LXR qemu/linux-user/i386/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/* from the Linux kernel - /arch/x86/include/uapi/asm/sigcontext.h */
  26
  27struct target_fpreg {
  28    uint16_t significand[4];
  29    uint16_t exponent;
  30};
  31
  32struct target_fpxreg {
  33    uint16_t significand[4];
  34    uint16_t exponent;
  35    uint16_t padding[3];
  36};
  37
  38struct target_xmmreg {
  39    uint32_t element[4];
  40};
  41
  42struct target_fpstate_32 {
  43    /* Regular FPU environment */
  44    uint32_t cw;
  45    uint32_t sw;
  46    uint32_t tag;
  47    uint32_t ipoff;
  48    uint32_t cssel;
  49    uint32_t dataoff;
  50    uint32_t datasel;
  51    struct target_fpreg st[8];
  52    uint16_t  status;
  53    uint16_t  magic;          /* 0xffff = regular FPU data only */
  54
  55    /* FXSR FPU environment */
  56    uint32_t _fxsr_env[6];   /* FXSR FPU env is ignored */
  57    uint32_t mxcsr;
  58    uint32_t reserved;
  59    struct target_fpxreg fxsr_st[8]; /* FXSR FPU reg data is ignored */
  60    struct target_xmmreg xmm[8];
  61    uint32_t padding[56];
  62};
  63
  64struct target_fpstate_64 {
  65    /* FXSAVE format */
  66    uint16_t cw;
  67    uint16_t sw;
  68    uint16_t twd;
  69    uint16_t fop;
  70    uint64_t rip;
  71    uint64_t rdp;
  72    uint32_t mxcsr;
  73    uint32_t mxcsr_mask;
  74    uint32_t st_space[32];
  75    uint32_t xmm_space[64];
  76    uint32_t reserved[24];
  77};
  78
  79#ifndef TARGET_X86_64
  80# define target_fpstate target_fpstate_32
  81#else
  82# define target_fpstate target_fpstate_64
  83#endif
  84
  85struct target_sigcontext_32 {
  86    uint16_t gs, __gsh;
  87    uint16_t fs, __fsh;
  88    uint16_t es, __esh;
  89    uint16_t ds, __dsh;
  90    uint32_t edi;
  91    uint32_t esi;
  92    uint32_t ebp;
  93    uint32_t esp;
  94    uint32_t ebx;
  95    uint32_t edx;
  96    uint32_t ecx;
  97    uint32_t eax;
  98    uint32_t trapno;
  99    uint32_t err;
 100    uint32_t eip;
 101    uint16_t cs, __csh;
 102    uint32_t eflags;
 103    uint32_t esp_at_signal;
 104    uint16_t ss, __ssh;
 105    uint32_t fpstate; /* pointer */
 106    uint32_t oldmask;
 107    uint32_t cr2;
 108};
 109
 110struct target_sigcontext_64 {
 111    uint64_t r8;
 112    uint64_t r9;
 113    uint64_t r10;
 114    uint64_t r11;
 115    uint64_t r12;
 116    uint64_t r13;
 117    uint64_t r14;
 118    uint64_t r15;
 119
 120    uint64_t rdi;
 121    uint64_t rsi;
 122    uint64_t rbp;
 123    uint64_t rbx;
 124    uint64_t rdx;
 125    uint64_t rax;
 126    uint64_t rcx;
 127    uint64_t rsp;
 128    uint64_t rip;
 129
 130    uint64_t eflags;
 131
 132    uint16_t cs;
 133    uint16_t gs;
 134    uint16_t fs;
 135    uint16_t ss;
 136
 137    uint64_t err;
 138    uint64_t trapno;
 139    uint64_t oldmask;
 140    uint64_t cr2;
 141
 142    uint64_t fpstate; /* pointer */
 143    uint64_t padding[8];
 144};
 145
 146#ifndef TARGET_X86_64
 147# define target_sigcontext target_sigcontext_32
 148#else
 149# define target_sigcontext target_sigcontext_64
 150#endif
 151
