linux-user/sh4/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 /*
  25  * code and data structures from linux kernel:
  26  * include/asm-sh/sigcontext.h
  27  * arch/sh/kernel/signal.c
  28  */
  29
  30 struct target_sigcontext {
  31     target_ulong  oldmask;
  32
  33     /* CPU registers */
  34     target_ulong  sc_gregs[16];
  35     target_ulong  sc_pc;
  36     target_ulong  sc_pr;
  37     target_ulong  sc_sr;
  38     target_ulong  sc_gbr;
  39     target_ulong  sc_mach;
  40     target_ulong  sc_macl;
  41
  42     /* FPU registers */
  43     target_ulong  sc_fpregs[16];
  44     target_ulong  sc_xfpregs[16];
  45     unsigned int sc_fpscr;
  46     unsigned int sc_fpul;
  47     unsigned int sc_ownedfp;
  48 };
  49
  50 struct target_sigframe
  51 {
  52     struct target_sigcontext sc;
  53     target_ulong extramask[TARGET_NSIG_WORDS-1];
  54     uint16_t retcode[3];
  55 };
  56
  57
  58 struct target_ucontext {
  59     target_ulong tuc_flags;
  60     struct target_ucontext *tuc_link;
  61     target_stack_t tuc_stack;
  62     struct target_sigcontext tuc_mcontext;
  63     target_sigset_t tuc_sigmask;        /* mask last for extensibility */
  64 };
  65
  66 struct target_rt_sigframe
  67 {
  68     struct target_siginfo info;
  69     struct target_ucontext uc;
  70     uint16_t retcode[3];
  71 };
  72
  73
  74 #define MOVW(n)  (0x9300|((n)-2)) /* Move mem word at PC+n to R3 */
  75 #define TRAP_NOARG 0xc310         /* Syscall w/no args (NR in R3) SH3/4 */
  76
  77 static abi_ulong get_sigframe(struct target_sigaction *ka,
  78                               unsigned long sp, size_t frame_size)
  79 {
  80     sp = target_sigsp(sp, ka);
  81
  82     return (sp - frame_size) & -8ul;
  83 }
  84
  85 /*
  86  * Notice when we're in the middle of a gUSA region and reset.
  87  * Note that this will only occur when #CF_PARALLEL is unset, as we
  88  * will translate such sequences differently in a parallel context.
  89  */
  90 static void unwind_gusa(CPUSH4State *regs)
  91 {
  92     /* If the stack pointer is sufficiently negative, and we haven't
  93        completed the sequence, then reset to the entry to the region.  */
  94     /* ??? The SH4 kernel checks for and address above 0xC0000000.
  95        However, the page mappings in qemu linux-user aren't as restricted
  96        and we wind up with the normal stack mapped above 0xF0000000.
  97        That said, there is no reason why the kernel should be allowing
  98        a gUSA region that spans 1GB.  Use a tighter check here, for what
  99        can actually be enabled by the immediate move.  */
 100     if (regs->gregs[15] >= -128u && regs->pc < regs->gregs[0]) {
 101         /* Reset the PC to before the gUSA region, as computed from
 102            R0 = region end, SP = -(region size), plus one more for the
 103            insn that actually initializes SP to the region size.  */
 104         regs->pc = regs->gregs[0] + regs->gregs[15] - 2;
 105
 106         /* Reset the SP to the saved version in R1.  */
 107         regs->gregs[15] = regs->gregs[1];
 108     }
 109 }
 110
 111 static void setup_sigcontext(struct target_sigcontext *sc,
 112                              CPUSH4State *regs, unsigned long mask)
 113 {
 114     int i;
 115
 116 #define COPY(x)         __put_user(regs->x, &sc->sc_##x)
 117     COPY(gregs[0]); COPY(gregs[1]);
 118     COPY(gregs[2]); COPY(gregs[3]);
 119     COPY(gregs[4]); COPY(gregs[5]);
 120     COPY(gregs[6]); COPY(gregs[7]);
 121     COPY(gregs[8]); COPY(gregs[9]);
 122     COPY(gregs[10]); COPY(gregs[11]);
 123     COPY(gregs[12]); COPY(gregs[13]);
 124     COPY(gregs[14]); COPY(gregs[15]);
 125     COPY(gbr); COPY(mach);
