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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright IBM Corp. 1999, 2006
4 * Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
5 *
6 * Based on Intel version
7 *
8 * Copyright (C) 1991, 1992 Linus Torvalds
9 *
10 * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
11 */
12
13#include <linux/sched.h>
14#include <linux/sched/task_stack.h>
15#include <linux/mm.h>
16#include <linux/smp.h>
17#include <linux/kernel.h>
18#include <linux/signal.h>
19#include <linux/entry-common.h>
20#include <linux/errno.h>
21#include <linux/wait.h>
22#include <linux/ptrace.h>
23#include <linux/unistd.h>
24#include <linux/stddef.h>
25#include <linux/tty.h>
26#include <linux/personality.h>
27#include <linux/binfmts.h>
28#include <linux/syscalls.h>
29#include <linux/compat.h>
30#include <asm/ucontext.h>
31#include <linux/uaccess.h>
32#include <asm/lowcore.h>
33#include <asm/switch_to.h>
34#include <asm/vdso.h>
35#include "entry.h"
36
37/*
38 * Layout of an old-style signal-frame:
39 * -----------------------------------------
40 * | save area (_SIGNAL_FRAMESIZE) |
41 * -----------------------------------------
42 * | struct sigcontext |
43 * | oldmask |
44 * | _sigregs * |
45 * -----------------------------------------
46 * | _sigregs with |
47 * | _s390_regs_common |
48 * | _s390_fp_regs |
49 * -----------------------------------------
50 * | int signo |
51 * -----------------------------------------
52 * | _sigregs_ext with |
53 * | gprs_high 64 byte (opt) |
54 * | vxrs_low 128 byte (opt) |
55 * | vxrs_high 256 byte (opt) |
56 * | reserved 128 byte (opt) |
57 * -----------------------------------------
58 * | __u16 svc_insn |
59 * -----------------------------------------
60 * The svc_insn entry with the sigreturn system call opcode does not
61 * have a fixed position and moves if gprs_high or vxrs exist.
62 * Future extensions will be added to _sigregs_ext.
63 */
64struct sigframe
65{
66 __u8 callee_used_stack[__SIGNAL_FRAMESIZE];
67 struct sigcontext sc;
68 _sigregs sregs;
69 int signo;
70 _sigregs_ext sregs_ext;
71 __u16 svc_insn; /* Offset of svc_insn is NOT fixed! */
72};
73
74/*
75 * Layout of an rt signal-frame:
76 * -----------------------------------------
77 * | save area (_SIGNAL_FRAMESIZE) |
78 * -----------------------------------------
79 * | svc __NR_rt_sigreturn 2 byte |
80 * -----------------------------------------
81 * | struct siginfo |
82 * -----------------------------------------
83 * | struct ucontext_extended with |
84 * | unsigned long uc_flags |
85 * | struct ucontext *uc_link |
86 * | stack_t uc_stack |
87 * | _sigregs uc_mcontext with |
88 * | _s390_regs_common |
89 * | _s390_fp_regs |
90 * | sigset_t uc_sigmask |
91 * | _sigregs_ext uc_mcontext_ext |
92 * | gprs_high 64 byte (opt) |
93 * | vxrs_low 128 byte (opt) |
94 * | vxrs_high 256 byte (opt)|
95 * | reserved 128 byte (opt) |
96 * -----------------------------------------
97 * Future extensions will be added to _sigregs_ext.