 152/* see Linux/include/uapi/asm-generic/ucontext.h */
 153struct target_ucontext {
 154    abi_ulong         tuc_flags;
 155    abi_ulong         tuc_link;
 156    target_stack_t    tuc_stack;
 157    struct target_sigcontext tuc_mcontext;
 158    target_sigset_t   tuc_sigmask;  /* mask last for extensibility */
 159};
 160
 161#ifndef TARGET_X86_64
 162struct sigframe {
 163    abi_ulong pretcode;
 164    int sig;
 165    struct target_sigcontext sc;
 166    struct target_fpstate fpstate;
 167    abi_ulong extramask[TARGET_NSIG_WORDS-1];
 168    char retcode[8];
 169};
 170
 171struct rt_sigframe {
 172    abi_ulong pretcode;
 173    int sig;
 174    abi_ulong pinfo;
 175    abi_ulong puc;
 176    struct target_siginfo info;
 177    struct target_ucontext uc;
 178    struct target_fpstate fpstate;
 179    char retcode[8];
 180};
 181
 182#else
 183
 184struct rt_sigframe {
 185    abi_ulong pretcode;
 186    struct target_ucontext uc;
 187    struct target_siginfo info;
 188    struct target_fpstate fpstate;
 189};
 190
 191#endif
 192
 193/*
 194 * Set up a signal frame.
 195 */
 196
 197/* XXX: save x87 state */
 198static void setup_sigcontext(struct target_sigcontext *sc,
 199        struct target_fpstate *fpstate, CPUX86State *env, abi_ulong mask,
 200        abi_ulong fpstate_addr)
 201{
 202    CPUState *cs = env_cpu(env);
 203#ifndef TARGET_X86_64
 204    uint16_t magic;
 205
 206    /* already locked in setup_frame() */
 207    __put_user(env->segs[R_GS].selector, (unsigned int *)&sc->gs);
 208    __put_user(env->segs[R_FS].selector, (unsigned int *)&sc->fs);
 209    __put_user(env->segs[R_ES].selector, (unsigned int *)&sc->es);
 210    __put_user(env->segs[R_DS].selector, (unsigned int *)&sc->ds);
 211    __put_user(env->regs[R_EDI], &sc->edi);
 212    __put_user(env->regs[R_ESI], &sc->esi);
 213    __put_user(env->regs[R_EBP], &sc->ebp);
 214    __put_user(env->regs[R_ESP], &sc->esp);
 215    __put_user(env->regs[R_EBX], &sc->ebx);
 216    __put_user(env->regs[R_EDX], &sc->edx);
 217    __put_user(env->regs[R_ECX], &sc->ecx);
 218    __put_user(env->regs[R_EAX], &sc->eax);
 219    __put_user(cs->exception_index, &sc->trapno);
 220    __put_user(env->error_code, &sc->err);
 221    __put_user(env->eip, &sc->eip);
 222    __put_user(env->segs[R_CS].selector, (unsigned int *)&sc->cs);
 223    __put_user(env->eflags, &sc->eflags);
 224    __put_user(env->regs[R_ESP], &sc->esp_at_signal);
 225    __put_user(env->segs[R_SS].selector, (unsigned int *)&sc->ss);
 226
 227    cpu_x86_fsave(env, fpstate_addr, 1);
 228    fpstate->status = fpstate->sw;
 229    magic = 0xffff;
 230    __put_user(magic, &fpstate->magic);
 231    __put_user(fpstate_addr, &sc->fpstate);
 232
 233    /* non-iBCS2 extensions.. */
 234    __put_user(mask, &sc->oldmask);
 235    __put_user(env->cr[2], &sc->cr2);
 236#else
 237    __put_user(env->regs[R_EDI], &sc->rdi);
 238    __put_user(env->regs[R_ESI], &sc->rsi);
 239    __put_user(env->regs[R_EBP], &sc->rbp);
 240    __put_user(env->regs[R_ESP], &sc->rsp);
 241    __put_user(env->regs[R_EBX], &sc->rbx);
 242    __put_user(env->regs[R_EDX], &sc->rdx);
