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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright IBM Corp. 1999, 2006
4 * Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
5 *
6 * Based on Intel version
7 *
8 * Copyright (C) 1991, 1992 Linus Torvalds
9 *
10 * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
11 */
12
13#include <linux/sched.h>
14#include <linux/sched/task_stack.h>
15#include <linux/mm.h>
16#include <linux/smp.h>
17#include <linux/kernel.h>
18#include <linux/signal.h>
19#include <linux/errno.h>
20#include <linux/wait.h>
21#include <linux/ptrace.h>
22#include <linux/unistd.h>
23#include <linux/stddef.h>
24#include <linux/tty.h>
25#include <linux/personality.h>
26#include <linux/binfmts.h>
27#include <linux/tracehook.h>
28#include <linux/syscalls.h>
29#include <linux/compat.h>
30#include <asm/ucontext.h>
31#include <linux/uaccess.h>
32#include <asm/lowcore.h>
33#include <asm/switch_to.h>
34#include "entry.h"
35
36/*
37 * Layout of an old-style signal-frame:
38 * -----------------------------------------
39 * | save area (_SIGNAL_FRAMESIZE) |
40 * -----------------------------------------
41 * | struct sigcontext |
42 * | oldmask |
43 * | _sigregs * |
44 * -----------------------------------------
45 * | _sigregs with |
46 * | _s390_regs_common |
47 * | _s390_fp_regs |
48 * -----------------------------------------
49 * | int signo |
50 * -----------------------------------------
51 * | _sigregs_ext with |
52 * | gprs_high 64 byte (opt) |
53 * | vxrs_low 128 byte (opt) |
54 * | vxrs_high 256 byte (opt) |
55 * | reserved 128 byte (opt) |
56 * -----------------------------------------
57 * | __u16 svc_insn |
58 * -----------------------------------------
59 * The svc_insn entry with the sigreturn system call opcode does not
60 * have a fixed position and moves if gprs_high or vxrs exist.
61 * Future extensions will be added to _sigregs_ext.
62 */
63struct sigframe
64{
65 __u8 callee_used_stack[__SIGNAL_FRAMESIZE];
66 struct sigcontext sc;
67 _sigregs sregs;
68 int signo;
69 _sigregs_ext sregs_ext;
70 __u16 svc_insn; /* Offset of svc_insn is NOT fixed! */
71};
72
73/*
74 * Layout of an rt signal-frame:
75 * -----------------------------------------
76 * | save area (_SIGNAL_FRAMESIZE) |
77 * -----------------------------------------
78 * | svc __NR_rt_sigreturn 2 byte |
79 * -----------------------------------------
80 * | struct siginfo |
81 * -----------------------------------------
82 * | struct ucontext_extended with |
83 * | unsigned long uc_flags |
84 * | struct ucontext *uc_link |
85 * | stack_t uc_stack |
86 * | _sigregs uc_mcontext with |
87 * | _s390_regs_common |
88 * | _s390_fp_regs |
89 * | sigset_t uc_sigmask |
90 * | _sigregs_ext uc_mcontext_ext |
91 * | gprs_high 64 byte (opt) |
92 * | vxrs_low 128 byte (opt) |
93 * | vxrs_high 256 byte (opt)|
94 * | reserved 128 byte (opt) |
95 * -----------------------------------------
96 * Future extensions will be added to _sigregs_ext.
