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 "target_signal.h"
  22 #include "signal-common.h"
  23 #include "linux-user/trace.h"
  24
  25 # if defined(TARGET_ABI_MIPSO32)
  26 struct target_sigcontext {
  27     uint32_t   sc_regmask;     /* Unused */
  28     uint32_t   sc_status;
  29     uint64_t   sc_pc;
  30     uint64_t   sc_regs[32];
  31     uint64_t   sc_fpregs[32];
  32     uint32_t   sc_ownedfp;     /* Unused */
  33     uint32_t   sc_fpc_csr;
  34     uint32_t   sc_fpc_eir;     /* Unused */
  35     uint32_t   sc_used_math;
  36     uint32_t   sc_dsp;         /* dsp status, was sc_ssflags */
  37     uint32_t   pad0;
  38     uint64_t   sc_mdhi;
  39     uint64_t   sc_mdlo;
  40     target_ulong   sc_hi1;         /* Was sc_cause */
  41     target_ulong   sc_lo1;         /* Was sc_badvaddr */
  42     target_ulong   sc_hi2;         /* Was sc_sigset[4] */
  43     target_ulong   sc_lo2;
  44     target_ulong   sc_hi3;
  45     target_ulong   sc_lo3;
  46 };
  47 # else /* N32 || N64 */
  48 struct target_sigcontext {
  49     uint64_t sc_regs[32];
  50     uint64_t sc_fpregs[32];
  51     uint64_t sc_mdhi;
  52     uint64_t sc_hi1;
  53     uint64_t sc_hi2;
  54     uint64_t sc_hi3;
  55     uint64_t sc_mdlo;
  56     uint64_t sc_lo1;
  57     uint64_t sc_lo2;
  58     uint64_t sc_lo3;
  59     uint64_t sc_pc;
  60     uint32_t sc_fpc_csr;
  61     uint32_t sc_used_math;
  62     uint32_t sc_dsp;
  63     uint32_t sc_reserved;
  64 };
  65 # endif /* O32 */
  66
  67 struct sigframe {
  68     uint32_t sf_ass[4];                 /* argument save space for o32 */
  69     uint32_t sf_code[2];                        /* signal trampoline */
  70     struct target_sigcontext sf_sc;
  71     target_sigset_t sf_mask;
  72 };
  73
  74 struct target_ucontext {
  75     target_ulong tuc_flags;
  76     target_ulong tuc_link;
  77     target_stack_t tuc_stack;
  78     target_ulong pad0;
  79     struct target_sigcontext tuc_mcontext;
  80     target_sigset_t tuc_sigmask;
  81 };
  82
  83 struct target_rt_sigframe {
  84     uint32_t rs_ass[4];               /* argument save space for o32 */
  85     uint32_t rs_code[2];              /* signal trampoline */
  86     struct target_siginfo rs_info;
  87     struct target_ucontext rs_uc;
  88 };
  89
  90 /* Install trampoline to jump back from signal handler */
  91 static inline int install_sigtramp(unsigned int *tramp,   unsigned int syscall)
  92 {
  93     int err = 0;
  94
  95     /*
  96      * Set up the return code ...
