xref: /openbmc/linux/arch/sparc/kernel/signal_64.c (revision b627b4ed)
1 /*
2  *  arch/sparc64/kernel/signal.c
3  *
4  *  Copyright (C) 1991, 1992  Linus Torvalds
5  *  Copyright (C) 1995, 2008 David S. Miller (davem@davemloft.net)
6  *  Copyright (C) 1996 Miguel de Icaza (miguel@nuclecu.unam.mx)
7  *  Copyright (C) 1997 Eddie C. Dost   (ecd@skynet.be)
8  *  Copyright (C) 1997,1998 Jakub Jelinek   (jj@sunsite.mff.cuni.cz)
9  */
10 
11 #ifdef CONFIG_COMPAT
12 #include <linux/compat.h>	/* for compat_old_sigset_t */
13 #endif
14 #include <linux/sched.h>
15 #include <linux/kernel.h>
16 #include <linux/signal.h>
17 #include <linux/errno.h>
18 #include <linux/wait.h>
19 #include <linux/ptrace.h>
20 #include <linux/tracehook.h>
21 #include <linux/unistd.h>
22 #include <linux/mm.h>
23 #include <linux/tty.h>
24 #include <linux/binfmts.h>
25 #include <linux/bitops.h>
26 
27 #include <asm/uaccess.h>
28 #include <asm/ptrace.h>
29 #include <asm/pgtable.h>
30 #include <asm/fpumacro.h>
31 #include <asm/uctx.h>
32 #include <asm/siginfo.h>
33 #include <asm/visasm.h>
34 
35 #include "entry.h"
36 #include "systbls.h"
37 
38 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
39 
40 /* {set, get}context() needed for 64-bit SparcLinux userland. */
41 asmlinkage void sparc64_set_context(struct pt_regs *regs)
42 {
43 	struct ucontext __user *ucp = (struct ucontext __user *)
44 		regs->u_regs[UREG_I0];
45 	mc_gregset_t __user *grp;
46 	unsigned long pc, npc, tstate;
47 	unsigned long fp, i7;
48 	unsigned char fenab;
49 	int err;
50 
51 	flush_user_windows();
52 	if (get_thread_wsaved()					||
53 	    (((unsigned long)ucp) & (sizeof(unsigned long)-1))	||
54 	    (!__access_ok(ucp, sizeof(*ucp))))
55 		goto do_sigsegv;
56 	grp  = &ucp->uc_mcontext.mc_gregs;
57 	err  = __get_user(pc, &((*grp)[MC_PC]));
58 	err |= __get_user(npc, &((*grp)[MC_NPC]));
59 	if (err || ((pc | npc) & 3))
60 		goto do_sigsegv;
61 	if (regs->u_regs[UREG_I1]) {
62 		sigset_t set;
63 
64 		if (_NSIG_WORDS == 1) {
65 			if (__get_user(set.sig[0], &ucp->uc_sigmask.sig[0]))
66 				goto do_sigsegv;
67 		} else {
68 			if (__copy_from_user(&set, &ucp->uc_sigmask, sizeof(sigset_t)))
69 				goto do_sigsegv;
70 		}
71 		sigdelsetmask(&set, ~_BLOCKABLE);
72 		spin_lock_irq(&current->sighand->siglock);
73 		current->blocked = set;
74 		recalc_sigpending();
75 		spin_unlock_irq(&current->sighand->siglock);
76 	}
77 	if (test_thread_flag(TIF_32BIT)) {
78 		pc &= 0xffffffff;
79 		npc &= 0xffffffff;
80 	}
81 	regs->tpc = pc;
82 	regs->tnpc = npc;
83 	err |= __get_user(regs->y, &((*grp)[MC_Y]));
84 	err |= __get_user(tstate, &((*grp)[MC_TSTATE]));
85 	regs->tstate &= ~(TSTATE_ASI | TSTATE_ICC | TSTATE_XCC);
86 	regs->tstate |= (tstate & (TSTATE_ASI | TSTATE_ICC | TSTATE_XCC));
87 	err |= __get_user(regs->u_regs[UREG_G1], (&(*grp)[MC_G1]));
