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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/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 <linux/uaccess.h>
32#include <asm/lowcore.h>
33#include <asm/switch_to.h>
34#include "entry.h"
35
36/*
37 * Layout of an old-style signal-frame:
38 * -----------------------------------------
39 * | save area (_SIGNAL_FRAMESIZE) |
40 * -----------------------------------------
41 * | struct sigcontext |
42 * | oldmask |
43 * | _sigregs * |
44 * -----------------------------------------
45 * | _sigregs with |
46 * | _s390_regs_common |
47 * | _s390_fp_regs |
48 * -----------------------------------------
49 * | int signo |
50 * -----------------------------------------
51 * | _sigregs_ext with |
52 * | gprs_high 64 byte (opt) |
53 * | vxrs_low 128 byte (opt) |
54 * | vxrs_high 256 byte (opt) |
55 * | reserved 128 byte (opt) |
56 * -----------------------------------------
57 * | __u16 svc_insn |
58 * -----------------------------------------
59 * The svc_insn entry with the sigreturn system call opcode does not
60 * have a fixed position and moves if gprs_high or vxrs exist.
61 * Future extensions will be added to _sigregs_ext.
62 */
63struct sigframe
64{
65 __u8 callee_used_stack[__SIGNAL_FRAMESIZE];
66 struct sigcontext sc;
67 _sigregs sregs;
68 int signo;
69 _sigregs_ext sregs_ext;
70 __u16 svc_insn; /* Offset of svc_insn is NOT fixed! */
71};
72
73/*
74 * Layout of an rt signal-frame:
75 * -----------------------------------------
76 * | save area (_SIGNAL_FRAMESIZE) |
77 * -----------------------------------------
78 * | svc __NR_rt_sigreturn 2 byte |
79 * -----------------------------------------
80 * | struct siginfo |
81 * -----------------------------------------
82 * | struct ucontext_extended with |
83 * | unsigned long uc_flags |
84 * | struct ucontext *uc_link |
85 * | stack_t uc_stack |
86 * | _sigregs uc_mcontext with |
87 * | _s390_regs_common |
88 * | _s390_fp_regs |
89 * | sigset_t uc_sigmask |
90 * | _sigregs_ext uc_mcontext_ext |
91 * | gprs_high 64 byte (opt) |
92 * | vxrs_low 128 byte (opt) |
93 * | vxrs_high 256 byte (opt)|
94 * | reserved 128 byte (opt) |
95 * -----------------------------------------
96 * Future extensions will be added to _sigregs_ext.
97 */
98struct rt_sigframe
99{
100 __u8 callee_used_stack[__SIGNAL_FRAMESIZE];
101 __u16 svc_insn;
102 struct siginfo info;
103 struct ucontext_extended uc;
104};
105
106/* Store registers needed to create the signal frame */
107static void store_sigregs(void)
108{
109 save_access_regs(current->thread.acrs);
110 save_fpu_regs();
111}
112
113/* Load registers after signal return */
114static void load_sigregs(void)
115{
116 restore_access_regs(current->thread.acrs);
117}
118
119/* Returns non-zero on fault. */
120static int save_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
121{
122 _sigregs user_sregs;
123
124 /* Copy a 'clean' PSW mask to the user to avoid leaking
125 information about whether PER is currently on. */
126 user_sregs.regs.psw.mask = PSW_USER_BITS |
127 (regs->psw.mask & (PSW_MASK_USER | PSW_MASK_RI));
128 user_sregs.regs.psw.addr = regs->psw.addr;
129 memcpy(&user_sregs.regs.gprs, ®s->gprs, sizeof(sregs->regs.gprs));
130 memcpy(&user_sregs.regs.acrs, current->thread.acrs,
131 sizeof(user_sregs.regs.acrs));
132 fpregs_store(&user_sregs.fpregs, ¤t->thread.fpu);
133 if (__copy_to_user(sregs, &user_sregs, sizeof(_sigregs)))
134 return -EFAULT;
135 return 0;
136}
137
