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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 "entry.h"
34
35#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
36
37
38typedef struct
39{
40 __u8 callee_used_stack[__SIGNAL_FRAMESIZE];
41 struct sigcontext sc;
42 _sigregs sregs;
43 int signo;
44 __u8 retcode[S390_SYSCALL_SIZE];
45} sigframe;
46
47typedef struct
48{
49 __u8 callee_used_stack[__SIGNAL_FRAMESIZE];
50 __u8 retcode[S390_SYSCALL_SIZE];
51 struct siginfo info;
52 struct ucontext uc;
53} rt_sigframe;
54
55/*
56 * Atomically swap in the new signal mask, and wait for a signal.
57 */
58SYSCALL_DEFINE3(sigsuspend, int, history0, int, history1, old_sigset_t, mask)
59{
60 sigset_t blocked;
61
62 current->saved_sigmask = current->blocked;
63 mask &= _BLOCKABLE;
64 siginitset(&blocked, mask);
65 set_current_blocked(&blocked);
66 set_current_state(TASK_INTERRUPTIBLE);
67 schedule();
68 set_restore_sigmask();
69 return -ERESTARTNOHAND;
70}
71
72SYSCALL_DEFINE3(sigaction, int, sig, const struct old_sigaction __user *, act,
73 struct old_sigaction __user *, oact)
74{
75 struct k_sigaction new_ka, old_ka;
76 int ret;
77
78 if (act) {
79 old_sigset_t mask;
80 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
81 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
82 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
83 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
84 __get_user(mask, &act->sa_mask))
85 return -EFAULT;
86 siginitset(&new_ka.sa.sa_mask, mask);
87 }
88
89 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
90
91 if (!ret && oact) {
92 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
93 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
94 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
95 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
96 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
97 return -EFAULT;
98 }
99
100 return ret;
101}
102
103SYSCALL_DEFINE2(sigaltstack, const stack_t __user *, uss,
104 stack_t __user *, uoss)
105{
106 struct pt_regs *regs = task_pt_regs(current);
107 return do_sigaltstack(uss, uoss, regs->gprs[15]);
108}
109
110/* Returns non-zero on fault. */
111static int save_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
112{
113 _sigregs user_sregs;
114
115 save_access_regs(current->thread.acrs);
116
117 /* Copy a 'clean' PSW mask to the user to avoid leaking
118 information about whether PER is currently on. */
119 user_sregs.regs.psw.mask = PSW_MASK_MERGE(psw_user_bits, regs->psw.mask);
120 user_sregs.regs.psw.addr = regs->psw.addr;
121 memcpy(&user_sregs.regs.gprs, ®s->gprs, sizeof(sregs->regs.gprs));
122 memcpy(&user_sregs.regs.acrs, current->thread.acrs,
123 sizeof(sregs->regs.acrs));
124 /*
125 * We have to store the fp registers to current->thread.fp_regs
126 * to merge them with the emulated registers.
127 */
128 save_fp_regs(¤t->thread.fp_regs);
129 memcpy(&user_sregs.fpregs, ¤t->thread.fp_regs,
130 sizeof(s390_fp_regs));
131 return __copy_to_user(sregs, &user_sregs, sizeof(_sigregs));
132}
133
134/* Returns positive number on error */
135static int restore_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
136{
137 int err;
138 _sigregs user_sregs;
139
140 /* Alwys make any pending restarted system call return -EINTR */
141 current_thread_info()->restart_block.fn = do_no_restart_syscall;
142
143 err = __copy_from_user(&user_sregs, sregs, sizeof(_sigregs));
144 if (err)
145 return err;
146 regs->psw.mask = PSW_MASK_MERGE(regs->psw.mask,
147 user_sregs.regs.psw.mask);
148 regs->psw.addr = PSW_ADDR_AMODE | user_sregs.regs.psw.addr;
149 memcpy(®s->gprs, &user_sregs.regs.gprs, sizeof(sregs->regs.gprs));
150 memcpy(¤t->thread.acrs, &user_sregs.regs.acrs,
151 sizeof(sregs->regs.acrs));
152 restore_access_regs(current->thread.acrs);
153
154 memcpy(¤t->thread.fp_regs, &user_sregs.fpregs,
155 sizeof(s390_fp_regs));
156 current->thread.fp_regs.fpc &= FPC_VALID_MASK;
157
158 restore_fp_regs(¤t->thread.fp_regs);