  97      *
  98      *         li      v0, __NR__foo_sigreturn
  99      *         syscall
 100      */
 101
 102     __put_user(0x24020000 + syscall, tramp + 0);
 103     __put_user(0x0000000c          , tramp + 1);
 104     return err;
 105 }
 106
 107 static inline void setup_sigcontext(CPUMIPSState *regs,
 108                                     struct target_sigcontext *sc)
 109 {
 110     int i;
 111
 112     __put_user(exception_resume_pc(regs), &sc->sc_pc);
 113     regs->hflags &= ~MIPS_HFLAG_BMASK;
 114
 115     __put_user(0, &sc->sc_regs[0]);
 116     for (i = 1; i < 32; ++i) {
 117         __put_user(regs->active_tc.gpr[i], &sc->sc_regs[i]);
 118     }
 119
 120     __put_user(regs->active_tc.HI[0], &sc->sc_mdhi);
 121     __put_user(regs->active_tc.LO[0], &sc->sc_mdlo);
 122
 123     /* Rather than checking for dsp existence, always copy.  The storage
 124        would just be garbage otherwise.  */
 125     __put_user(regs->active_tc.HI[1], &sc->sc_hi1);
 126     __put_user(regs->active_tc.HI[2], &sc->sc_hi2);
 127     __put_user(regs->active_tc.HI[3], &sc->sc_hi3);
 128     __put_user(regs->active_tc.LO[1], &sc->sc_lo1);
 129     __put_user(regs->active_tc.LO[2], &sc->sc_lo2);
 130     __put_user(regs->active_tc.LO[3], &sc->sc_lo3);
 131     {
 132         uint32_t dsp = cpu_rddsp(0x3ff, regs);
 133         __put_user(dsp, &sc->sc_dsp);
 134     }
 135
 136     __put_user(1, &sc->sc_used_math);
 137
 138     for (i = 0; i < 32; ++i) {
 139         __put_user(regs->active_fpu.fpr[i].d, &sc->sc_fpregs[i]);
 140     }
 141 }
 142
 143 static inline void
 144 restore_sigcontext(CPUMIPSState *regs, struct target_sigcontext *sc)
 145 {
 146     int i;
 147
 148     __get_user(regs->CP0_EPC, &sc->sc_pc);
 149
 150     __get_user(regs->active_tc.HI[0], &sc->sc_mdhi);
 151     __get_user(regs->active_tc.LO[0], &sc->sc_mdlo);
 152
 153     for (i = 1; i < 32; ++i) {
 154         __get_user(regs->active_tc.gpr[i], &sc->sc_regs[i]);
 155     }
 156
 157     __get_user(regs->active_tc.HI[1], &sc->sc_hi1);
 158     __get_user(regs->active_tc.HI[2], &sc->sc_hi2);
 159     __get_user(regs->active_tc.HI[3], &sc->sc_hi3);
 160     __get_user(regs->active_tc.LO[1], &sc->sc_lo1);
 161     __get_user(regs->active_tc.LO[2], &sc->sc_lo2);
 162     __get_user(regs->active_tc.LO[3], &sc->sc_lo3);
 163     {
 164         uint32_t dsp;
 165         __get_user(dsp, &sc->sc_dsp);
 166         cpu_wrdsp(dsp, 0x3ff, regs);
 167     }
 168
 169     for (i = 0; i < 32; ++i) {
 170         __get_user(regs->active_fpu.fpr[i].d, &sc->sc_fpregs[i]);
 171     }
 172 }
 173
 174 /*
 175  * Determine which stack to use..
 176  */
 177 static inline abi_ulong
 178 get_sigframe(struct target_sigaction *ka, CPUMIPSState *regs, size_t frame_size)
 179 {
 180     unsigned long sp;
 181
 182     /*
 183      * FPU emulator may have its own trampoline active just
 184      * above the user stack, 16-bytes before the next lowest
 185      * 16 byte boundary.  Try to avoid trashing it.
