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/resume_user_mode.h> |
23 | |
24 | #include <linux/uaccess.h> |
25 | #include <asm/ptrace.h> |
26 | #include <asm/cacheflush.h> /* flush_sig_insns */ |
27 | #include <asm/switch_to.h> |
28 | |
29 | #include "sigutil.h" |
30 | #include "kernel.h" |
31 | |
32 | extern void fpsave(unsigned long *fpregs, unsigned long *fsr, |
33 | void *fpqueue, unsigned long *fpqdepth); |
34 | extern void fpload(unsigned long *fpregs, unsigned long *fsr); |
35 | |
36 | struct signal_frame { |
37 | struct sparc_stackf ss; |
38 | __siginfo32_t info; |
39 | __siginfo_fpu_t __user *fpu_save; |
40 | unsigned long insns[2] __attribute__ ((aligned (8))); |
41 | unsigned int [_NSIG_WORDS - 1]; |
42 | unsigned int ; /* Should be 0 */ |
43 | __siginfo_rwin_t __user *rwin_save; |
44 | } __attribute__((aligned(8))); |
45 | |
46 | struct rt_signal_frame { |
47 | struct sparc_stackf ss; |
48 | siginfo_t info; |
49 | struct pt_regs regs; |
50 | sigset_t mask; |
51 | __siginfo_fpu_t __user *fpu_save; |
52 | unsigned int insns[2]; |
53 | stack_t stack; |
54 | unsigned int ; /* Should be 0 */ |
55 | __siginfo_rwin_t __user *rwin_save; |
56 | } __attribute__((aligned(8))); |
57 | |
58 | /* Align macros */ |
59 | #define SF_ALIGNEDSZ (((sizeof(struct signal_frame) + 7) & (~7))) |
60 | #define RT_ALIGNEDSZ (((sizeof(struct rt_signal_frame) + 7) & (~7))) |
61 | |
62 | /* Checks if the fp is valid. We always build signal frames which are |
63 | * 16-byte aligned, therefore we can always enforce that the restore |
64 | * frame has that property as well. |
65 | */ |
66 | static inline bool invalid_frame_pointer(void __user *fp, int fplen) |
67 | { |
68 | if ((((unsigned long) fp) & 15) || !access_ok(fp, fplen)) |
69 | return true; |
70 | |
71 | return false; |
72 | } |
73 | |
74 | asmlinkage void do_sigreturn(struct pt_regs *regs) |
75 | { |
76 | unsigned long up_psr, pc, npc, ufp; |
77 | struct signal_frame __user *sf; |
78 | sigset_t set; |
79 | __siginfo_fpu_t __user *fpu_save; |
80 | __siginfo_rwin_t __user *rwin_save; |
81 | int err; |
82 | |
83 | /* Always make any pending restarted system calls return -EINTR */ |
84 | current->restart_block.fn = do_no_restart_syscall; |
85 | |
86 | synchronize_user_stack(); |
87 | |
88 | sf = (struct signal_frame __user *) regs->u_regs[UREG_FP]; |
89 | |
90 | /* 1. Make sure we are not getting garbage from the user */ |
91 | if (invalid_frame_pointer(fp: sf, fplen: sizeof(*sf))) |
92 | goto segv_and_exit; |
93 | |
94 | if (get_user(ufp, &sf->info.si_regs.u_regs[UREG_FP])) |
95 | goto segv_and_exit; |
96 | |
97 | if (ufp & 0x7) |
98 | goto segv_and_exit; |
99 | |
100 | err = __get_user(pc, &sf->info.si_regs.pc); |
101 | err |= __get_user(npc, &sf->info.si_regs.npc); |
102 | |
103 | if ((pc | npc) & 3) |
104 | goto segv_and_exit; |
105 | |
106 | /* 2. Restore the state */ |
107 | up_psr = regs->psr; |
108 | err |= __copy_from_user(to: regs, from: &sf->info.si_regs, n: sizeof(struct pt_regs)); |
109 | |
110 | /* User can only change condition codes and FPU enabling in %psr. */ |
