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 #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
  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
 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
 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
 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
 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
 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
 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
 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
 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
 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 }