 243    __put_user(env->regs[R_ECX], &sc->rcx);
 244    __put_user(env->regs[R_EAX], &sc->rax);
 245
 246    __put_user(env->regs[8], &sc->r8);
 247    __put_user(env->regs[9], &sc->r9);
 248    __put_user(env->regs[10], &sc->r10);
 249    __put_user(env->regs[11], &sc->r11);
 250    __put_user(env->regs[12], &sc->r12);
 251    __put_user(env->regs[13], &sc->r13);
 252    __put_user(env->regs[14], &sc->r14);
 253    __put_user(env->regs[15], &sc->r15);
 254
 255    __put_user(cs->exception_index, &sc->trapno);
 256    __put_user(env->error_code, &sc->err);
 257    __put_user(env->eip, &sc->rip);
 258
 259    __put_user(env->eflags, &sc->eflags);
 260    __put_user(env->segs[R_CS].selector, &sc->cs);
 261    __put_user((uint16_t)0, &sc->gs);
 262    __put_user((uint16_t)0, &sc->fs);
 263    __put_user(env->segs[R_SS].selector, &sc->ss);
 264
 265    __put_user(mask, &sc->oldmask);
 266    __put_user(env->cr[2], &sc->cr2);
 267
 268    /* fpstate_addr must be 16 byte aligned for fxsave */
 269    assert(!(fpstate_addr & 0xf));
 270
 271    cpu_x86_fxsave(env, fpstate_addr);
 272    __put_user(fpstate_addr, &sc->fpstate);
 273#endif
 274}
 275
 276/*
 277 * Determine which stack to use..
 278 */
 279
 280static inline abi_ulong
 281get_sigframe(struct target_sigaction *ka, CPUX86State *env, size_t frame_size)
 282{
 283    unsigned long esp;
 284
 285    /* Default to using normal stack */
 286    esp = get_sp_from_cpustate(env);
 287#ifdef TARGET_X86_64
 288    esp -= 128; /* this is the redzone */
 289#endif
 290
 291    /* This is the X/Open sanctioned signal stack switching.  */
 292    if (ka->sa_flags & TARGET_SA_ONSTACK) {
 293        esp = target_sigsp(esp, ka);
 294    } else {
 295#ifndef TARGET_X86_64
 296        /* This is the legacy signal stack switching. */
 297        if ((env->segs[R_SS].selector & 0xffff) != __USER_DS &&
 298                !(ka->sa_flags & TARGET_SA_RESTORER) &&
 299                ka->sa_restorer) {
 300            esp = (unsigned long) ka->sa_restorer;
 301        }
 302#endif
 303    }
 304
 305#ifndef TARGET_X86_64
 306    return (esp - frame_size) & -8ul;
 307#else
 308    return ((esp - frame_size) & (~15ul)) - 8;
 309#endif
 310}
 311
 312#ifndef TARGET_X86_64
 313static void install_sigtramp(void *tramp)
 314{
 315    /* This is popl %eax ; movl $syscall,%eax ; int $0x80 */
 316    __put_user(0xb858, (uint16_t *)(tramp + 0));
 317    __put_user(TARGET_NR_sigreturn, (int32_t *)(tramp + 2));
 318    __put_user(0x80cd, (uint16_t *)(tramp + 6));
 319}
 320
 321static void install_rt_sigtramp(void *tramp)
 322{
 323    /* This is movl $syscall,%eax ; int $0x80 */
 324    __put_user(0xb8, (uint8_t *)(tramp + 0));
 325    __put_user(TARGET_NR_rt_sigreturn, (int32_t *)(tramp + 1));
 326    __put_user(0x80cd, (uint16_t *)(tramp + 5));
 327}
 328
 329/* compare linux/arch/i386/kernel/signal.c:setup_frame() */
 330void setup_frame(int sig, struct target_sigaction *ka,
 331                 target_sigset_t *set, CPUX86State *env)
 332{
 333    abi_ulong frame_addr;
 334    struct sigframe *frame;