98 */
99struct rt_sigframe
100{
101 __u8 callee_used_stack[__SIGNAL_FRAMESIZE];
102 __u16 svc_insn;
103 struct siginfo info;
104 struct ucontext_extended uc;
105};
106
107/* Store registers needed to create the signal frame */
108static void store_sigregs(void)
109{
110 save_access_regs(current->thread.acrs);
111 save_fpu_regs();
112}
113
114/* Load registers after signal return */
115static void load_sigregs(void)
116{
117 restore_access_regs(current->thread.acrs);
118}
119
120/* Returns non-zero on fault. */
121static int save_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
122{
123 _sigregs user_sregs;
124
125 /* Copy a 'clean' PSW mask to the user to avoid leaking
126 information about whether PER is currently on. */
127 user_sregs.regs.psw.mask = PSW_USER_BITS |
128 (regs->psw.mask & (PSW_MASK_USER | PSW_MASK_RI));
129 user_sregs.regs.psw.addr = regs->psw.addr;
130 memcpy(&user_sregs.regs.gprs, ®s->gprs, sizeof(sregs->regs.gprs));
131 memcpy(&user_sregs.regs.acrs, current->thread.acrs,
132 sizeof(user_sregs.regs.acrs));
133 fpregs_store(&user_sregs.fpregs, ¤t->thread.fpu);
134 if (__copy_to_user(sregs, &user_sregs, sizeof(_sigregs)))
135 return -EFAULT;
136 return 0;
137}
138
139static int restore_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
140{
141 _sigregs user_sregs;
142
143 /* Always make any pending restarted system call return -EINTR */
144 current->restart_block.fn = do_no_restart_syscall;
145
146 if (__copy_from_user(&user_sregs, sregs, sizeof(user_sregs)))
147 return -EFAULT;
148
149 if (!is_ri_task(current) && (user_sregs.regs.psw.mask & PSW_MASK_RI))
150 return -EINVAL;
151
152 /* Test the floating-point-control word. */
153 if (test_fp_ctl(user_sregs.fpregs.fpc))
154 return -EINVAL;
155
156 /* Use regs->psw.mask instead of PSW_USER_BITS to preserve PER bit. */
157 regs->psw.mask = (regs->psw.mask & ~(PSW_MASK_USER | PSW_MASK_RI)) |
158 (user_sregs.regs.psw.mask & (PSW_MASK_USER | PSW_MASK_RI));
159 /* Check for invalid user address space control. */
160 if ((regs->psw.mask & PSW_MASK_ASC) == PSW_ASC_HOME)
161 regs->psw.mask = PSW_ASC_PRIMARY |
162 (regs->psw.mask & ~PSW_MASK_ASC);
163 /* Check for invalid amode */
164 if (regs->psw.mask & PSW_MASK_EA)
165 regs->psw.mask |= PSW_MASK_BA;
166 regs->psw.addr = user_sregs.regs.psw.addr;
167 memcpy(®s->gprs, &user_sregs.regs.gprs, sizeof(sregs->regs.gprs));
168 memcpy(¤t->thread.acrs, &user_sregs.regs.acrs,
169 sizeof(current->thread.acrs));
170
171 fpregs_load(&user_sregs.fpregs, ¤t->thread.fpu);
172
173 clear_pt_regs_flag(regs, PIF_SYSCALL); /* No longer in a system call */
174 return 0;
175}
176
177/* Returns non-zero on fault. */
178static int save_sigregs_ext(struct pt_regs *regs,
179 _sigregs_ext __user *sregs_ext)
180{
181 __u64 vxrs[__NUM_VXRS_LOW];
182 int i;
183
184 /* Save vector registers to signal stack */
185 if (MACHINE_HAS_VX) {
186 for (i = 0; i < __NUM_VXRS_LOW; i++)
187 vxrs[i] = *((__u64 *)(current->thread.fpu.vxrs + i) + 1);
188 if (__copy_to_user(&sregs_ext->vxrs_low, vxrs,
189 sizeof(sregs_ext->vxrs_low)) ||
190 __copy_to_user(&sregs_ext->vxrs_high,
191 current->thread.fpu.vxrs + __NUM_VXRS_LOW,
192 sizeof(sregs_ext->vxrs_high)))
193 return -EFAULT;
194 }
195 return 0;
196}
197
198static int restore_sigregs_ext(struct pt_regs *regs,
199 _sigregs_ext __user *sregs_ext)
200{
201 __u64 vxrs[__NUM_VXRS_LOW];
202 int i;
203
204 /* Restore vector registers from signal stack */
205 if (MACHINE_HAS_VX) {
206 if (__copy_from_user(vxrs, &sregs_ext->vxrs_low,
207 sizeof(sregs_ext->vxrs_low)) ||
208 __copy_from_user(current->thread.fpu.vxrs + __NUM_VXRS_LOW,
209 &sregs_ext->vxrs_high,
210 sizeof(sregs_ext->vxrs_high)))
211 return -EFAULT;
212 for (i = 0; i < __NUM_VXRS_LOW; i++)
213 *((__u64 *)(current->thread.fpu.vxrs + i) + 1) = vxrs[i];
214 }
215 return 0;
216}
217
218SYSCALL_DEFINE0(sigreturn)
219{
220 struct pt_regs *regs = task_pt_regs(current);
221 struct sigframe __user *frame =
222 (struct sigframe __user *) regs->gprs[15];
223 sigset_t set;
224
225 if (__copy_from_user(&set.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE))
226 goto badframe;
227 set_current_blocked(&set);
228 save_fpu_regs();
229 if (restore_sigregs(regs, &frame->sregs))
230 goto badframe;
231 if (restore_sigregs_ext(regs, &frame->sregs_ext))
232 goto badframe;
233 load_sigregs();
234 return regs->gprs[2];
235badframe:
236 force_sig(SIGSEGV);
237 return 0;
238}
239
240SYSCALL_DEFINE0(rt_sigreturn)
241{
242 struct pt_regs *regs = task_pt_regs(current);
243 struct rt_sigframe __user *frame =
244 (struct rt_sigframe __user *)regs->gprs[15];
245 sigset_t set;
246
247 if (__copy_from_user(&set.sig, &frame->uc.uc_sigmask, sizeof(set)))
248 goto badframe;
249 set_current_blocked(&set);
250 if (restore_altstack(&frame->uc.uc_stack))
251 goto badframe;
252 save_fpu_regs();
253 if (restore_sigregs(regs, &frame->uc.uc_mcontext))
254 goto badframe;
255 if (restore_sigregs_ext(regs, &frame->uc.uc_mcontext_ext))
256 goto badframe;
257 load_sigregs();
258 return regs->gprs[2];
259badframe:
260 force_sig(SIGSEGV);
261 return 0;
262}
263
264/*
265 * Determine which stack to use..
