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 "user-internals.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     abi_ulong tuc_flags;
  76     abi_ulong tuc_link;
  77     target_stack_t tuc_stack;
  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 void install_sigtramp(uint32_t *tramp, unsigned int syscall)
  91 {
  92     /*
  93      * Set up the return code ...
  94      *
  95      *         li      v0, __NR__foo_sigreturn
  96      *         syscall
  97      */
  98
  99     __put_user(0x24020000 + syscall, tramp + 0);
 100     __put_user(0x0000000c          , tramp + 1);
 101 }
 102
 103 static inline void setup_sigcontext(CPUMIPSState *regs,
 104                                     struct target_sigcontext *sc)
 105 {
 106     int i;
 107
 108     __put_user(exception_resume_pc(regs), &sc->sc_pc);
 109     regs->hflags &= ~MIPS_HFLAG_BMASK;
 110
 111     __put_user(0, &sc->sc_regs[0]);
 112     for (i = 1; i < 32; ++i) {
 113         __put_user(regs->active_tc.gpr[i], &sc->sc_regs[i]);
 114     }
 115
 116     __put_user(regs->active_tc.HI[0], &sc->sc_mdhi);
 117     __put_user(regs->active_tc.LO[0], &sc->sc_mdlo);
 118
 119     /* Rather than checking for dsp existence, always copy.  The storage
 120        would just be garbage otherwise.  */
 121     __put_user(regs->active_tc.HI[1], &sc->sc_hi1);
 122     __put_user(regs->active_tc.HI[2], &sc->sc_hi2);
 123     __put_user(regs->active_tc.HI[3], &sc->sc_hi3);
 124     __put_user(regs->active_tc.LO[1], &sc->sc_lo1);
 125     __put_user(regs->active_tc.LO[2], &sc->sc_lo2);
 126     __put_user(regs->active_tc.LO[3], &sc->sc_lo3);
 127     {
 128         uint32_t dsp = cpu_rddsp(0x3ff, regs);
 129         __put_user(dsp, &sc->sc_dsp);
 130     }
 131
 132     __put_user(1, &sc->sc_used_math);
 133
 134     for (i = 0; i < 32; ++i) {
 135         __put_user(regs->active_fpu.fpr[i].d, &sc->sc_fpregs[i]);
 136     }
 137 }
 138
 139 static inline void
 140 restore_sigcontext(CPUMIPSState *regs, struct target_sigcontext *sc)
 141 {
 142     int i;
 143
 144     __get_user(regs->CP0_EPC, &sc->sc_pc);
 145
 146     __get_user(regs->active_tc.HI[0], &sc->sc_mdhi);
 147     __get_user(regs->active_tc.LO[0], &sc->sc_mdlo);
 148
 149     for (i = 1; i < 32; ++i) {
 150         __get_user(regs->active_tc.gpr[i], &sc->sc_regs[i]);
 151     }
 152
 153     __get_user(regs->active_tc.HI[1], &sc->sc_hi1);
 154     __get_user(regs->active_tc.HI[2], &sc->sc_hi2);
 155     __get_user(regs->active_tc.HI[3], &sc->sc_hi3);
 156     __get_user(regs->active_tc.LO[1], &sc->sc_lo1);
 157     __get_user(regs->active_tc.LO[2], &sc->sc_lo2);
 158     __get_user(regs->active_tc.LO[3], &sc->sc_lo3);
 159     {
 160         uint32_t dsp;
 161         __get_user(dsp, &sc->sc_dsp);
 162         cpu_wrdsp(dsp, 0x3ff, regs);
 163     }
 164
 165     for (i = 0; i < 32; ++i) {
 166         __get_user(regs->active_fpu.fpr[i].d, &sc->sc_fpregs[i]);
 167     }
 168 }
 169
 170 /*
 171  * Determine which stack to use..
 172  */
 173 static inline abi_ulong
 174 get_sigframe(struct target_sigaction *ka, CPUMIPSState *regs, size_t frame_size)
 175 {
 176     unsigned long sp;
 177
 178     /*
 179      * FPU emulator may have its own trampoline active just
 180      * above the user stack, 16-bytes before the next lowest
 181      * 16 byte boundary.  Try to avoid trashing it.
