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Linux 6.13-rc4
[linux.git] / arch / sh / kernel / signal_32.c
bloba6bfc6f374911d5ac639030c196bd72ebd19d614
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * linux/arch/sh/kernel/signal.c
4 *
5 * Copyright (C) 1991, 1992 Linus Torvalds
6 *
7 * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
8 *
9 * SuperH version: Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima
10 *
11 */
12 #include <linux/sched.h>
13 #include <linux/sched/task_stack.h>
14 #include <linux/mm.h>
15 #include <linux/smp.h>
16 #include <linux/kernel.h>
17 #include <linux/signal.h>
18 #include <linux/errno.h>
19 #include <linux/wait.h>
20 #include <linux/ptrace.h>
21 #include <linux/unistd.h>
22 #include <linux/stddef.h>
23 #include <linux/tty.h>
24 #include <linux/elf.h>
25 #include <linux/personality.h>
26 #include <linux/binfmts.h>
27 #include <linux/io.h>
28 #include <linux/resume_user_mode.h>
29 #include <asm/ucontext.h>
30 #include <linux/uaccess.h>
31 #include <asm/cacheflush.h>
32 #include <asm/syscalls.h>
33 #include <asm/fpu.h>
34
35 struct fdpic_func_descriptor {
36 unsigned long text;
37 unsigned long GOT;
38 };
39
40 /*
41 * The following define adds a 64 byte gap between the signal
42 * stack frame and previous contents of the stack. This allows
43 * frame unwinding in a function epilogue but only if a frame
44 * pointer is used in the function. This is necessary because
45 * current gcc compilers (<4.3) do not generate unwind info on
46 * SH for function epilogues.
47 */
48 #define UNWINDGUARD 64
49
50 /*
51 * Do a signal return; undo the signal stack.
52 */
53
54 #define MOVW(n) (0x9300|((n)-2)) /* Move mem word at PC+n to R3 */
55 #if defined(CONFIG_CPU_SH2)
56 #define TRAP_NOARG 0xc320 /* Syscall w/no args (NR in R3) */
57 #else
58 #define TRAP_NOARG 0xc310 /* Syscall w/no args (NR in R3) */
59 #endif
60 #define OR_R0_R0 0x200b /* or r0,r0 (insert to avoid hardware bug) */
61
62 struct sigframe
63 {
64 struct sigcontext sc;
65 unsigned long extramask[_NSIG_WORDS-1];
66 u16 retcode[8];
67 };
68
69 struct rt_sigframe
70 {
71 struct siginfo info;
72 struct ucontext uc;
73 u16 retcode[8];
74 };
75
76 #ifdef CONFIG_SH_FPU
77 static inline int restore_sigcontext_fpu(struct sigcontext __user *sc)
78 {
79 struct task_struct *tsk = current;
80
81 if (!(boot_cpu_data.flags & CPU_HAS_FPU))
82 return 0;
83
84 set_used_math();
85 return __copy_from_user(&tsk->thread.xstate->hardfpu, &sc->sc_fpregs[0],
86 sizeof(long)*(16*2+2));
87 }
88
89 static inline int save_sigcontext_fpu(struct sigcontext __user *sc,
90 struct pt_regs *regs)
91 {
92 struct task_struct *tsk = current;
93
94 if (!(boot_cpu_data.flags & CPU_HAS_FPU))
95 return 0;
96
97 if (!used_math())
98 return __put_user(0, &sc->sc_ownedfp);
99
100 if (__put_user(1, &sc->sc_ownedfp))
101 return -EFAULT;
102
103 /* This will cause a "finit" to be triggered by the next
104 attempted FPU operation by the 'current' process.