111 | regs->psr = (up_psr & ~(PSR_ICC | PSR_EF)) |
112 | | (regs->psr & (PSR_ICC | PSR_EF)); |
113 | |
114 | /* Prevent syscall restart. */ |
115 | pt_regs_clear_syscall(regs); |
116 | |
117 | err |= __get_user(fpu_save, &sf->fpu_save); |
118 | if (fpu_save) |
119 | err |= restore_fpu_state(regs, fpu_save); |
120 | err |= __get_user(rwin_save, &sf->rwin_save); |
121 | if (rwin_save) |
122 | err |= restore_rwin_state(rwin_save); |
123 | |
124 | /* This is pretty much atomic, no amount locking would prevent |
125 | * the races which exist anyways. |
126 | */ |
127 | err |= __get_user(set.sig[0], &sf->info.si_mask); |
128 | err |= __copy_from_user(to: &set.sig[1], from: &sf->extramask, |
129 | n: (_NSIG_WORDS-1) * sizeof(unsigned int)); |
130 | |
131 | if (err) |
132 | goto segv_and_exit; |
133 | |
134 | set_current_blocked(&set); |
135 | return; |
136 | |
137 | segv_and_exit: |
138 | force_sig(SIGSEGV); |
139 | } |
140 | |
141 | asmlinkage void do_rt_sigreturn(struct pt_regs *regs) |
142 | { |
143 | struct rt_signal_frame __user *sf; |
144 | unsigned int psr, pc, npc, ufp; |
145 | __siginfo_fpu_t __user *fpu_save; |
146 | __siginfo_rwin_t __user *rwin_save; |
147 | sigset_t set; |
148 | int err; |
149 | |
150 | synchronize_user_stack(); |
151 | sf = (struct rt_signal_frame __user *) regs->u_regs[UREG_FP]; |
152 | if (invalid_frame_pointer(fp: sf, fplen: sizeof(*sf))) |
153 | goto segv; |
154 | |
155 | if (get_user(ufp, &sf->regs.u_regs[UREG_FP])) |
156 | goto segv; |
157 | |
158 | if (ufp & 0x7) |
159 | goto segv; |
160 | |
161 | err = __get_user(pc, &sf->regs.pc); |
162 | err |= __get_user(npc, &sf->regs.npc); |
163 | err |= ((pc | npc) & 0x03); |
164 | |
165 | err |= __get_user(regs->y, &sf->regs.y); |
166 | err |= __get_user(psr, &sf->regs.psr); |
167 | |
168 | err |= __copy_from_user(®s->u_regs[UREG_G1], |
169 | &sf->regs.u_regs[UREG_G1], 15 * sizeof(u32)); |
170 | |
171 | regs->psr = (regs->psr & ~PSR_ICC) | (psr & PSR_ICC); |
172 | |
173 | /* Prevent syscall restart. */ |
174 | pt_regs_clear_syscall(regs); |
175 | |
176 | err |= __get_user(fpu_save, &sf->fpu_save); |
177 | if (!err && fpu_save) |
178 | err |= restore_fpu_state(regs, fpu_save); |
179 | err |= __copy_from_user(to: &set, from: &sf->mask, n: sizeof(sigset_t)); |
180 | err |= restore_altstack(&sf->stack); |
181 | |
182 | if (err) |
183 | goto segv; |
184 | |
185 | regs->pc = pc; |
186 | regs->npc = npc; |
187 | |
188 | err |= __get_user(rwin_save, &sf->rwin_save); |
189 | if (!err && rwin_save) { |
190 | if (restore_rwin_state(rwin_save)) |
191 | goto segv; |
192 | } |
193 | |
194 | set_current_blocked(&set); |
195 | return; |
196 | segv: |
197 | force_sig(SIGSEGV); |
198 | } |
199 | |
200 | static inline void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, unsigned long framesize) |
201 | { |
202 | unsigned long sp = regs->u_regs[UREG_FP]; |
203 | |
204 | /* |
205 | * If we are on the alternate signal stack and would overflow it, don't. |
206 | * Return an always-bogus address instead so we will die with SIGSEGV. |
207 | */ |
