1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright IBM Corp. 2000, 2006
4 * Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
5 * Gerhard Tonn (ton@de.ibm.com)
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/compat.h>
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 <asm/ucontext.h>
28 #include <linux/uaccess.h>
29 #include <asm/lowcore.h>
30 #include <asm/switch_to.h>
31 #include "compat_linux.h"
32 #include "compat_ptrace.h"
33 #include "entry.h"
34
35 typedef struct
36 {
37 __u8 callee_used_stack[__SIGNAL_FRAMESIZE32];
38 struct sigcontext32 sc;
39 _sigregs32 sregs;
40 int signo;
41 _sigregs_ext32 sregs_ext;
42 __u16 svc_insn; /* Offset of svc_insn is NOT fixed! */
43 } sigframe32;
44
45 typedef struct
46 {
47 __u8 callee_used_stack[__SIGNAL_FRAMESIZE32];
48 __u16 svc_insn;
49 compat_siginfo_t info;
50 struct ucontext32 uc;
51 } rt_sigframe32;
52
53 /* Store registers needed to create the signal frame */
store_sigregs(void)54 static void store_sigregs(void)
55 {
56 save_access_regs(current->thread.acrs);
57 save_fpu_regs();
58 }
59
60 /* Load registers after signal return */
load_sigregs(void)61 static void load_sigregs(void)
62 {
63 restore_access_regs(current->thread.acrs);
64 }
65
save_sigregs32(struct pt_regs * regs,_sigregs32 __user * sregs)66 static int save_sigregs32(struct pt_regs *regs, _sigregs32 __user *sregs)
67 {
68 _sigregs32 user_sregs;
69 int i;
70
71 user_sregs.regs.psw.mask = (__u32)(regs->psw.mask >> 32);
72 user_sregs.regs.psw.mask &= PSW32_MASK_USER | PSW32_MASK_RI;
73 user_sregs.regs.psw.mask |= PSW32_USER_BITS;
74 user_sregs.regs.psw.addr = (__u32) regs->psw.addr |
75 (__u32)(regs->psw.mask & PSW_MASK_BA);
76 for (i = 0; i < NUM_GPRS; i++)
77 user_sregs.regs.gprs[i] = (__u32) regs->gprs[i];
78 memcpy(&user_sregs.regs.acrs, current->thread.acrs,
79 sizeof(user_sregs.regs.acrs));
80 fpregs_store((_s390_fp_regs *) &user_sregs.fpregs, ¤t->thread.fpu);
81 if (__copy_to_user(sregs, &user_sregs, sizeof(_sigregs32)))
82 return -EFAULT;
83 return 0;
84 }
85
restore_sigregs32(struct pt_regs * regs,_sigregs32 __user * sregs)86 static int restore_sigregs32(struct pt_regs *regs,_sigregs32 __user *sregs)
87 {
88 _sigregs32 user_sregs;
89 int i;
90
91 /* Alwys make any pending restarted system call return -EINTR */
92 current->restart_block.fn = do_no_restart_syscall;
93
94 if (__copy_from_user(&user_sregs, &sregs->regs, sizeof(user_sregs)))
95 return -EFAULT;
96
97 if (!is_ri_task(current) && (user_sregs.regs.psw.mask & PSW32_MASK_RI))
98 return -EINVAL;
99
100 /* Test the floating-point-control word. */
101 if (test_fp_ctl(user_sregs.fpregs.fpc))
102 return -EINVAL;
103
104 /* Use regs->psw.mask instead of PSW_USER_BITS to preserve PER bit. */
105 regs->psw.mask = (regs->psw.mask & ~(PSW_MASK_USER | PSW_MASK_RI)) |
106 (__u64)(user_sregs.regs.psw.mask & PSW32_MASK_USER) << 32 |
107 (__u64)(user_sregs.regs.psw.mask & PSW32_MASK_RI) << 32 |
108 (__u64)(user_sregs.regs.psw.addr & PSW32_ADDR_AMODE);
109 /* Check for invalid user address space control. */
110 if ((regs->psw.mask & PSW_MASK_ASC) == PSW_ASC_HOME)
111 regs->psw.mask = PSW_ASC_PRIMARY |
112 (regs->psw.mask & ~PSW_MASK_ASC);
113 regs->psw.addr = (__u64)(user_sregs.regs.psw.addr & PSW32_ADDR_INSN);
114 for (i = 0; i < NUM_GPRS; i++)
115 regs->gprs[i] = (__u64) user_sregs.regs.gprs[i];
116 memcpy(¤t->thread.acrs, &user_sregs.regs.acrs,
117 sizeof(current->thread.acrs));