97 */
98struct rt_sigframe
99{
100 __u8 callee_used_stack[__SIGNAL_FRAMESIZE];
101 __u16 svc_insn;
102 struct siginfo info;
103 struct ucontext_extended uc;
104};
105
106/* Store registers needed to create the signal frame */
107static void store_sigregs(void)
108{
109 save_access_regs(current->thread.acrs);
110 save_fpu_regs();
111}
112
113/* Load registers after signal return */
114static void load_sigregs(void)
115{
116 restore_access_regs(current->thread.acrs);
117}
118
119/* Returns non-zero on fault. */
120static int save_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
121{
122 _sigregs user_sregs;
123
124 /* Copy a 'clean' PSW mask to the user to avoid leaking
125 information about whether PER is currently on. */
126 user_sregs.regs.psw.mask = PSW_USER_BITS |
127 (regs->psw.mask & (PSW_MASK_USER | PSW_MASK_RI));
128 user_sregs.regs.psw.addr = regs->psw.addr;
129 memcpy(&user_sregs.regs.gprs, ®s->gprs, sizeof(sregs->regs.gprs));
130 memcpy(&user_sregs.regs.acrs, current->thread.acrs,
131 sizeof(user_sregs.regs.acrs));
132 fpregs_store(&user_sregs.fpregs, ¤t->thread.fpu);
133 if (__copy_to_user(sregs, &user_sregs, sizeof(_sigregs)))
134 return -EFAULT;
135 return 0;
136}
137
138static int restore_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
139{
140 _sigregs user_sregs;
141
142 /* Alwys make any pending restarted system call return -EINTR */
143 current->restart_block.fn = do_no_restart_syscall;
144
145 if (__copy_from_user(&user_sregs, sregs, sizeof(user_sregs)))
146 return -EFAULT;
147
148 if (!is_ri_task(current) && (user_sregs.regs.psw.mask & PSW_MASK_RI))
149 return -EINVAL;
150
151 /* Test the floating-point-control word. */
152 if (test_fp_ctl(user_sregs.fpregs.fpc))
153 return -EINVAL;
154
155 /* Use regs->psw.mask instead of PSW_USER_BITS to preserve PER bit. */
156 regs->psw.mask = (regs->psw.mask & ~(PSW_MASK_USER | PSW_MASK_RI)) |
157 (user_sregs.regs.psw.mask & (PSW_MASK_USER | PSW_MASK_RI));
158 /* Check for invalid user address space control. */
159 if ((regs->psw.mask & PSW_MASK_ASC) == PSW_ASC_HOME)
160 regs->psw.mask = PSW_ASC_PRIMARY |
161 (regs->psw.mask & ~PSW_MASK_ASC);
162 /* Check for invalid amode */
163 if (regs->psw.mask & PSW_MASK_EA)
164 regs->psw.mask |= PSW_MASK_BA;
165 regs->psw.addr = user_sregs.regs.psw.addr;
166 memcpy(®s->gprs, &user_sregs.regs.gprs, sizeof(sregs->regs.gprs));
167 memcpy(¤t->thread.acrs, &user_sregs.regs.acrs,
168 sizeof(current->thread.acrs));
169
170 fpregs_load(&user_sregs.fpregs, ¤t->thread.fpu);
171
172 clear_pt_regs_flag(regs, PIF_SYSCALL); /* No longer in a system call */
173 return 0;
174}
175
176/* Returns non-zero on fault. */
177static int save_sigregs_ext(struct pt_regs *regs,
178 _sigregs_ext __user *sregs_ext)
179{
180 __u64 vxrs[__NUM_VXRS_LOW];
181 int i;
182
183 /* Save vector registers to signal stack */
184 if (MACHINE_HAS_VX) {
185 for (i = 0; i < __NUM_VXRS_LOW; i++)
186 vxrs[i] = *((__u64 *)(current->thread.fpu.vxrs + i) + 1);
187 if (__copy_to_user(&sregs_ext->vxrs_low, vxrs,
188 sizeof(sregs_ext->vxrs_low)) ||
189 __copy_to_user(&sregs_ext->vxrs_high,