88 	err |= __get_user(regs->u_regs[UREG_G2], (&(*grp)[MC_G2]));
89 	err |= __get_user(regs->u_regs[UREG_G3], (&(*grp)[MC_G3]));
90 	err |= __get_user(regs->u_regs[UREG_G4], (&(*grp)[MC_G4]));
91 	err |= __get_user(regs->u_regs[UREG_G5], (&(*grp)[MC_G5]));
92 	err |= __get_user(regs->u_regs[UREG_G6], (&(*grp)[MC_G6]));
93 
94 	/* Skip %g7 as that's the thread register in userspace.  */
95 
96 	err |= __get_user(regs->u_regs[UREG_I0], (&(*grp)[MC_O0]));
97 	err |= __get_user(regs->u_regs[UREG_I1], (&(*grp)[MC_O1]));
98 	err |= __get_user(regs->u_regs[UREG_I2], (&(*grp)[MC_O2]));
99 	err |= __get_user(regs->u_regs[UREG_I3], (&(*grp)[MC_O3]));
100 	err |= __get_user(regs->u_regs[UREG_I4], (&(*grp)[MC_O4]));
101 	err |= __get_user(regs->u_regs[UREG_I5], (&(*grp)[MC_O5]));
102 	err |= __get_user(regs->u_regs[UREG_I6], (&(*grp)[MC_O6]));
103 	err |= __get_user(regs->u_regs[UREG_I7], (&(*grp)[MC_O7]));
104 
105 	err |= __get_user(fp, &(ucp->uc_mcontext.mc_fp));
106 	err |= __get_user(i7, &(ucp->uc_mcontext.mc_i7));
107 	err |= __put_user(fp,
108 	      (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[6])));
109 	err |= __put_user(i7,
110 	      (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[7])));
111 
112 	err |= __get_user(fenab, &(ucp->uc_mcontext.mc_fpregs.mcfpu_enab));
113 	if (fenab) {
114 		unsigned long *fpregs = current_thread_info()->fpregs;
115 		unsigned long fprs;
116 
117 		fprs_write(0);
118 		err |= __get_user(fprs, &(ucp->uc_mcontext.mc_fpregs.mcfpu_fprs));
119 		if (fprs & FPRS_DL)
120 			err |= copy_from_user(fpregs,
121 					      &(ucp->uc_mcontext.mc_fpregs.mcfpu_fregs),
122 					      (sizeof(unsigned int) * 32));
123 		if (fprs & FPRS_DU)
124 			err |= copy_from_user(fpregs+16,
125 			 ((unsigned long __user *)&(ucp->uc_mcontext.mc_fpregs.mcfpu_fregs))+16,
126 			 (sizeof(unsigned int) * 32));
127 		err |= __get_user(current_thread_info()->xfsr[0],
128 				  &(ucp->uc_mcontext.mc_fpregs.mcfpu_fsr));
129 		err |= __get_user(current_thread_info()->gsr[0],
130 				  &(ucp->uc_mcontext.mc_fpregs.mcfpu_gsr));
131 		regs->tstate &= ~TSTATE_PEF;
132 	}
133 	if (err)
134 		goto do_sigsegv;
135 
136 	return;
137 do_sigsegv:
138 	force_sig(SIGSEGV, current);
139 }
140 
141 asmlinkage void sparc64_get_context(struct pt_regs *regs)
142 {
143 	struct ucontext __user *ucp = (struct ucontext __user *)
144 		regs->u_regs[UREG_I0];
145 	mc_gregset_t __user *grp;
146 	mcontext_t __user *mcp;
147 	unsigned long fp, i7;
148 	unsigned char fenab;
149 	int err;
150 
151 	synchronize_user_stack();
152 	if (get_thread_wsaved() || clear_user(ucp, sizeof(*ucp)))
153 		goto do_sigsegv;
154 
155 #if 1
156 	fenab = 0; /* IMO get_context is like any other system call, thus modifies FPU state -jj */
157 #else
158 	fenab = (current_thread_info()->fpsaved[0] & FPRS_FEF);