266 */
267static inline void __user *
268get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
269{
270 unsigned long sp;
271
272 /* Default to using normal stack */
273 sp = regs->gprs[15];
274
275 /* Overflow on alternate signal stack gives SIGSEGV. */
276 if (on_sig_stack(sp) && !on_sig_stack((sp - frame_size) & -8UL))
277 return (void __user *) -1UL;
278
279 /* This is the X/Open sanctioned signal stack switching. */
280 if (ka->sa.sa_flags & SA_ONSTACK) {
281 if (! sas_ss_flags(sp))
282 sp = current->sas_ss_sp + current->sas_ss_size;
283 }
284
285 return (void __user *)((sp - frame_size) & -8ul);
286}
287
288static int setup_frame(int sig, struct k_sigaction *ka,
289 sigset_t *set, struct pt_regs * regs)
290{
291 struct sigframe __user *frame;
292 struct sigcontext sc;
293 unsigned long restorer;
294 size_t frame_size;
295
296 /*
297 * gprs_high are only present for a 31-bit task running on
298 * a 64-bit kernel (see compat_signal.c) but the space for
299 * gprs_high need to be allocated if vector registers are
300 * included in the signal frame on a 31-bit system.
301 */
302 frame_size = sizeof(*frame) - sizeof(frame->sregs_ext);
303 if (MACHINE_HAS_VX)
304 frame_size += sizeof(frame->sregs_ext);
305 frame = get_sigframe(ka, regs, frame_size);
306 if (frame == (void __user *) -1UL)
307 return -EFAULT;
308
309 /* Set up backchain. */
310 if (__put_user(regs->gprs[15], (addr_t __user *) frame))
311 return -EFAULT;
312
313 /* Create struct sigcontext on the signal stack */
314 memcpy(&sc.oldmask, &set->sig, _SIGMASK_COPY_SIZE);
315 sc.sregs = (_sigregs __user __force *) &frame->sregs;
316 if (__copy_to_user(&frame->sc, &sc, sizeof(frame->sc)))
317 return -EFAULT;
318
319 /* Store registers needed to create the signal frame */
320 store_sigregs();
321
322 /* Create _sigregs on the signal stack */
323 if (save_sigregs(regs, &frame->sregs))
324 return -EFAULT;
325
326 /* Place signal number on stack to allow backtrace from handler. */
327 if (__put_user(regs->gprs[2], (int __user *) &frame->signo))
328 return -EFAULT;
329
330 /* Create _sigregs_ext on the signal stack */
331 if (save_sigregs_ext(regs, &frame->sregs_ext))
332 return -EFAULT;
333
334 /* Set up to return from userspace. If provided, use a stub
335 already in userspace. */
336 if (ka->sa.sa_flags & SA_RESTORER)
337 restorer = (unsigned long) ka->sa.sa_restorer;
338 else
339 restorer = VDSO64_SYMBOL(current, sigreturn);
340
341 /* Set up registers for signal handler */
342 regs->gprs[14] = restorer;
343 regs->gprs[15] = (unsigned long) frame;
344 /* Force default amode and default user address space control. */
345 regs->psw.mask = PSW_MASK_EA | PSW_MASK_BA |
346 (PSW_USER_BITS & PSW_MASK_ASC) |
347 (regs->psw.mask & ~PSW_MASK_ASC);
348 regs->psw.addr = (unsigned long) ka->sa.sa_handler;
349
350 regs->gprs[2] = sig;
351 regs->gprs[3] = (unsigned long) &frame->sc;
352
353 /* We forgot to include these in the sigcontext.