190 current->thread.fpu.vxrs + __NUM_VXRS_LOW,
191 sizeof(sregs_ext->vxrs_high)))
192 return -EFAULT;
193 }
194 return 0;
195}
196
197static int restore_sigregs_ext(struct pt_regs *regs,
198 _sigregs_ext __user *sregs_ext)
199{
200 __u64 vxrs[__NUM_VXRS_LOW];
201 int i;
202
203 /* Restore vector registers from signal stack */
204 if (MACHINE_HAS_VX) {
205 if (__copy_from_user(vxrs, &sregs_ext->vxrs_low,
206 sizeof(sregs_ext->vxrs_low)) ||
207 __copy_from_user(current->thread.fpu.vxrs + __NUM_VXRS_LOW,
208 &sregs_ext->vxrs_high,
209 sizeof(sregs_ext->vxrs_high)))
210 return -EFAULT;
211 for (i = 0; i < __NUM_VXRS_LOW; i++)
212 *((__u64 *)(current->thread.fpu.vxrs + i) + 1) = vxrs[i];
213 }
214 return 0;
215}
216
217SYSCALL_DEFINE0(sigreturn)
218{
219 struct pt_regs *regs = task_pt_regs(current);
220 struct sigframe __user *frame =
221 (struct sigframe __user *) regs->gprs[15];
222 sigset_t set;
223
224 if (__copy_from_user(&set.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE))
225 goto badframe;
226 set_current_blocked(&set);
227 save_fpu_regs();
228 if (restore_sigregs(regs, &frame->sregs))
229 goto badframe;
230 if (restore_sigregs_ext(regs, &frame->sregs_ext))
231 goto badframe;
232 load_sigregs();
233 return regs->gprs[2];
234badframe:
235 force_sig(SIGSEGV);
236 return 0;
237}
238
239SYSCALL_DEFINE0(rt_sigreturn)
240{
241 struct pt_regs *regs = task_pt_regs(current);
242 struct rt_sigframe __user *frame =
243 (struct rt_sigframe __user *)regs->gprs[15];
244 sigset_t set;
245
246 if (__copy_from_user(&set.sig, &frame->uc.uc_sigmask, sizeof(set)))
247 goto badframe;
248 set_current_blocked(&set);
249 if (restore_altstack(&frame->uc.uc_stack))
250 goto badframe;
251 save_fpu_regs();
252 if (restore_sigregs(regs, &frame->uc.uc_mcontext))
253 goto badframe;
254 if (restore_sigregs_ext(regs, &frame->uc.uc_mcontext_ext))
255 goto badframe;
256 load_sigregs();
257 return regs->gprs[2];
258badframe:
259 force_sig(SIGSEGV);
260 return 0;
261}
262
263/*
264 * Determine which stack to use..
265 */
266static inline void __user *
267get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
268{
269 unsigned long sp;
270
271 /* Default to using normal stack */
272 sp = regs->gprs[15];
273
274 /* Overflow on alternate signal stack gives SIGSEGV. */
275 if (on_sig_stack(sp) && !on_sig_stack((sp - frame_size) & -8UL))
276 return (void __user *) -1UL;
277
278 /* This is the X/Open sanctioned signal stack switching. */
279 if (ka->sa.sa_flags & SA_ONSTACK) {
280 if (! sas_ss_flags(sp))
281 sp = current->sas_ss_sp + current->sas_ss_size;
282 }
283
284 return (void __user *)((sp - frame_size) & -8ul);
285}
286
287static int setup_frame(int sig, struct k_sigaction *ka,
288 sigset_t *set, struct pt_regs * regs)
289{
290 struct sigframe __user *frame;
291 struct sigcontext sc;
292 unsigned long restorer;
293 size_t frame_size;
294
295 /*
296 * gprs_high are only present for a 31-bit task running on
297 * a 64-bit kernel (see compat_signal.c) but the space for
298 * gprs_high need to be allocated if vector registers are
299 * included in the signal frame on a 31-bit system.