118 fpregs_load((_s390_fp_regs *) &user_sregs.fpregs, ¤t->thread.fpu);
119
120 clear_pt_regs_flag(regs, PIF_SYSCALL); /* No longer in a system call */
121 return 0;
122 }
123
save_sigregs_ext32(struct pt_regs * regs,_sigregs_ext32 __user * sregs_ext)124 static int save_sigregs_ext32(struct pt_regs *regs,
125 _sigregs_ext32 __user *sregs_ext)
126 {
127 __u32 gprs_high[NUM_GPRS];
128 __u64 vxrs[__NUM_VXRS_LOW];
129 int i;
130
131 /* Save high gprs to signal stack */
132 for (i = 0; i < NUM_GPRS; i++)
133 gprs_high[i] = regs->gprs[i] >> 32;
134 if (__copy_to_user(&sregs_ext->gprs_high, &gprs_high,
135 sizeof(sregs_ext->gprs_high)))
136 return -EFAULT;
137
138 /* Save vector registers to signal stack */
139 if (MACHINE_HAS_VX) {
140 for (i = 0; i < __NUM_VXRS_LOW; i++)
141 vxrs[i] = *((__u64 *)(current->thread.fpu.vxrs + i) + 1);
142 if (__copy_to_user(&sregs_ext->vxrs_low, vxrs,
143 sizeof(sregs_ext->vxrs_low)) ||
144 __copy_to_user(&sregs_ext->vxrs_high,
145 current->thread.fpu.vxrs + __NUM_VXRS_LOW,
146 sizeof(sregs_ext->vxrs_high)))
147 return -EFAULT;
148 }
149 return 0;
150 }
151
restore_sigregs_ext32(struct pt_regs * regs,_sigregs_ext32 __user * sregs_ext)152 static int restore_sigregs_ext32(struct pt_regs *regs,
153 _sigregs_ext32 __user *sregs_ext)
154 {
155 __u32 gprs_high[NUM_GPRS];
156 __u64 vxrs[__NUM_VXRS_LOW];
157 int i;
158
159 /* Restore high gprs from signal stack */
160 if (__copy_from_user(&gprs_high, &sregs_ext->gprs_high,
161 sizeof(sregs_ext->gprs_high)))
162 return -EFAULT;
163 for (i = 0; i < NUM_GPRS; i++)
164 *(__u32 *)®s->gprs[i] = gprs_high[i];
165
166 /* Restore vector registers from signal stack */
167 if (MACHINE_HAS_VX) {
168 if (__copy_from_user(vxrs, &sregs_ext->vxrs_low,
169 sizeof(sregs_ext->vxrs_low)) ||
170 __copy_from_user(current->thread.fpu.vxrs + __NUM_VXRS_LOW,
171 &sregs_ext->vxrs_high,
172 sizeof(sregs_ext->vxrs_high)))
173 return -EFAULT;
174 for (i = 0; i < __NUM_VXRS_LOW; i++)
175 *((__u64 *)(current->thread.fpu.vxrs + i) + 1) = vxrs[i];
176 }
177 return 0;
178 }
179
COMPAT_SYSCALL_DEFINE0(sigreturn)180 COMPAT_SYSCALL_DEFINE0(sigreturn)
181 {
182 struct pt_regs *regs = task_pt_regs(current);
183 sigframe32 __user *frame = (sigframe32 __user *)regs->gprs[15];
184 sigset_t set;
185
186 if (get_compat_sigset(&set, (compat_sigset_t __user *)frame->sc.oldmask))
187 goto badframe;
188 set_current_blocked(&set);
189 save_fpu_regs();
190 if (restore_sigregs32(regs, &frame->sregs))
191 goto badframe;
192 if (restore_sigregs_ext32(regs, &frame->sregs_ext))
193 goto badframe;
194 load_sigregs();
195 return regs->gprs[2];
196 badframe:
197 force_sig(SIGSEGV, current);
198 return 0;
199 }
200
COMPAT_SYSCALL_DEFINE0(rt_sigreturn)201 COMPAT_SYSCALL_DEFINE0(rt_sigreturn)
202 {
203 struct pt_regs *regs = task_pt_regs(current);
204 rt_sigframe32 __user *frame = (rt_sigframe32 __user *)regs->gprs[15];
205 sigset_t set;
206
207 if (get_compat_sigset(&set, &frame->uc.uc_sigmask))
208 goto badframe;
209 set_current_blocked(&set);
210 if (compat_restore_altstack(&frame->uc.uc_stack))
211 goto badframe;
212 save_fpu_regs();
213 if (restore_sigregs32(regs, &frame->uc.uc_mcontext))
214 goto badframe;
215 if (restore_sigregs_ext32(regs, &frame->uc.uc_mcontext_ext))
216 goto badframe;
217 load_sigregs();
218 return regs->gprs[2];
219 badframe:
220 force_sig(SIGSEGV, current);
221 return 0;
222 }
223
224 /*
225 * Set up a signal frame.