159 #endif
160 
161 	mcp = &ucp->uc_mcontext;
162 	grp = &mcp->mc_gregs;
163 
164 	/* Skip over the trap instruction, first. */
165 	if (test_thread_flag(TIF_32BIT)) {
166 		regs->tpc   = (regs->tnpc & 0xffffffff);
167 		regs->tnpc  = (regs->tnpc + 4) & 0xffffffff;
168 	} else {
169 		regs->tpc   = regs->tnpc;
170 		regs->tnpc += 4;
171 	}
172 	err = 0;
173 	if (_NSIG_WORDS == 1)
174 		err |= __put_user(current->blocked.sig[0],
175 				  (unsigned long __user *)&ucp->uc_sigmask);
176 	else
177 		err |= __copy_to_user(&ucp->uc_sigmask, &current->blocked,
178 				      sizeof(sigset_t));
179 
180 	err |= __put_user(regs->tstate, &((*grp)[MC_TSTATE]));
181 	err |= __put_user(regs->tpc, &((*grp)[MC_PC]));
182 	err |= __put_user(regs->tnpc, &((*grp)[MC_NPC]));
183 	err |= __put_user(regs->y, &((*grp)[MC_Y]));
184 	err |= __put_user(regs->u_regs[UREG_G1], &((*grp)[MC_G1]));
185 	err |= __put_user(regs->u_regs[UREG_G2], &((*grp)[MC_G2]));
186 	err |= __put_user(regs->u_regs[UREG_G3], &((*grp)[MC_G3]));
187 	err |= __put_user(regs->u_regs[UREG_G4], &((*grp)[MC_G4]));
188 	err |= __put_user(regs->u_regs[UREG_G5], &((*grp)[MC_G5]));
189 	err |= __put_user(regs->u_regs[UREG_G6], &((*grp)[MC_G6]));
190 	err |= __put_user(regs->u_regs[UREG_G7], &((*grp)[MC_G7]));
191 	err |= __put_user(regs->u_regs[UREG_I0], &((*grp)[MC_O0]));
192 	err |= __put_user(regs->u_regs[UREG_I1], &((*grp)[MC_O1]));
193 	err |= __put_user(regs->u_regs[UREG_I2], &((*grp)[MC_O2]));
194 	err |= __put_user(regs->u_regs[UREG_I3], &((*grp)[MC_O3]));
195 	err |= __put_user(regs->u_regs[UREG_I4], &((*grp)[MC_O4]));
196 	err |= __put_user(regs->u_regs[UREG_I5], &((*grp)[MC_O5]));
197 	err |= __put_user(regs->u_regs[UREG_I6], &((*grp)[MC_O6]));
198 	err |= __put_user(regs->u_regs[UREG_I7], &((*grp)[MC_O7]));
199 
200 	err |= __get_user(fp,
201 		 (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[6])));
202 	err |= __get_user(i7,
203 		 (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[7])));
204 	err |= __put_user(fp, &(mcp->mc_fp));
205 	err |= __put_user(i7, &(mcp->mc_i7));
206 
207 	err |= __put_user(fenab, &(mcp->mc_fpregs.mcfpu_enab));
208 	if (fenab) {
209 		unsigned long *fpregs = current_thread_info()->fpregs;
210 		unsigned long fprs;
211 
212 		fprs = current_thread_info()->fpsaved[0];
213 		if (fprs & FPRS_DL)
214 			err |= copy_to_user(&(mcp->mc_fpregs.mcfpu_fregs), fpregs,
215 					    (sizeof(unsigned int) * 32));
216 		if (fprs & FPRS_DU)
217 			err |= copy_to_user(
218                           ((unsigned long __user *)&(mcp->mc_fpregs.mcfpu_fregs))+16, fpregs+16,
219 			  (sizeof(unsigned int) * 32));
220 		err |= __put_user(current_thread_info()->xfsr[0], &(mcp->mc_fpregs.mcfpu_fsr));
221 		err |= __put_user(current_thread_info()->gsr[0], &(mcp->mc_fpregs.mcfpu_gsr));
