linux-user/xtensa/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 struct 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
  38 struct 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
  46 struct 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
  54 static 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
  65 static 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
 109 static 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
 131 static 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
 154 void 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     int is_fdpic = info_is_fdpic(get_task_state(thread_cpu)->info);
 161     abi_ulong handler = 0;
 162     abi_ulong handler_fdpic_GOT = 0;
 163     uint32_t ra;
 164     bool abi_call0;
 165     unsigned base;
 166     int i;
 167
 168     frame_addr = get_sigframe(ka, env, sizeof(*frame));
 169     trace_user_setup_rt_frame(env, frame_addr);
 170
 171     if (is_fdpic) {
 172         abi_ulong funcdesc_ptr = ka->_sa_handler;
 173
 174         if (get_user_ual(handler, funcdesc_ptr)
 175             || get_user_ual(handler_fdpic_GOT, funcdesc_ptr + 4)) {
 176             goto give_sigsegv;
 177         }
 178     } else {
 179         handler = ka->_sa_handler;
 180     }
 181
 182     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
 183         goto give_sigsegv;
 184     }
 185
 186     if (ka->sa_flags & SA_SIGINFO) {
 187         frame->info = *info;
 188     }
 189
 190     __put_user(0, &frame->uc.tuc_flags);
 191     __put_user(0, &frame->uc.tuc_link);
 192     target_save_altstack(&frame->uc.tuc_stack, env);
 193     if (!setup_sigcontext(frame, env)) {
 194         unlock_user_struct(frame, frame_addr, 0);
 195         goto give_sigsegv;
 196     }
 197     for (i = 0; i < TARGET_NSIG_WORDS; ++i) {
 198         __put_user(set->sig[i], &frame->uc.tuc_sigmask.sig[i]);
 199     }
 200
 201     if (ka->sa_flags & TARGET_SA_RESTORER) {
 202         if (is_fdpic) {
 203             if (get_user_ual(ra, ka->sa_restorer)) {
 204                 unlock_user_struct(frame, frame_addr, 0);
 205                 goto give_sigsegv;
 206             }
 207         } else {
 208             ra = ka->sa_restorer;
 209         }
 210     } else {
 211         /* Not used, but retain for ABI compatibility. */
 212         install_sigtramp(frame->retcode);
 213         ra = default_rt_sigreturn;
 214     }
 215     memset(env->regs, 0, sizeof(env->regs));
 216     env->pc = handler;
 217     env->regs[1] = frame_addr;
 218     env->sregs[WINDOW_BASE] = 0;
 219     env->sregs[WINDOW_START] = 1;
 220
 221     abi_call0 = (env->sregs[PS] & PS_WOE) == 0;
 222     env->sregs[PS] = PS_UM | (3 << PS_RING_SHIFT);
 223
 224     if (abi_call0) {
 225         base = 0;
 226         env->regs[base] = ra;
 227     } else {
 228         env->sregs[PS] |= PS_WOE | (1 << PS_CALLINC_SHIFT);
 229         base = 4;
 230         env->regs[base] = (ra & 0x3fffffff) | 0x40000000;
 231     }
 232     env->regs[base + 2] = sig;
 233     env->regs[base + 3] = frame_addr + offsetof(struct target_rt_sigframe,
 234                                                 info);
 235     env->regs[base + 4] = frame_addr + offsetof(struct target_rt_sigframe, uc);
 236     if (is_fdpic) {
 237         env->regs[base + 11] = handler_fdpic_GOT;
 238     }
 239     unlock_user_struct(frame, frame_addr, 1);
 240     return;
 241
 242 give_sigsegv:
 243     force_sigsegv(sig);
 244     return;
 245 }
 246
 247 static void restore_sigcontext(CPUXtensaState *env,
 248                                struct target_rt_sigframe *frame)
 249 {
 250     struct target_sigcontext *sc = &frame->uc.tuc_mcontext;
 251     uint32_t ps;
 252     int i;
 253
 254     __get_user(env->pc, &sc->sc_pc);
 255     __get_user(ps, &sc->sc_ps);
 256     __get_user(env->sregs[LBEG], &sc->sc_lbeg);
 257     __get_user(env->sregs[LEND], &sc->sc_lend);
 258     __get_user(env->sregs[LCOUNT], &sc->sc_lcount);
 259
 260     env->sregs[WINDOW_BASE] = 0;
 261     env->sregs[WINDOW_START] = 1;
 262     env->sregs[PS] = deposit32(env->sregs[PS],
 263                                PS_CALLINC_SHIFT,
 264                                PS_CALLINC_LEN,
 265                                extract32(ps, PS_CALLINC_SHIFT,
 266                                          PS_CALLINC_LEN));
 267     for (i = 0; i < 16; ++i) {
 268         __get_user(env->regs[i], sc->sc_a + i);
 269     }
 270     /* TODO: xtregs */
 271 }
 272
 273 long do_rt_sigreturn(CPUXtensaState *env)
 274 {
 275     abi_ulong frame_addr = env->regs[1];
 276     struct target_rt_sigframe *frame;
 277     sigset_t set;
 278
 279     trace_user_do_rt_sigreturn(env, frame_addr);
 280     if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
 281         goto badframe;
 282     }
 283     target_to_host_sigset(&set, &frame->uc.tuc_sigmask);
 284     set_sigmask(&set);
 285
 286     restore_sigcontext(env, frame);
 287     target_restore_altstack(&frame->uc.tuc_stack, env);
 288
 289     unlock_user_struct(frame, frame_addr, 0);
 290     return -QEMU_ESIGRETURN;
 291
 292 badframe:
 293     unlock_user_struct(frame, frame_addr, 0);
 294     force_sig(TARGET_SIGSEGV);
 295     return -QEMU_ESIGRETURN;
 296 }
 297
 298 void setup_sigtramp(abi_ulong sigtramp_page)
 299 {
 300     uint8_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 6, 0);
 301     assert(tramp != NULL);
 302
 303     default_rt_sigreturn = sigtramp_page;
 304     install_sigtramp(tramp);
 305     unlock_user(tramp, sigtramp_page, 6);
 306 }