354 To avoid breaking binary compatibility, they are passed as args. */
355 if (sig == SIGSEGV || sig == SIGBUS || sig == SIGILL ||
356 sig == SIGTRAP || sig == SIGFPE) {
357 /* set extra registers only for synchronous signals */
358 regs->gprs[4] = regs->int_code & 127;
359 regs->gprs[5] = regs->int_parm_long;
360 regs->gprs[6] = current->thread.last_break;
361 }
362 return 0;
363}
364
365static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
366 struct pt_regs *regs)
367{
368 struct rt_sigframe __user *frame;
369 unsigned long uc_flags, restorer;
370 size_t frame_size;
371
372 frame_size = sizeof(struct rt_sigframe) - sizeof(_sigregs_ext);
373 /*
374 * gprs_high are only present for a 31-bit task running on
375 * a 64-bit kernel (see compat_signal.c) but the space for
376 * gprs_high need to be allocated if vector registers are
377 * included in the signal frame on a 31-bit system.
378 */
379 uc_flags = 0;
380 if (MACHINE_HAS_VX) {
381 frame_size += sizeof(_sigregs_ext);
382 uc_flags |= UC_VXRS;
383 }
384 frame = get_sigframe(&ksig->ka, regs, frame_size);
385 if (frame == (void __user *) -1UL)
386 return -EFAULT;
387
388 /* Set up backchain. */
389 if (__put_user(regs->gprs[15], (addr_t __user *) frame))
390 return -EFAULT;
391
392 /* Set up to return from userspace. If provided, use a stub
393 already in userspace. */
394 if (ksig->ka.sa.sa_flags & SA_RESTORER)
395 restorer = (unsigned long) ksig->ka.sa.sa_restorer;
396 else
397 restorer = VDSO64_SYMBOL(current, rt_sigreturn);
398
399 /* Create siginfo on the signal stack */
400 if (copy_siginfo_to_user(&frame->info, &ksig->info))
401 return -EFAULT;
402
403 /* Store registers needed to create the signal frame */
404 store_sigregs();
405
406 /* Create ucontext on the signal stack. */
407 if (__put_user(uc_flags, &frame->uc.uc_flags) ||
408 __put_user(NULL, &frame->uc.uc_link) ||
409 __save_altstack(&frame->uc.uc_stack, regs->gprs[15]) ||
410 save_sigregs(regs, &frame->uc.uc_mcontext) ||
411 __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)) ||
412 save_sigregs_ext(regs, &frame->uc.uc_mcontext_ext))
413 return -EFAULT;
414
415 /* Set up registers for signal handler */
416 regs->gprs[14] = restorer;
417 regs->gprs[15] = (unsigned long) frame;
418 /* Force default amode and default user address space control. */
419 regs->psw.mask = PSW_MASK_EA | PSW_MASK_BA |
420 (PSW_USER_BITS & PSW_MASK_ASC) |
421 (regs->psw.mask & ~PSW_MASK_ASC);
422 regs->psw.addr = (unsigned long) ksig->ka.sa.sa_handler;
423
424 regs->gprs[2] = ksig->sig;
425 regs->gprs[3] = (unsigned long) &frame->info;
426 regs->gprs[4] = (unsigned long) &frame->uc;
427 regs->gprs[5] = current->thread.last_break;
428 return 0;
429}
430
431static void handle_signal(struct ksignal *ksig, sigset_t *oldset,
432 struct pt_regs *regs)
433{
434 int ret;
435
436 /* Set up the stack frame */
437 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
438 ret = setup_rt_frame(ksig, oldset, regs);
439 else
440 ret = setup_frame(ksig->sig, &ksig->ka, oldset, regs);
441
442 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLE_STEP));
443}
444
445/*
446 * Note that 'init' is a special process: it doesn't get signals it doesn't
447 * want to handle. Thus you cannot kill init even with a SIGKILL even by
448 * mistake.
449 *
450 * Note that we go through the signals twice: once to check the signals that
451 * the kernel can handle, and then we build all the user-level signal handling
452 * stack-frames in one go after that.
453 */
454
455void arch_do_signal_or_restart(struct pt_regs *regs)
456{
457 struct ksignal ksig;
458 sigset_t *oldset = sigmask_to_save();
459
460 /*
461 * Get signal to deliver. When running under ptrace, at this point
462 * the debugger may change all our registers, including the system
463 * call information.