 186      */
 187     sp = target_sigsp(get_sp_from_cpustate(regs) - 32, ka);
 188
 189     return (sp - frame_size) & ~7;
 190 }
 191
 192 static void mips_set_hflags_isa_mode_from_pc(CPUMIPSState *env)
 193 {
 194     if (env->insn_flags & (ASE_MIPS16 | ASE_MICROMIPS)) {
 195         env->hflags &= ~MIPS_HFLAG_M16;
 196         env->hflags |= (env->active_tc.PC & 1) << MIPS_HFLAG_M16_SHIFT;
 197         env->active_tc.PC &= ~(target_ulong) 1;
 198     }
 199 }
 200
 201 # if defined(TARGET_ABI_MIPSO32)
 202 /* compare linux/arch/mips/kernel/signal.c:setup_frame() */
 203 void setup_frame(int sig, struct target_sigaction * ka,
 204                  target_sigset_t *set, CPUMIPSState *regs)
 205 {
 206     struct sigframe *frame;
 207     abi_ulong frame_addr;
 208     int i;
 209
 210     frame_addr = get_sigframe(ka, regs, sizeof(*frame));
 211     trace_user_setup_frame(regs, frame_addr);
 212     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
 213         goto give_sigsegv;
 214     }
 215
 216     install_sigtramp(frame->sf_code, TARGET_NR_sigreturn);
 217
 218     setup_sigcontext(regs, &frame->sf_sc);
 219
 220     for(i = 0; i < TARGET_NSIG_WORDS; i++) {
 221         __put_user(set->sig[i], &frame->sf_mask.sig[i]);
 222     }
 223
 224     /*
 225     * Arguments to signal handler:
 226     *
 227     *   a0 = signal number
 228     *   a1 = 0 (should be cause)
 229     *   a2 = pointer to struct sigcontext
 230     *
 231     * $25 and PC point to the signal handler, $29 points to the
 232     * struct sigframe.
 233     */
 234     regs->active_tc.gpr[ 4] = sig;
 235     regs->active_tc.gpr[ 5] = 0;
 236     regs->active_tc.gpr[ 6] = frame_addr + offsetof(struct sigframe, sf_sc);
 237     regs->active_tc.gpr[29] = frame_addr;
 238     regs->active_tc.gpr[31] = frame_addr + offsetof(struct sigframe, sf_code);
 239     /* The original kernel code sets CP0_EPC to the handler
 240     * since it returns to userland using eret
 241     * we cannot do this here, and we must set PC directly */
 242     regs->active_tc.PC = regs->active_tc.gpr[25] = ka->_sa_handler;
 243     mips_set_hflags_isa_mode_from_pc(regs);
 244     unlock_user_struct(frame, frame_addr, 1);
 245     return;
 246
 247 give_sigsegv:
 248     force_sigsegv(sig);
 249 }
 250
 251 long do_sigreturn(CPUMIPSState *regs)
 252 {
 253     struct sigframe *frame;
 254     abi_ulong frame_addr;
 255     sigset_t blocked;
 256     target_sigset_t target_set;
 257     int i;
 258
 259     frame_addr = regs->active_tc.gpr[29];
 260     trace_user_do_sigreturn(regs, frame_addr);
 261     if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1))
 262         goto badframe;
 263
 264     for(i = 0; i < TARGET_NSIG_WORDS; i++) {
 265         __get_user(target_set.sig[i], &frame->sf_mask.sig[i]);
 266     }
 267
 268     target_to_host_sigset_internal(&blocked, &target_set);
 269     set_sigmask(&blocked);
 270
 271     restore_sigcontext(regs, &frame->sf_sc);
 272
 273 #if 0
 274     /*
 275      * Don't let your children do this ...