208 | if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize))) |
209 | return (void __user *) -1L; |
210 | |
211 | /* This is the X/Open sanctioned signal stack switching. */ |
212 | sp = sigsp(sp, ksig) - framesize; |
213 | |
214 | /* Always align the stack frame. This handles two cases. First, |
215 | * sigaltstack need not be mindful of platform specific stack |
216 | * alignment. Second, if we took this signal because the stack |
217 | * is not aligned properly, we'd like to take the signal cleanly |
218 | * and report that. |
219 | */ |
220 | sp &= ~15UL; |
221 | |
222 | return (void __user *) sp; |
223 | } |
224 | |
225 | static int setup_frame(struct ksignal *ksig, struct pt_regs *regs, |
226 | sigset_t *oldset) |
227 | { |
228 | struct signal_frame __user *sf; |
229 | int sigframe_size, err, wsaved; |
230 | void __user *tail; |
231 | |
232 | /* 1. Make sure everything is clean */ |
233 | synchronize_user_stack(); |
234 | |
235 | wsaved = current_thread_info()->w_saved; |
236 | |
237 | sigframe_size = sizeof(*sf); |
238 | if (used_math()) |
239 | sigframe_size += sizeof(__siginfo_fpu_t); |
240 | if (wsaved) |
241 | sigframe_size += sizeof(__siginfo_rwin_t); |
242 | |
243 | sf = (struct signal_frame __user *) |
244 | get_sigframe(ksig, regs, framesize: sigframe_size); |
245 | |
246 | if (invalid_frame_pointer(fp: sf, fplen: sigframe_size)) { |
247 | force_exit_sig(SIGILL); |
248 | return -EINVAL; |
249 | } |
250 | |
251 | tail = sf + 1; |
252 | |
253 | /* 2. Save the current process state */ |
254 | err = __copy_to_user(to: &sf->info.si_regs, from: regs, n: sizeof(struct pt_regs)); |
255 | |
256 | err |= __put_user(0, &sf->extra_size); |
257 | |
258 | if (used_math()) { |
259 | __siginfo_fpu_t __user *fp = tail; |
260 | tail += sizeof(*fp); |
261 | err |= save_fpu_state(regs, fp); |
262 | err |= __put_user(fp, &sf->fpu_save); |
263 | } else { |
264 | err |= __put_user(0, &sf->fpu_save); |
265 | } |
266 | if (wsaved) { |
267 | __siginfo_rwin_t __user *rwp = tail; |
268 | tail += sizeof(*rwp); |
269 | err |= save_rwin_state(wsaved, rwp); |
270 | err |= __put_user(rwp, &sf->rwin_save); |
271 | } else { |
272 | err |= __put_user(0, &sf->rwin_save); |
273 | } |
274 | |
275 | err |= __put_user(oldset->sig[0], &sf->info.si_mask); |
276 | err |= __copy_to_user(to: sf->extramask, from: &oldset->sig[1], |
277 | n: (_NSIG_WORDS - 1) * sizeof(unsigned int)); |
278 | if (!wsaved) { |
279 | err |= __copy_to_user(sf, (char *) regs->u_regs[UREG_FP], |
280 | sizeof(struct reg_window32)); |
281 | } else { |
282 | struct reg_window32 *rp; |
283 | |
284 | rp = ¤t_thread_info()->reg_window[wsaved - 1]; |
285 | err |= __copy_to_user(sf, rp, sizeof(struct reg_window32)); |
286 | } |
287 | if (err) |
288 | return err; |
289 | |
290 | /* 3. signal handler back-trampoline and parameters */ |
291 | regs->u_regs[UREG_FP] = (unsigned long) sf; |
292 | regs->u_regs[UREG_I0] = ksig->sig; |
293 | regs->u_regs[UREG_I1] = (unsigned long) &sf->info; |
294 | regs->u_regs[UREG_I2] = (unsigned long) &sf->info; |
295 | |
296 | /* 4. signal handler */ |