464 */
465 current->thread.system_call =
466 test_pt_regs_flag(regs, PIF_SYSCALL) ? regs->int_code : 0;
467
468 if (get_signal(&ksig)) {
469 /* Whee! Actually deliver the signal. */
470 if (current->thread.system_call) {
471 regs->int_code = current->thread.system_call;
472 /* Check for system call restarting. */
473 switch (regs->gprs[2]) {
474 case -ERESTART_RESTARTBLOCK:
475 case -ERESTARTNOHAND:
476 regs->gprs[2] = -EINTR;
477 break;
478 case -ERESTARTSYS:
479 if (!(ksig.ka.sa.sa_flags & SA_RESTART)) {
480 regs->gprs[2] = -EINTR;
481 break;
482 }
483 fallthrough;
484 case -ERESTARTNOINTR:
485 regs->gprs[2] = regs->orig_gpr2;
486 regs->psw.addr =
487 __rewind_psw(regs->psw,
488 regs->int_code >> 16);
489 break;
490 }
491 }
492 /* No longer in a system call */
493 clear_pt_regs_flag(regs, PIF_SYSCALL);
494
495 rseq_signal_deliver(&ksig, regs);
496 if (is_compat_task())
497 handle_signal32(&ksig, oldset, regs);
498 else
499 handle_signal(&ksig, oldset, regs);
500 return;
501 }
502
503 /* No handlers present - check for system call restart */
504 clear_pt_regs_flag(regs, PIF_SYSCALL);
505 if (current->thread.system_call) {
506 regs->int_code = current->thread.system_call;
507 switch (regs->gprs[2]) {
508 case -ERESTART_RESTARTBLOCK:
509 /* Restart with sys_restart_syscall */
510 regs->gprs[2] = regs->orig_gpr2;
511 current->restart_block.arch_data = regs->psw.addr;
512 if (is_compat_task())
513 regs->psw.addr = VDSO32_SYMBOL(current, restart_syscall);
514 else
515 regs->psw.addr = VDSO64_SYMBOL(current, restart_syscall);
516 if (test_thread_flag(TIF_SINGLE_STEP))
517 clear_thread_flag(TIF_PER_TRAP);
518 break;
519 case -ERESTARTNOHAND:
520 case -ERESTARTSYS:
521 case -ERESTARTNOINTR:
522 regs->gprs[2] = regs->orig_gpr2;
523 regs->psw.addr = __rewind_psw(regs->psw, regs->int_code >> 16);
524 if (test_thread_flag(TIF_SINGLE_STEP))
525 clear_thread_flag(TIF_PER_TRAP);
526 break;
527 }
528 }
529
530 /*
531 * If there's no signal to deliver, we just put the saved sigmask back.
532 */
533 restore_saved_sigmask();
534}
1/*
2 * arch/s390/kernel/signal.c
3 *
4 * Copyright (C) IBM Corp. 1999,2006
5 * Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
6 *
7 * Based on Intel version
8 *
9 * Copyright (C) 1991, 1992 Linus Torvalds
10 *
11 * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
12 */
13
14#include <linux/sched.h>
15#include <linux/mm.h>
16#include <linux/smp.h>
17#include <linux/kernel.h>
18#include <linux/signal.h>
19#include <linux/errno.h>
20#include <linux/wait.h>
21#include <linux/ptrace.h>
22#include <linux/unistd.h>
23#include <linux/stddef.h>
24#include <linux/tty.h>
25#include <linux/personality.h>
26#include <linux/binfmts.h>
27#include <linux/tracehook.h>
28#include <linux/syscalls.h>
29#include <linux/compat.h>
30#include <asm/ucontext.h>
31#include <asm/uaccess.h>
32#include <asm/lowcore.h>
33#include <asm/switch_to.h>
34#include "entry.h"
35
36typedef struct
37{
38 __u8 callee_used_stack[__SIGNAL_FRAMESIZE];
39 struct sigcontext sc;
40 _sigregs sregs;
41 int signo;
42 __u8 retcode[S390_SYSCALL_SIZE];
43} sigframe;
44
45typedef struct
46{
47 __u8 callee_used_stack[__SIGNAL_FRAMESIZE];
48 __u8 retcode[S390_SYSCALL_SIZE];
49 struct siginfo info;
50 struct ucontext uc;
51} rt_sigframe;
52
53/*
54 * Atomically swap in the new signal mask, and wait for a signal.
55 */
56SYSCALL_DEFINE3(sigsuspend, int, history0, int, history1, old_sigset_t, mask)
57{
58 sigset_t blocked;
59 siginitset(&blocked, mask);
60 return sigsuspend(&blocked);
61}
62
63SYSCALL_DEFINE3(sigaction, int, sig, const struct old_sigaction __user *, act,
64 struct old_sigaction __user *, oact)
65{
66 struct k_sigaction new_ka, old_ka;
67 int ret;
68
69 if (act) {
70 old_sigset_t mask;
71 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
72 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
73 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
74 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
75 __get_user(mask, &act->sa_mask))
76 return -EFAULT;
77 siginitset(&new_ka.sa.sa_mask, mask);
78 }
79
80 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
81
82 if (!ret && oact) {
83 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
84 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
85 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
86 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
87 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
88 return -EFAULT;
89 }
90
91 return ret;
92}
93
94SYSCALL_DEFINE2(sigaltstack, const stack_t __user *, uss,
95 stack_t __user *, uoss)
96{
97 struct pt_regs *regs = task_pt_regs(current);
98 return do_sigaltstack(uss, uoss, regs->gprs[15]);
99}
100
101/* Returns non-zero on fault. */
102static int save_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
103{
104 _sigregs user_sregs;
105
106 save_access_regs(current->thread.acrs);
107
108 /* Copy a 'clean' PSW mask to the user to avoid leaking
109 information about whether PER is currently on. */
110 user_sregs.regs.psw.mask = psw_user_bits |
111 (regs->psw.mask & PSW_MASK_USER);
112 user_sregs.regs.psw.addr = regs->psw.addr;
113 memcpy(&user_sregs.regs.gprs, ®s->gprs, sizeof(sregs->regs.gprs));
114 memcpy(&user_sregs.regs.acrs, current->thread.acrs,
115 sizeof(sregs->regs.acrs));
116 /*
117 * We have to store the fp registers to current->thread.fp_regs
118 * to merge them with the emulated registers.
