_pointer(sf, sizeof(*sf)))
154 goto segv;
155
156 if (get_user(ufp, &sf->regs.u_regs[UREG_FP]))
157 goto segv;
158
159 if (ufp & 0x7)
160 goto segv;
161
162 err = __get_user(pc, &sf->regs.pc);
163 err |= __get_user(npc, &sf->regs.npc);
164 err |= ((pc | npc) & 0x03);
165
166 err |= __get_user(regs->y, &sf->regs.y);
167 err |= __get_user(psr, &sf->regs.psr);
168
169 err |= __copy_from_user(&regs->u_regs[UREG_G1],
170 &sf->regs.u_regs[UREG_G1], 15 * sizeof(u32));
171
172 regs->psr = (regs->psr & ~PSR_ICC) | (psr & PSR_ICC);
173
174 /* Prevent syscall restart. */
175 pt_regs_clear_syscall(regs);
176
177 err |= __get_user(fpu_save, &sf->fpu_save);
178 if (!err && fpu_save)
179 err |= restore_fpu_state(regs, fpu_save);
180 err |= __copy_from_user(&set, &sf->mask, sizeof(sigset_t));
181 err |= restore_altstack(&sf->stack);
182
183 if (err)
184 goto segv;
185
186 regs->pc = pc;
187 regs->npc = npc;
188
189 err |= __get_user(rwin_save, &sf->rwin_save);
190 if (!err && rwin_save) {
191 if (restore_rwin_state(rwin_save))
192 goto segv;
193 }
194
195 set_current_blocked(&set);
196 return;
197 segv:
198 force_sig(SIGSEGV);
199 }
200
201 static inline void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, unsigned long framesize)
202 {
203 unsigned long sp = regs->u_regs[UREG_FP];
204
205 /*
206 * If we are on the alternate signal stack and would overflow it, don't.
207 * Return an always-bogus address instead so we will die with SIGSEGV.
208 */
209 if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize)))
210 return (void __user *) -1L;
211
212 /* This is the X/Open sanctioned signal stack switching. */
213 sp = sigsp(sp, ksig) - framesize;
214
215 /* Always align the stack frame. This handles two cases. First,
216 * sigaltstack need not be mindful of platform specific stack
217 * alignment. Second, if we took this signal because the stack
218 * is not aligned properly, we'd like to take the signal cleanly
219 * and report that.
220 */
221 sp &= ~15UL;
222
223 return (void __user *) sp;
224 }
225
226 static int setup_frame(struct ksignal *ksig, struct pt_regs *regs,
227 sigset_t *oldset)
228 {
229 struct signal_frame __user *sf;
230 int sigframe_size, err, wsaved;
231 void __user *tail;
232
233 /* 1. Make sure everything is clean */
234 synchronize_user_stack();
235
236 wsaved = current_thread_info()->w_saved;
237
238 sigframe_size = sizeof(*sf);
239 if (used_math())
240 sigframe_size += sizeof(__siginfo_fpu_t);
241 if (wsaved)
242 sigframe_size += sizeof(__siginfo_rwin_t);
243
244 sf = (struct signal_frame __user *)
245 get_sigframe(ksig, regs, sigframe_size);
246
247 if (invalid_frame_pointer(sf, sigframe_size)) {
248 do_exit(SIGILL);
249 return -EINVAL;
250 }
251
252 tail = sf + 1;
253
254 /* 2. Save the current process state */
255 err = __copy_to_user(&sf->info.si_regs, regs, sizeof(struct pt_regs));
256
257 err |= __put_user(0, &sf->extra_size);
258
259 if (used_math()) {
260 __siginfo_fpu_t __user *fp = tail;
261 tail += sizeof(*fp);
262 err |= save_fpu_state(regs, fp);