297 | regs->pc = (unsigned long) ksig->ka.sa.sa_handler; |
298 | regs->npc = (regs->pc + 4); |
299 | |
300 | /* 5. return to kernel instructions */ |
301 | if (ksig->ka.ka_restorer) |
302 | regs->u_regs[UREG_I7] = (unsigned long)ksig->ka.ka_restorer; |
303 | else { |
304 | regs->u_regs[UREG_I7] = (unsigned long)(&(sf->insns[0]) - 2); |
305 | |
306 | /* mov __NR_sigreturn, %g1 */ |
307 | err |= __put_user(0x821020d8, &sf->insns[0]); |
308 | |
309 | /* t 0x10 */ |
310 | err |= __put_user(0x91d02010, &sf->insns[1]); |
311 | if (err) |
312 | return err; |
313 | |
314 | /* Flush instruction space. */ |
315 | flush_sig_insns(current->mm, (unsigned long) &(sf->insns[0])); |
316 | } |
317 | return 0; |
318 | } |
319 | |
320 | static int setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs, |
321 | sigset_t *oldset) |
322 | { |
323 | struct rt_signal_frame __user *sf; |
324 | int sigframe_size, wsaved; |
325 | void __user *tail; |
326 | unsigned int psr; |
327 | int err; |
328 | |
329 | synchronize_user_stack(); |
330 | wsaved = current_thread_info()->w_saved; |
331 | sigframe_size = sizeof(*sf); |
332 | if (used_math()) |
333 | sigframe_size += sizeof(__siginfo_fpu_t); |
334 | if (wsaved) |
335 | sigframe_size += sizeof(__siginfo_rwin_t); |
336 | sf = (struct rt_signal_frame __user *) |
337 | get_sigframe(ksig, regs, framesize: sigframe_size); |
338 | if (invalid_frame_pointer(fp: sf, fplen: sigframe_size)) { |
339 | force_exit_sig(SIGILL); |
340 | return -EINVAL; |
341 | } |
342 | |
343 | tail = sf + 1; |
344 | err = __put_user(regs->pc, &sf->regs.pc); |
345 | err |= __put_user(regs->npc, &sf->regs.npc); |
346 | err |= __put_user(regs->y, &sf->regs.y); |
347 | psr = regs->psr; |
348 | if (used_math()) |
349 | psr |= PSR_EF; |
350 | err |= __put_user(psr, &sf->regs.psr); |
351 | err |= __copy_to_user(to: &sf->regs.u_regs, from: regs->u_regs, n: sizeof(regs->u_regs)); |
352 | err |= __put_user(0, &sf->extra_size); |
353 | |
354 | if (psr & PSR_EF) { |
355 | __siginfo_fpu_t __user *fp = tail; |
356 | tail += sizeof(*fp); |
357 | err |= save_fpu_state(regs, fp); |
358 | err |= __put_user(fp, &sf->fpu_save); |
359 | } else { |
360 | err |= __put_user(0, &sf->fpu_save); |
361 | } |
362 | if (wsaved) { |
363 | __siginfo_rwin_t __user *rwp = tail; |
364 | tail += sizeof(*rwp); |
365 | err |= save_rwin_state(wsaved, rwp); |
366 | err |= __put_user(rwp, &sf->rwin_save); |
367 | } else { |
368 | err |= __put_user(0, &sf->rwin_save); |
369 | } |
370 | err |= __copy_to_user(to: &sf->mask, from: &oldset->sig[0], n: sizeof(sigset_t)); |
371 | |
372 | /* Setup sigaltstack */ |
373 | err |= __save_altstack(&sf->stack, regs->u_regs[UREG_FP]); |
374 | |
375 | if (!wsaved) { |
376 | err |= __copy_to_user(sf, (char *) regs->u_regs[UREG_FP], |
377 | sizeof(struct reg_window32)); |
378 | } else { |
379 | struct reg_window32 *rp; |
380 | |
381 | rp = ¤t_thread_info()->reg_window[wsaved - 1]; |
382 | err |= __copy_to_user(sf, rp, sizeof(struct reg_window32)); |
383 | } |
384 | |
385 | err |= copy_siginfo_to_user(to: &sf->info, from: &ksig->info); |
