qemu/linux-user/xtensa/signal.c
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   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
  25struct target_sigcontext {
  26    abi_ulong sc_pc;
  27    abi_ulong sc_ps;
  28    abi_ulong sc_lbeg;
  29    abi_ulong sc_lend;
  30    abi_ulong sc_lcount;
  31    abi_ulong sc_sar;
  32    abi_ulong sc_acclo;
  33    abi_ulong sc_acchi;
  34    abi_ulong sc_a[16];
  35    abi_ulong sc_xtregs;
  36};
  37
  38struct target_ucontext {
  39    abi_ulong tuc_flags;
  40    abi_ulong tuc_link;
  41    target_stack_t tuc_stack;
  42    struct target_sigcontext tuc_mcontext;
  43    target_sigset_t tuc_sigmask;
  44};
  45
  46struct target_rt_sigframe {
  47    target_siginfo_t info;
  48    struct target_ucontext uc;
  49    /* TODO: xtregs */
  50    uint8_t retcode[6];
  51    abi_ulong window[4];
  52};
  53
  54static abi_ulong get_sigframe(struct target_sigaction *sa,
  55                              CPUXtensaState *env,
  56                              unsigned long framesize)
  57{
  58    abi_ulong sp;
  59
  60    sp = target_sigsp(get_sp_from_cpustate(env), sa);
  61
  62    return (sp - framesize) & -16;
  63}
  64
  65static int flush_window_regs(CPUXtensaState *env)
  66{
  67    uint32_t wb = env->sregs[WINDOW_BASE];
  68    uint32_t ws = xtensa_replicate_windowstart(env) >> (wb + 1);
  69    unsigned d = ctz32(ws) + 1;
  70    unsigned i;
  71    int ret = 0;
  72
  73    for (i = d; i < env->config->nareg / 4; i += d) {
  74        uint32_t ssp, osp;
  75        unsigned j;
  76
  77        ws >>= d;
  78        xtensa_rotate_window(env, d);
  79
  80        if (ws & 0x1) {
  81            ssp = env->regs[5];
  82            d = 1;
  83        } else if (ws & 0x2) {
  84            ssp = env->regs[9];
  85            ret |= get_user_ual(osp, env->regs[1] - 12);
  86            osp -= 32;
  87            d = 2;
  88        } else if (ws & 0x4) {
  89            ssp = env->regs[13];
  90            ret |= get_user_ual(osp, env->regs[1] - 12);
  91            osp -= 48;
  92            d = 3;
  93        } else {
  94            g_assert_not_reached();
  95        }
  96
  97        for (j = 0; j < 4; ++j) {
  98            ret |= put_user_ual(env->regs[j], ssp - 16 + j * 4);
  99        }
 100        for (j = 4; j < d * 4; ++j) {
 101            ret |= put_user_ual(env->regs[j], osp - 16 + j * 4);
 102        }
 103    }
 104    xtensa_rotate_window(env, d);
 105    g_assert(env->sregs[WINDOW_BASE] == wb);
 106    return ret == 0;
 107}
 108
 109static int setup_sigcontext(struct target_rt_sigframe *frame,
 110                            CPUXtensaState *env)
 111{
 112    struct target_sigcontext *sc = &frame->uc.tuc_mcontext;
 113    int i;
 114
 115    __put_user(env->pc, &sc->sc_pc);
 116    __put_user(env->sregs[PS], &sc->sc_ps);
 117    __put_user(env->sregs[LBEG], &sc->sc_lbeg);
 118    __put_user(env->sregs[LEND], &sc->sc_lend);
 119    __put_user(env->sregs[LCOUNT], &sc->sc_lcount);
 120    if (!flush_window_regs(env)) {
 121        return 0;
 122    }
 123    for (i = 0; i < 16; ++i) {
 124        __put_user(env->regs[i], sc->sc_a + i);
 125    }
 126    __put_user(0, &sc->sc_xtregs);
 127    /* TODO: xtregs */
 128    return 1;
 129}
 130
 131static void install_sigtramp(uint8_t *tramp)
 132{
 133#if TARGET_BIG_ENDIAN
 134    /* Generate instruction:  MOVI a2, __NR_rt_sigreturn */
 135    __put_user(0x22, &tramp[0]);
 136    __put_user(0x0a, &tramp[1]);
 137    __put_user(TARGET_NR_rt_sigreturn, &tramp[2]);
 138    /* Generate instruction:  SYSCALL */
 139    __put_user(0x00, &tramp[3]);
 140    __put_user(0x05, &tramp[4]);
 141    __put_user(0x00, &tramp[5]);
 142#else
 143    /* Generate instruction:  MOVI a2, __NR_rt_sigreturn */
 144    __put_user(0x22, &tramp[0]);
 145    __put_user(0xa0, &tramp[1]);
 146    __put_user(TARGET_NR_rt_sigreturn, &tramp[2]);
 147    /* Generate instruction:  SYSCALL */
 148    __put_user(0x00, &tramp[3]);
 149    __put_user(0x50, &tramp[4]);
 150    __put_user(0x00, &tramp[5]);
 151#endif
 152}
 153
 154void setup_rt_frame(int sig, struct target_sigaction *ka,
 155                    target_siginfo_t *info,
