linux-user/s390x/signal.c

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