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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 * Copyright IBM Corp. 1999, 2006
3 * Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
4 *
5 * Based on Intel version
6 *
7 * Copyright (C) 1991, 1992 Linus Torvalds
8 *
9 * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
10 */
11
12#include <linux/sched.h>
13#include <linux/mm.h>
14#include <linux/smp.h>
15#include <linux/kernel.h>
16#include <linux/signal.h>
17#include <linux/errno.h>
18#include <linux/wait.h>
19#include <linux/ptrace.h>
20#include <linux/unistd.h>
21#include <linux/stddef.h>
22#include <linux/tty.h>
23#include <linux/personality.h>
24#include <linux/binfmts.h>
25#include <linux/tracehook.h>
26#include <linux/syscalls.h>
27#include <linux/compat.h>
28#include <asm/ucontext.h>
29#include <asm/uaccess.h>
30#include <asm/lowcore.h>
31#include <asm/switch_to.h>
32#include "entry.h"
33
34/*
35 * Layout of an old-style signal-frame:
36 * -----------------------------------------
37 * | save area (_SIGNAL_FRAMESIZE) |
38 * -----------------------------------------
39 * | struct sigcontext |
40 * | oldmask |
41 * | _sigregs * |
42 * -----------------------------------------
43 * | _sigregs with |
44 * | _s390_regs_common |
45 * | _s390_fp_regs |
46 * -----------------------------------------
47 * | int signo |
48 * -----------------------------------------
49 * | _sigregs_ext with |
50 * | gprs_high 64 byte (opt) |
51 * | vxrs_low 128 byte (opt) |
52 * | vxrs_high 256 byte (opt) |
53 * | reserved 128 byte (opt) |
54 * -----------------------------------------
55 * | __u16 svc_insn |
56 * -----------------------------------------
57 * The svc_insn entry with the sigreturn system call opcode does not
58 * have a fixed position and moves if gprs_high or vxrs exist.
59 * Future extensions will be added to _sigregs_ext.
60 */
61struct sigframe
62{
63 __u8 callee_used_stack[__SIGNAL_FRAMESIZE];
64 struct sigcontext sc;
65 _sigregs sregs;
66 int signo;
67 _sigregs_ext sregs_ext;
68 __u16 svc_insn; /* Offset of svc_insn is NOT fixed! */
69};
70
71/*
72 * Layout of an rt signal-frame:
73 * -----------------------------------------
74 * | save area (_SIGNAL_FRAMESIZE) |
75 * -----------------------------------------
76 * | svc __NR_rt_sigreturn 2 byte |
77 * -----------------------------------------
78 * | struct siginfo |
79 * -----------------------------------------
80 * | struct ucontext_extended with |
81 * | unsigned long uc_flags |
82 * | struct ucontext *uc_link |
83 * | stack_t uc_stack |
84 * | _sigregs uc_mcontext with |
85 * | _s390_regs_common |
86 * | _s390_fp_regs |
87 * | sigset_t uc_sigmask |
88 * | _sigregs_ext uc_mcontext_ext |
89 * | gprs_high 64 byte (opt) |
90 * | vxrs_low 128 byte (opt) |
91 * | vxrs_high 256 byte (opt)|
92 * | reserved 128 byte (opt) |
93 * -----------------------------------------
94 * Future extensions will be added to _sigregs_ext.