138static int restore_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
139{
140 _sigregs user_sregs;
141
142 /* Alwys make any pending restarted system call return -EINTR */
143 current->restart_block.fn = do_no_restart_syscall;
144
145 if (__copy_from_user(&user_sregs, sregs, sizeof(user_sregs)))
146 return -EFAULT;
147
148 if (!is_ri_task(current) && (user_sregs.regs.psw.mask & PSW_MASK_RI))
149 return -EINVAL;
150
151 /* Test the floating-point-control word. */
152 if (test_fp_ctl(user_sregs.fpregs.fpc))
153 return -EINVAL;
154
155 /* Use regs->psw.mask instead of PSW_USER_BITS to preserve PER bit. */
156 regs->psw.mask = (regs->psw.mask & ~(PSW_MASK_USER | PSW_MASK_RI)) |
157 (user_sregs.regs.psw.mask & (PSW_MASK_USER | PSW_MASK_RI));
158 /* Check for invalid user address space control. */
159 if ((regs->psw.mask & PSW_MASK_ASC) == PSW_ASC_HOME)
160 regs->psw.mask = PSW_ASC_PRIMARY |
161 (regs->psw.mask & ~PSW_MASK_ASC);
162 /* Check for invalid amode */
163 if (regs->psw.mask & PSW_MASK_EA)
164 regs->psw.mask |= PSW_MASK_BA;
165 regs->psw.addr = user_sregs.regs.psw.addr;
166 memcpy(®s->gprs, &user_sregs.regs.gprs, sizeof(sregs->regs.gprs));
167 memcpy(¤t->thread.acrs, &user_sregs.regs.acrs,
168 sizeof(current->thread.acrs));
169
170 fpregs_load(&user_sregs.fpregs, ¤t->thread.fpu);
171
172 clear_pt_regs_flag(regs, PIF_SYSCALL); /* No longer in a system call */
173 return 0;
174}
175
176/* Returns non-zero on fault. */
177static int save_sigregs_ext(struct pt_regs *regs,
178 _sigregs_ext __user *sregs_ext)
179{
180 __u64 vxrs[__NUM_VXRS_LOW];
181 int i;
182
183 /* Save vector registers to signal stack */
184 if (MACHINE_HAS_VX) {
185 for (i = 0; i < __NUM_VXRS_LOW; i++)
186 vxrs[i] = *((__u64 *)(current->thread.fpu.vxrs + i) + 1);
187 if (__copy_to_user(&sregs_ext->vxrs_low, vxrs,
188 sizeof(sregs_ext->vxrs_low)) ||
189 __copy_to_user(&sregs_ext->vxrs_high,
190 current->thread.fpu.vxrs + __NUM_VXRS_LOW,
191 sizeof(sregs_ext->vxrs_high)))
192 return -EFAULT;
193 }
194 return 0;
195}
196
197static int restore_sigregs_ext(struct pt_regs *regs,
198 _sigregs_ext __user *sregs_ext)
199{
200 __u64 vxrs[__NUM_VXRS_LOW];
201 int i;
202
203 /* Restore vector registers from signal stack */
204 if (MACHINE_HAS_VX) {
205 if (__copy_from_user(vxrs, &sregs_ext->vxrs_low,
206 sizeof(sregs_ext->vxrs_low)) ||
207 __copy_from_user(current->thread.fpu.vxrs + __NUM_VXRS_LOW,
208 &sregs_ext->vxrs_high,
209 sizeof(sregs_ext->vxrs_high)))
210 return -EFAULT;
211 for (i = 0; i < __NUM_VXRS_LOW; i++)
212 *((__u64 *)(current->thread.fpu.vxrs + i) + 1) = vxrs[i];
213 }
214 return 0;
215}
216
217SYSCALL_DEFINE0(sigreturn)
218{
219 struct pt_regs *regs = task_pt_regs(current);
220 struct sigframe __user *frame =
221 (struct sigframe __user *) regs->gprs[15];
222 sigset_t set;
223
224 if (__copy_from_user(&set.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE))
225 goto badframe;
226 set_current_blocked(&set);
227 save_fpu_regs();
228 if (restore_sigregs(regs, &frame->sregs))
229 goto badframe;
230 if (restore_sigregs_ext(regs, &frame->sregs_ext))
231 goto badframe;
232 load_sigregs();
233 return regs->gprs[2];
234badframe:
235 force_sig(SIGSEGV);
236 return 0;
237}
238
239SYSCALL_DEFINE0(rt_sigreturn)
240{
241 struct pt_regs *regs = task_pt_regs(current);
242 struct rt_sigframe __user *frame =
243 (struct rt_sigframe __user *)regs->gprs[15];
244 sigset_t set;
245
246 if (__copy_from_user(&set.sig, &frame->uc.uc_sigmask, sizeof(set)))
247 goto badframe;
248 set_current_blocked(&set);