 335    int i;
 336
 337    frame_addr = get_sigframe(ka, env, sizeof(*frame));
 338    trace_user_setup_frame(env, frame_addr);
 339
 340    if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0))
 341        goto give_sigsegv;
 342
 343    __put_user(sig, &frame->sig);
 344
 345    setup_sigcontext(&frame->sc, &frame->fpstate, env, set->sig[0],
 346            frame_addr + offsetof(struct sigframe, fpstate));
 347
 348    for(i = 1; i < TARGET_NSIG_WORDS; i++) {
 349        __put_user(set->sig[i], &frame->extramask[i - 1]);
 350    }
 351
 352    /* Set up to return from userspace.  If provided, use a stub
 353       already in userspace.  */
 354    if (ka->sa_flags & TARGET_SA_RESTORER) {
 355        __put_user(ka->sa_restorer, &frame->pretcode);
 356    } else {
 357        /* This is no longer used, but is retained for ABI compatibility. */
 358        install_sigtramp(frame->retcode);
 359        __put_user(default_sigreturn, &frame->pretcode);
 360    }
 361
 362    /* Set up registers for signal handler */
 363    env->regs[R_ESP] = frame_addr;
 364    env->eip = ka->_sa_handler;
 365
 366    cpu_x86_load_seg(env, R_DS, __USER_DS);
 367    cpu_x86_load_seg(env, R_ES, __USER_DS);
 368    cpu_x86_load_seg(env, R_SS, __USER_DS);
 369    cpu_x86_load_seg(env, R_CS, __USER_CS);
 370    env->eflags &= ~TF_MASK;
 371
 372    unlock_user_struct(frame, frame_addr, 1);
 373
 374    return;
 375
 376give_sigsegv:
 377    force_sigsegv(sig);
 378}
 379#endif
 380
 381/* compare linux/arch/x86/kernel/signal.c:setup_rt_frame() */
 382void setup_rt_frame(int sig, struct target_sigaction *ka,
 383                    target_siginfo_t *info,
 384                    target_sigset_t *set, CPUX86State *env)
 385{
 386    abi_ulong frame_addr;
 387#ifndef TARGET_X86_64
 388    abi_ulong addr;
 389#endif
 390    struct rt_sigframe *frame;
 391    int i;
 392
 393    frame_addr = get_sigframe(ka, env, sizeof(*frame));
 394    trace_user_setup_rt_frame(env, frame_addr);
 395
 396    if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0))
 397        goto give_sigsegv;
 398
 399    /* These fields are only in rt_sigframe on 32 bit */
 400#ifndef TARGET_X86_64
 401    __put_user(sig, &frame->sig);
 402    addr = frame_addr + offsetof(struct rt_sigframe, info);
 403    __put_user(addr, &frame->pinfo);
 404    addr = frame_addr + offsetof(struct rt_sigframe, uc);
 405    __put_user(addr, &frame->puc);
 406#endif
 407    if (ka->sa_flags & TARGET_SA_SIGINFO) {
 408        tswap_siginfo(&frame->info, info);
 409    }
 410
 411    /* Create the ucontext.  */
 412    __put_user(0, &frame->uc.tuc_flags);
 413    __put_user(0, &frame->uc.tuc_link);
 414    target_save_altstack(&frame->uc.tuc_stack, env);
 415    setup_sigcontext(&frame->uc.tuc_mcontext, &frame->fpstate, env,
 416            set->sig[0], frame_addr + offsetof(struct rt_sigframe, fpstate));
 417
 418    for(i = 0; i < TARGET_NSIG_WORDS; i++) {
 419        __put_user(set->sig[i], &frame->uc.tuc_sigmask.sig[i]);
 420    }
 421
 422    /* Set up to return from userspace.  If provided, use a stub