95 */
96struct rt_sigframe
97{
98 __u8 callee_used_stack[__SIGNAL_FRAMESIZE];
99 __u16 svc_insn;
100 struct siginfo info;
101 struct ucontext_extended uc;
102};
103
104/* Store registers needed to create the signal frame */
105static void store_sigregs(void)
106{
107 save_access_regs(current->thread.acrs);
108 save_fpu_regs();
109}
110
111/* Load registers after signal return */
112static void load_sigregs(void)
113{
114 restore_access_regs(current->thread.acrs);
115}
116
117/* Returns non-zero on fault. */
118static int save_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
119{
120 _sigregs user_sregs;
121
122 /* Copy a 'clean' PSW mask to the user to avoid leaking
123 information about whether PER is currently on. */
124 user_sregs.regs.psw.mask = PSW_USER_BITS |
125 (regs->psw.mask & (PSW_MASK_USER | PSW_MASK_RI));
126 user_sregs.regs.psw.addr = regs->psw.addr;
127 memcpy(&user_sregs.regs.gprs, ®s->gprs, sizeof(sregs->regs.gprs));
128 memcpy(&user_sregs.regs.acrs, current->thread.acrs,
129 sizeof(user_sregs.regs.acrs));
130 fpregs_store(&user_sregs.fpregs, ¤t->thread.fpu);
131 if (__copy_to_user(sregs, &user_sregs, sizeof(_sigregs)))
132 return -EFAULT;
133 return 0;
134}
135
136static int restore_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
137{
138 _sigregs user_sregs;
139
140 /* Alwys make any pending restarted system call return -EINTR */
141 current->restart_block.fn = do_no_restart_syscall;
142
143 if (__copy_from_user(&user_sregs, sregs, sizeof(user_sregs)))
144 return -EFAULT;
145
146 if (!is_ri_task(current) && (user_sregs.regs.psw.mask & PSW_MASK_RI))
147 return -EINVAL;
148
149 /* Test the floating-point-control word. */
150 if (test_fp_ctl(user_sregs.fpregs.fpc))
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.fpu);
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 (MACHINE_HAS_VX) {
183 for (i = 0; i < __NUM_VXRS_LOW; i++)
184 vxrs[i] = *((__u64 *)(current->thread.fpu.vxrs + i) + 1);
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.fpu.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 (MACHINE_HAS_VX) {
203 if (__copy_from_user(vxrs, &sregs_ext->vxrs_low,
204 sizeof(sregs_ext->vxrs_low)) ||
205 __copy_from_user(current->thread.fpu.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 *((__u64 *)(current->thread.fpu.vxrs + i) + 1) = 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_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, current);
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_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, current);
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 (MACHINE_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 /* Signal frame without vector registers are short ! */
337 __u16 __user *svc = (void __user *) frame + frame_size - 2;
338 if (__put_user(S390_SYSCALL_OPCODE | __NR_sigreturn, svc))
339 return -EFAULT;
340 restorer = (unsigned long) svc;
341 }
342
343 /* Set up registers for signal handler */
344 regs->gprs[14] = restorer;
345 regs->gprs[15] = (unsigned long) frame;
346 /* Force default amode and default user address space control. */
347 regs->psw.mask = PSW_MASK_EA | PSW_MASK_BA |
348 (PSW_USER_BITS & PSW_MASK_ASC) |
349 (regs->psw.mask & ~PSW_MASK_ASC);
350 regs->psw.addr = (unsigned long) ka->sa.sa_handler;
351
352 regs->gprs[2] = sig;
353 regs->gprs[3] = (unsigned long) &frame->sc;
354
355 /* We forgot to include these in the sigcontext.
356 To avoid breaking binary compatibility, they are passed as args. */
357 if (sig == SIGSEGV || sig == SIGBUS || sig == SIGILL ||
358 sig == SIGTRAP || sig == SIGFPE) {
359 /* set extra registers only for synchronous signals */
360 regs->gprs[4] = regs->int_code & 127;
361 regs->gprs[5] = regs->int_parm_long;
362 regs->gprs[6] = task_thread_info(current)->last_break;
363 }
364 return 0;
365}
366
367static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
368 struct pt_regs *regs)
369{
370 struct rt_sigframe __user *frame;
371 unsigned long uc_flags, restorer;
372 size_t frame_size;
373
374 frame_size = sizeof(struct rt_sigframe) - sizeof(_sigregs_ext);
375 /*
376 * gprs_high are only present for a 31-bit task running on
377 * a 64-bit kernel (see compat_signal.c) but the space for
378 * gprs_high need to be allocated if vector registers are
379 * included in the signal frame on a 31-bit system.