222 		err |= __put_user(fprs, &(mcp->mc_fpregs.mcfpu_fprs));
223 	}
224 	if (err)
225 		goto do_sigsegv;
226 
227 	return;
228 do_sigsegv:
229 	force_sig(SIGSEGV, current);
230 }
231 
232 struct rt_signal_frame {
233 	struct sparc_stackf	ss;
234 	siginfo_t		info;
235 	struct pt_regs		regs;
236 	__siginfo_fpu_t __user	*fpu_save;
237 	stack_t			stack;
238 	sigset_t		mask;
239 	__siginfo_fpu_t		fpu_state;
240 };
241 
242 static long _sigpause_common(old_sigset_t set)
243 {
244 	set &= _BLOCKABLE;
245 	spin_lock_irq(&current->sighand->siglock);
246 	current->saved_sigmask = current->blocked;
247 	siginitset(&current->blocked, set);
248 	recalc_sigpending();
249 	spin_unlock_irq(&current->sighand->siglock);
250 
251 	current->state = TASK_INTERRUPTIBLE;
252 	schedule();
253 
254 	set_restore_sigmask();
255 
256 	return -ERESTARTNOHAND;
257 }
258 
259 asmlinkage long sys_sigpause(unsigned int set)
260 {
261 	return _sigpause_common(set);
262 }
263 
264 asmlinkage long sys_sigsuspend(old_sigset_t set)
265 {
266 	return _sigpause_common(set);
267 }
268 
269 static inline int
270 restore_fpu_state(struct pt_regs *regs, __siginfo_fpu_t __user *fpu)
271 {
272 	unsigned long *fpregs = current_thread_info()->fpregs;
273 	unsigned long fprs;
274 	int err;
275 
276 	err = __get_user(fprs, &fpu->si_fprs);
277 	fprs_write(0);
278 	regs->tstate &= ~TSTATE_PEF;
279 	if (fprs & FPRS_DL)
280 		err |= copy_from_user(fpregs, &fpu->si_float_regs[0],
281 		       	       (sizeof(unsigned int) * 32));
282 	if (fprs & FPRS_DU)
283 		err |= copy_from_user(fpregs+16, &fpu->si_float_regs[32],
284 		       	       (sizeof(unsigned int) * 32));
285 	err |= __get_user(current_thread_info()->xfsr[0], &fpu->si_fsr);
286 	err |= __get_user(current_thread_info()->gsr[0], &fpu->si_gsr);
287 	current_thread_info()->fpsaved[0] |= fprs;
288 	return err;
289 }
290 
291 void do_rt_sigreturn(struct pt_regs *regs)
292 {
293 	struct rt_signal_frame __user *sf;
294 	unsigned long tpc, tnpc, tstate;
295 	__siginfo_fpu_t __user *fpu_save;
296 	sigset_t set;
297 	int err;
298 
299 	/* Always make any pending restarted system calls return -EINTR */
300 	current_thread_info()->restart_block.fn = do_no_restart_syscall;
301 
302 	synchronize_user_stack ();
303 	sf = (struct rt_signal_frame __user *)
304 		(regs->u_regs [UREG_FP] + STACK_BIAS);
305 
306 	/* 1. Make sure we are not getting garbage from the user */
307 	if (((unsigned long) sf) & 3)
308 		goto segv;
309 
310 	err = get_user(tpc, &sf->regs.tpc);
311 	err |= __get_user(tnpc, &sf->regs.tnpc);
312 	if (test_thread_flag(TIF_32BIT)) {
313 		tpc &= 0xffffffff;
314 		tnpc &= 0xffffffff;
315 	}
316 	err |= ((tpc | tnpc) & 3);
317 
318 	/* 2. Restore the state */
319 	err |= __get_user(regs->y, &sf->regs.y);
320 	err |= __get_user(tstate, &sf->regs.tstate);
