LXR qemu/linux-user/sh4/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/*
  26 * code and data structures from linux kernel:
  27 * include/asm-sh/sigcontext.h
  28 * arch/sh/kernel/signal.c
  29 */
  30
  31struct target_sigcontext {
  32    target_ulong  oldmask;
  33
  34    /* CPU registers */
  35    target_ulong  sc_gregs[16];
  36    target_ulong  sc_pc;
  37    target_ulong  sc_pr;
  38    target_ulong  sc_sr;
  39    target_ulong  sc_gbr;
  40    target_ulong  sc_mach;
  41    target_ulong  sc_macl;
  42
  43    /* FPU registers */
  44    target_ulong  sc_fpregs[16];
  45    target_ulong  sc_xfpregs[16];
  46    unsigned int sc_fpscr;
  47    unsigned int sc_fpul;
  48    unsigned int sc_ownedfp;
  49};
  50
  51struct target_sigframe
  52{
  53    struct target_sigcontext sc;
  54    target_ulong extramask[TARGET_NSIG_WORDS-1];
  55};
  56
  57
  58struct target_ucontext {
  59    target_ulong tuc_flags;
  60    struct target_ucontext *tuc_link;
  61    target_stack_t tuc_stack;
  62    struct target_sigcontext tuc_mcontext;
  63    target_sigset_t tuc_sigmask;        /* mask last for extensibility */
  64};
  65
  66struct target_rt_sigframe
  67{
  68    struct target_siginfo info;
  69    struct target_ucontext uc;
  70};
  71
  72
  73#define MOVW(n)  (0x9300|((n)-2)) /* Move mem word at PC+n to R3 */
  74#define TRAP_NOARG 0xc310         /* Syscall w/no args (NR in R3) SH3/4 */
  75
  76static abi_ulong get_sigframe(struct target_sigaction *ka,
  77                              unsigned long sp, size_t frame_size)
  78{
  79    sp = target_sigsp(sp, ka);
  80
  81    return (sp - frame_size) & -8ul;
  82}
  83
  84/*
  85 * Notice when we're in the middle of a gUSA region and reset.
  86 * Note that this will only occur when #CF_PARALLEL is unset, as we
  87 * will translate such sequences differently in a parallel context.
  88 */
  89static void unwind_gusa(CPUSH4State *regs)
  90{
  91    /* If the stack pointer is sufficiently negative, and we haven't
  92       completed the sequence, then reset to the entry to the region.  */
  93    /* ??? The SH4 kernel checks for and address above 0xC0000000.
  94       However, the page mappings in qemu linux-user aren't as restricted
  95       and we wind up with the normal stack mapped above 0xF0000000.
  96       That said, there is no reason why the kernel should be allowing
  97       a gUSA region that spans 1GB.  Use a tighter check here, for what
  98       can actually be enabled by the immediate move.  */
  99    if (regs->gregs[15] >= -128u && regs->pc < regs->gregs[0]) {
 100        /* Reset the PC to before the gUSA region, as computed from
 101           R0 = region end, SP = -(region size), plus one more for the
 102           insn that actually initializes SP to the region size.  */
 103        regs->pc = regs->gregs[0] + regs->gregs[15] - 2;
 104
 105        /* Reset the SP to the saved version in R1.  */
 106        regs->gregs[15] = regs->gregs[1];
 107    }
 108}
 109
 110static void setup_sigcontext(struct target_sigcontext *sc,
 111                             CPUSH4State *regs, unsigned long mask)
 112{
 113    int i;
 114
 115#define COPY(x)         __put_user(regs->x, &sc->sc_##x)
 116    COPY(gregs[0]); COPY(gregs[1]);
 117    COPY(gregs[2]); COPY(gregs[3]);
 118    COPY(gregs[4]); COPY(gregs[5]);
 119    COPY(gregs[6]); COPY(gregs[7]);
 120    COPY(gregs[8]); COPY(gregs[9]);
 121    COPY(gregs[10]); COPY(gregs[11]);
 122    COPY(gregs[12]); COPY(gregs[13]);
 123    COPY(gregs[14]); COPY(gregs[15]);