249 if (restore_altstack(&frame->uc.uc_stack))
250 goto badframe;
251 save_fpu_regs();
252 if (restore_sigregs(regs, &frame->uc.uc_mcontext))
253 goto badframe;
254 if (restore_sigregs_ext(regs, &frame->uc.uc_mcontext_ext))
255 goto badframe;
256 load_sigregs();
257 return regs->gprs[2];
258badframe:
259 force_sig(SIGSEGV);
260 return 0;
261}
262
263/*
264 * Determine which stack to use..
265 */
266static inline void __user *
267get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
268{
269 unsigned long sp;
270
271 /* Default to using normal stack */
272 sp = regs->gprs[15];
273
274 /* Overflow on alternate signal stack gives SIGSEGV. */
275 if (on_sig_stack(sp) && !on_sig_stack((sp - frame_size) & -8UL))
276 return (void __user *) -1UL;
277
278 /* This is the X/Open sanctioned signal stack switching. */
279 if (ka->sa.sa_flags & SA_ONSTACK) {
280 if (! sas_ss_flags(sp))
281 sp = current->sas_ss_sp + current->sas_ss_size;
282 }
283
284 return (void __user *)((sp - frame_size) & -8ul);
285}
286
287static int setup_frame(int sig, struct k_sigaction *ka,
288 sigset_t *set, struct pt_regs * regs)
289{
290 struct sigframe __user *frame;
291 struct sigcontext sc;
292 unsigned long restorer;
293 size_t frame_size;
294
295 /*
296 * gprs_high are only present for a 31-bit task running on
297 * a 64-bit kernel (see compat_signal.c) but the space for
298 * gprs_high need to be allocated if vector registers are
299 * included in the signal frame on a 31-bit system.
300 */
301 frame_size = sizeof(*frame) - sizeof(frame->sregs_ext);
302 if (MACHINE_HAS_VX)
303 frame_size += sizeof(frame->sregs_ext);
304 frame = get_sigframe(ka, regs, frame_size);
305 if (frame == (void __user *) -1UL)
306 return -EFAULT;
307
308 /* Set up backchain. */
309 if (__put_user(regs->gprs[15], (addr_t __user *) frame))
310 return -EFAULT;
311
312 /* Create struct sigcontext on the signal stack */
313 memcpy(&sc.oldmask, &set->sig, _SIGMASK_COPY_SIZE);
314 sc.sregs = (_sigregs __user __force *) &frame->sregs;
315 if (__copy_to_user(&frame->sc, &sc, sizeof(frame->sc)))
316 return -EFAULT;
317
318 /* Store registers needed to create the signal frame */
319 store_sigregs();
320
321 /* Create _sigregs on the signal stack */
322 if (save_sigregs(regs, &frame->sregs))
323 return -EFAULT;
324
325 /* Place signal number on stack to allow backtrace from handler. */
326 if (__put_user(regs->gprs[2], (int __user *) &frame->signo))
327 return -EFAULT;
328
329 /* Create _sigregs_ext on the signal stack */
330 if (save_sigregs_ext(regs, &frame->sregs_ext))
331 return -EFAULT;
332
333 /* Set up to return from userspace. If provided, use a stub
334 already in userspace. */
335 if (ka->sa.sa_flags & SA_RESTORER) {
336 restorer = (unsigned long) ka->sa.sa_restorer;
337 } else {
338 /* Signal frame without vector registers are short ! */
339 __u16 __user *svc = (void __user *) frame + frame_size - 2;
340 if (__put_user(S390_SYSCALL_OPCODE | __NR_sigreturn, svc))
341 return -EFAULT;
342 restorer = (unsigned long) svc;
343 }
344
345 /* Set up registers for signal handler */
346 regs->gprs[14] = restorer;
347 regs->gprs[15] = (unsigned long) frame;
348 /* Force default amode and default user address space control. */
349 regs->psw.mask = PSW_MASK_EA | PSW_MASK_BA |
350 (PSW_USER_BITS & PSW_MASK_ASC) |
351 (regs->psw.mask & ~PSW_MASK_ASC);
352 regs->psw.addr = (unsigned long) ka->sa.sa_handler;
353
354 regs->gprs[2] = sig;
355 regs->gprs[3] = (unsigned long) &frame->sc;
356
357 /* We forgot to include these in the sigcontext.