386 | |
387 | if (err) |
388 | return err; |
389 | |
390 | regs->u_regs[UREG_FP] = (unsigned long) sf; |
391 | regs->u_regs[UREG_I0] = ksig->sig; |
392 | regs->u_regs[UREG_I1] = (unsigned long) &sf->info; |
393 | regs->u_regs[UREG_I2] = (unsigned long) &sf->regs; |
394 | |
395 | regs->pc = (unsigned long) ksig->ka.sa.sa_handler; |
396 | regs->npc = (regs->pc + 4); |
397 | |
398 | if (ksig->ka.ka_restorer) |
399 | regs->u_regs[UREG_I7] = (unsigned long)ksig->ka.ka_restorer; |
400 | else { |
401 | regs->u_regs[UREG_I7] = (unsigned long)(&(sf->insns[0]) - 2); |
402 | |
403 | /* mov __NR_rt_sigreturn, %g1 */ |
404 | err |= __put_user(0x82102065, &sf->insns[0]); |
405 | |
406 | /* t 0x10 */ |
407 | err |= __put_user(0x91d02010, &sf->insns[1]); |
408 | if (err) |
409 | return err; |
410 | |
411 | /* Flush instruction space. */ |
412 | flush_sig_insns(current->mm, (unsigned long) &(sf->insns[0])); |
413 | } |
414 | return 0; |
415 | } |
416 | |
417 | static inline void |
418 | handle_signal(struct ksignal *ksig, struct pt_regs *regs) |
419 | { |
420 | sigset_t *oldset = sigmask_to_save(); |
421 | int err; |
422 | |
423 | if (ksig->ka.sa.sa_flags & SA_SIGINFO) |
424 | err = setup_rt_frame(ksig, regs, oldset); |
425 | else |
426 | err = setup_frame(ksig, regs, oldset); |
427 | signal_setup_done(failed: err, ksig, stepping: 0); |
428 | } |
429 | |
430 | static inline void syscall_restart(unsigned long orig_i0, struct pt_regs *regs, |
431 | struct sigaction *sa) |
432 | { |
433 | switch(regs->u_regs[UREG_I0]) { |
434 | case ERESTART_RESTARTBLOCK: |
435 | case ERESTARTNOHAND: |
436 | no_system_call_restart: |
437 | regs->u_regs[UREG_I0] = EINTR; |
438 | regs->psr |= PSR_C; |
439 | break; |
440 | case ERESTARTSYS: |
441 | if (!(sa->sa_flags & SA_RESTART)) |
442 | goto no_system_call_restart; |
443 | fallthrough; |
444 | case ERESTARTNOINTR: |
445 | regs->u_regs[UREG_I0] = orig_i0; |
446 | regs->pc -= 4; |
447 | regs->npc -= 4; |
448 | } |
449 | } |
450 | |
451 | /* Note that 'init' is a special process: it doesn't get signals it doesn't |
452 | * want to handle. Thus you cannot kill init even with a SIGKILL even by |
453 | * mistake. |
454 | */ |
455 | static void do_signal(struct pt_regs *regs, unsigned long orig_i0) |
456 | { |
457 | struct ksignal ksig; |
458 | int restart_syscall; |
459 | bool has_handler; |
460 | |
461 | /* It's a lot of work and synchronization to add a new ptrace |
462 | * register for GDB to save and restore in order to get |
463 | * orig_i0 correct for syscall restarts when debugging. |
464 | * |
465 | * Although it should be the case that most of the global |
466 | * registers are volatile across a system call, glibc already |
467 | * depends upon that fact that we preserve them. So we can't |
468 | * just use any global register to save away the orig_i0 value. |
469 | * |
470 | * In particular %g2, %g3, %g4, and %g5 are all assumed to be |
471 | * preserved across a system call trap by various pieces of |
472 | * code in glibc. |
473 | * |
474 | * %g7 is used as the "thread register". %g6 is not used in |
