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 "signal-common.h"
  22 #include "linux-user/trace.h"
  23
  24 #define __NUM_GPRS 16
  25 #define __NUM_FPRS 16
  26 #define __NUM_ACRS 16
  27
  28 #define __SIGNAL_FRAMESIZE      160 /* FIXME: 31-bit mode -> 96 */
  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[__SIGNAL_FRAMESIZE];
  66     target_sigcontext sc;
  67     target_sigregs sregs;
  68     int signo;
  69     target_sigregs_ext sregs_ext;
  70     uint16_t retcode;
  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     uint16_t retcode;
  88     struct target_siginfo info;
  89     struct target_ucontext uc;
  90 } rt_sigframe;
  91
  92 static inline abi_ulong
  93 get_sigframe(struct target_sigaction *ka, CPUS390XState *env, size_t frame_size)
  94 {
  95     abi_ulong sp;
  96
  97     /* Default to using normal stack */
  98     sp = get_sp_from_cpustate(env);
  99
 100     /* This is the X/Open sanctioned signal stack switching.  */
 101     if (ka->sa_flags & TARGET_SA_ONSTACK) {
 102         sp = target_sigsp(sp, ka);
 103     }
 104
 105     /* This is the legacy signal stack switching. */
 106     else if (/* FIXME !user_mode(regs) */ 0 &&
 107              !(ka->sa_flags & TARGET_SA_RESTORER) &&
 108              ka->sa_restorer) {
 109         sp = (abi_ulong) ka->sa_restorer;
 110     }
 111
 112     return (sp - frame_size) & -8ul;
 113 }
 114
 115 #define PSW_USER_BITS   (PSW_MASK_DAT | PSW_MASK_IO | PSW_MASK_EXT | \
 116                          PSW_MASK_MCHECK | PSW_MASK_PSTATE | PSW_ASC_PRIMARY)
 117 #define PSW_MASK_USER   (PSW_MASK_ASC | PSW_MASK_CC | PSW_MASK_PM | \
 118                          PSW_MASK_64 | PSW_MASK_32)
 119
 120 static void save_sigregs(CPUS390XState *env, target_sigregs *sregs)
 121 {
 122     uint64_t psw_mask = s390_cpu_get_psw_mask(env);
 123     int i;
 124
 125     /*
 126      * Copy a 'clean' PSW mask to the user to avoid leaking
 127      * information about whether PER is currently on.
 128      * TODO: qemu does not support PSW_MASK_RI; it will never be set.
 129      */
 130     psw_mask = PSW_USER_BITS | (psw_mask & PSW_MASK_USER);
 131     __put_user(psw_mask, &sregs->regs.psw.mask);
 132     __put_user(env->psw.addr, &sregs->regs.psw.addr);
 133
 134     for (i = 0; i < 16; i++) {
 135         __put_user(env->regs[i], &sregs->regs.gprs[i]);
 136     }
 137     for (i = 0; i < 16; i++) {
 138         __put_user(env->aregs[i], &sregs->regs.acrs[i]);
 139     }
 140
 141     /*
 142      * We have to store the fp registers to current->thread.fp_regs
 143      * to merge them with the emulated registers.
 144      */
 145     for (i = 0; i < 16; i++) {
 146         __put_user(*get_freg(env, i), &sregs->fpregs.fprs[i]);
 147     }
 148 }
 149
 150 static void save_sigregs_ext(CPUS390XState *env, target_sigregs_ext *ext)
 151 {
 152     int i;
 153
 154     /*
 155      * if (MACHINE_HAS_VX) ...
 156      * That said, we always allocate the stack storage and the
 157      * space is always available in env.
 158      */
 159     for (i = 0; i < 16; ++i) {
 160         __put_user(env->vregs[i][1], &ext->vxrs_low[i]);
 161     }
 162     for (i = 0; i < 16; ++i) {
 163         __put_user(env->vregs[i + 16][0], &ext->vxrs_high[i][0]);
 164         __put_user(env->vregs[i + 16][1], &ext->vxrs_high[i][1]);
 165     }
 166 }
 167
 168 void setup_frame(int sig, struct target_sigaction *ka,
 169                  target_sigset_t *set, CPUS390XState *env)
 170 {
 171     sigframe *frame;
 172     abi_ulong frame_addr;
 173     abi_ulong restorer;
 174
 175     frame_addr = get_sigframe(ka, env, sizeof(*frame));
 176     trace_user_setup_frame(env, frame_addr);
 177     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
 178         force_sigsegv(sig);
 179         return;
 180     }
 181
 182     /* Set up backchain. */
 183     __put_user(env->regs[15], (abi_ulong *) frame);
 184
 185     /* Create struct sigcontext on the signal stack. */
 186     /* Make sure that we're initializing all of oldmask. */
 187     QEMU_BUILD_BUG_ON(ARRAY_SIZE(frame->sc.oldmask) != 1);
 188     __put_user(set->sig[0], &frame->sc.oldmask[0]);
 189     __put_user(frame_addr + offsetof(sigframe, sregs), &frame->sc.sregs);
 190
 191     /* Create _sigregs on the signal stack */
 192     save_sigregs(env, &frame->sregs);
 193
 194     /*
 195      * ??? The kernel uses regs->gprs[2] here, which is not yet the signo.
 196      * Moreover the comment talks about allowing backtrace, which is really
 197      * done by the r15 copy above.
 198      */
 199     __put_user(sig, &frame->signo);
 200
 201     /* Create sigregs_ext on the signal stack. */
 202     save_sigregs_ext(env, &frame->sregs_ext);
 203
 204     /*
 205      * Set up to return from userspace.
 206      * If provided, use a stub already in userspace.