358 To avoid breaking binary compatibility, they are passed as args. */
359 if (sig == SIGSEGV || sig == SIGBUS || sig == SIGILL ||
360 sig == SIGTRAP || sig == SIGFPE) {
361 /* set extra registers only for synchronous signals */
362 regs->gprs[4] = regs->int_code & 127;
363 regs->gprs[5] = regs->int_parm_long;
364 regs->gprs[6] = current->thread.last_break;
365 }
366 return 0;
367}
368
369static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
370 struct pt_regs *regs)
371{
372 struct rt_sigframe __user *frame;
373 unsigned long uc_flags, restorer;
374 size_t frame_size;
375
376 frame_size = sizeof(struct rt_sigframe) - sizeof(_sigregs_ext);
377 /*
378 * gprs_high are only present for a 31-bit task running on
379 * a 64-bit kernel (see compat_signal.c) but the space for
380 * gprs_high need to be allocated if vector registers are
381 * included in the signal frame on a 31-bit system.
382 */
383 uc_flags = 0;
384 if (MACHINE_HAS_VX) {
385 frame_size += sizeof(_sigregs_ext);
386 uc_flags |= UC_VXRS;
387 }
388 frame = get_sigframe(&ksig->ka, regs, frame_size);
389 if (frame == (void __user *) -1UL)
390 return -EFAULT;
391
392 /* Set up backchain. */
393 if (__put_user(regs->gprs[15], (addr_t __user *) frame))
394 return -EFAULT;
395
396 /* Set up to return from userspace. If provided, use a stub
397 already in userspace. */
398 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
399 restorer = (unsigned long) ksig->ka.sa.sa_restorer;
400 } else {
401 __u16 __user *svc = &frame->svc_insn;
402 if (__put_user(S390_SYSCALL_OPCODE | __NR_rt_sigreturn, svc))
403 return -EFAULT;
404 restorer = (unsigned long) svc;
405 }
406
407 /* Create siginfo on the signal stack */
408 if (copy_siginfo_to_user(&frame->info, &ksig->info))
409 return -EFAULT;
410
411 /* Store registers needed to create the signal frame */
412 store_sigregs();
413
414 /* Create ucontext on the signal stack. */
415 if (__put_user(uc_flags, &frame->uc.uc_flags) ||
416 __put_user(NULL, &frame->uc.uc_link) ||
417 __save_altstack(&frame->uc.uc_stack, regs->gprs[15]) ||
418 save_sigregs(regs, &frame->uc.uc_mcontext) ||
419 __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)) ||
420 save_sigregs_ext(regs, &frame->uc.uc_mcontext_ext))
421 return -EFAULT;
422
423 /* Set up registers for signal handler */
424 regs->gprs[14] = restorer;
425 regs->gprs[15] = (unsigned long) frame;
426 /* Force default amode and default user address space control. */
427 regs->psw.mask = PSW_MASK_EA | PSW_MASK_BA |
428 (PSW_USER_BITS & PSW_MASK_ASC) |
429 (regs->psw.mask & ~PSW_MASK_ASC);
430 regs->psw.addr = (unsigned long) ksig->ka.sa.sa_handler;
431
432 regs->gprs[2] = ksig->sig;
433 regs->gprs[3] = (unsigned long) &frame->info;
434 regs->gprs[4] = (unsigned long) &frame->uc;
435 regs->gprs[5] = current->thread.last_break;
436 return 0;
437}
438
439static void handle_signal(struct ksignal *ksig, sigset_t *oldset,
440 struct pt_regs *regs)
441{
442 int ret;
443
444 /* Set up the stack frame */
445 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
446 ret = setup_rt_frame(ksig, oldset, regs);
447 else
448 ret = setup_frame(ksig->sig, &ksig->ka, oldset, regs);
449
450 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLE_STEP));
451}
452
453/*
454 * Note that 'init' is a special process: it doesn't get signals it doesn't
455 * want to handle. Thus you cannot kill init even with a SIGKILL even by
456 * mistake.