159 regs->svcnr = 0; /* disable syscall checks */
160 return 0;
161}
162
163SYSCALL_DEFINE0(sigreturn)
164{
165 struct pt_regs *regs = task_pt_regs(current);
166 sigframe __user *frame = (sigframe __user *)regs->gprs[15];
167 sigset_t set;
168
169 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
170 goto badframe;
171 if (__copy_from_user(&set.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE))
172 goto badframe;
173 sigdelsetmask(&set, ~_BLOCKABLE);
174 set_current_blocked(&set);
175 if (restore_sigregs(regs, &frame->sregs))
176 goto badframe;
177 return regs->gprs[2];
178badframe:
179 force_sig(SIGSEGV, current);
180 return 0;
181}
182
183SYSCALL_DEFINE0(rt_sigreturn)
184{
185 struct pt_regs *regs = task_pt_regs(current);
186 rt_sigframe __user *frame = (rt_sigframe __user *)regs->gprs[15];
187 sigset_t set;
188
189 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
190 goto badframe;
191 if (__copy_from_user(&set.sig, &frame->uc.uc_sigmask, sizeof(set)))
192 goto badframe;
193 sigdelsetmask(&set, ~_BLOCKABLE);
194 set_current_blocked(&set);
195 if (restore_sigregs(regs, &frame->uc.uc_mcontext))
196 goto badframe;
197 if (do_sigaltstack(&frame->uc.uc_stack, NULL,
198 regs->gprs[15]) == -EFAULT)
199 goto badframe;
200 return regs->gprs[2];
201badframe:
202 force_sig(SIGSEGV, current);
203 return 0;
204}
205
206/*
207 * Set up a signal frame.
208 */
209
210
211/*
212 * Determine which stack to use..
213 */
214static inline void __user *
215get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
216{
217 unsigned long sp;
218
219 /* Default to using normal stack */
220 sp = regs->gprs[15];
221
222 /* Overflow on alternate signal stack gives SIGSEGV. */
223 if (on_sig_stack(sp) && !on_sig_stack((sp - frame_size) & -8UL))
224 return (void __user *) -1UL;
225
226 /* This is the X/Open sanctioned signal stack switching. */
227 if (ka->sa.sa_flags & SA_ONSTACK) {
228 if (! sas_ss_flags(sp))
229 sp = current->sas_ss_sp + current->sas_ss_size;
230 }
231
232 /* This is the legacy signal stack switching. */
233 else if (!user_mode(regs) &&
234 !(ka->sa.sa_flags & SA_RESTORER) &&
235 ka->sa.sa_restorer) {
236 sp = (unsigned long) ka->sa.sa_restorer;
237 }
238
239 return (void __user *)((sp - frame_size) & -8ul);
240}
241
242static inline int map_signal(int sig)
243{
244 if (current_thread_info()->exec_domain
245 && current_thread_info()->exec_domain->signal_invmap
246 && sig < 32)
247 return current_thread_info()->exec_domain->signal_invmap[sig];
248 else
249 return sig;
250}
251
252static int setup_frame(int sig, struct k_sigaction *ka,
253 sigset_t *set, struct pt_regs * regs)
254{
255 sigframe __user *frame;
256
257 frame = get_sigframe(ka, regs, sizeof(sigframe));
258 if (!access_ok(VERIFY_WRITE, frame, sizeof(sigframe)))
259 goto give_sigsegv;
260
261 if (frame == (void __user *) -1UL)
262 goto give_sigsegv;
263
264 if (__copy_to_user(&frame->sc.oldmask, &set->sig, _SIGMASK_COPY_SIZE))
265 goto give_sigsegv;
266
267 if (save_sigregs(regs, &frame->sregs))
268 goto give_sigsegv;
269 if (__put_user(&frame->sregs, &frame->sc.sregs))
270 goto give_sigsegv;
271
272 /* Set up to return from userspace. If provided, use a stub
273 already in userspace. */
274 if (ka->sa.sa_flags & SA_RESTORER) {
275 regs->gprs[14] = (unsigned long)
276 ka->sa.sa_restorer | PSW_ADDR_AMODE;
277 } else {
278 regs->gprs[14] = (unsigned long)
279 frame->retcode | PSW_ADDR_AMODE;
280 if (__put_user(S390_SYSCALL_OPCODE | __NR_sigreturn,
281 (u16 __user *)(frame->retcode)))
282 goto give_sigsegv;
283 }
284
285 /* Set up backchain. */
286 if (__put_user(regs->gprs[15], (addr_t __user *) frame))
287 goto give_sigsegv;
288
289 /* Set up registers for signal handler */
290 regs->gprs[15] = (unsigned long) frame;
291 regs->psw.addr = (unsigned long) ka->sa.sa_handler | PSW_ADDR_AMODE;
292
293 regs->gprs[2] = map_signal(sig);
294 regs->gprs[3] = (unsigned long) &frame->sc;
295
296 /* We forgot to include these in the sigcontext.