105 */
106 clear_used_math();
107
108 unlazy_fpu(tsk, regs);
109 return __copy_to_user(&sc->sc_fpregs[0], &tsk->thread.xstate->hardfpu,
110 sizeof(long)*(16*2+2));
111 }
112 #endif /* CONFIG_SH_FPU */
113
114 static int
115 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *r0_p)
116 {
117 unsigned int err = 0;
118 unsigned int sr = regs->sr & ~SR_USER_MASK;
119
120 #define COPY(x) err |= __get_user(regs->x, &sc->sc_##x)
121 COPY(regs[1]);
122 COPY(regs[2]); COPY(regs[3]);
123 COPY(regs[4]); COPY(regs[5]);
124 COPY(regs[6]); COPY(regs[7]);
125 COPY(regs[8]); COPY(regs[9]);
126 COPY(regs[10]); COPY(regs[11]);
127 COPY(regs[12]); COPY(regs[13]);
128 COPY(regs[14]); COPY(regs[15]);
129 COPY(gbr); COPY(mach);
130 COPY(macl); COPY(pr);
131 COPY(sr); COPY(pc);
132 #undef COPY
133
134 regs->sr = (regs->sr & SR_USER_MASK) | sr;
135
136 #ifdef CONFIG_SH_FPU
137 if (boot_cpu_data.flags & CPU_HAS_FPU) {
138 int owned_fp;
139 struct task_struct *tsk = current;
140
141 regs->sr |= SR_FD; /* Release FPU */
142 clear_fpu(tsk, regs);
143 clear_used_math();
144 err |= __get_user (owned_fp, &sc->sc_ownedfp);
145 if (owned_fp)
146 err |= restore_sigcontext_fpu(sc);
147 }
148 #endif
149
150 regs->tra = -1; /* disable syscall checks */
151 err |= __get_user(*r0_p, &sc->sc_regs[0]);
152 return err;
153 }
154
155 asmlinkage int sys_sigreturn(void)
156 {
157 struct pt_regs *regs = current_pt_regs();
158 struct sigframe __user *frame = (struct sigframe __user *)regs->regs[15];
159 sigset_t set;
160 int r0;
161
162 /* Always make any pending restarted system calls return -EINTR */
163 current->restart_block.fn = do_no_restart_syscall;
164
165 if (!access_ok(frame, sizeof(*frame)))
166 goto badframe;
167
168 if (__get_user(set.sig[0], &frame->sc.oldmask)
169 || (_NSIG_WORDS > 1
170 && __copy_from_user(&set.sig[1], &frame->extramask,
171 sizeof(frame->extramask))))
172 goto badframe;
173
174 set_current_blocked(&set);
175
176 if (restore_sigcontext(regs, &frame->sc, &r0))
177 goto badframe;
178 return r0;
179
180 badframe:
181 force_sig(SIGSEGV);
182 return 0;
183 }
184
185 asmlinkage int sys_rt_sigreturn(void)
186 {
187 struct pt_regs *regs = current_pt_regs();
188 struct rt_sigframe __user *frame = (struct rt_sigframe __user *)regs->regs[15];
189 sigset_t set;
190 int r0;
191
192 /* Always make any pending restarted system calls return -EINTR */
193 current->restart_block.fn = do_no_restart_syscall;
194
195 if (!access_ok(frame, sizeof(*frame)))
196 goto badframe;
197
198 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
199 goto badframe;
200
201 set_current_blocked(&set);
202
203 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0))
204 goto badframe;
205
206 if (restore_altstack(&frame->uc.uc_stack))
207 goto badframe;
208
209 return r0;
210
211 badframe:
212 force_sig(SIGSEGV);
213 return 0;
214 }
215
216 /*
217 * Set up a signal frame.
218 */
219
220 static int
221 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
222 unsigned long mask)
223 {
224 int err = 0;
225
226 #define COPY(x) err |= __put_user(regs->x, &sc->sc_##x)
227 COPY(regs[0]); COPY(regs[1]);
228 COPY(regs[2]); COPY(regs[3]);
229 COPY(regs[4]); COPY(regs[5]);
230 COPY(regs[6]); COPY(regs[7]);
231 COPY(regs[8]); COPY(regs[9]);
232 COPY(regs[10]); COPY(regs[11]);
233 COPY(regs[12]); COPY(regs[13]);
234 COPY(regs[14]); COPY(regs[15]);
235 COPY(gbr); COPY(mach);
236 COPY(macl); COPY(pr);
237 COPY(sr); COPY(pc);
238 #undef COPY
239
240 #ifdef CONFIG_SH_FPU
241 err |= save_sigcontext_fpu(sc, regs);
242 #endif
243
244 /* non-iBCS2 extensions.. */
245 err |= __put_user(mask, &sc->oldmask);
246
247 return err;
248 }
249
250 /*
251 * Determine which stack to use..
252 */
253 static inline void __user *
254 get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
255 {
256 if (ka->sa.sa_flags & SA_ONSTACK) {
257 if (sas_ss_flags(sp) == 0)
258 sp = current->sas_ss_sp + current->sas_ss_size;
259 }
260
261 return (void __user *)((sp - (frame_size+UNWINDGUARD)) & -8ul);
262 }
263
264 /* These symbols are defined with the addresses in the vsyscall page.