 156                    target_sigset_t *set, CPUXtensaState *env)
 157{
 158    abi_ulong frame_addr;
 159    struct target_rt_sigframe *frame;
 160    uint32_t ra;
 161    bool abi_call0;
 162    unsigned base;
 163    int i;
 164
 165    frame_addr = get_sigframe(ka, env, sizeof(*frame));
 166    trace_user_setup_rt_frame(env, frame_addr);
 167
 168    if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
 169        goto give_sigsegv;
 170    }
 171
 172    if (ka->sa_flags & SA_SIGINFO) {
 173        tswap_siginfo(&frame->info, info);
 174    }
 175
 176    __put_user(0, &frame->uc.tuc_flags);
 177    __put_user(0, &frame->uc.tuc_link);
 178    target_save_altstack(&frame->uc.tuc_stack, env);
 179    if (!setup_sigcontext(frame, env)) {
 180        unlock_user_struct(frame, frame_addr, 0);
 181        goto give_sigsegv;
 182    }
 183    for (i = 0; i < TARGET_NSIG_WORDS; ++i) {
 184        __put_user(set->sig[i], &frame->uc.tuc_sigmask.sig[i]);
 185    }
 186
 187    if (ka->sa_flags & TARGET_SA_RESTORER) {
 188        ra = ka->sa_restorer;
 189    } else {
 190        /* Not used, but retain for ABI compatibility. */
 191        install_sigtramp(frame->retcode);
 192        ra = default_rt_sigreturn;
 193    }
 194    memset(env->regs, 0, sizeof(env->regs));
 195    env->pc = ka->_sa_handler;
 196    env->regs[1] = frame_addr;
 197    env->sregs[WINDOW_BASE] = 0;
 198    env->sregs[WINDOW_START] = 1;
 199
 200    abi_call0 = (env->sregs[PS] & PS_WOE) == 0;
 201    env->sregs[PS] = PS_UM | (3 << PS_RING_SHIFT);
 202
 203    if (abi_call0) {
 204        base = 0;
 205        env->regs[base] = ra;
 206    } else {
 207        env->sregs[PS] |= PS_WOE | (1 << PS_CALLINC_SHIFT);
 208        base = 4;
 209        env->regs[base] = (ra & 0x3fffffff) | 0x40000000;
 210    }
 211    env->regs[base + 2] = sig;
 212    env->regs[base + 3] = frame_addr + offsetof(struct target_rt_sigframe,
 213                                                info);
 214    env->regs[base + 4] = frame_addr + offsetof(struct target_rt_sigframe, uc);
 215    unlock_user_struct(frame, frame_addr, 1);
 216    return;
 217
 218give_sigsegv:
 219    force_sigsegv(sig);
 220    return;
 221}
 222
 223static void restore_sigcontext(CPUXtensaState *env,
 224                               struct target_rt_sigframe *frame)
 225{
 226    struct target_sigcontext *sc = &frame->uc.tuc_mcontext;
 227    uint32_t ps;
 228    int i;
 229
 230    __get_user(env->pc, &sc->sc_pc);
 231    __get_user(ps, &sc->sc_ps);
 232    __get_user(env->sregs[LBEG], &sc->sc_lbeg);
 233    __get_user(env->sregs[LEND], &sc->sc_lend);
 234    __get_user(env->sregs[LCOUNT], &sc->sc_lcount);
 235
 236    env->sregs[WINDOW_BASE] = 0;
 237    env->sregs[WINDOW_START] = 1;
 238    env->sregs[PS] = deposit32(env->sregs[PS],
 239                               PS_CALLINC_SHIFT,
 240                               PS_CALLINC_LEN,
 241                               extract32(ps, PS_CALLINC_SHIFT,
 242                                         PS_CALLINC_LEN));
 243    for (i = 0; i < 16; ++i) {
 244        __get_user(env->regs[i], sc->sc_a + i);
 245    }
 246    /* TODO: xtregs */
 247}
 248
 249long do_rt_sigreturn(CPUXtensaState *env)
 250{
 251    abi_ulong frame_addr = env->regs[1];
 252    struct target_rt_sigframe *frame;
 253    sigset_t set;
 254
 255    trace_user_do_rt_sigreturn(env, frame_addr);
 256    if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
 257        goto badframe;
 258    }
 259    target_to_host_sigset(&set, &frame->uc.tuc_sigmask);
 260    set_sigmask(&set);
 261
 262    restore_sigcontext(env, frame);
 263    target_restore_altstack(&frame->uc.tuc_stack, env);
 264
 265    unlock_user_struct(frame, frame_addr, 0);
 266    return -QEMU_ESIGRETURN;
 267
 268badframe:
 269    unlock_user_struct(frame, frame_addr, 0);
 270    force_sig(TARGET_SIGSEGV);
 271    return -QEMU_ESIGRETURN;
 272}
 273
 274void setup_sigtramp(abi_ulong sigtramp_page)
 275{
 276    uint8_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 6, 0);
 277    assert(tramp != NULL);
 278
 279    default_rt_sigreturn = sigtramp_page;
 280    install_sigtramp(tramp);
 281    unlock_user(tramp, sigtramp_page, 6);
 282}
 283