297 To avoid breaking binary compatibility, they are passed as args. */
298 regs->gprs[4] = current->thread.trap_no;
299 regs->gprs[5] = current->thread.prot_addr;
300 regs->gprs[6] = task_thread_info(current)->last_break;
301
302 /* Place signal number on stack to allow backtrace from handler. */
303 if (__put_user(regs->gprs[2], (int __user *) &frame->signo))
304 goto give_sigsegv;
305 return 0;
306
307give_sigsegv:
308 force_sigsegv(sig, current);
309 return -EFAULT;
310}
311
312static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
313 sigset_t *set, struct pt_regs * regs)
314{
315 int err = 0;
316 rt_sigframe __user *frame;
317
318 frame = get_sigframe(ka, regs, sizeof(rt_sigframe));
319 if (!access_ok(VERIFY_WRITE, frame, sizeof(rt_sigframe)))
320 goto give_sigsegv;
321
322 if (frame == (void __user *) -1UL)
323 goto give_sigsegv;
324
325 if (copy_siginfo_to_user(&frame->info, info))
326 goto give_sigsegv;
327
328 /* Create the ucontext. */
329 err |= __put_user(0, &frame->uc.uc_flags);
330 err |= __put_user(NULL, &frame->uc.uc_link);
331 err |= __put_user((void __user *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
332 err |= __put_user(sas_ss_flags(regs->gprs[15]),
333 &frame->uc.uc_stack.ss_flags);
334 err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
335 err |= save_sigregs(regs, &frame->uc.uc_mcontext);
336 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
337 if (err)
338 goto give_sigsegv;
339
340 /* Set up to return from userspace. If provided, use a stub
341 already in userspace. */
342 if (ka->sa.sa_flags & SA_RESTORER) {
343 regs->gprs[14] = (unsigned long)
344 ka->sa.sa_restorer | PSW_ADDR_AMODE;
345 } else {
346 regs->gprs[14] = (unsigned long)
347 frame->retcode | PSW_ADDR_AMODE;
348 if (__put_user(S390_SYSCALL_OPCODE | __NR_rt_sigreturn,
349 (u16 __user *)(frame->retcode)))
350 goto give_sigsegv;
351 }
352
353 /* Set up backchain. */
354 if (__put_user(regs->gprs[15], (addr_t __user *) frame))
355 goto give_sigsegv;
356
357 /* Set up registers for signal handler */
358 regs->gprs[15] = (unsigned long) frame;
359 regs->psw.addr = (unsigned long) ka->sa.sa_handler | PSW_ADDR_AMODE;
360
361 regs->gprs[2] = map_signal(sig);
362 regs->gprs[3] = (unsigned long) &frame->info;
363 regs->gprs[4] = (unsigned long) &frame->uc;
364 regs->gprs[5] = task_thread_info(current)->last_break;
365 return 0;
366
367give_sigsegv:
368 force_sigsegv(sig, current);
369 return -EFAULT;
370}
371
372static int handle_signal(unsigned long sig, struct k_sigaction *ka,
373 siginfo_t *info, sigset_t *oldset,
374 struct pt_regs *regs)
375{
376 sigset_t blocked;
377 int ret;
378
379 /* Set up the stack frame */
380 if (ka->sa.sa_flags & SA_SIGINFO)
381 ret = setup_rt_frame(sig, ka, info, oldset, regs);
382 else
383 ret = setup_frame(sig, ka, oldset, regs);
384 if (ret)
385 return ret;
386 sigorsets(&blocked, ¤t->blocked, &ka->sa.sa_mask);
387 if (!(ka->sa.sa_flags & SA_NODEFER))
388 sigaddset(&blocked, sig);
389 set_current_blocked(&blocked);
390 return 0;
391}
392
393/*
394 * Note that 'init' is a special process: it doesn't get signals it doesn't
395 * want to handle. Thus you cannot kill init even with a SIGKILL even by
396 * mistake.