321 	err |= copy_from_user(regs->u_regs, sf->regs.u_regs, sizeof(regs->u_regs));
322 
323 	/* User can only change condition codes and %asi in %tstate. */
324 	regs->tstate &= ~(TSTATE_ASI | TSTATE_ICC | TSTATE_XCC);
325 	regs->tstate |= (tstate & (TSTATE_ASI | TSTATE_ICC | TSTATE_XCC));
326 
327 	err |= __get_user(fpu_save, &sf->fpu_save);
328 	if (fpu_save)
329 		err |= restore_fpu_state(regs, &sf->fpu_state);
330 
331 	err |= __copy_from_user(&set, &sf->mask, sizeof(sigset_t));
332 	err |= do_sigaltstack(&sf->stack, NULL, (unsigned long)sf);
333 
334 	if (err)
335 		goto segv;
336 
337 	regs->tpc = tpc;
338 	regs->tnpc = tnpc;
339 
340 	/* Prevent syscall restart.  */
341 	pt_regs_clear_syscall(regs);
342 
343 	sigdelsetmask(&set, ~_BLOCKABLE);
344 	spin_lock_irq(&current->sighand->siglock);
345 	current->blocked = set;
346 	recalc_sigpending();
347 	spin_unlock_irq(&current->sighand->siglock);
348 	return;
349 segv:
350 	force_sig(SIGSEGV, current);
351 }
352 
353 /* Checks if the fp is valid */
354 static int invalid_frame_pointer(void __user *fp, int fplen)
355 {
356 	if (((unsigned long) fp) & 7)
357 		return 1;
358 	return 0;
359 }
360 
361 static inline int
362 save_fpu_state(struct pt_regs *regs, __siginfo_fpu_t __user *fpu)
363 {
364 	unsigned long *fpregs = current_thread_info()->fpregs;
365 	unsigned long fprs;
366 	int err = 0;
367 
368 	fprs = current_thread_info()->fpsaved[0];
369 	if (fprs & FPRS_DL)
370 		err |= copy_to_user(&fpu->si_float_regs[0], fpregs,
371 				    (sizeof(unsigned int) * 32));
372 	if (fprs & FPRS_DU)
373 		err |= copy_to_user(&fpu->si_float_regs[32], fpregs+16,
374 				    (sizeof(unsigned int) * 32));
375 	err |= __put_user(current_thread_info()->xfsr[0], &fpu->si_fsr);
376 	err |= __put_user(current_thread_info()->gsr[0], &fpu->si_gsr);
377 	err |= __put_user(fprs, &fpu->si_fprs);
378 
379 	return err;
380 }
381 
382 static inline void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, unsigned long framesize)
383 {
384 	unsigned long sp = regs->u_regs[UREG_FP] + STACK_BIAS;
385 
386 	/*
387 	 * If we are on the alternate signal stack and would overflow it, don't.
388 	 * Return an always-bogus address instead so we will die with SIGSEGV.
389 	 */
390 	if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize)))
391 		return (void __user *) -1L;
392 
393 	/* This is the X/Open sanctioned signal stack switching.  */
394 	if (ka->sa.sa_flags & SA_ONSTACK) {
395 		if (sas_ss_flags(sp) == 0)
396 			sp = current->sas_ss_sp + current->sas_ss_size;
397 	}
398 
399 	/* Always align the stack frame.  This handles two cases.  First,
400 	 * sigaltstack need not be mindful of platform specific stack
401 	 * alignment.  Second, if we took this signal because the stack
402 	 * is not aligned properly, we'd like to take the signal cleanly
403 	 * and report that.
