1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright IBM Corp. 1999, 2006
4 * Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
6 * Based on Intel version
8 * Copyright (C) 1991, 1992 Linus Torvalds
10 * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
13 #include <linux/sched.h>
14 #include <linux/sched/task_stack.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>
37 * Layout of an old-style signal-frame:
38 * -----------------------------------------
39 * | save area (_SIGNAL_FRAMESIZE) |
40 * -----------------------------------------
41 * | struct sigcontext |
44 * -----------------------------------------
46 * | _s390_regs_common |
48 * -----------------------------------------
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 * -----------------------------------------
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.
65 __u8 callee_used_stack
[__SIGNAL_FRAMESIZE
];
69 _sigregs_ext sregs_ext
;
70 __u16 svc_insn
; /* Offset of svc_insn is NOT fixed! */
74 * Layout of an rt signal-frame:
75 * -----------------------------------------
76 * | save area (_SIGNAL_FRAMESIZE) |
77 * -----------------------------------------
78 * | svc __NR_rt_sigreturn 2 byte |
79 * -----------------------------------------
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 |
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.
100 __u8 callee_used_stack
[__SIGNAL_FRAMESIZE
];
103 struct ucontext_extended uc
;
106 /* Store registers needed to create the signal frame */
107 static void store_sigregs(void)
109 save_access_regs(current
->thread
.acrs
);
113 /* Load registers after signal return */
114 static void load_sigregs(void)
116 restore_access_regs(current
->thread
.acrs
);
119 /* Returns non-zero on fault. */
120 static int save_sigregs(struct pt_regs
*regs
, _sigregs __user
*sregs
)
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
)))
138 static int restore_sigregs(struct pt_regs
*regs
, _sigregs __user
*sregs
)
142 /* Alwys make any pending restarted system call return -EINTR */
143 current
->restart_block
.fn
= do_no_restart_syscall
;
145 if (__copy_from_user(&user_sregs
, sregs
, sizeof(user_sregs
)))
148 if (!is_ri_task(current
) && (user_sregs
.regs
.psw
.mask
& PSW_MASK_RI
))
151 /* Test the floating-point-control word. */
152 if (test_fp_ctl(user_sregs
.fpregs
.fpc
))
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
));
170 fpregs_load(&user_sregs
.fpregs
, ¤t
->thread
.fpu
);
172 clear_pt_regs_flag(regs
, PIF_SYSCALL
); /* No longer in a system call */
176 /* Returns non-zero on fault. */
177 static int save_sigregs_ext(struct pt_regs
*regs
,
178 _sigregs_ext __user
*sregs_ext
)
180 __u64 vxrs
[__NUM_VXRS_LOW
];
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
)))
197 static int restore_sigregs_ext(struct pt_regs
*regs
,
198 _sigregs_ext __user
*sregs_ext
)
200 __u64 vxrs
[__NUM_VXRS_LOW
];
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
)))
211 for (i
= 0; i
< __NUM_VXRS_LOW
; i
++)
212 *((__u64
*)(current
->thread
.fpu
.vxrs
+ i
) + 1) = vxrs
[i
];
217 SYSCALL_DEFINE0(sigreturn
)
219 struct pt_regs
*regs
= task_pt_regs(current
);
220 struct sigframe __user
*frame
=
221 (struct sigframe __user
*) regs
->gprs
[15];
224 if (__copy_from_user(&set
.sig
, &frame
->sc
.oldmask
, _SIGMASK_COPY_SIZE
))
226 set_current_blocked(&set
);
228 if (restore_sigregs(regs
, &frame
->sregs
))
230 if (restore_sigregs_ext(regs
, &frame
->sregs_ext
))
233 return regs
->gprs
[2];
235 force_sig(SIGSEGV
, current
);
239 SYSCALL_DEFINE0(rt_sigreturn
)
241 struct pt_regs
*regs
= task_pt_regs(current
);
242 struct rt_sigframe __user
*frame
=
243 (struct rt_sigframe __user
*)regs
->gprs
[15];
246 if (__copy_from_user(&set
.sig
, &frame
->uc
.uc_sigmask
, sizeof(set
)))
248 set_current_blocked(&set
);
249 if (restore_altstack(&frame
->uc
.uc_stack
))
252 if (restore_sigregs(regs
, &frame
->uc
.uc_mcontext
))
254 if (restore_sigregs_ext(regs
, &frame
->uc
.uc_mcontext_ext
))
257 return regs
->gprs
[2];
259 force_sig(SIGSEGV
, current
);
264 * Determine which stack to use..