397 *
398 * Note that we go through the signals twice: once to check the signals that
399 * the kernel can handle, and then we build all the user-level signal handling
400 * stack-frames in one go after that.
401 */
402void do_signal(struct pt_regs *regs)
403{
404 unsigned long retval = 0, continue_addr = 0, restart_addr = 0;
405 siginfo_t info;
406 int signr;
407 struct k_sigaction ka;
408 sigset_t *oldset;
409
410 /*
411 * We want the common case to go fast, which
412 * is why we may in certain cases get here from
413 * kernel mode. Just return without doing anything
414 * if so.
415 */
416 if (!user_mode(regs))
417 return;
418
419 if (test_thread_flag(TIF_RESTORE_SIGMASK))
420 oldset = ¤t->saved_sigmask;
421 else
422 oldset = ¤t->blocked;
423
424 /* Are we from a system call? */
425 if (regs->svcnr) {
426 continue_addr = regs->psw.addr;
427 restart_addr = continue_addr - regs->ilc;
428 retval = regs->gprs[2];
429
430 /* Prepare for system call restart. We do this here so that a
431 debugger will see the already changed PSW. */
432 switch (retval) {
433 case -ERESTARTNOHAND:
434 case -ERESTARTSYS:
435 case -ERESTARTNOINTR:
436 regs->gprs[2] = regs->orig_gpr2;
437 regs->psw.addr = restart_addr;
438 break;
439 case -ERESTART_RESTARTBLOCK:
440 regs->gprs[2] = -EINTR;
441 }
442 regs->svcnr = 0; /* Don't deal with this again. */
443 }
444
445 /* Get signal to deliver. When running under ptrace, at this point
446 the debugger may change all our registers ... */
447 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
448
449 /* Depending on the signal settings we may need to revert the
450 decision to restart the system call. */
451 if (signr > 0 && regs->psw.addr == restart_addr) {
452 if (retval == -ERESTARTNOHAND
453 || (retval == -ERESTARTSYS
454 && !(current->sighand->action[signr-1].sa.sa_flags
455 & SA_RESTART))) {
456 regs->gprs[2] = -EINTR;
457 regs->psw.addr = continue_addr;
458 }
459 }
460
461 if (signr > 0) {
462 /* Whee! Actually deliver the signal. */
463 int ret;
464#ifdef CONFIG_COMPAT
465 if (is_compat_task()) {
466 ret = handle_signal32(signr, &ka, &info, oldset, regs);
467 }
468 else
469#endif
470 ret = handle_signal(signr, &ka, &info, oldset, regs);
471 if (!ret) {
472 /*
473 * A signal was successfully delivered; the saved
474 * sigmask will have been stored in the signal frame,
475 * and will be restored by sigreturn, so we can simply
476 * clear the TIF_RESTORE_SIGMASK flag.
477 */
478 if (test_thread_flag(TIF_RESTORE_SIGMASK))
479 clear_thread_flag(TIF_RESTORE_SIGMASK);
480
481 /*
482 * Let tracing know that we've done the handler setup.
483 */
484 tracehook_signal_handler(signr, &info, &ka, regs,
485 test_thread_flag(TIF_SINGLE_STEP));
486 }
487 return;
488 }
489
490 /*
491 * If there's no signal to deliver, we just put the saved sigmask back.
492 */
493 if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
494 clear_thread_flag(TIF_RESTORE_SIGMASK);
495 sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL);
496 }
497
498 /* Restart a different system call. */
499 if (retval == -ERESTART_RESTARTBLOCK
500 && regs->psw.addr == continue_addr) {
501 regs->gprs[2] = __NR_restart_syscall;
502 set_thread_flag(TIF_RESTART_SVC);
503 }
504}
505
506void do_notify_resume(struct pt_regs *regs)
507{
508 clear_thread_flag(TIF_NOTIFY_RESUME);
509 tracehook_notify_resume(regs);
510 if (current->replacement_session_keyring)
511 key_replace_session_keyring();
512}