LXR qemu/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
  36typedef struct {
  37    target_psw_t psw;
  38    abi_ulong gprs[__NUM_GPRS];
  39    abi_uint acrs[__NUM_ACRS];
  40} target_s390_regs_common;
  41
  42typedef struct {
  43    uint32_t fpc;
  44    uint32_t pad;
  45    uint64_t fprs[__NUM_FPRS];
  46} target_s390_fp_regs;
  47
  48typedef struct {
  49    target_s390_regs_common regs;
  50    target_s390_fp_regs     fpregs;
  51} target_sigregs;
  52
  53typedef struct {
  54    uint64_t vxrs_low[16];
  55    uint64_t vxrs_high[16][2];
  56    uint8_t reserved[128];
  57} target_sigregs_ext;
  58
  59typedef struct {
  60    abi_ulong oldmask[_SIGCONTEXT_NSIG_WORDS];
  61    abi_ulong sregs;
  62} target_sigcontext;
  63
  64typedef 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
  75struct 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
  85typedef 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
  92static inline abi_ulong
  93get_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
 120static 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
 150static 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
 168void 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
 238void 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
 298static 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
 339static 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
 357long 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
 384long 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}
 407