265 See vsyscall-trapa.S. */
266 extern void __kernel_sigreturn(void);
267 extern void __kernel_rt_sigreturn(void);
268
269 static int setup_frame(struct ksignal *ksig, sigset_t *set,
270 struct pt_regs *regs)
271 {
272 struct sigframe __user *frame;
273 int err = 0, sig = ksig->sig;
274
275 frame = get_sigframe(&ksig->ka, regs->regs[15], sizeof(*frame));
276
277 if (!access_ok(frame, sizeof(*frame)))
278 return -EFAULT;
279
280 err |= setup_sigcontext(&frame->sc, regs, set->sig[0]);
281
282 if (_NSIG_WORDS > 1)
283 err |= __copy_to_user(frame->extramask, &set->sig[1],
284 sizeof(frame->extramask));
285
286 /* Set up to return from userspace. If provided, use a stub
287 already in userspace. */
288 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
289 regs->pr = (unsigned long) ksig->ka.sa.sa_restorer;
290 #ifdef CONFIG_VSYSCALL
291 } else if (likely(current->mm->context.vdso)) {
292 regs->pr = VDSO_SYM(&__kernel_sigreturn);
293 #endif
294 } else {
295 /* Generate return code (system call to sigreturn) */
296 err |= __put_user(MOVW(7), &frame->retcode[0]);
297 err |= __put_user(TRAP_NOARG, &frame->retcode[1]);
298 err |= __put_user(OR_R0_R0, &frame->retcode[2]);
299 err |= __put_user(OR_R0_R0, &frame->retcode[3]);
300 err |= __put_user(OR_R0_R0, &frame->retcode[4]);
301 err |= __put_user(OR_R0_R0, &frame->retcode[5]);
302 err |= __put_user(OR_R0_R0, &frame->retcode[6]);
303 err |= __put_user((__NR_sigreturn), &frame->retcode[7]);
304 regs->pr = (unsigned long) frame->retcode;
305 flush_icache_range(regs->pr, regs->pr + sizeof(frame->retcode));
306 }
307
308 if (err)
309 return -EFAULT;
310
311 /* Set up registers for signal handler */
312 regs->regs[15] = (unsigned long) frame;
313 regs->regs[4] = sig; /* Arg for signal handler */
314 regs->regs[5] = 0;
315 regs->regs[6] = (unsigned long) &frame->sc;
316
317 if (current->personality & FDPIC_FUNCPTRS) {
318 struct fdpic_func_descriptor __user *funcptr =
319 (struct fdpic_func_descriptor __user *)ksig->ka.sa.sa_handler;
320
321 err |= __get_user(regs->pc, &funcptr->text);
322 err |= __get_user(regs->regs[12], &funcptr->GOT);
323 } else
324 regs->pc = (unsigned long)ksig->ka.sa.sa_handler;
325
326 if (err)
327 return -EFAULT;
328
329 pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n",
330 current->comm, task_pid_nr(current), frame, regs->pc, regs->pr);
331
332 return 0;
333 }
334
335 static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
336 struct pt_regs *regs)
337 {
338 struct rt_sigframe __user *frame;
339 int err = 0, sig = ksig->sig;
340
341 frame = get_sigframe(&ksig->ka, regs->regs[15], sizeof(*frame));
342
343 if (!access_ok(frame, sizeof(*frame)))
344 return -EFAULT;
345
346 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
347
348 /* Create the ucontext. */
349 err |= __put_user(0, &frame->uc.uc_flags);
350 err |= __put_user(NULL, &frame->uc.uc_link);
351 err |= __save_altstack(&frame->uc.uc_stack, regs->regs[15]);
352 err |= setup_sigcontext(&frame->uc.uc_mcontext,
353 regs, set->sig[0]);
354 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
355
356 /* Set up to return from userspace. If provided, use a stub
357 already in userspace. */
358 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
359 regs->pr = (unsigned long) ksig->ka.sa.sa_restorer;
360 #ifdef CONFIG_VSYSCALL
361 } else if (likely(current->mm->context.vdso)) {
362 regs->pr = VDSO_SYM(&__kernel_rt_sigreturn);
363 #endif
364 } else {
365 /* Generate return code (system call to rt_sigreturn) */
366 err |= __put_user(MOVW(7), &frame->retcode[0]);
367 err |= __put_user(TRAP_NOARG, &frame->retcode[1]);
368 err |= __put_user(OR_R0_R0, &frame->retcode[2]);
369 err |= __put_user(OR_R0_R0, &frame->retcode[3]);
370 err |= __put_user(OR_R0_R0, &frame->retcode[4]);
371 err |= __put_user(OR_R0_R0, &frame->retcode[5]);
372 err |= __put_user(OR_R0_R0, &frame->retcode[6]);
373 err |= __put_user((__NR_rt_sigreturn), &frame->retcode[7]);
