linux-user/mips/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 "signal-common.h"
  22 #include "linux-user/trace.h"
  23
  24 # if defined(TARGET_ABI_MIPSO32)
  25 struct target_sigcontext {
  26     uint32_t   sc_regmask;     /* Unused */
  27     uint32_t   sc_status;
  28     uint64_t   sc_pc;
  29     uint64_t   sc_regs[32];
  30     uint64_t   sc_fpregs[32];
  31     uint32_t   sc_ownedfp;     /* Unused */
  32     uint32_t   sc_fpc_csr;
  33     uint32_t   sc_fpc_eir;     /* Unused */
  34     uint32_t   sc_used_math;
  35     uint32_t   sc_dsp;         /* dsp status, was sc_ssflags */
  36     uint32_t   pad0;
  37     uint64_t   sc_mdhi;
  38     uint64_t   sc_mdlo;
  39     target_ulong   sc_hi1;         /* Was sc_cause */
  40     target_ulong   sc_lo1;         /* Was sc_badvaddr */
  41     target_ulong   sc_hi2;         /* Was sc_sigset[4] */
  42     target_ulong   sc_lo2;
  43     target_ulong   sc_hi3;
  44     target_ulong   sc_lo3;
  45 };
  46 # else /* N32 || N64 */
  47 struct target_sigcontext {
  48     uint64_t sc_regs[32];
  49     uint64_t sc_fpregs[32];
  50     uint64_t sc_mdhi;
  51     uint64_t sc_hi1;
  52     uint64_t sc_hi2;
  53     uint64_t sc_hi3;
  54     uint64_t sc_mdlo;
  55     uint64_t sc_lo1;
  56     uint64_t sc_lo2;
  57     uint64_t sc_lo3;
  58     uint64_t sc_pc;
  59     uint32_t sc_fpc_csr;
  60     uint32_t sc_used_math;
  61     uint32_t sc_dsp;
  62     uint32_t sc_reserved;
  63 };
  64 # endif /* O32 */
  65
  66 struct sigframe {
  67     uint32_t sf_ass[4];                 /* argument save space for o32 */
  68     uint32_t sf_code[2];                        /* signal trampoline */
  69     struct target_sigcontext sf_sc;
  70     target_sigset_t sf_mask;
  71 };
  72
  73 struct target_ucontext {
  74     target_ulong tuc_flags;
  75     target_ulong tuc_link;
  76     target_stack_t tuc_stack;
  77     target_ulong pad0;
  78     struct target_sigcontext tuc_mcontext;
  79     target_sigset_t tuc_sigmask;
  80 };
  81
  82 struct target_rt_sigframe {
  83     uint32_t rs_ass[4];               /* argument save space for o32 */
  84     uint32_t rs_code[2];              /* signal trampoline */
  85     struct target_siginfo rs_info;
  86     struct target_ucontext rs_uc;
  87 };
  88
  89 /* Install trampoline to jump back from signal handler */
  90 static inline int install_sigtramp(unsigned int *tramp,   unsigned int syscall)
  91 {
  92     int err = 0;
  93
  94     /*
  95      * Set up the return code ...