 126     COPY(macl); COPY(pr);
 127     COPY(sr); COPY(pc);
 128 #undef COPY
 129
 130     for (i=0; i<16; i++) {
 131         __put_user(regs->fregs[i], &sc->sc_fpregs[i]);
 132     }
 133     __put_user(regs->fpscr, &sc->sc_fpscr);
 134     __put_user(regs->fpul, &sc->sc_fpul);
 135
 136     /* non-iBCS2 extensions.. */
 137     __put_user(mask, &sc->oldmask);
 138 }
 139
 140 static void restore_sigcontext(CPUSH4State *regs, struct target_sigcontext *sc)
 141 {
 142     int i;
 143
 144 #define COPY(x)         __get_user(regs->x, &sc->sc_##x)
 145     COPY(gregs[0]); COPY(gregs[1]);
 146     COPY(gregs[2]); COPY(gregs[3]);
 147     COPY(gregs[4]); COPY(gregs[5]);
 148     COPY(gregs[6]); COPY(gregs[7]);
 149     COPY(gregs[8]); COPY(gregs[9]);
 150     COPY(gregs[10]); COPY(gregs[11]);
 151     COPY(gregs[12]); COPY(gregs[13]);
 152     COPY(gregs[14]); COPY(gregs[15]);
 153     COPY(gbr); COPY(mach);
 154     COPY(macl); COPY(pr);
 155     COPY(sr); COPY(pc);
 156 #undef COPY
 157
 158     for (i=0; i<16; i++) {
 159         __get_user(regs->fregs[i], &sc->sc_fpregs[i]);
 160     }
 161     __get_user(regs->fpscr, &sc->sc_fpscr);
 162     __get_user(regs->fpul, &sc->sc_fpul);
 163
 164     regs->tra = -1;         /* disable syscall checks */
 165     regs->flags &= ~(DELAY_SLOT_MASK | GUSA_MASK);
 166 }
 167
 168 void setup_frame(int sig, struct target_sigaction *ka,
 169                  target_sigset_t *set, CPUSH4State *regs)
 170 {
 171     struct target_sigframe *frame;
 172     abi_ulong frame_addr;
 173     int i;
 174
 175     unwind_gusa(regs);
 176
 177     frame_addr = get_sigframe(ka, regs->gregs[15], sizeof(*frame));
 178     trace_user_setup_frame(regs, frame_addr);
 179     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
 180         goto give_sigsegv;
 181     }
 182
 183     setup_sigcontext(&frame->sc, regs, set->sig[0]);
 184
 185     for (i = 0; i < TARGET_NSIG_WORDS - 1; i++) {
 186         __put_user(set->sig[i + 1], &frame->extramask[i]);
 187     }
 188
 189     /* Set up to return from userspace.  If provided, use a stub
 190        already in userspace.  */
 191     if (ka->sa_flags & TARGET_SA_RESTORER) {
 192         regs->pr = (unsigned long) ka->sa_restorer;
 193     } else {
 194         /* Generate return code (system call to sigreturn) */
 195         abi_ulong retcode_addr = frame_addr +
 196                                  offsetof(struct target_sigframe, retcode);
 197         __put_user(MOVW(2), &frame->retcode[0]);
 198         __put_user(TRAP_NOARG, &frame->retcode[1]);
 199         __put_user((TARGET_NR_sigreturn), &frame->retcode[2]);
 200         regs->pr = (unsigned long) retcode_addr;
 201     }
 202
 203     /* Set up registers for signal handler */
 204     regs->gregs[15] = frame_addr;
 205     regs->gregs[4] = sig; /* Arg for signal handler */
 206     regs->gregs[5] = 0;
 207     regs->gregs[6] = frame_addr += offsetof(typeof(*frame), sc);
 208     regs->pc = (unsigned long) ka->_sa_handler;
 209     regs->flags &= ~(DELAY_SLOT_MASK | GUSA_MASK);
 210
 211     unlock_user_struct(frame, frame_addr, 1);
 212     return;
 213
 214 give_sigsegv:
 215     unlock_user_struct(frame, frame_addr, 1);
 216     force_sigsegv(sig);
 217 }
 218
 219 void setup_rt_frame(int sig, struct target_sigaction *ka,
 220                     target_siginfo_t *info,
 221                     target_sigset_t *set, CPUSH4State *regs)
 222 {
 223     struct target_rt_sigframe *frame;
 224     abi_ulong frame_addr;
 225     int i;
 226
 227     unwind_gusa(regs);
 228
 229     frame_addr = get_sigframe(ka, regs->gregs[15], sizeof(*frame));
 230     trace_user_setup_rt_frame(regs, frame_addr);