 276      */
 277     __asm__ __volatile__(
 278         "move\t$29, %0\n\t"
 279         "j\tsyscall_exit"
 280         :/* no outputs */
 281         :"r" (&regs));
 282     /* Unreached */
 283 #endif
 284
 285     regs->active_tc.PC = regs->CP0_EPC;
 286     mips_set_hflags_isa_mode_from_pc(regs);
 287     /* I am not sure this is right, but it seems to work
 288     * maybe a problem with nested signals ? */
 289     regs->CP0_EPC = 0;
 290     return -TARGET_QEMU_ESIGRETURN;
 291
 292 badframe:
 293     force_sig(TARGET_SIGSEGV);
 294     return -TARGET_QEMU_ESIGRETURN;
 295 }
 296 # endif /* O32 */
 297
 298 void setup_rt_frame(int sig, struct target_sigaction *ka,
 299                     target_siginfo_t *info,
 300                     target_sigset_t *set, CPUMIPSState *env)
 301 {
 302     struct target_rt_sigframe *frame;
 303     abi_ulong frame_addr;
 304     int i;
 305
 306     frame_addr = get_sigframe(ka, env, sizeof(*frame));
 307     trace_user_setup_rt_frame(env, frame_addr);
 308     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
 309         goto give_sigsegv;
 310     }
 311
 312     install_sigtramp(frame->rs_code, TARGET_NR_rt_sigreturn);
 313
 314     tswap_siginfo(&frame->rs_info, info);
 315
 316     __put_user(0, &frame->rs_uc.tuc_flags);
 317     __put_user(0, &frame->rs_uc.tuc_link);
 318     target_save_altstack(&frame->rs_uc.tuc_stack, env);
 319
 320     setup_sigcontext(env, &frame->rs_uc.tuc_mcontext);
 321
 322     for(i = 0; i < TARGET_NSIG_WORDS; i++) {
 323         __put_user(set->sig[i], &frame->rs_uc.tuc_sigmask.sig[i]);
 324     }
 325
 326     /*
 327     * Arguments to signal handler:
 328     *
 329     *   a0 = signal number
 330     *   a1 = pointer to siginfo_t
 331     *   a2 = pointer to ucontext_t
 332     *
 333     * $25 and PC point to the signal handler, $29 points to the
 334     * struct sigframe.
 335     */
 336     env->active_tc.gpr[ 4] = sig;
 337     env->active_tc.gpr[ 5] = frame_addr
 338                              + offsetof(struct target_rt_sigframe, rs_info);
 339     env->active_tc.gpr[ 6] = frame_addr
 340                              + offsetof(struct target_rt_sigframe, rs_uc);
 341     env->active_tc.gpr[29] = frame_addr;
 342     env->active_tc.gpr[31] = frame_addr
 343                              + offsetof(struct target_rt_sigframe, rs_code);
 344     /* The original kernel code sets CP0_EPC to the handler
 345     * since it returns to userland using eret
 346     * we cannot do this here, and we must set PC directly */
 347     env->active_tc.PC = env->active_tc.gpr[25] = ka->_sa_handler;
 348     mips_set_hflags_isa_mode_from_pc(env);
 349     unlock_user_struct(frame, frame_addr, 1);
 350     return;
 351
 352 give_sigsegv:
 353     unlock_user_struct(frame, frame_addr, 1);
 354     force_sigsegv(sig);
 355 }
 356
 357 long do_rt_sigreturn(CPUMIPSState *env)
 358 {
 359     struct target_rt_sigframe *frame;
 360     abi_ulong frame_addr;
 361     sigset_t blocked;
 362
 363     frame_addr = env->active_tc.gpr[29];
 364     trace_user_do_rt_sigreturn(env, frame_addr);
 365     if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
 366         goto badframe;
 367     }
 368
 369     target_to_host_sigset(&blocked, &frame->rs_uc.tuc_sigmask);
 370     set_sigmask(&blocked);
 371
 372     restore_sigcontext(env, &frame->rs_uc.tuc_mcontext);
 373
 374     if (do_sigaltstack(frame_addr +
 375                        offsetof(struct target_rt_sigframe, rs_uc.tuc_stack),
 376                        0, get_sp_from_cpustate(env)) == -EFAULT)
 377         goto badframe;
 378
 379     env->active_tc.PC = env->CP0_EPC;
 380     mips_set_hflags_isa_mode_from_pc(env);
 381     /* I am not sure this is right, but it seems to work
 382     * maybe a problem with nested signals ? */
 383     env->CP0_EPC = 0;
 384     return -TARGET_QEMU_ESIGRETURN;
 385
 386 badframe:
 387     force_sig(TARGET_SIGSEGV);
 388     return -TARGET_QEMU_ESIGRETURN;
 389 }