119 */
120 save_fp_regs(¤t->thread.fp_regs);
121 memcpy(&user_sregs.fpregs, ¤t->thread.fp_regs,
122 sizeof(s390_fp_regs));
123 return __copy_to_user(sregs, &user_sregs, sizeof(_sigregs));
124}
125
126/* Returns positive number on error */
127static int restore_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
128{
129 int err;
130 _sigregs user_sregs;
131
132 /* Alwys make any pending restarted system call return -EINTR */
133 current_thread_info()->restart_block.fn = do_no_restart_syscall;
134
135 err = __copy_from_user(&user_sregs, sregs, sizeof(_sigregs));
136 if (err)
137 return err;
138 /* Use regs->psw.mask instead of psw_user_bits to preserve PER bit. */
139 regs->psw.mask = (regs->psw.mask & ~PSW_MASK_USER) |
140 (user_sregs.regs.psw.mask & PSW_MASK_USER);
141 /* Check for invalid amode */
142 if (regs->psw.mask & PSW_MASK_EA)
143 regs->psw.mask |= PSW_MASK_BA;
144 regs->psw.addr = user_sregs.regs.psw.addr;
145 memcpy(®s->gprs, &user_sregs.regs.gprs, sizeof(sregs->regs.gprs));
146 memcpy(¤t->thread.acrs, &user_sregs.regs.acrs,
147 sizeof(sregs->regs.acrs));
148 restore_access_regs(current->thread.acrs);
149
150 memcpy(¤t->thread.fp_regs, &user_sregs.fpregs,
151 sizeof(s390_fp_regs));
152 current->thread.fp_regs.fpc &= FPC_VALID_MASK;
153
154 restore_fp_regs(¤t->thread.fp_regs);
155 clear_thread_flag(TIF_SYSCALL); /* No longer in a system call */
156 return 0;
157}
158
159SYSCALL_DEFINE0(sigreturn)
160{
161 struct pt_regs *regs = task_pt_regs(current);
162 sigframe __user *frame = (sigframe __user *)regs->gprs[15];
163 sigset_t set;
164
165 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
166 goto badframe;
167 if (__copy_from_user(&set.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE))
168 goto badframe;
169 set_current_blocked(&set);
170 if (restore_sigregs(regs, &frame->sregs))
171 goto badframe;
172 return regs->gprs[2];
173badframe:
174 force_sig(SIGSEGV, current);
175 return 0;
176}
177
178SYSCALL_DEFINE0(rt_sigreturn)
179{
180 struct pt_regs *regs = task_pt_regs(current);
181 rt_sigframe __user *frame = (rt_sigframe __user *)regs->gprs[15];
182 sigset_t set;
183
184 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
185 goto badframe;
186 if (__copy_from_user(&set.sig, &frame->uc.uc_sigmask, sizeof(set)))
187 goto badframe;
188 set_current_blocked(&set);
189 if (restore_sigregs(regs, &frame->uc.uc_mcontext))
190 goto badframe;
191 if (do_sigaltstack(&frame->uc.uc_stack, NULL,
192 regs->gprs[15]) == -EFAULT)
193 goto badframe;
194 return regs->gprs[2];
195badframe:
196 force_sig(SIGSEGV, current);
197 return 0;
198}
199
200/*
201 * Set up a signal frame.
202 */
203
204
205/*
206 * Determine which stack to use..