266 static inline void __user
*
267 get_sigframe(struct k_sigaction
*ka
, struct pt_regs
* regs
, size_t frame_size
)
271 /* Default to using normal stack */
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;
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
;
284 return (void __user
*)((sp
- frame_size
) & -8ul);
287 static int setup_frame(int sig
, struct k_sigaction
*ka
,
288 sigset_t
*set
, struct pt_regs
* regs
)
290 struct sigframe __user
*frame
;
291 struct sigcontext sc
;
292 unsigned long restorer
;
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.
301 frame_size
= sizeof(*frame
) - sizeof(frame
->sregs_ext
);
303 frame_size
+= sizeof(frame
->sregs_ext
);
304 frame
= get_sigframe(ka
, regs
, frame_size
);
305 if (frame
== (void __user
*) -1UL)
308 /* Set up backchain. */
309 if (__put_user(regs
->gprs
[15], (addr_t __user
*) frame
))
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
)))
318 /* Store registers needed to create the signal frame */
321 /* Create _sigregs on the signal stack */
322 if (save_sigregs(regs
, &frame
->sregs
))
325 /* Place signal number on stack to allow backtrace from handler. */
326 if (__put_user(regs
->gprs
[2], (int __user
*) &frame
->signo
))
329 /* Create _sigregs_ext on the signal stack */
330 if (save_sigregs_ext(regs
, &frame
->sregs_ext
))
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
;
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
))
342 restorer
= (unsigned long) svc
;
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
;
355 regs
->gprs
[3] = (unsigned long) &frame
->sc
;
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
;
369 static int setup_rt_frame(struct ksignal
*ksig
, sigset_t
*set
,
370 struct pt_regs
*regs
)
372 struct rt_sigframe __user
*frame
;
373 unsigned long uc_flags
, restorer
;
376 frame_size
= sizeof(struct rt_sigframe
) - sizeof(_sigregs_ext
);
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.
384 if (MACHINE_HAS_VX
) {
385 frame_size
+= sizeof(_sigregs_ext
);
388 frame
= get_sigframe(&ksig
->ka
, regs
, frame_size
);
389 if (frame
== (void __user
*) -1UL)
392 /* Set up backchain. */
393 if (__put_user(regs
->gprs
[15], (addr_t __user
*) frame
))
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
;
401 __u16 __user
*svc
= &frame
->svc_insn
;
402 if (__put_user(S390_SYSCALL_OPCODE
| __NR_rt_sigreturn
, svc
))
404 restorer
= (unsigned long) svc
;
407 /* Create siginfo on the signal stack */
408 if (copy_siginfo_to_user(&frame
->info
, &ksig
->info
))
411 /* Store registers needed to create the signal frame */
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
))
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
;
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
;
439 static void handle_signal(struct ksignal
*ksig
, sigset_t
*oldset
,
440 struct pt_regs
*regs
)
444 /* Set up the stack frame */
445 if (ksig
->ka
.sa
.sa_flags
& SA_SIGINFO
)
446 ret
= setup_rt_frame(ksig
, oldset
, regs
);
448 ret
= setup_frame(ksig
->sig
, &ksig
->ka
, oldset
, regs
);
450 signal_setup_done(ret
, ksig
, test_thread_flag(TIF_SINGLE_STEP
));
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
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.
462 void do_signal(struct pt_regs
*regs
)
465 sigset_t
*oldset
= sigmask_to_save();
468 * Get signal to deliver. When running under ptrace, at this point
469 * the debugger may change all our registers, including the system
472 current
->thread
.system_call
=
473 test_pt_regs_flag(regs
, PIF_SYSCALL
) ? regs
->int_code
: 0;
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
;
486 if (!(ksig
.ka
.sa
.sa_flags
& SA_RESTART
)) {
487 regs
->gprs
[2] = -EINTR
;
491 case -ERESTARTNOINTR
:
492 regs
->gprs
[2] = regs
->orig_gpr2
;
494 __rewind_psw(regs
->psw
,
495 regs
->int_code
>> 16);
499 /* No longer in a system call */
500 clear_pt_regs_flag(regs
, PIF_SYSCALL
);
502 if (is_compat_task())
503 handle_signal32(&ksig
, oldset
, regs
);
505 handle_signal(&ksig
, oldset
, regs
);
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
;
518 case -ERESTARTNOHAND
:
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
);
531 * If there's no signal to deliver, we just put the saved sigmask back.
533 restore_saved_sigmask();
536 void do_notify_resume(struct pt_regs
*regs
)
538 clear_thread_flag(TIF_NOTIFY_RESUME
);
539 tracehook_notify_resume(regs
);