 423       already in userspace.  */
 424    if (ka->sa_flags & TARGET_SA_RESTORER) {
 425        __put_user(ka->sa_restorer, &frame->pretcode);
 426    } else {
 427#ifdef TARGET_X86_64
 428        /* For x86_64, SA_RESTORER is required ABI.  */
 429        goto give_sigsegv;
 430#else
 431        /* This is no longer used, but is retained for ABI compatibility. */
 432        install_rt_sigtramp(frame->retcode);
 433        __put_user(default_rt_sigreturn, &frame->pretcode);
 434#endif
 435    }
 436
 437    /* Set up registers for signal handler */
 438    env->regs[R_ESP] = frame_addr;
 439    env->eip = ka->_sa_handler;
 440
 441#ifndef TARGET_X86_64
 442    env->regs[R_EAX] = sig;
 443    env->regs[R_EDX] = frame_addr + offsetof(struct rt_sigframe, info);
 444    env->regs[R_ECX] = frame_addr + offsetof(struct rt_sigframe, uc);
 445#else
 446    env->regs[R_EAX] = 0;
 447    env->regs[R_EDI] = sig;
 448    env->regs[R_ESI] = frame_addr + offsetof(struct rt_sigframe, info);
 449    env->regs[R_EDX] = frame_addr + offsetof(struct rt_sigframe, uc);
 450#endif
 451
 452    cpu_x86_load_seg(env, R_DS, __USER_DS);
 453    cpu_x86_load_seg(env, R_ES, __USER_DS);
 454    cpu_x86_load_seg(env, R_CS, __USER_CS);
 455    cpu_x86_load_seg(env, R_SS, __USER_DS);
 456    env->eflags &= ~TF_MASK;
 457
 458    unlock_user_struct(frame, frame_addr, 1);
 459
 460    return;
 461
 462give_sigsegv:
 463    force_sigsegv(sig);
 464}
 465
 466static int
 467restore_sigcontext(CPUX86State *env, struct target_sigcontext *sc)
 468{
 469    unsigned int err = 0;
 470    abi_ulong fpstate_addr;
 471    unsigned int tmpflags;
 472
 473#ifndef TARGET_X86_64
 474    cpu_x86_load_seg(env, R_GS, tswap16(sc->gs));
 475    cpu_x86_load_seg(env, R_FS, tswap16(sc->fs));
 476    cpu_x86_load_seg(env, R_ES, tswap16(sc->es));
 477    cpu_x86_load_seg(env, R_DS, tswap16(sc->ds));
 478
 479    env->regs[R_EDI] = tswapl(sc->edi);
 480    env->regs[R_ESI] = tswapl(sc->esi);
 481    env->regs[R_EBP] = tswapl(sc->ebp);
 482    env->regs[R_ESP] = tswapl(sc->esp);
 483    env->regs[R_EBX] = tswapl(sc->ebx);
 484    env->regs[R_EDX] = tswapl(sc->edx);
 485    env->regs[R_ECX] = tswapl(sc->ecx);
 486    env->regs[R_EAX] = tswapl(sc->eax);
 487
 488    env->eip = tswapl(sc->eip);
 489#else
 490    env->regs[8] = tswapl(sc->r8);
 491    env->regs[9] = tswapl(sc->r9);
 492    env->regs[10] = tswapl(sc->r10);
 493    env->regs[11] = tswapl(sc->r11);
 494    env->regs[12] = tswapl(sc->r12);
 495    env->regs[13] = tswapl(sc->r13);
 496    env->regs[14] = tswapl(sc->r14);
 497    env->regs[15] = tswapl(sc->r15);
 498
 499    env->regs[R_EDI] = tswapl(sc->rdi);
 500    env->regs[R_ESI] = tswapl(sc->rsi);
 501    env->regs[R_EBP] = tswapl(sc->rbp);
 502    env->regs[R_EBX] = tswapl(sc->rbx);
 503    env->regs[R_EDX] = tswapl(sc->rdx);
 504    env->regs[R_EAX] = tswapl(sc->rax);
 505    env->regs[R_ECX] = tswapl(sc->rcx);
 506    env->regs[R_ESP] = tswapl(sc->rsp);
 507
 508    env->eip = tswapl(sc->rip);
 509#endif
 510
 511    cpu_x86_load_seg(env, R_CS, lduw_p(&sc->cs) | 3);
 512    cpu_x86_load_seg(env, R_SS, lduw_p(&sc->ss) | 3);
