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