207 */
208static inline void __user *
209get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
210{
211 unsigned long sp;
212
213 /* Default to using normal stack */
214 sp = regs->gprs[15];
215
216 /* Overflow on alternate signal stack gives SIGSEGV. */
217 if (on_sig_stack(sp) && !on_sig_stack((sp - frame_size) & -8UL))
218 return (void __user *) -1UL;
219
220 /* This is the X/Open sanctioned signal stack switching. */
221 if (ka->sa.sa_flags & SA_ONSTACK) {
222 if (! sas_ss_flags(sp))
223 sp = current->sas_ss_sp + current->sas_ss_size;
224 }
225
226 return (void __user *)((sp - frame_size) & -8ul);
227}
228
229static inline int map_signal(int sig)
230{
231 if (current_thread_info()->exec_domain
232 && current_thread_info()->exec_domain->signal_invmap
233 && sig < 32)
234 return current_thread_info()->exec_domain->signal_invmap[sig];
235 else
236 return sig;
237}
238
239static int setup_frame(int sig, struct k_sigaction *ka,
240 sigset_t *set, struct pt_regs * regs)
241{
242 sigframe __user *frame;
243
244 frame = get_sigframe(ka, regs, sizeof(sigframe));
245 if (!access_ok(VERIFY_WRITE, frame, sizeof(sigframe)))
246 goto give_sigsegv;
247
248 if (frame == (void __user *) -1UL)
249 goto give_sigsegv;
250
251 if (__copy_to_user(&frame->sc.oldmask, &set->sig, _SIGMASK_COPY_SIZE))
252 goto give_sigsegv;
253
254 if (save_sigregs(regs, &frame->sregs))
255 goto give_sigsegv;
256 if (__put_user(&frame->sregs, &frame->sc.sregs))
257 goto give_sigsegv;
258
259 /* Set up to return from userspace. If provided, use a stub
260 already in userspace. */
261 if (ka->sa.sa_flags & SA_RESTORER) {
262 regs->gprs[14] = (unsigned long)
263 ka->sa.sa_restorer | PSW_ADDR_AMODE;
264 } else {
265 regs->gprs[14] = (unsigned long)
266 frame->retcode | PSW_ADDR_AMODE;
267 if (__put_user(S390_SYSCALL_OPCODE | __NR_sigreturn,
268 (u16 __user *)(frame->retcode)))
269 goto give_sigsegv;
270 }
271
272 /* Set up backchain. */
273 if (__put_user(regs->gprs[15], (addr_t __user *) frame))
274 goto give_sigsegv;
275
276 /* Set up registers for signal handler */
277 regs->gprs[15] = (unsigned long) frame;
278 regs->psw.mask |= PSW_MASK_EA | PSW_MASK_BA; /* 64 bit amode */
279 regs->psw.addr = (unsigned long) ka->sa.sa_handler | PSW_ADDR_AMODE;
280
281 regs->gprs[2] = map_signal(sig);
282 regs->gprs[3] = (unsigned long) &frame->sc;
283
284 /* We forgot to include these in the sigcontext.
285 To avoid breaking binary compatibility, they are passed as args. */
286 if (sig == SIGSEGV || sig == SIGBUS || sig == SIGILL ||
287 sig == SIGTRAP || sig == SIGFPE) {
288 /* set extra registers only for synchronous signals */
289 regs->gprs[4] = regs->int_code & 127;
290 regs->gprs[5] = regs->int_parm_long;
291 regs->gprs[6] = task_thread_info(current)->last_break;
292 }
293
294 /* Place signal number on stack to allow backtrace from handler. */
295 if (__put_user(regs->gprs[2], (int __user *) &frame->signo))
296 goto give_sigsegv;
297 return 0;
298
299give_sigsegv:
300 force_sigsegv(sig, current);
301 return -EFAULT;
302}
303
304static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
305 sigset_t *set, struct pt_regs * regs)
306{
307 int err = 0;
308 rt_sigframe __user *frame;
309
310 frame = get_sigframe(ka, regs, sizeof(rt_sigframe));
311 if (!access_ok(VERIFY_WRITE, frame, sizeof(rt_sigframe)))
312 goto give_sigsegv;
313
314 if (frame == (void __user *) -1UL)
315 goto give_sigsegv;
316
317 if (copy_siginfo_to_user(&frame->info, info))
318 goto give_sigsegv;
319
320 /* Create the ucontext. */
321 err |= __put_user(0, &frame->uc.uc_flags);
322 err |= __put_user(NULL, &frame->uc.uc_link);
323 err |= __put_user((void __user *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
324 err |= __put_user(sas_ss_flags(regs->gprs[15]),
325 &frame->uc.uc_stack.ss_flags);
326 err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
327 err |= save_sigregs(regs, &frame->uc.uc_mcontext);
328 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
329 if (err)
330 goto give_sigsegv;
331
332 /* Set up to return from userspace. If provided, use a stub