475 | * any fixed manner. %g6 is used as a scratch register and |
476 | * a compiler temporary, but its value is never used across |
477 | * a system call. Therefore %g6 is usable for orig_i0 storage. |
478 | */ |
479 | if (pt_regs_is_syscall(regs) && (regs->psr & PSR_C)) |
480 | regs->u_regs[UREG_G6] = orig_i0; |
481 | |
482 | has_handler = get_signal(ksig: &ksig); |
483 | |
484 | /* If the debugger messes with the program counter, it clears |
485 | * the software "in syscall" bit, directing us to not perform |
486 | * a syscall restart. |
487 | */ |
488 | restart_syscall = 0; |
489 | if (pt_regs_is_syscall(regs) && (regs->psr & PSR_C)) { |
490 | restart_syscall = 1; |
491 | orig_i0 = regs->u_regs[UREG_G6]; |
492 | } |
493 | |
494 | if (has_handler) { |
495 | if (restart_syscall) |
496 | syscall_restart(orig_i0, regs, sa: &ksig.ka.sa); |
497 | handle_signal(ksig: &ksig, regs); |
498 | } else { |
499 | if (restart_syscall) { |
500 | switch (regs->u_regs[UREG_I0]) { |
501 | case ERESTARTNOHAND: |
502 | case ERESTARTSYS: |
503 | case ERESTARTNOINTR: |
504 | /* replay the system call when we are done */ |
505 | regs->u_regs[UREG_I0] = orig_i0; |
506 | regs->pc -= 4; |
507 | regs->npc -= 4; |
508 | pt_regs_clear_syscall(regs); |
509 | fallthrough; |
510 | case ERESTART_RESTARTBLOCK: |
511 | regs->u_regs[UREG_G1] = __NR_restart_syscall; |
512 | regs->pc -= 4; |
513 | regs->npc -= 4; |
514 | pt_regs_clear_syscall(regs); |
515 | } |
516 | } |
517 | restore_saved_sigmask(); |
518 | } |
519 | } |
520 | |
521 | void do_notify_resume(struct pt_regs *regs, unsigned long orig_i0, |
522 | unsigned long thread_info_flags) |
523 | { |
524 | if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) |
525 | do_signal(regs, orig_i0); |
526 | if (thread_info_flags & _TIF_NOTIFY_RESUME) |
527 | resume_user_mode_work(regs); |
528 | } |
529 | |
530 | asmlinkage int do_sys_sigstack(struct sigstack __user *ssptr, |
531 | struct sigstack __user *ossptr, |
532 | unsigned long sp) |
533 | { |
534 | int ret = -EFAULT; |
535 | |
536 | /* First see if old state is wanted. */ |
537 | if (ossptr) { |
538 | if (put_user(current->sas_ss_sp + current->sas_ss_size, |
539 | &ossptr->the_stack) || |
540 | __put_user(on_sig_stack(sp), &ossptr->cur_status)) |
541 | goto out; |
542 | } |
543 | |
544 | /* Now see if we want to update the new state. */ |
545 | if (ssptr) { |
546 | char *ss_sp; |
547 | |
548 | if (get_user(ss_sp, &ssptr->the_stack)) |
549 | goto out; |
550 | /* If the current stack was set with sigaltstack, don't |
551 | swap stacks while we are on it. */ |
552 | ret = -EPERM; |
553 | if (current->sas_ss_sp && on_sig_stack(sp)) |
554 | goto out; |
555 | |
556 | /* Since we don't know the extent of the stack, and we don't |
557 | track onstack-ness, but rather calculate it, we must |
558 | presume a size. Ho hum this interface is lossy. */ |
559 | current->sas_ss_sp = (unsigned long)ss_sp - SIGSTKSZ; |
560 | current->sas_ss_size = SIGSTKSZ; |
561 | } |
562 | ret = 0; |
563 | out: |
564 | return ret; |
565 | } |
566 | |