1 /*
2 * Emulation of Linux signals
3 *
4 * Copyright (c) 2003 Fabrice Bellard
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, see <http://www.gnu.org/licenses/>.
18 */
19 #include "qemu/osdep.h"
20 #include "qemu.h"
21 #include "user-internals.h"
22 #include "signal-common.h"
23 #include "linux-user/trace.h"
24 #include "vdso-asmoffset.h"
25
26 #define __NUM_GPRS 16
27 #define __NUM_FPRS 16
28 #define __NUM_ACRS 16
29
30 #define _SIGCONTEXT_NSIG 64
31 #define _SIGCONTEXT_NSIG_BPW 64 /* FIXME: 31-bit mode -> 32 */
32 #define _SIGCONTEXT_NSIG_WORDS (_SIGCONTEXT_NSIG / _SIGCONTEXT_NSIG_BPW)
33 #define _SIGMASK_COPY_SIZE (sizeof(unsigned long)*_SIGCONTEXT_NSIG_WORDS)
34 #define S390_SYSCALL_OPCODE ((uint16_t)0x0a00)
35
36 typedef struct {
37 target_psw_t psw;
38 abi_ulong gprs[__NUM_GPRS];
39 abi_uint acrs[__NUM_ACRS];
40 } target_s390_regs_common;
41
42 typedef struct {
43 uint32_t fpc;
44 uint32_t pad;
45 uint64_t fprs[__NUM_FPRS];
46 } target_s390_fp_regs;
47
48 typedef struct {
49 target_s390_regs_common regs;
50 target_s390_fp_regs fpregs;
51 } target_sigregs;
52
53 typedef struct {
54 uint64_t vxrs_low[16];
55 uint64_t vxrs_high[16][2];
56 uint8_t reserved[128];
57 } target_sigregs_ext;
58
59 typedef struct {
60 abi_ulong oldmask[_SIGCONTEXT_NSIG_WORDS];
61 abi_ulong sregs;
62 } target_sigcontext;
63
64 typedef struct {
65 uint8_t callee_used_stack[STACK_FRAME_OVERHEAD];
66 target_sigcontext sc;
67 target_sigregs sregs;
68 int signo;
69 target_sigregs_ext sregs_ext;
70 } sigframe;
71
72 #define TARGET_UC_VXRS 2
73
74 struct target_ucontext {
75 abi_ulong tuc_flags;
76 abi_ulong tuc_link;
77 target_stack_t tuc_stack;
78 target_sigregs tuc_mcontext;
79 target_sigset_t tuc_sigmask;
80 uint8_t reserved[128 - sizeof(target_sigset_t)];
81 target_sigregs_ext tuc_mcontext_ext;
82 };
83
84 typedef struct {
85 uint8_t callee_used_stack[STACK_FRAME_OVERHEAD];
86 /*
87 * This field is no longer initialized by the kernel, but it's still a part
88 * of the ABI.
89 */
90 uint16_t svc_insn;
91 struct target_siginfo info;
92 struct target_ucontext uc;
93 } rt_sigframe;
94
95 static inline abi_ulong
get_sigframe(struct target_sigaction * ka,CPUS390XState * env,size_t frame_size)96 get_sigframe(struct target_sigaction *ka, CPUS390XState *env, size_t frame_size)
97 {
98 abi_ulong sp;
99
100 /* Default to using normal stack */
101 sp = get_sp_from_cpustate(env);
102
103 /* This is the X/Open sanctioned signal stack switching. */
104 if (ka->sa_flags & TARGET_SA_ONSTACK) {
105 sp = target_sigsp(sp, ka);
106 }
107
108 /* This is the legacy signal stack switching. */
109 else if (/* FIXME !user_mode(regs) */ 0 &&
110 !(ka->sa_flags & TARGET_SA_RESTORER) &&
111 ka->sa_restorer) {
112 sp = (abi_ulong) ka->sa_restorer;
113 }
114
115 return (sp - frame_size) & -8ul;
116 }
117
118 #define PSW_USER_BITS (PSW_MASK_DAT | PSW_MASK_IO | PSW_MASK_EXT | \
119 PSW_MASK_MCHECK | PSW_MASK_PSTATE | PSW_ASC_PRIMARY)
120 #define PSW_MASK_USER (PSW_MASK_ASC | PSW_MASK_CC | PSW_MASK_PM | \
121 PSW_MASK_64 | PSW_MASK_32)
122
save_sigregs(CPUS390XState * env,target_sigregs * sregs)123 static void save_sigregs(CPUS390XState *env, target_sigregs *sregs)
124 {
125 uint64_t psw_mask = s390_cpu_get_psw_mask(env);
126 int i;
127
128 /*
129 * Copy a 'clean' PSW mask to the user to avoid leaking
130 * information about whether PER is currently on.