333 already in userspace. */
334 if (ka->sa.sa_flags & SA_RESTORER) {
335 regs->gprs[14] = (unsigned long)
336 ka->sa.sa_restorer | PSW_ADDR_AMODE;
337 } else {
338 regs->gprs[14] = (unsigned long)
339 frame->retcode | PSW_ADDR_AMODE;
340 if (__put_user(S390_SYSCALL_OPCODE | __NR_rt_sigreturn,
341 (u16 __user *)(frame->retcode)))
342 goto give_sigsegv;
343 }
344
345 /* Set up backchain. */
346 if (__put_user(regs->gprs[15], (addr_t __user *) frame))
347 goto give_sigsegv;
348
349 /* Set up registers for signal handler */
350 regs->gprs[15] = (unsigned long) frame;
351 regs->psw.mask |= PSW_MASK_EA | PSW_MASK_BA; /* 64 bit amode */
352 regs->psw.addr = (unsigned long) ka->sa.sa_handler | PSW_ADDR_AMODE;
353
354 regs->gprs[2] = map_signal(sig);
355 regs->gprs[3] = (unsigned long) &frame->info;
356 regs->gprs[4] = (unsigned long) &frame->uc;
357 regs->gprs[5] = task_thread_info(current)->last_break;
358 return 0;
359
360give_sigsegv:
361 force_sigsegv(sig, current);
362 return -EFAULT;
363}
364
365static void handle_signal(unsigned long sig, struct k_sigaction *ka,
366 siginfo_t *info, sigset_t *oldset,
367 struct pt_regs *regs)
368{
369 int ret;
370
371 /* Set up the stack frame */
372 if (ka->sa.sa_flags & SA_SIGINFO)
373 ret = setup_rt_frame(sig, ka, info, oldset, regs);
374 else
375 ret = setup_frame(sig, ka, oldset, regs);
376 if (ret)
377 return;
378 signal_delivered(sig, info, ka, regs,
379 test_thread_flag(TIF_SINGLE_STEP));
380}
381
382/*
383 * Note that 'init' is a special process: it doesn't get signals it doesn't
384 * want to handle. Thus you cannot kill init even with a SIGKILL even by
385 * mistake.
386 *
387 * Note that we go through the signals twice: once to check the signals that
388 * the kernel can handle, and then we build all the user-level signal handling
389 * stack-frames in one go after that.
390 */
391void do_signal(struct pt_regs *regs)
392{
393 siginfo_t info;
394 int signr;
395 struct k_sigaction ka;
396 sigset_t *oldset = sigmask_to_save();
397
398 /*
399 * Get signal to deliver. When running under ptrace, at this point
400 * the debugger may change all our registers, including the system
401 * call information.
402 */
403 current_thread_info()->system_call =
404 test_thread_flag(TIF_SYSCALL) ? regs->int_code : 0;
405 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
406
407 if (signr > 0) {
408 /* Whee! Actually deliver the signal. */
409 if (current_thread_info()->system_call) {
410 regs->int_code = current_thread_info()->system_call;
411 /* Check for system call restarting. */
412 switch (regs->gprs[2]) {
413 case -ERESTART_RESTARTBLOCK:
414 case -ERESTARTNOHAND:
415 regs->gprs[2] = -EINTR;
416 break;
417 case -ERESTARTSYS:
418 if (!(ka.sa.sa_flags & SA_RESTART)) {
419 regs->gprs[2] = -EINTR;
420 break;
421 }
422 /* fallthrough */
423 case -ERESTARTNOINTR:
424 regs->gprs[2] = regs->orig_gpr2;
425 regs->psw.addr =
426 __rewind_psw(regs->psw,
427 regs->int_code >> 16);
428 break;
429 }
430 }
431 /* No longer in a system call */
432 clear_thread_flag(TIF_SYSCALL);
433
434 if (is_compat_task())
435 handle_signal32(signr, &ka, &info, oldset, regs);
436 else
437 handle_signal(signr, &ka, &info, oldset, regs);
438 return;
439 }
440
441 /* No handlers present - check for system call restart */
442 clear_thread_flag(TIF_SYSCALL);
443 if (current_thread_info()->system_call) {
444 regs->int_code = current_thread_info()->system_call;
445 switch (regs->gprs[2]) {
446 case -ERESTART_RESTARTBLOCK:
447 /* Restart with sys_restart_syscall */
448 regs->int_code = __NR_restart_syscall;
449 /* fallthrough */
450 case -ERESTARTNOHAND:
451 case -ERESTARTSYS:
452 case -ERESTARTNOINTR:
453 /* Restart system call with magic TIF bit. */
454 regs->gprs[2] = regs->orig_gpr2;
455 set_thread_flag(TIF_SYSCALL);
456 break;
457 }
458 }
459
460 /*
461 * If there's no signal to deliver, we just put the saved sigmask back.
462 */
463 restore_saved_sigmask();
464}
465
466void do_notify_resume(struct pt_regs *regs)
467{
468 clear_thread_flag(TIF_NOTIFY_RESUME);
469 tracehook_notify_resume(regs);
470}