 124    COPY(gbr); COPY(mach);
 125    COPY(macl); COPY(pr);
 126    COPY(sr); COPY(pc);
 127#undef COPY
 128
 129    for (i=0; i<16; i++) {
 130        __put_user(regs->fregs[i], &sc->sc_fpregs[i]);
 131    }
 132    __put_user(regs->fpscr, &sc->sc_fpscr);
 133    __put_user(regs->fpul, &sc->sc_fpul);
 134
 135    /* non-iBCS2 extensions.. */
 136    __put_user(mask, &sc->oldmask);
 137}
 138
 139static void restore_sigcontext(CPUSH4State *regs, struct target_sigcontext *sc)
 140{
 141    int i;
 142
 143#define COPY(x)         __get_user(regs->x, &sc->sc_##x)
 144    COPY(gregs[0]); COPY(gregs[1]);
 145    COPY(gregs[2]); COPY(gregs[3]);
 146    COPY(gregs[4]); COPY(gregs[5]);
 147    COPY(gregs[6]); COPY(gregs[7]);
 148    COPY(gregs[8]); COPY(gregs[9]);
 149    COPY(gregs[10]); COPY(gregs[11]);
 150    COPY(gregs[12]); COPY(gregs[13]);
 151    COPY(gregs[14]); COPY(gregs[15]);
 152    COPY(gbr); COPY(mach);
 153    COPY(macl); COPY(pr);
 154    COPY(sr); COPY(pc);
 155#undef COPY
 156
 157    for (i=0; i<16; i++) {
 158        __get_user(regs->fregs[i], &sc->sc_fpregs[i]);
 159    }
 160    __get_user(regs->fpscr, &sc->sc_fpscr);
 161    __get_user(regs->fpul, &sc->sc_fpul);
 162
 163    regs->tra = -1;         /* disable syscall checks */
 164    regs->flags &= ~(DELAY_SLOT_MASK | GUSA_MASK);
 165}
 166
 167void setup_frame(int sig, struct target_sigaction *ka,
 168                 target_sigset_t *set, CPUSH4State *regs)
 169{
 170    struct target_sigframe *frame;
 171    abi_ulong frame_addr;
 172    int i;
 173
 174    unwind_gusa(regs);
 175
 176    frame_addr = get_sigframe(ka, regs->gregs[15], sizeof(*frame));
 177    trace_user_setup_frame(regs, frame_addr);
 178    if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
 179        goto give_sigsegv;
 180    }
 181
 182    setup_sigcontext(&frame->sc, regs, set->sig[0]);
 183
 184    for (i = 0; i < TARGET_NSIG_WORDS - 1; i++) {
 185        __put_user(set->sig[i + 1], &frame->extramask[i]);
 186    }
 187
 188    /* Set up to return from userspace.  If provided, use a stub
 189       already in userspace.  */
 190    if (ka->sa_flags & TARGET_SA_RESTORER) {
 191        regs->pr = ka->sa_restorer;
 192    } else {
 193        regs->pr = default_sigreturn;
 194    }
 195
 196    /* Set up registers for signal handler */
 197    regs->gregs[15] = frame_addr;
 198    regs->gregs[4] = sig; /* Arg for signal handler */
 199    regs->gregs[5] = 0;
 200    regs->gregs[6] = frame_addr += offsetof(typeof(*frame), sc);
 201    regs->pc = (unsigned long) ka->_sa_handler;
 202    regs->flags &= ~(DELAY_SLOT_MASK | GUSA_MASK);
 203
 204    unlock_user_struct(frame, frame_addr, 1);
 205    return;
 206
 207give_sigsegv:
 208    unlock_user_struct(frame, frame_addr, 1);
 209    force_sigsegv(sig);
 210}
 211
 212void setup_rt_frame(int sig, struct target_sigaction *ka,
 213                    target_siginfo_t *info,
 214                    target_sigset_t *set, CPUSH4State *regs)
 215{
 216    struct target_rt_sigframe *frame;
 217    abi_ulong frame_addr;
 218    int i;
 219
 220    unwind_gusa(regs);
 221
 222    frame_addr = get_sigframe(ka, regs->gregs[15], sizeof(*frame));
 223    trace_user_setup_rt_frame(regs, frame_addr);
 224    if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
 225        goto give_sigsegv;
 226    }
 227
 228    tswap_siginfo(&frame->info, info);
 229
 230    /* Create the ucontext.  */
 231    __put_user(0, &frame->uc.tuc_flags);
 232    __put_user(0, (unsigned long *)&frame->uc.tuc_link);