  96      *
  97      *         li      v0, __NR__foo_sigreturn
  98      *         syscall
  99      */
 100
 101     __put_user(0x24020000 + syscall, tramp + 0);
 102     __put_user(0x0000000c          , tramp + 1);
 103     return err;
 104 }
 105
 106 static inline void setup_sigcontext(CPUMIPSState *regs,
 107                                     struct target_sigcontext *sc)
 108 {
 109     int i;
 110
 111     __put_user(exception_resume_pc(regs), &sc->sc_pc);
 112     regs->hflags &= ~MIPS_HFLAG_BMASK;
 113
 114     __put_user(0, &sc->sc_regs[0]);
 115     for (i = 1; i < 32; ++i) {
 116         __put_user(regs->active_tc.gpr[i], &sc->sc_regs[i]);
 117     }
 118
 119     __put_user(regs->active_tc.HI[0], &sc->sc_mdhi);
 120     __put_user(regs->active_tc.LO[0], &sc->sc_mdlo);
 121
 122     /* Rather than checking for dsp existence, always copy.  The storage
 123        would just be garbage otherwise.  */
 124     __put_user(regs->active_tc.HI[1], &sc->sc_hi1);
 125     __put_user(regs->active_tc.HI[2], &sc->sc_hi2);
 126     __put_user(regs->active_tc.HI[3], &sc->sc_hi3);
 127     __put_user(regs->active_tc.LO[1], &sc->sc_lo1);
 128     __put_user(regs->active_tc.LO[2], &sc->sc_lo2);
 129     __put_user(regs->active_tc.LO[3], &sc->sc_lo3);
 130     {
 131         uint32_t dsp = cpu_rddsp(0x3ff, regs);
 132         __put_user(dsp, &sc->sc_dsp);
 133     }
 134
 135     __put_user(1, &sc->sc_used_math);
 136
 137     for (i = 0; i < 32; ++i) {
 138         __put_user(regs->active_fpu.fpr[i].d, &sc->sc_fpregs[i]);
 139     }
 140 }
 141
 142 static inline void
 143 restore_sigcontext(CPUMIPSState *regs, struct target_sigcontext *sc)
 144 {
 145     int i;
 146
 147     __get_user(regs->CP0_EPC, &sc->sc_pc);
 148
 149     __get_user(regs->active_tc.HI[0], &sc->sc_mdhi);
 150     __get_user(regs->active_tc.LO[0], &sc->sc_mdlo);
 151
 152     for (i = 1; i < 32; ++i) {
 153         __get_user(regs->active_tc.gpr[i], &sc->sc_regs[i]);
 154     }
 155
 156     __get_user(regs->active_tc.HI[1], &sc->sc_hi1);
 157     __get_user(regs->active_tc.HI[2], &sc->sc_hi2);
 158     __get_user(regs->active_tc.HI[3], &sc->sc_hi3);
 159     __get_user(regs->active_tc.LO[1], &sc->sc_lo1);
 160     __get_user(regs->active_tc.LO[2], &sc->sc_lo2);
 161     __get_user(regs->active_tc.LO[3], &sc->sc_lo3);
 162     {
 163         uint32_t dsp;
 164         __get_user(dsp, &sc->sc_dsp);
 165         cpu_wrdsp(dsp, 0x3ff, regs);
 166     }
 167
 168     for (i = 0; i < 32; ++i) {
 169         __get_user(regs->active_fpu.fpr[i].d, &sc->sc_fpregs[i]);
 170     }
 171 }
 172
 173 /*
 174  * Determine which stack to use..
 175  */
 176 static inline abi_ulong
 177 get_sigframe(struct target_sigaction *ka, CPUMIPSState *regs, size_t frame_size)
 178 {
 179     unsigned long sp;
 180
 181     /*
 182      * FPU emulator may have its own trampoline active just
 183      * above the user stack, 16-bytes before the next lowest
 184      * 16 byte boundary.  Try to avoid trashing it.