380 */
381 uc_flags = 0;
382 if (MACHINE_HAS_VX) {
383 frame_size += sizeof(_sigregs_ext);
384 uc_flags |= UC_VXRS;
385 }
386 frame = get_sigframe(&ksig->ka, regs, frame_size);
387 if (frame == (void __user *) -1UL)
388 return -EFAULT;
389
390 /* Set up backchain. */
391 if (__put_user(regs->gprs[15], (addr_t __user *) frame))
392 return -EFAULT;
393
394 /* Set up to return from userspace. If provided, use a stub
395 already in userspace. */
396 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
397 restorer = (unsigned long) ksig->ka.sa.sa_restorer;
398 } else {
399 __u16 __user *svc = &frame->svc_insn;
400 if (__put_user(S390_SYSCALL_OPCODE | __NR_rt_sigreturn, svc))
401 return -EFAULT;
402 restorer = (unsigned long) svc;
403 }
404
405 /* Create siginfo on the signal stack */
406 if (copy_siginfo_to_user(&frame->info, &ksig->info))
407 return -EFAULT;
408
409 /* Store registers needed to create the signal frame */
410 store_sigregs();
411
412 /* Create ucontext on the signal stack. */
413 if (__put_user(uc_flags, &frame->uc.uc_flags) ||
414 __put_user(NULL, &frame->uc.uc_link) ||
415 __save_altstack(&frame->uc.uc_stack, regs->gprs[15]) ||
416 save_sigregs(regs, &frame->uc.uc_mcontext) ||
417 __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)) ||
418 save_sigregs_ext(regs, &frame->uc.uc_mcontext_ext))
419 return -EFAULT;
420
421 /* Set up registers for signal handler */
422 regs->gprs[14] = restorer;
423 regs->gprs[15] = (unsigned long) frame;
424 /* Force default amode and default user address space control. */
425 regs->psw.mask = PSW_MASK_EA | PSW_MASK_BA |
426 (PSW_USER_BITS & PSW_MASK_ASC) |
427 (regs->psw.mask & ~PSW_MASK_ASC);
428 regs->psw.addr = (unsigned long) ksig->ka.sa.sa_handler;
429
430 regs->gprs[2] = ksig->sig;
431 regs->gprs[3] = (unsigned long) &frame->info;
432 regs->gprs[4] = (unsigned long) &frame->uc;
433 regs->gprs[5] = task_thread_info(current)->last_break;
434 return 0;
435}
436
437static void handle_signal(struct ksignal *ksig, sigset_t *oldset,
438 struct pt_regs *regs)
439{
440 int ret;
441
442 /* Set up the stack frame */
443 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
444 ret = setup_rt_frame(ksig, oldset, regs);
445 else
446 ret = setup_frame(ksig->sig, &ksig->ka, oldset, regs);
447
448 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLE_STEP));
449}
450
451/*
452 * Note that 'init' is a special process: it doesn't get signals it doesn't
453 * want to handle. Thus you cannot kill init even with a SIGKILL even by
454 * mistake.
455 *
456 * Note that we go through the signals twice: once to check the signals that
457 * the kernel can handle, and then we build all the user-level signal handling
458 * stack-frames in one go after that.
459 */
460void do_signal(struct pt_regs *regs)
461{
462 struct ksignal ksig;
463 sigset_t *oldset = sigmask_to_save();
464
465 /*
466 * Get signal to deliver. When running under ptrace, at this point
467 * the debugger may change all our registers, including the system
468 * call information.
469 */
470 current_thread_info()->system_call =
471 test_pt_regs_flag(regs, PIF_SYSCALL) ? regs->int_code : 0;
472
473 if (get_signal(&ksig)) {
474 /* Whee! Actually deliver the signal. */
475 if (current_thread_info()->system_call) {
476 regs->int_code = current_thread_info()->system_call;
477 /* Check for system call restarting. */
478 switch (regs->gprs[2]) {
479 case -ERESTART_RESTARTBLOCK:
480 case -ERESTARTNOHAND:
481 regs->gprs[2] = -EINTR;
482 break;
483 case -ERESTARTSYS:
484 if (!(ksig.ka.sa.sa_flags & SA_RESTART)) {
485 regs->gprs[2] = -EINTR;
486 break;
487 }
488 /* fallthrough */
489 case -ERESTARTNOINTR:
490 regs->gprs[2] = regs->orig_gpr2;
491 regs->psw.addr =
492 __rewind_psw(regs->psw,
493 regs->int_code >> 16);
494 break;
495 }
496 }
497 /* No longer in a system call */
498 clear_pt_regs_flag(regs, PIF_SYSCALL);
499
500 if (is_compat_task())
501 handle_signal32(&ksig, oldset, regs);
502 else
503 handle_signal(&ksig, oldset, regs);
504 return;
505 }
506
507 /* No handlers present - check for system call restart */
508 clear_pt_regs_flag(regs, PIF_SYSCALL);
509 if (current_thread_info()->system_call) {
510 regs->int_code = current_thread_info()->system_call;
511 switch (regs->gprs[2]) {
512 case -ERESTART_RESTARTBLOCK:
513 /* Restart with sys_restart_syscall */
514 regs->int_code = __NR_restart_syscall;
515 /* fallthrough */
516 case -ERESTARTNOHAND:
517 case -ERESTARTSYS:
518 case -ERESTARTNOINTR:
519 /* Restart system call with magic TIF bit. */
520 regs->gprs[2] = regs->orig_gpr2;
521 set_pt_regs_flag(regs, PIF_SYSCALL);
522 if (test_thread_flag(TIF_SINGLE_STEP))
523 clear_pt_regs_flag(regs, PIF_PER_TRAP);
524 break;
525 }
526 }
527
528 /*
529 * If there's no signal to deliver, we just put the saved sigmask back.
530 */
531 restore_saved_sigmask();
532}
533
534void do_notify_resume(struct pt_regs *regs)
535{
536 clear_thread_flag(TIF_NOTIFY_RESUME);
537 tracehook_notify_resume(regs);
538}