131 * TODO: qemu does not support PSW_MASK_RI; it will never be set.
132 */
133 psw_mask = PSW_USER_BITS | (psw_mask & PSW_MASK_USER);
134 __put_user(psw_mask, &sregs->regs.psw.mask);
135 __put_user(env->psw.addr, &sregs->regs.psw.addr);
136
137 for (i = 0; i < 16; i++) {
138 __put_user(env->regs[i], &sregs->regs.gprs[i]);
139 }
140 for (i = 0; i < 16; i++) {
141 __put_user(env->aregs[i], &sregs->regs.acrs[i]);
142 }
143
144 /*
145 * We have to store the fp registers to current->thread.fp_regs
146 * to merge them with the emulated registers.
147 */
148 __put_user(env->fpc, &sregs->fpregs.fpc);
149 for (i = 0; i < 16; i++) {
150 __put_user(*get_freg(env, i), &sregs->fpregs.fprs[i]);
151 }
152 }
153
save_sigregs_ext(CPUS390XState * env,target_sigregs_ext * ext)154 static void save_sigregs_ext(CPUS390XState *env, target_sigregs_ext *ext)
155 {
156 int i;
157
158 /*
159 * if (MACHINE_HAS_VX) ...
160 * That said, we always allocate the stack storage and the
161 * space is always available in env.
162 */
163 for (i = 0; i < 16; ++i) {
164 __put_user(env->vregs[i][1], &ext->vxrs_low[i]);
165 }
166 for (i = 0; i < 16; ++i) {
167 __put_user(env->vregs[i + 16][0], &ext->vxrs_high[i][0]);
168 __put_user(env->vregs[i + 16][1], &ext->vxrs_high[i][1]);
169 }
170 }
171
setup_frame(int sig,struct target_sigaction * ka,target_sigset_t * set,CPUS390XState * env)172 void setup_frame(int sig, struct target_sigaction *ka,
173 target_sigset_t *set, CPUS390XState *env)
174 {
175 sigframe *frame;
176 abi_ulong frame_addr;
177 abi_ulong restorer;
178
179 frame_addr = get_sigframe(ka, env, sizeof(*frame));
180 trace_user_setup_frame(env, frame_addr);
181 if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
182 force_sigsegv(sig);
183 return;
184 }
185
186 /* Set up backchain. */
187 __put_user(env->regs[15], (abi_ulong *) frame);
188
189 /* Create struct sigcontext on the signal stack. */
190 /* Make sure that we're initializing all of oldmask. */
191 QEMU_BUILD_BUG_ON(ARRAY_SIZE(frame->sc.oldmask) != 1);
192 __put_user(set->sig[0], &frame->sc.oldmask[0]);
193 __put_user(frame_addr + offsetof(sigframe, sregs), &frame->sc.sregs);
194
195 /* Create _sigregs on the signal stack */
196 save_sigregs(env, &frame->sregs);
197
198 /*
199 * ??? The kernel uses regs->gprs[2] here, which is not yet the signo.
200 * Moreover the comment talks about allowing backtrace, which is really
201 * done by the r15 copy above.
202 */
203 __put_user(sig, &frame->signo);
204
205 /* Create sigregs_ext on the signal stack. */
206 save_sigregs_ext(env, &frame->sregs_ext);
207
208 /*
209 * Set up to return from userspace.
210 * If provided, use a stub already in userspace.
211 */
212 if (ka->sa_flags & TARGET_SA_RESTORER) {
213 restorer = ka->sa_restorer;
214 } else {
215 restorer = default_sigreturn;
216 }
217
218 /* Set up registers for signal handler */
219 env->regs[14] = restorer;
220 env->regs[15] = frame_addr;
221 /* Force default amode and default user address space control. */
222 env->psw.mask = PSW_MASK_64 | PSW_MASK_32 | PSW_ASC_PRIMARY
223 | (env->psw.mask & ~PSW_MASK_ASC);
224 env->psw.addr = ka->_sa_handler;
225
226 env->regs[2] = sig;
227 env->regs[3] = frame_addr + offsetof(typeof(*frame), sc);
228
229 /*
230 * We forgot to include these in the sigcontext.