457 *
458 * Note that we go through the signals twice: once to check the signals that
459 * the kernel can handle, and then we build all the user-level signal handling
460 * stack-frames in one go after that.
461 */
462void do_signal(struct pt_regs *regs)
463{
464 struct ksignal ksig;
465 sigset_t *oldset = sigmask_to_save();
466
467 /*
468 * Get signal to deliver. When running under ptrace, at this point
469 * the debugger may change all our registers, including the system
470 * call information.
471 */
472 current->thread.system_call =
473 test_pt_regs_flag(regs, PIF_SYSCALL) ? regs->int_code : 0;
474
475 if (get_signal(&ksig)) {
476 /* Whee! Actually deliver the signal. */
477 if (current->thread.system_call) {
478 regs->int_code = current->thread.system_call;
479 /* Check for system call restarting. */
480 switch (regs->gprs[2]) {
481 case -ERESTART_RESTARTBLOCK:
482 case -ERESTARTNOHAND:
483 regs->gprs[2] = -EINTR;
484 break;
485 case -ERESTARTSYS:
486 if (!(ksig.ka.sa.sa_flags & SA_RESTART)) {
487 regs->gprs[2] = -EINTR;
488 break;
489 }
490 /* fallthrough */
491 case -ERESTARTNOINTR:
492 regs->gprs[2] = regs->orig_gpr2;
493 regs->psw.addr =
494 __rewind_psw(regs->psw,
495 regs->int_code >> 16);
496 break;
497 }
498 }
499 /* No longer in a system call */
500 clear_pt_regs_flag(regs, PIF_SYSCALL);
501 rseq_signal_deliver(&ksig, regs);
502 if (is_compat_task())
503 handle_signal32(&ksig, oldset, regs);
504 else
505 handle_signal(&ksig, oldset, regs);
506 return;
507 }
508
509 /* No handlers present - check for system call restart */
510 clear_pt_regs_flag(regs, PIF_SYSCALL);
511 if (current->thread.system_call) {
512 regs->int_code = current->thread.system_call;
513 switch (regs->gprs[2]) {
514 case -ERESTART_RESTARTBLOCK:
515 /* Restart with sys_restart_syscall */
516 regs->int_code = __NR_restart_syscall;
517 /* fallthrough */
518 case -ERESTARTNOHAND:
519 case -ERESTARTSYS:
520 case -ERESTARTNOINTR:
521 /* Restart system call with magic TIF bit. */
522 regs->gprs[2] = regs->orig_gpr2;
523 set_pt_regs_flag(regs, PIF_SYSCALL);
524 if (test_thread_flag(TIF_SINGLE_STEP))
525 clear_pt_regs_flag(regs, PIF_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}
535
536void do_notify_resume(struct pt_regs *regs)
537{
538 clear_thread_flag(TIF_NOTIFY_RESUME);
539 tracehook_notify_resume(regs);
540 rseq_handle_notify_resume(NULL, regs);
541}
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}