300 */
301 frame_size = sizeof(*frame) - sizeof(frame->sregs_ext);
302 if (MACHINE_HAS_VX)
303 frame_size += sizeof(frame->sregs_ext);
304 frame = get_sigframe(ka, regs, frame_size);
305 if (frame == (void __user *) -1UL)
306 return -EFAULT;
307
308 /* Set up backchain. */
309 if (__put_user(regs->gprs[15], (addr_t __user *) frame))
310 return -EFAULT;
311
312 /* Create struct sigcontext on the signal stack */
313 memcpy(&sc.oldmask, &set->sig, _SIGMASK_COPY_SIZE);
314 sc.sregs = (_sigregs __user __force *) &frame->sregs;
315 if (__copy_to_user(&frame->sc, &sc, sizeof(frame->sc)))
316 return -EFAULT;
317
318 /* Store registers needed to create the signal frame */
319 store_sigregs();
320
321 /* Create _sigregs on the signal stack */
322 if (save_sigregs(regs, &frame->sregs))
323 return -EFAULT;
324
325 /* Place signal number on stack to allow backtrace from handler. */
326 if (__put_user(regs->gprs[2], (int __user *) &frame->signo))
327 return -EFAULT;
328
329 /* Create _sigregs_ext on the signal stack */
330 if (save_sigregs_ext(regs, &frame->sregs_ext))
331 return -EFAULT;
332
333 /* Set up to return from userspace. If provided, use a stub
334 already in userspace. */
335 if (ka->sa.sa_flags & SA_RESTORER) {
336 restorer = (unsigned long) ka->sa.sa_restorer;
337 } else {
338 /* Signal frame without vector registers are short ! */
339 __u16 __user *svc = (void __user *) frame + frame_size - 2;
340 if (__put_user(S390_SYSCALL_OPCODE | __NR_sigreturn, svc))
341 return -EFAULT;
342 restorer = (unsigned long) svc;
343 }
344
345 /* Set up registers for signal handler */
346 regs->gprs[14] = restorer;
347 regs->gprs[15] = (unsigned long) frame;
348 /* Force default amode and default user address space control. */
349 regs->psw.mask = PSW_MASK_EA | PSW_MASK_BA |
350 (PSW_USER_BITS & PSW_MASK_ASC) |
351 (regs->psw.mask & ~PSW_MASK_ASC);
352 regs->psw.addr = (unsigned long) ka->sa.sa_handler;
353
354 regs->gprs[2] = sig;
355 regs->gprs[3] = (unsigned long) &frame->sc;
356
357 /* We forgot to include these in the sigcontext.
358 To avoid breaking binary compatibility, they are passed as args. */
359 if (sig == SIGSEGV || sig == SIGBUS || sig == SIGILL ||
360 sig == SIGTRAP || sig == SIGFPE) {
361 /* set extra registers only for synchronous signals */
362 regs->gprs[4] = regs->int_code & 127;
363 regs->gprs[5] = regs->int_parm_long;
364 regs->gprs[6] = current->thread.last_break;
365 }
366 return 0;
367}
368
369static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
370 struct pt_regs *regs)
371{
372 struct rt_sigframe __user *frame;
373 unsigned long uc_flags, restorer;
374 size_t frame_size;
375
376 frame_size = sizeof(struct rt_sigframe) - sizeof(_sigregs_ext);
377 /*
378 * gprs_high are only present for a 31-bit task running on
379 * a 64-bit kernel (see compat_signal.c) but the space for
380 * gprs_high need to be allocated if vector registers are
381 * included in the signal frame on a 31-bit system.
382 */
383 uc_flags = 0;
384 if (MACHINE_HAS_VX) {
385 frame_size += sizeof(_sigregs_ext);
386 uc_flags |= UC_VXRS;
387 }
388 frame = get_sigframe(&ksig->ka, regs, frame_size);
389 if (frame == (void __user *) -1UL)
390 return -EFAULT;
391
392 /* Set up backchain. */
393 if (__put_user(regs->gprs[15], (addr_t __user *) frame))
394 return -EFAULT;
395
396 /* Set up to return from userspace. If provided, use a stub
397 already in userspace. */
398 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
399 restorer = (unsigned long) ksig->ka.sa.sa_restorer;
400 } else {
401 __u16 __user *svc = &frame->svc_insn;
402 if (__put_user(S390_SYSCALL_OPCODE | __NR_rt_sigreturn, svc))
403 return -EFAULT;
404 restorer = (unsigned long) svc;
405 }
406
407 /* Create siginfo on the signal stack */
408 if (copy_siginfo_to_user(&frame->info, &ksig->info))
409 return -EFAULT;
410
411 /* Store registers needed to create the signal frame */
412 store_sigregs();
413
414 /* Create ucontext on the signal stack. */
415 if (__put_user(uc_flags, &frame->uc.uc_flags) ||
416 __put_user(NULL, &frame->uc.uc_link) ||
417 __save_altstack(&frame->uc.uc_stack, regs->gprs[15]) ||
418 save_sigregs(regs, &frame->uc.uc_mcontext) ||
419 __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)) ||
420 save_sigregs_ext(regs, &frame->uc.uc_mcontext_ext))
421 return -EFAULT;
422
423 /* Set up registers for signal handler */
424 regs->gprs[14] = restorer;
425 regs->gprs[15] = (unsigned long) frame;
426 /* Force default amode and default user address space control. */
427 regs->psw.mask = PSW_MASK_EA | PSW_MASK_BA |
428 (PSW_USER_BITS & PSW_MASK_ASC) |
429 (regs->psw.mask & ~PSW_MASK_ASC);
430 regs->psw.addr = (unsigned long) ksig->ka.sa.sa_handler;
431
432 regs->gprs[2] = ksig->sig;
433 regs->gprs[3] = (unsigned long) &frame->info;
434 regs->gprs[4] = (unsigned long) &frame->uc;
435 regs->gprs[5] = current->thread.last_break;
436 return 0;
437}
438
439static void handle_signal(struct ksignal *ksig, sigset_t *oldset,
440 struct pt_regs *regs)
441{
442 int ret;
443
444 /* Set up the stack frame */
445 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
446 ret = setup_rt_frame(ksig, oldset, regs);
447 else
448 ret = setup_frame(ksig->sig, &ksig->ka, oldset, regs);
449
450 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLE_STEP));
451}
452
453/*
454 * Note that 'init' is a special process: it doesn't get signals it doesn't
455 * want to handle. Thus you cannot kill init even with a SIGKILL even by
456 * mistake.