404 	 */
405 	sp &= ~7UL;
406 
407 	return (void __user *)(sp - framesize);
408 }
409 
410 static inline void
411 setup_rt_frame(struct k_sigaction *ka, struct pt_regs *regs,
412 	       int signo, sigset_t *oldset, siginfo_t *info)
413 {
414 	struct rt_signal_frame __user *sf;
415 	int sigframe_size, err;
416 
417 	/* 1. Make sure everything is clean */
418 	synchronize_user_stack();
419 	save_and_clear_fpu();
420 
421 	sigframe_size = sizeof(struct rt_signal_frame);
422 	if (!(current_thread_info()->fpsaved[0] & FPRS_FEF))
423 		sigframe_size -= sizeof(__siginfo_fpu_t);
424 
425 	sf = (struct rt_signal_frame __user *)
426 		get_sigframe(ka, regs, sigframe_size);
427 
428 	if (invalid_frame_pointer (sf, sigframe_size))
429 		goto sigill;
430 
431 	if (get_thread_wsaved() != 0)
432 		goto sigill;
433 
434 	/* 2. Save the current process state */
435 	err = copy_to_user(&sf->regs, regs, sizeof (*regs));
436 
437 	if (current_thread_info()->fpsaved[0] & FPRS_FEF) {
438 		err |= save_fpu_state(regs, &sf->fpu_state);
439 		err |= __put_user((u64)&sf->fpu_state, &sf->fpu_save);
440 	} else {
441 		err |= __put_user(0, &sf->fpu_save);
442 	}
443 
444 	/* Setup sigaltstack */
445 	err |= __put_user(current->sas_ss_sp, &sf->stack.ss_sp);
446 	err |= __put_user(sas_ss_flags(regs->u_regs[UREG_FP]), &sf->stack.ss_flags);
447 	err |= __put_user(current->sas_ss_size, &sf->stack.ss_size);
448 
449 	err |= copy_to_user(&sf->mask, oldset, sizeof(sigset_t));
450 
451 	err |= copy_in_user((u64 __user *)sf,
452 			    (u64 __user *)(regs->u_regs[UREG_FP]+STACK_BIAS),
453 			    sizeof(struct reg_window));
454 
455 	if (info)
456 		err |= copy_siginfo_to_user(&sf->info, info);
457 	else {
458 		err |= __put_user(signo, &sf->info.si_signo);
459 		err |= __put_user(SI_NOINFO, &sf->info.si_code);
460 	}
461 	if (err)
462 		goto sigsegv;
463 
464 	/* 3. signal handler back-trampoline and parameters */
465 	regs->u_regs[UREG_FP] = ((unsigned long) sf) - STACK_BIAS;
466 	regs->u_regs[UREG_I0] = signo;
467 	regs->u_regs[UREG_I1] = (unsigned long) &sf->info;
468 
469 	/* The sigcontext is passed in this way because of how it
470 	 * is defined in GLIBC's /usr/include/bits/sigcontext.h
471 	 * for sparc64.  It includes the 128 bytes of siginfo_t.
472 	 */
473 	regs->u_regs[UREG_I2] = (unsigned long) &sf->info;
474 
475 	/* 5. signal handler */
476 	regs->tpc = (unsigned long) ka->sa.sa_handler;
477 	regs->tnpc = (regs->tpc + 4);
478 	if (test_thread_flag(TIF_32BIT)) {
479 		regs->tpc &= 0xffffffff;
480 		regs->tnpc &= 0xffffffff;
481 	}
482 	/* 4. return to kernel instructions */
483 	regs->u_regs[UREG_I7] = (unsigned long)ka->ka_restorer;
484 	return;
485 
486 sigill:
487 	do_exit(SIGILL);
488 sigsegv:
489 	force_sigsegv(signo, current);
490 }
491 
492 static inline void handle_signal(unsigned long signr, struct k_sigaction *ka,
493 				 siginfo_t *info,
494 				 sigset_t *oldset, struct pt_regs *regs)
495 {
496 	setup_rt_frame(ka, regs, signr, oldset,
497 		       (ka->sa.sa_flags & SA_SIGINFO) ? info : NULL);
498 	spin_lock_irq(&current->sighand->siglock);
499 	sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
500 	if (!(ka->sa.sa_flags & SA_NOMASK))
501 		sigaddset(&current->blocked,signr);
502 	recalc_sigpending();
503 	spin_unlock_irq(&current->sighand->siglock);
504 }
505 
506 static inline void syscall_restart(unsigned long orig_i0, struct pt_regs *regs,
507 				   struct sigaction *sa)
508 {
509 	switch (regs->u_regs[UREG_I0]) {
510 	case ERESTART_RESTARTBLOCK:
511 	case ERESTARTNOHAND:
512 	no_system_call_restart:
513 		regs->u_regs[UREG_I0] = EINTR;
514 		regs->tstate |= (TSTATE_ICARRY|TSTATE_XCARRY);
515 		break;
516 	case ERESTARTSYS:
517 		if (!(sa->sa_flags & SA_RESTART))
518 			goto no_system_call_restart;
519 		/* fallthrough */
520 	case ERESTARTNOINTR:
521 		regs->u_regs[UREG_I0] = orig_i0;
522 		regs->tpc -= 4;
523 		regs->tnpc -= 4;
524 	}
525 }
526 
527 /* Note that 'init' is a special process: it doesn't get signals it doesn't
528  * want to handle. Thus you cannot kill init even with a SIGKILL even by
529  * mistake.