263 err |= __put_user(fp, &sf->fpu_save);
264 } else {
265 err |= __put_user(0, &sf->fpu_save);
266 }
267 if (wsaved) {
268 __siginfo_rwin_t __user *rwp = tail;
269 tail += sizeof(*rwp);
270 err |= save_rwin_state(wsaved, rwp);
271 err |= __put_user(rwp, &sf->rwin_save);
272 } else {
273 err |= __put_user(0, &sf->rwin_save);
274 }
275
276 err |= __put_user(oldset->sig[0], &sf->info.si_mask);
277 err |= __copy_to_user(sf->extramask, &oldset->sig[1],
278 (_NSIG_WORDS - 1) * sizeof(unsigned int));
279 if (!wsaved) {
280 err |= __copy_to_user(sf, (char *) regs->u_regs[UREG_FP],
281 sizeof(struct reg_window32));
282 } else {
283 struct reg_window32 *rp;
284
285 rp = &current_thread_info()->reg_window[wsaved - 1];
286 err |= __copy_to_user(sf, rp, sizeof(struct reg_window32));
287 }
288 if (err)
289 return err;
290
291 /* 3. signal handler back-trampoline and parameters */
292 regs->u_regs[UREG_FP] = (unsigned long) sf;
293 regs->u_regs[UREG_I0] = ksig->sig;
294 regs->u_regs[UREG_I1] = (unsigned long) &sf->info;
295 regs->u_regs[UREG_I2] = (unsigned long) &sf->info;
296
297 /* 4. signal handler */
298 regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
299 regs->npc = (regs->pc + 4);
300
301 /* 5. return to kernel instructions */
302 if (ksig->ka.ka_restorer)
303 regs->u_regs[UREG_I7] = (unsigned long)ksig->ka.ka_restorer;
304 else {
305 regs->u_regs[UREG_I7] = (unsigned long)(&(sf->insns[0]) - 2);
306
307 /* mov __NR_sigreturn, %g1 */
308 err |= __put_user(0x821020d8, &sf->insns[0]);
309
310 /* t 0x10 */
311 err |= __put_user(0x91d02010, &sf->insns[1]);
312 if (err)
313 return err;
314
315 /* Flush instruction space. */
316 flush_sig_insns(current->mm, (unsigned long) &(sf->insns[0]));
317 }
318 return 0;
319 }
320
321 static int setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs,
322 sigset_t *oldset)
323 {
324 struct rt_signal_frame __user *sf;
325 int sigframe_size, wsaved;
326 void __user *tail;
327 unsigned int psr;
328 int err;
329
330 synchronize_user_stack();
331 wsaved = current_thread_info()->w_saved;
332 sigframe_size = sizeof(*sf);
333 if (used_math())
334 sigframe_size += sizeof(__siginfo_fpu_t);
335 if (wsaved)
336 sigframe_size += sizeof(__siginfo_rwin_t);
337 sf = (struct rt_signal_frame __user *)
338 get_sigframe(ksig, regs, sigframe_size);
339 if (invalid_frame_pointer(sf, sigframe_size)) {
340 do_exit(SIGILL);
341 return -EINVAL;
342 }
343
344 tail = sf + 1;
345 err = __put_user(regs->pc, &sf->regs.pc);
346 err |= __put_user(regs->npc, &sf->regs.npc);
347 err |= __put_user(regs->y, &sf->regs.y);
348 psr = regs->psr;
349 if (used_math())
350 psr |= PSR_EF;
351 err |= __put_user(psr, &sf->regs.psr);
352 err |= __copy_to_user(&sf->regs.u_regs, regs->u_regs, sizeof(regs->u_regs));
353 err |= __put_user(0, &sf->extra_size);
354
355 if (psr & PSR_EF) {
356 __siginfo_fpu_t __user *fp = tail;
357 tail += sizeof(*fp);
358 err |= save_fpu_state(regs, fp);
359 err |= __put_user(fp, &sf->fpu_save);
360 } else {
361 err |= __put_user(0, &sf->fpu_save);