 185      */
 186     sp = target_sigsp(get_sp_from_cpustate(regs) - 32, ka);
 187
 188     return (sp - frame_size) & ~7;
 189 }
 190
 191 static void mips_set_hflags_isa_mode_from_pc(CPUMIPSState *env)
 192 {
 193     if (env->insn_flags & (ASE_MIPS16 | ASE_MICROMIPS)) {
 194         env->hflags &= ~MIPS_HFLAG_M16;
 195         env->hflags |= (env->active_tc.PC & 1) << MIPS_HFLAG_M16_SHIFT;
 196         env->active_tc.PC &= ~(target_ulong) 1;
 197     }
 198 }
 199
 200 # if defined(TARGET_ABI_MIPSO32)
 201 /* compare linux/arch/mips/kernel/signal.c:setup_frame() */
 202 void setup_frame(int sig, struct target_sigaction * ka,
 203                  target_sigset_t *set, CPUMIPSState *regs)
 204 {
 205     struct sigframe *frame;
 206     abi_ulong frame_addr;
 207     int i;
 208
 209     frame_addr = get_sigframe(ka, regs, sizeof(*frame));
 210     trace_user_setup_frame(regs, frame_addr);
 211     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
 212         goto give_sigsegv;
 213     }
 214
 215     install_sigtramp(frame->sf_code, TARGET_NR_sigreturn);
 216
 217     setup_sigcontext(regs, &frame->sf_sc);
 218
 219     for(i = 0; i < TARGET_NSIG_WORDS; i++) {
 220         __put_user(set->sig[i], &frame->sf_mask.sig[i]);
 221     }
 222
 223     /*
 224     * Arguments to signal handler:
 225     *
 226     *   a0 = signal number
 227     *   a1 = 0 (should be cause)
 228     *   a2 = pointer to struct sigcontext
 229     *
 230     * $25 and PC point to the signal handler, $29 points to the
 231     * struct sigframe.
 232     */
 233     regs->active_tc.gpr[ 4] = sig;
 234     regs->active_tc.gpr[ 5] = 0;
 235     regs->active_tc.gpr[ 6] = frame_addr + offsetof(struct sigframe, sf_sc);
 236     regs->active_tc.gpr[29] = frame_addr;
 237     regs->active_tc.gpr[31] = frame_addr + offsetof(struct sigframe, sf_code);
 238     /* The original kernel code sets CP0_EPC to the handler
 239     * since it returns to userland using eret
 240     * we cannot do this here, and we must set PC directly */
 241     regs->active_tc.PC = regs->active_tc.gpr[25] = ka->_sa_handler;
 242     mips_set_hflags_isa_mode_from_pc(regs);
 243     unlock_user_struct(frame, frame_addr, 1);
 244     return;
 245
 246 give_sigsegv:
 247     force_sigsegv(sig);
 248 }
 249
 250 long do_sigreturn(CPUMIPSState *regs)
 251 {
 252     struct sigframe *frame;
 253     abi_ulong frame_addr;
 254     sigset_t blocked;
 255     target_sigset_t target_set;
 256     int i;
 257
 258     frame_addr = regs->active_tc.gpr[29];
 259     trace_user_do_sigreturn(regs, frame_addr);
 260     if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1))
 261         goto badframe;
 262
 263     for(i = 0; i < TARGET_NSIG_WORDS; i++) {
 264         __get_user(target_set.sig[i], &frame->sf_mask.sig[i]);
 265     }
 266
 267     target_to_host_sigset_internal(&blocked, &target_set);
 268     set_sigmask(&blocked);
 269
 270     restore_sigcontext(regs, &frame->sf_sc);
 271
 272 #if 0
 273     /*
 274      * Don't let your children do this ...