374 regs->pr = (unsigned long) frame->retcode;
375 flush_icache_range(regs->pr, regs->pr + sizeof(frame->retcode));
376 }
377
378 if (err)
379 return -EFAULT;
380
381 /* Set up registers for signal handler */
382 regs->regs[15] = (unsigned long) frame;
383 regs->regs[4] = sig; /* Arg for signal handler */
384 regs->regs[5] = (unsigned long) &frame->info;
385 regs->regs[6] = (unsigned long) &frame->uc;
386
387 if (current->personality & FDPIC_FUNCPTRS) {
388 struct fdpic_func_descriptor __user *funcptr =
389 (struct fdpic_func_descriptor __user *)ksig->ka.sa.sa_handler;
390
391 err |= __get_user(regs->pc, &funcptr->text);
392 err |= __get_user(regs->regs[12], &funcptr->GOT);
393 } else
394 regs->pc = (unsigned long)ksig->ka.sa.sa_handler;
395
396 if (err)
397 return -EFAULT;
398
399 pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n",
400 current->comm, task_pid_nr(current), frame, regs->pc, regs->pr);
401
402 return 0;
403 }
404
405 static inline void
406 handle_syscall_restart(unsigned long save_r0, struct pt_regs *regs,
407 struct sigaction *sa)
408 {
409 /* If we're not from a syscall, bail out */
410 if (regs->tra < 0)
411 return;
412
413 /* check for system call restart.. */
414 switch (regs->regs[0]) {
415 case -ERESTART_RESTARTBLOCK:
416 case -ERESTARTNOHAND:
417 no_system_call_restart:
418 regs->regs[0] = -EINTR;
419 break;
420
421 case -ERESTARTSYS:
422 if (!(sa->sa_flags & SA_RESTART))
423 goto no_system_call_restart;
424 fallthrough;
425 case -ERESTARTNOINTR:
426 regs->regs[0] = save_r0;
427 regs->pc -= instruction_size(__raw_readw(regs->pc - 4));
428 break;
429 }
430 }
431
432 /*
433 * OK, we're invoking a handler
434 */
435 static void
436 handle_signal(struct ksignal *ksig, struct pt_regs *regs, unsigned int save_r0)
437 {
438 sigset_t *oldset = sigmask_to_save();
439 int ret;
440
441 /* Set up the stack frame */
442 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
443 ret = setup_rt_frame(ksig, oldset, regs);
444 else
445 ret = setup_frame(ksig, oldset, regs);
446
447 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
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 * Note that we go through the signals twice: once to check the signals that
456 * the kernel can handle, and then we build all the user-level signal handling
457 * stack-frames in one go after that.
458 */
459 static void do_signal(struct pt_regs *regs, unsigned int save_r0)
460 {
461 struct ksignal ksig;
462
463 /*
464 * We want the common case to go fast, which
465 * is why we may in certain cases get here from
466 * kernel mode. Just return without doing anything
467 * if so.
468 */
469 if (!user_mode(regs))
470 return;
471
472 if (get_signal(&ksig)) {
473 handle_syscall_restart(save_r0, regs, &ksig.ka.sa);
474
475 /* Whee! Actually deliver the signal. */
476 handle_signal(&ksig, regs, save_r0);
477 return;
478 }
479
480 /* Did we come from a system call? */
481 if (regs->tra >= 0) {
482 /* Restart the system call - no handlers present */
483 if (regs->regs[0] == -ERESTARTNOHAND ||
484 regs->regs[0] == -ERESTARTSYS ||
485 regs->regs[0] == -ERESTARTNOINTR) {
486 regs->regs[0] = save_r0;
487 regs->pc -= instruction_size(__raw_readw(regs->pc - 4));
488 } else if (regs->regs[0] == -ERESTART_RESTARTBLOCK) {
489 regs->pc -= instruction_size(__raw_readw(regs->pc - 4));
490 regs->regs[3] = __NR_restart_syscall;
491 }
492 }
493
494 /*
495 * If there's no signal to deliver, we just put the saved sigmask
496 * back.
497 */
498 restore_saved_sigmask();
499 }
500
501 asmlinkage void do_notify_resume(struct pt_regs *regs, unsigned int save_r0,
502 unsigned long thread_info_flags)
503 {
504 /* deal with pending signal delivery */
505 if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
506 do_signal(regs, save_r0);
507
508 if (thread_info_flags & _TIF_NOTIFY_RESUME)
509 resume_user_mode_work(regs);
510 }
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