362 }
363 if (wsaved) {
364 __siginfo_rwin_t __user *rwp = tail;
365 tail += sizeof(*rwp);
366 err |= save_rwin_state(wsaved, rwp);
367 err |= __put_user(rwp, &sf->rwin_save);
368 } else {
369 err |= __put_user(0, &sf->rwin_save);
370 }
371 err |= __copy_to_user(&sf->mask, &oldset->sig[0], sizeof(sigset_t));
372
373 /* Setup sigaltstack */
374 err |= __save_altstack(&sf->stack, regs->u_regs[UREG_FP]);
375
376 if (!wsaved) {
377 err |= __copy_to_user(sf, (char *) regs->u_regs[UREG_FP],
378 sizeof(struct reg_window32));
379 } else {
380 struct reg_window32 *rp;
381
382 rp = &current_thread_info()->reg_window[wsaved - 1];
383 err |= __copy_to_user(sf, rp, sizeof(struct reg_window32));
384 }
385
386 err |= copy_siginfo_to_user(&sf->info, &ksig->info);
387
388 if (err)
389 return err;
390
391 regs->u_regs[UREG_FP] = (unsigned long) sf;
392 regs->u_regs[UREG_I0] = ksig->sig;
393 regs->u_regs[UREG_I1] = (unsigned long) &sf->info;
394 regs->u_regs[UREG_I2] = (unsigned long) &sf->regs;
395
396 regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
397 regs->npc = (regs->pc + 4);
398
399 if (ksig->ka.ka_restorer)
400 regs->u_regs[UREG_I7] = (unsigned long)ksig->ka.ka_restorer;
401 else {
402 regs->u_regs[UREG_I7] = (unsigned long)(&(sf->insns[0]) - 2);
403
404 /* mov __NR_sigreturn, %g1 */
405 err |= __put_user(0x821020d8, &sf->insns[0]);
406
407 /* t 0x10 */
408 err |= __put_user(0x91d02010, &sf->insns[1]);
409 if (err)
410 return err;
411
412 /* Flush instruction space. */
413 flush_sig_insns(current->mm, (unsigned long) &(sf->insns[0]));
414 }
415 return 0;
416 }
417
418 static inline void
419 handle_signal(struct ksignal *ksig, struct pt_regs *regs)
420 {
421 sigset_t *oldset = sigmask_to_save();
422 int err;
423
424 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
425 err = setup_rt_frame(ksig, regs, oldset);
426 else
427 err = setup_frame(ksig, regs, oldset);
428 signal_setup_done(err, ksig, 0);
429 }
430
431 static inline void syscall_restart(unsigned long orig_i0, struct pt_regs *regs,
432 struct sigaction *sa)
433 {
434 switch(regs->u_regs[UREG_I0]) {
435 case ERESTART_RESTARTBLOCK:
436 case ERESTARTNOHAND:
437 no_system_call_restart:
438 regs->u_regs[UREG_I0] = EINTR;
439 regs->psr |= PSR_C;
440 break;
441 case ERESTARTSYS:
442 if (!(sa->sa_flags & SA_RESTART))
443 goto no_system_call_restart;
444 /* fallthrough */
445 case ERESTARTNOINTR:
446 regs->u_regs[UREG_I0] = orig_i0;
447 regs->pc -= 4;
448 regs->npc -= 4;
449 }
450 }
451
452 /* Note that 'init' is a special process: it doesn't get signals it doesn't
453 * want to handle. Thus you cannot kill init even with a SIGKILL even by
454 * mistake.
455 */
456 static void do_signal(struct pt_regs *regs, unsigned long orig_i0)
457 {
458 struct ksignal ksig;
459 int restart_syscall;
460 bool has_handler;
461
462 /* It's a lot of work and synchronization to add a new ptrace
463 * register for GDB to save and restore in order to get
464 * orig_i0 correct for syscall restarts when debugging.