 233    target_save_altstack(&frame->uc.tuc_stack, regs);
 234    setup_sigcontext(&frame->uc.tuc_mcontext,
 235                     regs, set->sig[0]);
 236    for(i = 0; i < TARGET_NSIG_WORDS; i++) {
 237        __put_user(set->sig[i], &frame->uc.tuc_sigmask.sig[i]);
 238    }
 239
 240    /* Set up to return from userspace.  If provided, use a stub
 241       already in userspace.  */
 242    if (ka->sa_flags & TARGET_SA_RESTORER) {
 243        regs->pr = ka->sa_restorer;
 244    } else {
 245        regs->pr = default_rt_sigreturn;
 246    }
 247
 248    /* Set up registers for signal handler */
 249    regs->gregs[15] = frame_addr;
 250    regs->gregs[4] = sig; /* Arg for signal handler */
 251    regs->gregs[5] = frame_addr + offsetof(typeof(*frame), info);
 252    regs->gregs[6] = frame_addr + offsetof(typeof(*frame), uc);
 253    regs->pc = (unsigned long) ka->_sa_handler;
 254    regs->flags &= ~(DELAY_SLOT_MASK | GUSA_MASK);
 255
 256    unlock_user_struct(frame, frame_addr, 1);
 257    return;
 258
 259give_sigsegv:
 260    unlock_user_struct(frame, frame_addr, 1);
 261    force_sigsegv(sig);
 262}
 263
 264long do_sigreturn(CPUSH4State *regs)
 265{
 266    struct target_sigframe *frame;
 267    abi_ulong frame_addr;
 268    sigset_t blocked;
 269    target_sigset_t target_set;
 270    int i;
 271
 272    frame_addr = regs->gregs[15];
 273    trace_user_do_sigreturn(regs, frame_addr);
 274    if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
 275        goto badframe;
 276    }
 277
 278    __get_user(target_set.sig[0], &frame->sc.oldmask);
 279    for(i = 1; i < TARGET_NSIG_WORDS; i++) {
 280        __get_user(target_set.sig[i], &frame->extramask[i - 1]);
 281    }
 282
 283    target_to_host_sigset_internal(&blocked, &target_set);
 284    set_sigmask(&blocked);
 285
 286    restore_sigcontext(regs, &frame->sc);
 287
 288    unlock_user_struct(frame, frame_addr, 0);
 289    return -TARGET_QEMU_ESIGRETURN;
 290
 291badframe:
 292    unlock_user_struct(frame, frame_addr, 0);
 293    force_sig(TARGET_SIGSEGV);
 294    return -TARGET_QEMU_ESIGRETURN;
 295}
 296
 297long do_rt_sigreturn(CPUSH4State *regs)
 298{
 299    struct target_rt_sigframe *frame;
 300    abi_ulong frame_addr;
 301    sigset_t blocked;
 302
 303    frame_addr = regs->gregs[15];
 304    trace_user_do_rt_sigreturn(regs, frame_addr);
 305    if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
 306        goto badframe;
 307    }
 308
 309    target_to_host_sigset(&blocked, &frame->uc.tuc_sigmask);
 310    set_sigmask(&blocked);
 311
 312    restore_sigcontext(regs, &frame->uc.tuc_mcontext);
 313    target_restore_altstack(&frame->uc.tuc_stack, regs);
 314
 315    unlock_user_struct(frame, frame_addr, 0);
 316    return -TARGET_QEMU_ESIGRETURN;
 317
 318badframe:
 319    unlock_user_struct(frame, frame_addr, 0);
 320    force_sig(TARGET_SIGSEGV);
 321    return -TARGET_QEMU_ESIGRETURN;
 322}
 323
 324void setup_sigtramp(abi_ulong sigtramp_page)
 325{
 326    uint16_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 2 * 6, 0);
 327    assert(tramp != NULL);
 328
 329    default_sigreturn = sigtramp_page;
 330    __put_user(MOVW(2), &tramp[0]);
 331    __put_user(TRAP_NOARG, &tramp[1]);
 332    __put_user(TARGET_NR_sigreturn, &tramp[2]);
 333
 334    default_rt_sigreturn = sigtramp_page + 6;
 335    __put_user(MOVW(2), &tramp[3]);
 336    __put_user(TRAP_NOARG, &tramp[4]);
 337    __put_user(TARGET_NR_rt_sigreturn, &tramp[5]);
 338
 339    unlock_user(tramp, sigtramp_page, 2 * 6);
 340}
 341