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