 513
 514    tmpflags = tswapl(sc->eflags);
 515    env->eflags = (env->eflags & ~0x40DD5) | (tmpflags & 0x40DD5);
 516    //          regs->orig_eax = -1;            /* disable syscall checks */
 517
 518    fpstate_addr = tswapl(sc->fpstate);
 519    if (fpstate_addr != 0) {
 520        if (!access_ok(env_cpu(env), VERIFY_READ, fpstate_addr,
 521                       sizeof(struct target_fpstate))) {
 522            goto badframe;
 523        }
 524#ifndef TARGET_X86_64
 525        cpu_x86_frstor(env, fpstate_addr, 1);
 526#else
 527        cpu_x86_fxrstor(env, fpstate_addr);
 528#endif
 529    }
 530
 531    return err;
 532badframe:
 533    return 1;
 534}
 535
 536/* Note: there is no sigreturn on x86_64, there is only rt_sigreturn */
 537#ifndef TARGET_X86_64
 538long do_sigreturn(CPUX86State *env)
 539{
 540    struct sigframe *frame;
 541    abi_ulong frame_addr = env->regs[R_ESP] - 8;
 542    target_sigset_t target_set;
 543    sigset_t set;
 544    int i;
 545
 546    trace_user_do_sigreturn(env, frame_addr);
 547    if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1))
 548        goto badframe;
 549    /* set blocked signals */
 550    __get_user(target_set.sig[0], &frame->sc.oldmask);
 551    for(i = 1; i < TARGET_NSIG_WORDS; i++) {
 552        __get_user(target_set.sig[i], &frame->extramask[i - 1]);
 553    }
 554
 555    target_to_host_sigset_internal(&set, &target_set);
 556    set_sigmask(&set);
 557
 558    /* restore registers */
 559    if (restore_sigcontext(env, &frame->sc))
 560        goto badframe;
 561    unlock_user_struct(frame, frame_addr, 0);
 562    return -QEMU_ESIGRETURN;
 563
 564badframe:
 565    unlock_user_struct(frame, frame_addr, 0);
 566    force_sig(TARGET_SIGSEGV);
 567    return -QEMU_ESIGRETURN;
 568}
 569#endif
 570
 571long do_rt_sigreturn(CPUX86State *env)
 572{
 573    abi_ulong frame_addr;
 574    struct rt_sigframe *frame;
 575    sigset_t set;
 576
 577    frame_addr = env->regs[R_ESP] - sizeof(abi_ulong);
 578    trace_user_do_rt_sigreturn(env, frame_addr);
 579    if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1))
 580        goto badframe;
 581    target_to_host_sigset(&set, &frame->uc.tuc_sigmask);
 582    set_sigmask(&set);
 583
 584    if (restore_sigcontext(env, &frame->uc.tuc_mcontext)) {
 585        goto badframe;
 586    }
 587
 588    target_restore_altstack(&frame->uc.tuc_stack, env);
 589
 590    unlock_user_struct(frame, frame_addr, 0);
 591    return -QEMU_ESIGRETURN;
 592
 593badframe:
 594    unlock_user_struct(frame, frame_addr, 0);
 595    force_sig(TARGET_SIGSEGV);
 596    return -QEMU_ESIGRETURN;
 597}
 598
 599#ifndef TARGET_X86_64
 600void setup_sigtramp(abi_ulong sigtramp_page)
 601{
 602    uint16_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 2 * 8, 0);
 603    assert(tramp != NULL);
 604
 605    default_sigreturn = sigtramp_page;
 606    install_sigtramp(tramp);
 607
 608    default_rt_sigreturn = sigtramp_page + 8;
 609    install_rt_sigtramp(tramp + 8);
 610
 611    unlock_user(tramp, sigtramp_page, 2 * 8);
 612}
 613#endif
 614