 207      */
 208     if (ka->sa_flags & TARGET_SA_RESTORER) {
 209         restorer = ka->sa_restorer;
 210     } else {
 211         restorer = frame_addr + offsetof(sigframe, retcode);
 212         __put_user(S390_SYSCALL_OPCODE | TARGET_NR_sigreturn,
 213                    &frame->retcode);
 214     }
 215
 216     /* Set up registers for signal handler */
 217     env->regs[14] = restorer;
 218     env->regs[15] = frame_addr;
 219     /* Force default amode and default user address space control. */
 220     env->psw.mask = PSW_MASK_64 | PSW_MASK_32 | PSW_ASC_PRIMARY
 221                   | (env->psw.mask & ~PSW_MASK_ASC);
 222     env->psw.addr = ka->_sa_handler;
 223
 224     env->regs[2] = sig;
 225     env->regs[3] = frame_addr + offsetof(typeof(*frame), sc);
 226
 227     /*
 228      * We forgot to include these in the sigcontext.
 229      * To avoid breaking binary compatibility, they are passed as args.
 230      */
 231     env->regs[4] = 0; /* FIXME: regs->int_code & 127 */
 232     env->regs[5] = 0; /* FIXME: regs->int_parm_long */
 233     env->regs[6] = 0; /* FIXME: current->thread.last_break */
 234
 235     unlock_user_struct(frame, frame_addr, 1);
 236 }
 237
 238 void setup_rt_frame(int sig, struct target_sigaction *ka,
 239                     target_siginfo_t *info,
 240                     target_sigset_t *set, CPUS390XState *env)
 241 {
 242     rt_sigframe *frame;
 243     abi_ulong frame_addr;
 244     abi_ulong restorer;
 245     abi_ulong uc_flags;
 246
 247     frame_addr = get_sigframe(ka, env, sizeof *frame);
 248     trace_user_setup_rt_frame(env, frame_addr);
 249     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
 250         force_sigsegv(sig);
 251         return;
 252     }
 253
 254     /* Set up backchain. */
 255     __put_user(env->regs[15], (abi_ulong *) frame);
 256
 257     /*
 258      * Set up to return from userspace.
 259      * If provided, use a stub already in userspace.
 260      */
 261     if (ka->sa_flags & TARGET_SA_RESTORER) {
 262         restorer = ka->sa_restorer;
 263     } else {
 264         restorer = frame_addr + offsetof(typeof(*frame), retcode);
 265         __put_user(S390_SYSCALL_OPCODE | TARGET_NR_rt_sigreturn,
 266                    &frame->retcode);
 267     }
 268
 269     /* Create siginfo on the signal stack. */
 270     tswap_siginfo(&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
 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     for (i = 0; i < 16; i++) {
 335         __get_user(*get_freg(env, i), &sc->fpregs.fprs[i]);
 336     }
 337 }
 338
 339 static void restore_sigregs_ext(CPUS390XState *env, target_sigregs_ext *ext)
 340 {
 341     int i;
 342
 343     /*
 344      * if (MACHINE_HAS_VX) ...
 345      * That said, we always allocate the stack storage and the
 346      * space is always available in env.
 347      */
 348     for (i = 0; i < 16; ++i) {
 349         __get_user(env->vregs[i][1], &ext->vxrs_low[i]);
 350     }
 351     for (i = 0; i < 16; ++i) {
 352         __get_user(env->vregs[i + 16][0], &ext->vxrs_high[i][0]);
 353         __get_user(env->vregs[i + 16][1], &ext->vxrs_high[i][1]);
 354     }
 355 }
 356
 357 long do_sigreturn(CPUS390XState *env)
 358 {
 359     sigframe *frame;
 360     abi_ulong frame_addr = env->regs[15];
 361     target_sigset_t target_set;
 362     sigset_t set;
 363
 364     trace_user_do_sigreturn(env, frame_addr);
 365     if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
 366         force_sig(TARGET_SIGSEGV);
 367         return -TARGET_QEMU_ESIGRETURN;
 368     }
 369
 370     /* Make sure that we're initializing all of target_set. */
 371     QEMU_BUILD_BUG_ON(ARRAY_SIZE(target_set.sig) != 1);
 372     __get_user(target_set.sig[0], &frame->sc.oldmask[0]);
 373
 374     target_to_host_sigset_internal(&set, &target_set);
 375     set_sigmask(&set); /* ~_BLOCKABLE? */
 376
 377     restore_sigregs(env, &frame->sregs);
 378     restore_sigregs_ext(env, &frame->sregs_ext);
 379
 380     unlock_user_struct(frame, frame_addr, 0);
 381     return -TARGET_QEMU_ESIGRETURN;
 382 }
 383
 384 long do_rt_sigreturn(CPUS390XState *env)
 385 {
 386     rt_sigframe *frame;
 387     abi_ulong frame_addr = env->regs[15];
 388     sigset_t set;
 389
 390     trace_user_do_rt_sigreturn(env, frame_addr);
 391     if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
 392         force_sig(TARGET_SIGSEGV);
 393         return -TARGET_QEMU_ESIGRETURN;
 394     }
 395     target_to_host_sigset(&set, &frame->uc.tuc_sigmask);
 396
 397     set_sigmask(&set); /* ~_BLOCKABLE? */
 398
 399     restore_sigregs(env, &frame->uc.tuc_mcontext);
 400     restore_sigregs_ext(env, &frame->uc.tuc_mcontext_ext);
 401
 402     target_restore_altstack(&frame->uc.tuc_stack, env);
 403
 404     unlock_user_struct(frame, frame_addr, 0);
 405     return -TARGET_QEMU_ESIGRETURN;
 406 }