231 * To avoid breaking binary compatibility, they are passed as args.
232 */
233 env->regs[4] = 0; /* FIXME: regs->int_code & 127 */
234 env->regs[5] = 0; /* FIXME: regs->int_parm_long */
235 env->regs[6] = 0; /* FIXME: current->thread.last_break */
236
237 unlock_user_struct(frame, frame_addr, 1);
238 }
239
setup_rt_frame(int sig,struct target_sigaction * ka,target_siginfo_t * info,target_sigset_t * set,CPUS390XState * env)240 void setup_rt_frame(int sig, struct target_sigaction *ka,
241 target_siginfo_t *info,
242 target_sigset_t *set, CPUS390XState *env)
243 {
244 rt_sigframe *frame;
245 abi_ulong frame_addr;
246 abi_ulong restorer;
247 abi_ulong uc_flags;
248
249 frame_addr = get_sigframe(ka, env, sizeof *frame);
250 trace_user_setup_rt_frame(env, frame_addr);
251 if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
252 force_sigsegv(sig);
253 return;
254 }
255
256 /* Set up backchain. */
257 __put_user(env->regs[15], (abi_ulong *) frame);
258
259 /*
260 * Set up to return from userspace.
261 * If provided, use a stub already in userspace.
262 */
263 if (ka->sa_flags & TARGET_SA_RESTORER) {
264 restorer = ka->sa_restorer;
265 } else {
266 restorer = default_rt_sigreturn;
267 }
268
269 /* Create siginfo on the signal stack. */
270 frame->info = *info;
271
272 /* Create ucontext on the signal stack. */
273 uc_flags = 0;
274 if (s390_has_feat(S390_FEAT_VECTOR)) {
275 uc_flags |= TARGET_UC_VXRS;
276 }
277 __put_user(uc_flags, &frame->uc.tuc_flags);
278 __put_user(0, &frame->uc.tuc_link);
279 target_save_altstack(&frame->uc.tuc_stack, env);
280 save_sigregs(env, &frame->uc.tuc_mcontext);
281 save_sigregs_ext(env, &frame->uc.tuc_mcontext_ext);
282 tswap_sigset(&frame->uc.tuc_sigmask, set);
283
284 /* Set up registers for signal handler */
285 env->regs[14] = restorer;
286 env->regs[15] = frame_addr;
287 /* Force default amode and default user address space control. */
288 env->psw.mask = PSW_MASK_64 | PSW_MASK_32 | PSW_ASC_PRIMARY
289 | (env->psw.mask & ~PSW_MASK_ASC);
290 env->psw.addr = ka->_sa_handler;
291
292 env->regs[2] = sig;
293 env->regs[3] = frame_addr + offsetof(typeof(*frame), info);
294 env->regs[4] = frame_addr + offsetof(typeof(*frame), uc);
295 env->regs[5] = 0; /* FIXME: current->thread.last_break */
296 }
297
restore_sigregs(CPUS390XState * env,target_sigregs * sc)298 static void restore_sigregs(CPUS390XState *env, target_sigregs *sc)
299 {
300 uint64_t prev_addr, prev_mask, mask, addr;
301 int i;
302
303 for (i = 0; i < 16; i++) {
304 __get_user(env->regs[i], &sc->regs.gprs[i]);
305 }
306
307 prev_addr = env->psw.addr;
308 __get_user(mask, &sc->regs.psw.mask);
309 __get_user(addr, &sc->regs.psw.addr);
310 trace_user_s390x_restore_sigregs(env, addr, prev_addr);
311
312 /*
313 * Use current psw.mask to preserve PER bit.
314 * TODO:
315 * if (!is_ri_task(current) && (user_sregs.regs.psw.mask & PSW_MASK_RI))
316 * return -EINVAL;
317 * Simply do not allow it to be set in mask.