 182      */
 183     sp = target_sigsp(get_sp_from_cpustate(regs) - 32, ka);
 184
 185     return (sp - frame_size) & ~7;
 186 }
 187
 188 static void mips_set_hflags_isa_mode_from_pc(CPUMIPSState *env)
 189 {
 190     if (env->insn_flags & (ASE_MIPS16 | ASE_MICROMIPS)) {
 191         env->hflags &= ~MIPS_HFLAG_M16;
 192         env->hflags |= (env->active_tc.PC & 1) << MIPS_HFLAG_M16_SHIFT;
 193         env->active_tc.PC &= ~(target_ulong) 1;
 194     }
 195 }
 196
 197 # if defined(TARGET_ABI_MIPSO32)
 198 /* compare linux/arch/mips/kernel/signal.c:setup_frame() */
 199 void setup_frame(int sig, struct target_sigaction * ka,
 200                  target_sigset_t *set, CPUMIPSState *regs)
 201 {
 202     struct sigframe *frame;
 203     abi_ulong frame_addr;
 204     int i;
 205
 206     frame_addr = get_sigframe(ka, regs, sizeof(*frame));
 207     trace_user_setup_frame(regs, frame_addr);
 208     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
 209         goto give_sigsegv;
 210     }
 211
 212     setup_sigcontext(regs, &frame->sf_sc);
 213
 214     for(i = 0; i < TARGET_NSIG_WORDS; i++) {
 215         __put_user(set->sig[i], &frame->sf_mask.sig[i]);
 216     }
 217
 218     /*
 219     * Arguments to signal handler:
 220     *
 221     *   a0 = signal number
 222     *   a1 = 0 (should be cause)
 223     *   a2 = pointer to struct sigcontext
 224     *
 225     * $25 and PC point to the signal handler, $29 points to the
 226     * struct sigframe.
 227     */
 228     regs->active_tc.gpr[ 4] = sig;
 229     regs->active_tc.gpr[ 5] = 0;
 230     regs->active_tc.gpr[ 6] = frame_addr + offsetof(struct sigframe, sf_sc);
 231     regs->active_tc.gpr[29] = frame_addr;
 232     regs->active_tc.gpr[31] = default_sigreturn;
 233     /* The original kernel code sets CP0_EPC to the handler
 234     * since it returns to userland using eret
 235     * we cannot do this here, and we must set PC directly */
 236     regs->active_tc.PC = regs->active_tc.gpr[25] = ka->_sa_handler;
 237     mips_set_hflags_isa_mode_from_pc(regs);
 238     unlock_user_struct(frame, frame_addr, 1);
 239     return;
 240
 241 give_sigsegv:
 242     force_sigsegv(sig);
 243 }
 244
 245 long do_sigreturn(CPUMIPSState *regs)
 246 {
 247     struct sigframe *frame;
 248     abi_ulong frame_addr;
 249     sigset_t blocked;
 250     target_sigset_t target_set;
 251     int i;
 252
 253     frame_addr = regs->active_tc.gpr[29];
 254     trace_user_do_sigreturn(regs, frame_addr);
 255     if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1))
 256         goto badframe;
 257
 258     for(i = 0; i < TARGET_NSIG_WORDS; i++) {
 259         __get_user(target_set.sig[i], &frame->sf_mask.sig[i]);
 260     }
 261
 262     target_to_host_sigset_internal(&blocked, &target_set);
 263     set_sigmask(&blocked);
 264
 265     restore_sigcontext(regs, &frame->sf_sc);
 266
 267 #if 0
 268     /*
 269      * Don't let your children do this ...