457 *
458 * Note that we go through the signals twice: once to check the signals that
459 * the kernel can handle, and then we build all the user-level signal handling
460 * stack-frames in one go after that.
461 */
462void do_signal(struct pt_regs *regs)
463{
464 struct ksignal ksig;
465 sigset_t *oldset = sigmask_to_save();
466
467 /*
468 * Get signal to deliver. When running under ptrace, at this point
469 * the debugger may change all our registers, including the system
470 * call information.
471 */
472 current->thread.system_call =
473 test_pt_regs_flag(regs, PIF_SYSCALL) ? regs->int_code : 0;
474
475 if (get_signal(&ksig)) {
476 /* Whee! Actually deliver the signal. */
477 if (current->thread.system_call) {
478 regs->int_code = current->thread.system_call;
479 /* Check for system call restarting. */
480 switch (regs->gprs[2]) {
481 case -ERESTART_RESTARTBLOCK:
482 case -ERESTARTNOHAND:
483 regs->gprs[2] = -EINTR;
484 break;
485 case -ERESTARTSYS:
486 if (!(ksig.ka.sa.sa_flags & SA_RESTART)) {
487 regs->gprs[2] = -EINTR;
488 break;
489 }
490 /* fallthrough */
491 case -ERESTARTNOINTR:
492 regs->gprs[2] = regs->orig_gpr2;
493 regs->psw.addr =
494 __rewind_psw(regs->psw,
495 regs->int_code >> 16);
496 break;
497 }
498 }
499 /* No longer in a system call */
500 clear_pt_regs_flag(regs, PIF_SYSCALL);
501 rseq_signal_deliver(&ksig, regs);
502 if (is_compat_task())
503 handle_signal32(&ksig, oldset, regs);
504 else
505 handle_signal(&ksig, oldset, regs);
506 return;
507 }
508
509 /* No handlers present - check for system call restart */
510 clear_pt_regs_flag(regs, PIF_SYSCALL);
511 if (current->thread.system_call) {
512 regs->int_code = current->thread.system_call;
513 switch (regs->gprs[2]) {
514 case -ERESTART_RESTARTBLOCK:
515 /* Restart with sys_restart_syscall */
516 regs->int_code = __NR_restart_syscall;
517 /* fallthrough */
518 case -ERESTARTNOHAND:
519 case -ERESTARTSYS:
520 case -ERESTARTNOINTR:
521 /* Restart system call with magic TIF bit. */
522 regs->gprs[2] = regs->orig_gpr2;
523 set_pt_regs_flag(regs, PIF_SYSCALL);
524 if (test_thread_flag(TIF_SINGLE_STEP))
525 clear_pt_regs_flag(regs, PIF_PER_TRAP);
526 break;
527 }
528 }
529
530 /*
531 * If there's no signal to deliver, we just put the saved sigmask back.
532 */
533 restore_saved_sigmask();
534}
535
536void do_notify_resume(struct pt_regs *regs)
537{
538 clear_thread_flag(TIF_NOTIFY_RESUME);
539 tracehook_notify_resume(regs);
540 rseq_handle_notify_resume(NULL, regs);
541}
1// 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}