530  */
531 static void do_signal(struct pt_regs *regs, unsigned long orig_i0)
532 {
533 	struct k_sigaction ka;
534 	int restart_syscall;
535 	sigset_t *oldset;
536 	siginfo_t info;
537 	int signr;
538 
539 	if (pt_regs_is_syscall(regs) &&
540 	    (regs->tstate & (TSTATE_XCARRY | TSTATE_ICARRY))) {
541 		restart_syscall = 1;
542 	} else
543 		restart_syscall = 0;
544 
545 	if (current_thread_info()->status & TS_RESTORE_SIGMASK)
546 		oldset = &current->saved_sigmask;
547 	else
548 		oldset = &current->blocked;
549 
550 #ifdef CONFIG_COMPAT
551 	if (test_thread_flag(TIF_32BIT)) {
552 		extern void do_signal32(sigset_t *, struct pt_regs *,
553 					int restart_syscall,
554 					unsigned long orig_i0);
555 		do_signal32(oldset, regs, restart_syscall, orig_i0);
556 		return;
557 	}
558 #endif
559 
560 	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
561 
562 	/* If the debugger messes with the program counter, it clears
563 	 * the software "in syscall" bit, directing us to not perform
564 	 * a syscall restart.
565 	 */
566 	if (restart_syscall && !pt_regs_is_syscall(regs))
567 		restart_syscall = 0;
568 
569 	if (signr > 0) {
570 		if (restart_syscall)
571 			syscall_restart(orig_i0, regs, &ka.sa);
572 		handle_signal(signr, &ka, &info, oldset, regs);
573 
574 		/* A signal was successfully delivered; the saved
575 		 * sigmask will have been stored in the signal frame,
576 		 * and will be restored by sigreturn, so we can simply
577 		 * clear the TS_RESTORE_SIGMASK flag.
578 		 */
579 		current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
580 
581 		tracehook_signal_handler(signr, &info, &ka, regs, 0);
582 		return;
583 	}
584 	if (restart_syscall &&
585 	    (regs->u_regs[UREG_I0] == ERESTARTNOHAND ||
586 	     regs->u_regs[UREG_I0] == ERESTARTSYS ||
587 	     regs->u_regs[UREG_I0] == ERESTARTNOINTR)) {
588 		/* replay the system call when we are done */
589 		regs->u_regs[UREG_I0] = orig_i0;
590 		regs->tpc -= 4;
591 		regs->tnpc -= 4;
592 	}
593 	if (restart_syscall &&
594 	    regs->u_regs[UREG_I0] == ERESTART_RESTARTBLOCK) {
595 		regs->u_regs[UREG_G1] = __NR_restart_syscall;
596 		regs->tpc -= 4;
597 		regs->tnpc -= 4;
598 	}
599 
600 	/* If there's no signal to deliver, we just put the saved sigmask
601 	 * back
602 	 */
603 	if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
604 		current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
605 		sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
606 	}
607 }
608 
609 void do_notify_resume(struct pt_regs *regs, unsigned long orig_i0, unsigned long thread_info_flags)
610 {
611 	if (thread_info_flags & _TIF_SIGPENDING)
612 		do_signal(regs, orig_i0);
613 	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
614 		clear_thread_flag(TIF_NOTIFY_RESUME);
615 		tracehook_notify_resume(regs);
616 	}
617 }
618