318 */
319 prev_mask = s390_cpu_get_psw_mask(env);
320 mask = (prev_mask & ~PSW_MASK_USER) | (mask & PSW_MASK_USER);
321 /* Check for invalid user address space control. */
322 if ((mask & PSW_MASK_ASC) == PSW_ASC_HOME) {
323 mask = (mask & ~PSW_MASK_ASC) | PSW_ASC_PRIMARY;
324 }
325 /* Check for invalid amode. */
326 if (mask & PSW_MASK_64) {
327 mask |= PSW_MASK_32;
328 }
329 s390_cpu_set_psw(env, mask, addr);
330
331 for (i = 0; i < 16; i++) {
332 __get_user(env->aregs[i], &sc->regs.acrs[i]);
333 }
334 __get_user(env->fpc, &sc->fpregs.fpc);
335 for (i = 0; i < 16; i++) {
336 __get_user(*get_freg(env, i), &sc->fpregs.fprs[i]);
337 }
338 }
339
restore_sigregs_ext(CPUS390XState * env,target_sigregs_ext * ext)340 static void restore_sigregs_ext(CPUS390XState *env, target_sigregs_ext *ext)
341 {
342 int i;
343
344 /*
345 * if (MACHINE_HAS_VX) ...
346 * That said, we always allocate the stack storage and the
347 * space is always available in env.
348 */
349 for (i = 0; i < 16; ++i) {
350 __get_user(env->vregs[i][1], &ext->vxrs_low[i]);
351 }
352 for (i = 0; i < 16; ++i) {
353 __get_user(env->vregs[i + 16][0], &ext->vxrs_high[i][0]);
354 __get_user(env->vregs[i + 16][1], &ext->vxrs_high[i][1]);
355 }
356 }
357
do_sigreturn(CPUS390XState * env)358 long do_sigreturn(CPUS390XState *env)
359 {
360 sigframe *frame;
361 abi_ulong frame_addr = env->regs[15];
362 target_sigset_t target_set;
363 sigset_t set;
364
365 trace_user_do_sigreturn(env, frame_addr);
366 if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
367 force_sig(TARGET_SIGSEGV);
368 return -QEMU_ESIGRETURN;
369 }
370
371 /* Make sure that we're initializing all of target_set. */
372 QEMU_BUILD_BUG_ON(ARRAY_SIZE(target_set.sig) != 1);
373 __get_user(target_set.sig[0], &frame->sc.oldmask[0]);
374
375 target_to_host_sigset_internal(&set, &target_set);
376 set_sigmask(&set); /* ~_BLOCKABLE? */
377
378 restore_sigregs(env, &frame->sregs);
379 restore_sigregs_ext(env, &frame->sregs_ext);
380
381 unlock_user_struct(frame, frame_addr, 0);
382 return -QEMU_ESIGRETURN;
383 }
384
do_rt_sigreturn(CPUS390XState * env)385 long do_rt_sigreturn(CPUS390XState *env)
386 {
387 rt_sigframe *frame;
388 abi_ulong frame_addr = env->regs[15];
389 sigset_t set;
390
391 trace_user_do_rt_sigreturn(env, frame_addr);
392 if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
393 force_sig(TARGET_SIGSEGV);
394 return -QEMU_ESIGRETURN;
395 }
396 target_to_host_sigset(&set, &frame->uc.tuc_sigmask);
397
398 set_sigmask(&set); /* ~_BLOCKABLE? */
399
400 restore_sigregs(env, &frame->uc.tuc_mcontext);
401 restore_sigregs_ext(env, &frame->uc.tuc_mcontext_ext);
402
403 target_restore_altstack(&frame->uc.tuc_stack, env);
404
405 unlock_user_struct(frame, frame_addr, 0);
406 return -QEMU_ESIGRETURN;
407 }
408
setup_sigtramp(abi_ulong sigtramp_page)409 void setup_sigtramp(abi_ulong sigtramp_page)
410 {
411 uint16_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 2 + 2, 0);
412 assert(tramp != NULL);
413
414 default_sigreturn = sigtramp_page;
415 __put_user(S390_SYSCALL_OPCODE | TARGET_NR_sigreturn, &tramp[0]);
416
417 default_rt_sigreturn = sigtramp_page + 2;
418 __put_user(S390_SYSCALL_OPCODE | TARGET_NR_rt_sigreturn, &tramp[1]);
419
420 unlock_user(tramp, sigtramp_page, 2 + 2);
421 }
422