465 *
466 * Although it should be the case that most of the global
467 * registers are volatile across a system call, glibc already
468 * depends upon that fact that we preserve them. So we can't
469 * just use any global register to save away the orig_i0 value.
470 *
471 * In particular %g2, %g3, %g4, and %g5 are all assumed to be
472 * preserved across a system call trap by various pieces of
473 * code in glibc.
474 *
475 * %g7 is used as the "thread register". %g6 is not used in
476 * any fixed manner. %g6 is used as a scratch register and
477 * a compiler temporary, but it's value is never used across
478 * a system call. Therefore %g6 is usable for orig_i0 storage.
479 */
480 if (pt_regs_is_syscall(regs) && (regs->psr & PSR_C))
481 regs->u_regs[UREG_G6] = orig_i0;
482
483 has_handler = get_signal(&ksig);
484
485 /* If the debugger messes with the program counter, it clears
486 * the software "in syscall" bit, directing us to not perform
487 * a syscall restart.
488 */
489 restart_syscall = 0;
490 if (pt_regs_is_syscall(regs) && (regs->psr & PSR_C)) {
491 restart_syscall = 1;
492 orig_i0 = regs->u_regs[UREG_G6];
493 }
494
495 if (has_handler) {
496 if (restart_syscall)
497 syscall_restart(orig_i0, regs, &ksig.ka.sa);
498 handle_signal(&ksig, regs);
499 } else {
500 if (restart_syscall) {
501 switch (regs->u_regs[UREG_I0]) {
502 case ERESTARTNOHAND:
503 case ERESTARTSYS:
504 case ERESTARTNOINTR:
505 /* replay the system call when we are done */
506 regs->u_regs[UREG_I0] = orig_i0;
507 regs->pc -= 4;
508 regs->npc -= 4;
509 pt_regs_clear_syscall(regs);
510 /* fall through */
511 case ERESTART_RESTARTBLOCK:
512 regs->u_regs[UREG_G1] = __NR_restart_syscall;
513 regs->pc -= 4;
514 regs->npc -= 4;
515 pt_regs_clear_syscall(regs);
516 }
517 }
518 restore_saved_sigmask();
519 }
520 }
521
522 void do_notify_resume(struct pt_regs *regs, unsigned long orig_i0,
523 unsigned long thread_info_flags)
524 {
525 if (thread_info_flags & _TIF_SIGPENDING)
526 do_signal(regs, orig_i0);
527 if (thread_info_flags & _TIF_NOTIFY_RESUME) {
528 clear_thread_flag(TIF_NOTIFY_RESUME);
529 tracehook_notify_resume(regs);
530 }
531 }
532
533 asmlinkage int do_sys_sigstack(struct sigstack __user *ssptr,
534 struct sigstack __user *ossptr,
535 unsigned long sp)
536 {
537 int ret = -EFAULT;
538
539 /* First see if old state is wanted. */
540 if (ossptr) {
541 if (put_user(current->sas_ss_sp + current->sas_ss_size,
542 &ossptr->the_stack) ||
543 __put_user(on_sig_stack(sp), &ossptr->cur_status))
544 goto out;
545 }
546
547 /* Now see if we want to update the new state. */
548 if (ssptr) {
549 char *ss_sp;
550
551 if (get_user(ss_sp, &ssptr->the_stack))
552 goto out;
553 /* If the current stack was set with sigaltstack, don't
554 swap stacks while we are on it. */
555 ret = -EPERM;
556 if (current->sas_ss_sp && on_sig_stack(sp))
557 goto out;
558
559 /* Since we don't know the extent of the stack, and we don't
560 track onstack-ness, but rather calculate it, we must
561 presume a size. Ho hum this interface is lossy. */
562 current->sas_ss_sp = (unsigned long)ss_sp - SIGSTKSZ;
563 current->sas_ss_size = SIGSTKSZ;
564 }
565 ret = 0;
566 out:
567 return ret;
568 }
Linux with added FPC-III support