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