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 "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
  37typedef struct {
  38    target_psw_t psw;
  39    abi_ulong gprs[__NUM_GPRS];
  40    abi_uint acrs[__NUM_ACRS];
  41} target_s390_regs_common;
  42
  43typedef struct {
  44    uint32_t fpc;
  45    uint32_t pad;
  46    uint64_t fprs[__NUM_FPRS];
  47} target_s390_fp_regs;
  48
  49typedef struct {
  50    target_s390_regs_common regs;
  51    target_s390_fp_regs     fpregs;
  52} target_sigregs;
  53
  54typedef struct {
  55    uint64_t vxrs_low[16];
  56    uint64_t vxrs_high[16][2];
  57    uint8_t reserved[128];
  58} target_sigregs_ext;
  59
  60typedef struct {
  61    abi_ulong oldmask[_SIGCONTEXT_NSIG_WORDS];
  62    abi_ulong sregs;
  63} target_sigcontext;
  64
  65typedef 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
  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    struct target_siginfo info;
  88    struct target_ucontext uc;
  89} rt_sigframe;
  90
  91static inline abi_ulong
  92get_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
 119static 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
 149static 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
 167void 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
 235void 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
 293static 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
 334static 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
 352long 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 -TARGET_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 -TARGET_QEMU_ESIGRETURN;
 377}
 378
 379long 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 -TARGET_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 -TARGET_QEMU_ESIGRETURN;
 401}
 402
 403void 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}
 416