 231     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
 232         goto give_sigsegv;
 233     }
 234
 235     tswap_siginfo(&frame->info, info);
 236
 237     /* Create the ucontext.  */
 238     __put_user(0, &frame->uc.tuc_flags);
 239     __put_user(0, (unsigned long *)&frame->uc.tuc_link);
 240     target_save_altstack(&frame->uc.tuc_stack, regs);
 241     setup_sigcontext(&frame->uc.tuc_mcontext,
 242                      regs, set->sig[0]);
 243     for(i = 0; i < TARGET_NSIG_WORDS; i++) {
 244         __put_user(set->sig[i], &frame->uc.tuc_sigmask.sig[i]);
 245     }
 246
 247     /* Set up to return from userspace.  If provided, use a stub
 248        already in userspace.  */
 249     if (ka->sa_flags & TARGET_SA_RESTORER) {
 250         regs->pr = (unsigned long) ka->sa_restorer;
 251     } else {
 252         /* Generate return code (system call to sigreturn) */
 253         abi_ulong retcode_addr = frame_addr +
 254                                  offsetof(struct target_rt_sigframe, retcode);
 255         __put_user(MOVW(2), &frame->retcode[0]);
 256         __put_user(TRAP_NOARG, &frame->retcode[1]);
 257         __put_user((TARGET_NR_rt_sigreturn), &frame->retcode[2]);
 258         regs->pr = (unsigned long) retcode_addr;
 259     }
 260
 261     /* Set up registers for signal handler */
 262     regs->gregs[15] = frame_addr;
 263     regs->gregs[4] = sig; /* Arg for signal handler */
 264     regs->gregs[5] = frame_addr + offsetof(typeof(*frame), info);
 265     regs->gregs[6] = frame_addr + offsetof(typeof(*frame), uc);
 266     regs->pc = (unsigned long) ka->_sa_handler;
 267     regs->flags &= ~(DELAY_SLOT_MASK | GUSA_MASK);
 268
 269     unlock_user_struct(frame, frame_addr, 1);
 270     return;
 271
 272 give_sigsegv:
 273     unlock_user_struct(frame, frame_addr, 1);
 274     force_sigsegv(sig);
 275 }
 276
 277 long do_sigreturn(CPUSH4State *regs)
 278 {
 279     struct target_sigframe *frame;
 280     abi_ulong frame_addr;
 281     sigset_t blocked;
 282     target_sigset_t target_set;
 283     int i;
 284
 285     frame_addr = regs->gregs[15];
 286     trace_user_do_sigreturn(regs, frame_addr);
 287     if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
 288         goto badframe;
 289     }
 290
 291     __get_user(target_set.sig[0], &frame->sc.oldmask);
 292     for(i = 1; i < TARGET_NSIG_WORDS; i++) {
 293         __get_user(target_set.sig[i], &frame->extramask[i - 1]);
 294     }
 295
 296     target_to_host_sigset_internal(&blocked, &target_set);
 297     set_sigmask(&blocked);
 298
 299     restore_sigcontext(regs, &frame->sc);
 300
 301     unlock_user_struct(frame, frame_addr, 0);
 302     return -TARGET_QEMU_ESIGRETURN;
 303
 304 badframe:
 305     unlock_user_struct(frame, frame_addr, 0);
 306     force_sig(TARGET_SIGSEGV);
 307     return -TARGET_QEMU_ESIGRETURN;
 308 }
 309
 310 long do_rt_sigreturn(CPUSH4State *regs)
 311 {
 312     struct target_rt_sigframe *frame;
 313     abi_ulong frame_addr;
 314     sigset_t blocked;
 315
 316     frame_addr = regs->gregs[15];
 317     trace_user_do_rt_sigreturn(regs, frame_addr);
 318     if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
 319         goto badframe;
 320     }
 321
 322     target_to_host_sigset(&blocked, &frame->uc.tuc_sigmask);
 323     set_sigmask(&blocked);
 324
 325     restore_sigcontext(regs, &frame->uc.tuc_mcontext);
 326     target_restore_altstack(&frame->uc.tuc_stack, regs);
 327
 328     unlock_user_struct(frame, frame_addr, 0);
 329     return -TARGET_QEMU_ESIGRETURN;
 330
 331 badframe:
 332     unlock_user_struct(frame, frame_addr, 0);
 333     force_sig(TARGET_SIGSEGV);
 334     return -TARGET_QEMU_ESIGRETURN;
 335 }