226 */
227
228
229 /*
230 * Determine which stack to use..
231 */
232 static inline void __user *
get_sigframe(struct k_sigaction * ka,struct pt_regs * regs,size_t frame_size)233 get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
234 {
235 unsigned long sp;
236
237 /* Default to using normal stack */
238 sp = (unsigned long) A(regs->gprs[15]);
239
240 /* Overflow on alternate signal stack gives SIGSEGV. */
241 if (on_sig_stack(sp) && !on_sig_stack((sp - frame_size) & -8UL))
242 return (void __user *) -1UL;
243
244 /* This is the X/Open sanctioned signal stack switching. */
245 if (ka->sa.sa_flags & SA_ONSTACK) {
246 if (! sas_ss_flags(sp))
247 sp = current->sas_ss_sp + current->sas_ss_size;
248 }
249
250 return (void __user *)((sp - frame_size) & -8ul);
251 }
252
setup_frame32(struct ksignal * ksig,sigset_t * set,struct pt_regs * regs)253 static int setup_frame32(struct ksignal *ksig, sigset_t *set,
254 struct pt_regs *regs)
255 {
256 int sig = ksig->sig;
257 sigframe32 __user *frame;
258 unsigned long restorer;
259 size_t frame_size;
260
261 /*
262 * gprs_high are always present for 31-bit compat tasks.
263 * The space for vector registers is only allocated if
264 * the machine supports it
265 */
266 frame_size = sizeof(*frame) - sizeof(frame->sregs_ext.__reserved);
267 if (!MACHINE_HAS_VX)
268 frame_size -= sizeof(frame->sregs_ext.vxrs_low) +
269 sizeof(frame->sregs_ext.vxrs_high);
270 frame = get_sigframe(&ksig->ka, regs, frame_size);
271 if (frame == (void __user *) -1UL)
272 return -EFAULT;
273
274 /* Set up backchain. */
275 if (__put_user(regs->gprs[15], (unsigned int __user *) frame))
276 return -EFAULT;
277
278 /* Create struct sigcontext32 on the signal stack */
279 if (put_compat_sigset((compat_sigset_t __user *)frame->sc.oldmask,
280 set, sizeof(compat_sigset_t)))
281 return -EFAULT;
282 if (__put_user(ptr_to_compat(&frame->sregs), &frame->sc.sregs))
283 return -EFAULT;
284
285 /* Store registers needed to create the signal frame */
286 store_sigregs();
287
288 /* Create _sigregs32 on the signal stack */
289 if (save_sigregs32(regs, &frame->sregs))
290 return -EFAULT;
291
292 /* Place signal number on stack to allow backtrace from handler. */
293 if (__put_user(regs->gprs[2], (int __force __user *) &frame->signo))
294 return -EFAULT;
295
296 /* Create _sigregs_ext32 on the signal stack */
297 if (save_sigregs_ext32(regs, &frame->sregs_ext))
298 return -EFAULT;
299
300 /* Set up to return from userspace. If provided, use a stub
301 already in userspace. */
302 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
303 restorer = (unsigned long __force)
304 ksig->ka.sa.sa_restorer | PSW32_ADDR_AMODE;
305 } else {
306 /* Signal frames without vectors registers are short ! */
307 __u16 __user *svc = (void __user *) frame + frame_size - 2;
308 if (__put_user(S390_SYSCALL_OPCODE | __NR_sigreturn, svc))
309 return -EFAULT;
310 restorer = (unsigned long __force) svc | PSW32_ADDR_AMODE;
311 }
312
313 /* Set up registers for signal handler */
314 regs->gprs[14] = restorer;
315 regs->gprs[15] = (__force __u64) frame;
316 /* Force 31 bit amode and default user address space control. */
317 regs->psw.mask = PSW_MASK_BA |
318 (PSW_USER_BITS & PSW_MASK_ASC) |
319 (regs->psw.mask & ~PSW_MASK_ASC);
320 regs->psw.addr = (__force __u64) ksig->ka.sa.sa_handler;
321
322 regs->gprs[2] = sig;
323 regs->gprs[3] = (__force __u64) &frame->sc;
324
325 /* We forgot to include these in the sigcontext.