 270      */
 271     __asm__ __volatile__(
 272         "move\t$29, %0\n\t"
 273         "j\tsyscall_exit"
 274         :/* no outputs */
 275         :"r" (&regs));
 276     /* Unreached */
 277 #endif
 278
 279     regs->active_tc.PC = regs->CP0_EPC;
 280     mips_set_hflags_isa_mode_from_pc(regs);
 281     /* I am not sure this is right, but it seems to work
 282     * maybe a problem with nested signals ? */
 283     regs->CP0_EPC = 0;
 284     return -QEMU_ESIGRETURN;
 285
 286 badframe:
 287     force_sig(TARGET_SIGSEGV);
 288     return -QEMU_ESIGRETURN;
 289 }
 290 # endif /* O32 */
 291
 292 void setup_rt_frame(int sig, struct target_sigaction *ka,
 293                     target_siginfo_t *info,
 294                     target_sigset_t *set, CPUMIPSState *env)
 295 {
 296     struct target_rt_sigframe *frame;
 297     abi_ulong frame_addr;
 298     int i;
 299
 300     frame_addr = get_sigframe(ka, env, sizeof(*frame));
 301     trace_user_setup_rt_frame(env, frame_addr);
 302     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
 303         goto give_sigsegv;
 304     }
 305
 306     frame->rs_info = *info;
 307
 308     __put_user(0, &frame->rs_uc.tuc_flags);
 309     __put_user(0, &frame->rs_uc.tuc_link);
 310     target_save_altstack(&frame->rs_uc.tuc_stack, env);
 311
 312     setup_sigcontext(env, &frame->rs_uc.tuc_mcontext);
 313
 314     for (i = 0; i < TARGET_NSIG_WORDS; i++) {
 315         __put_user(set->sig[i], &frame->rs_uc.tuc_sigmask.sig[i]);
 316     }
 317
 318     /*
 319     * Arguments to signal handler:
 320     *
 321     *   a0 = signal number
 322     *   a1 = pointer to siginfo_t
 323     *   a2 = pointer to ucontext_t
 324     *
 325     * $25 and PC point to the signal handler, $29 points to the
 326     * struct sigframe.
 327     */
 328     env->active_tc.gpr[ 4] = sig;
 329     env->active_tc.gpr[ 5] = frame_addr
 330                              + offsetof(struct target_rt_sigframe, rs_info);
 331     env->active_tc.gpr[ 6] = frame_addr
 332                              + offsetof(struct target_rt_sigframe, rs_uc);
 333     env->active_tc.gpr[29] = frame_addr;
 334     env->active_tc.gpr[31] = default_rt_sigreturn;
 335
 336     /*
 337      * The original kernel code sets CP0_EPC to the handler
 338      * since it returns to userland using eret
 339      * we cannot do this here, and we must set PC directly
 340      */
 341     env->active_tc.PC = env->active_tc.gpr[25] = ka->_sa_handler;
 342     mips_set_hflags_isa_mode_from_pc(env);
 343     unlock_user_struct(frame, frame_addr, 1);
 344     return;
 345
 346 give_sigsegv:
 347     unlock_user_struct(frame, frame_addr, 1);
 348     force_sigsegv(sig);
 349 }
 350
 351 long do_rt_sigreturn(CPUMIPSState *env)
 352 {
 353     struct target_rt_sigframe *frame;
 354     abi_ulong frame_addr;
 355     sigset_t blocked;
 356
 357     frame_addr = env->active_tc.gpr[29];
 358     trace_user_do_rt_sigreturn(env, frame_addr);
 359     if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
 360         goto badframe;
 361     }
 362
 363     target_to_host_sigset(&blocked, &frame->rs_uc.tuc_sigmask);
 364     set_sigmask(&blocked);
 365
 366     restore_sigcontext(env, &frame->rs_uc.tuc_mcontext);
 367     target_restore_altstack(&frame->rs_uc.tuc_stack, env);
 368
 369     env->active_tc.PC = env->CP0_EPC;
 370     mips_set_hflags_isa_mode_from_pc(env);
 371     /* I am not sure this is right, but it seems to work
 372     * maybe a problem with nested signals ? */
 373     env->CP0_EPC = 0;
 374     return -QEMU_ESIGRETURN;
 375
 376 badframe:
 377     force_sig(TARGET_SIGSEGV);
 378     return -QEMU_ESIGRETURN;
 379 }
 380
 381 void setup_sigtramp(abi_ulong sigtramp_page)
 382 {
 383     uint32_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 2 * 8, 0);
 384     assert(tramp != NULL);
 385
 386 #ifdef TARGET_ARCH_HAS_SETUP_FRAME
 387     default_sigreturn = sigtramp_page;
 388     install_sigtramp(tramp, TARGET_NR_sigreturn);
 389 #endif
 390
 391     default_rt_sigreturn = sigtramp_page + 8;
 392     install_sigtramp(tramp + 2, TARGET_NR_rt_sigreturn);
 393
 394     unlock_user(tramp, sigtramp_page, 2 * 8);
 395 }