 275      */
 276     __asm__ __volatile__(
 277         "move\t$29, %0\n\t"
 278         "j\tsyscall_exit"
 279         :/* no outputs */
 280         :"r" (&regs));
 281     /* Unreached */
 282 #endif
 283
 284     regs->active_tc.PC = regs->CP0_EPC;
 285     mips_set_hflags_isa_mode_from_pc(regs);
 286     /* I am not sure this is right, but it seems to work
 287     * maybe a problem with nested signals ? */
 288     regs->CP0_EPC = 0;
 289     return -TARGET_QEMU_ESIGRETURN;
 290
 291 badframe:
 292     force_sig(TARGET_SIGSEGV);
 293     return -TARGET_QEMU_ESIGRETURN;
 294 }
 295 # endif /* O32 */
 296
 297 void setup_rt_frame(int sig, struct target_sigaction *ka,
 298                     target_siginfo_t *info,
 299                     target_sigset_t *set, CPUMIPSState *env)
 300 {
 301     struct target_rt_sigframe *frame;
 302     abi_ulong frame_addr;
 303     int i;
 304
 305     frame_addr = get_sigframe(ka, env, sizeof(*frame));
 306     trace_user_setup_rt_frame(env, frame_addr);
 307     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
 308         goto give_sigsegv;
 309     }
 310
 311     install_sigtramp(frame->rs_code, TARGET_NR_rt_sigreturn);
 312
 313     tswap_siginfo(&frame->rs_info, info);
 314
 315     __put_user(0, &frame->rs_uc.tuc_flags);
 316     __put_user(0, &frame->rs_uc.tuc_link);
 317     target_save_altstack(&frame->rs_uc.tuc_stack, env);
 318
 319     setup_sigcontext(env, &frame->rs_uc.tuc_mcontext);
 320
 321     for(i = 0; i < TARGET_NSIG_WORDS; i++) {
 322         __put_user(set->sig[i], &frame->rs_uc.tuc_sigmask.sig[i]);
 323     }
 324
 325     /*
 326     * Arguments to signal handler:
 327     *
 328     *   a0 = signal number
 329     *   a1 = pointer to siginfo_t
 330     *   a2 = pointer to ucontext_t
 331     *
 332     * $25 and PC point to the signal handler, $29 points to the
 333     * struct sigframe.
 334     */
 335     env->active_tc.gpr[ 4] = sig;
 336     env->active_tc.gpr[ 5] = frame_addr
 337                              + offsetof(struct target_rt_sigframe, rs_info);
 338     env->active_tc.gpr[ 6] = frame_addr
 339                              + offsetof(struct target_rt_sigframe, rs_uc);
 340     env->active_tc.gpr[29] = frame_addr;
 341     env->active_tc.gpr[31] = frame_addr
 342                              + offsetof(struct target_rt_sigframe, rs_code);
 343     /* The original kernel code sets CP0_EPC to the handler
 344     * since it returns to userland using eret
 345     * we cannot do this here, and we must set PC directly */
 346     env->active_tc.PC = env->active_tc.gpr[25] = ka->_sa_handler;
 347     mips_set_hflags_isa_mode_from_pc(env);
 348     unlock_user_struct(frame, frame_addr, 1);
 349     return;
 350
 351 give_sigsegv:
 352     unlock_user_struct(frame, frame_addr, 1);
 353     force_sigsegv(sig);
 354 }
 355
 356 long do_rt_sigreturn(CPUMIPSState *env)
 357 {
 358     struct target_rt_sigframe *frame;
 359     abi_ulong frame_addr;
 360     sigset_t blocked;
 361
 362     frame_addr = env->active_tc.gpr[29];
 363     trace_user_do_rt_sigreturn(env, frame_addr);
 364     if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
 365         goto badframe;
 366     }
 367
 368     target_to_host_sigset(&blocked, &frame->rs_uc.tuc_sigmask);
 369     set_sigmask(&blocked);
 370
 371     restore_sigcontext(env, &frame->rs_uc.tuc_mcontext);
 372
 373     if (do_sigaltstack(frame_addr +
 374                        offsetof(struct target_rt_sigframe, rs_uc.tuc_stack),
 375                        0, get_sp_from_cpustate(env)) == -EFAULT)
 376         goto badframe;
 377
 378     env->active_tc.PC = env->CP0_EPC;
 379     mips_set_hflags_isa_mode_from_pc(env);
 380     /* I am not sure this is right, but it seems to work
 381     * maybe a problem with nested signals ? */
 382     env->CP0_EPC = 0;
 383     return -TARGET_QEMU_ESIGRETURN;
 384
 385 badframe:
 386     force_sig(TARGET_SIGSEGV);
 387     return -TARGET_QEMU_ESIGRETURN;
 388 }