326 To avoid breaking binary compatibility, they are passed as args. */
327 if (sig == SIGSEGV || sig == SIGBUS || sig == SIGILL ||
328 sig == SIGTRAP || sig == SIGFPE) {
329 /* set extra registers only for synchronous signals */
330 regs->gprs[4] = regs->int_code & 127;
331 regs->gprs[5] = regs->int_parm_long;
332 regs->gprs[6] = current->thread.last_break;
333 }
334
335 return 0;
336 }
337
setup_rt_frame32(struct ksignal * ksig,sigset_t * set,struct pt_regs * regs)338 static int setup_rt_frame32(struct ksignal *ksig, sigset_t *set,
339 struct pt_regs *regs)
340 {
341 rt_sigframe32 __user *frame;
342 unsigned long restorer;
343 size_t frame_size;
344 u32 uc_flags;
345
346 frame_size = sizeof(*frame) -
347 sizeof(frame->uc.uc_mcontext_ext.__reserved);
348 /*
349 * gprs_high are always present for 31-bit compat tasks.
350 * The space for vector registers is only allocated if
351 * the machine supports it
352 */
353 uc_flags = UC_GPRS_HIGH;
354 if (MACHINE_HAS_VX) {
355 uc_flags |= UC_VXRS;
356 } else
357 frame_size -= sizeof(frame->uc.uc_mcontext_ext.vxrs_low) +
358 sizeof(frame->uc.uc_mcontext_ext.vxrs_high);
359 frame = get_sigframe(&ksig->ka, regs, frame_size);
360 if (frame == (void __user *) -1UL)
361 return -EFAULT;
362
363 /* Set up backchain. */
364 if (__put_user(regs->gprs[15], (unsigned int __force __user *) frame))
365 return -EFAULT;
366
367 /* Set up to return from userspace. If provided, use a stub
368 already in userspace. */
369 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
370 restorer = (unsigned long __force)
371 ksig->ka.sa.sa_restorer | PSW32_ADDR_AMODE;
372 } else {
373 __u16 __user *svc = &frame->svc_insn;
374 if (__put_user(S390_SYSCALL_OPCODE | __NR_rt_sigreturn, svc))
375 return -EFAULT;
376 restorer = (unsigned long __force) svc | PSW32_ADDR_AMODE;
377 }
378
379 /* Create siginfo on the signal stack */
380 if (copy_siginfo_to_user32(&frame->info, &ksig->info))
381 return -EFAULT;
382
383 /* Store registers needed to create the signal frame */
384 store_sigregs();
385
386 /* Create ucontext on the signal stack. */
387 if (__put_user(uc_flags, &frame->uc.uc_flags) ||
388 __put_user(0, &frame->uc.uc_link) ||
389 __compat_save_altstack(&frame->uc.uc_stack, regs->gprs[15]) ||
390 save_sigregs32(regs, &frame->uc.uc_mcontext) ||
391 put_compat_sigset(&frame->uc.uc_sigmask, set, sizeof(compat_sigset_t)) ||
392 save_sigregs_ext32(regs, &frame->uc.uc_mcontext_ext))
393 return -EFAULT;
394
395 /* Set up registers for signal handler */
396 regs->gprs[14] = restorer;
397 regs->gprs[15] = (__force __u64) frame;
398 /* Force 31 bit amode and default user address space control. */
399 regs->psw.mask = PSW_MASK_BA |
400 (PSW_USER_BITS & PSW_MASK_ASC) |
401 (regs->psw.mask & ~PSW_MASK_ASC);
402 regs->psw.addr = (__u64 __force) ksig->ka.sa.sa_handler;
403
404 regs->gprs[2] = ksig->sig;
405 regs->gprs[3] = (__force __u64) &frame->info;
406 regs->gprs[4] = (__force __u64) &frame->uc;
407 regs->gprs[5] = current->thread.last_break;
408 return 0;
409 }
410
411 /*
412 * OK, we're invoking a handler
413 */
414
handle_signal32(struct ksignal * ksig,sigset_t * oldset,struct pt_regs * regs)415 void handle_signal32(struct ksignal *ksig, sigset_t *oldset,
416 struct pt_regs *regs)
417 {
418 int ret;
419
420 /* Set up the stack frame */
421 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
422 ret = setup_rt_frame32(ksig, oldset, regs);
423 else
424 ret = setup_frame32(ksig, oldset, regs);
425
426 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLE_STEP));
427 }
428
429
