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 /* Notice when we're in the middle of a gUSA region and reset.
  86    Note that this will only occur for !parallel_cpus, as we will
  87    translate such sequences differently in a parallel context.  */
  88 static void unwind_gusa(CPUSH4State *regs)
  89 {
  90     /* If the stack pointer is sufficiently negative, and we haven't
  91        completed the sequence, then reset to the entry to the region.  */
  92     /* ??? The SH4 kernel checks for and address above 0xC0000000.
  93        However, the page mappings in qemu linux-user aren't as restricted
  94        and we wind up with the normal stack mapped above 0xF0000000.
  95        That said, there is no reason why the kernel should be allowing
  96        a gUSA region that spans 1GB.  Use a tighter check here, for what
  97        can actually be enabled by the immediate move.  */
  98     if (regs->gregs[15] >= -128u && regs->pc < regs->gregs[0]) {
  99         /* Reset the PC to before the gUSA region, as computed from
 100            R0 = region end, SP = -(region size), plus one more for the
 101            insn that actually initializes SP to the region size.  */
 102         regs->pc = regs->gregs[0] + regs->gregs[15] - 2;
 103
 104         /* Reset the SP to the saved version in R1.  */
 105         regs->gregs[15] = regs->gregs[1];
 106     }
 107 }
 108
 109 static void setup_sigcontext(struct target_sigcontext *sc,
 110                              CPUSH4State *regs, unsigned long mask)
 111 {
 112     int i;
 113
 114 #define COPY(x)         __put_user(regs->x, &sc->sc_##x)
 115     COPY(gregs[0]); COPY(gregs[1]);
 116     COPY(gregs[2]); COPY(gregs[3]);
 117     COPY(gregs[4]); COPY(gregs[5]);
 118     COPY(gregs[6]); COPY(gregs[7]);
 119     COPY(gregs[8]); COPY(gregs[9]);
 120     COPY(gregs[10]); COPY(gregs[11]);
 121     COPY(gregs[12]); COPY(gregs[13]);
 122     COPY(gregs[14]); COPY(gregs[15]);
 123     COPY(gbr); COPY(mach);
 124     COPY(macl); COPY(pr);
 125     COPY(sr); COPY(pc);
 126 #undef COPY
 127
 128     for (i=0; i<16; i++) {
 129         __put_user(regs->fregs[i], &sc->sc_fpregs[i]);
 130     }
 131     __put_user(regs->fpscr, &sc->sc_fpscr);
 132     __put_user(regs->fpul, &sc->sc_fpul);
 133
 134     /* non-iBCS2 extensions.. */
 135     __put_user(mask, &sc->oldmask);
 136 }
 137
 138 static void restore_sigcontext(CPUSH4State *regs, struct target_sigcontext *sc)
 139 {
 140     int i;
 141
 142 #define COPY(x)         __get_user(regs->x, &sc->sc_##x)
 143     COPY(gregs[0]); COPY(gregs[1]);
 144     COPY(gregs[2]); COPY(gregs[3]);
 145     COPY(gregs[4]); COPY(gregs[5]);
 146     COPY(gregs[6]); COPY(gregs[7]);
 147     COPY(gregs[8]); COPY(gregs[9]);
 148     COPY(gregs[10]); COPY(gregs[11]);
 149     COPY(gregs[12]); COPY(gregs[13]);
 150     COPY(gregs[14]); COPY(gregs[15]);
 151     COPY(gbr); COPY(mach);
 152     COPY(macl); COPY(pr);
 153     COPY(sr); COPY(pc);
 154 #undef COPY
 155
 156     for (i=0; i<16; i++) {
 157         __get_user(regs->fregs[i], &sc->sc_fpregs[i]);
 158     }
 159     __get_user(regs->fpscr, &sc->sc_fpscr);
 160     __get_user(regs->fpul, &sc->sc_fpul);
 161
 162     regs->tra = -1;         /* disable syscall checks */
 163     regs->flags &= ~(DELAY_SLOT_MASK | GUSA_MASK);
 164 }
 165
 166 void setup_frame(int sig, struct target_sigaction *ka,
 167                  target_sigset_t *set, CPUSH4State *regs)
 168 {
 169     struct target_sigframe *frame;
 170     abi_ulong frame_addr;
 171     int i;
 172
 173     unwind_gusa(regs);
 174
 175     frame_addr = get_sigframe(ka, regs->gregs[15], sizeof(*frame));
 176     trace_user_setup_frame(regs, frame_addr);
 177     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
 178         goto give_sigsegv;
 179     }
 180
 181     setup_sigcontext(&frame->sc, regs, set->sig[0]);
 182
 183     for (i = 0; i < TARGET_NSIG_WORDS - 1; i++) {
 184         __put_user(set->sig[i + 1], &frame->extramask[i]);
 185     }
 186
 187     /* Set up to return from userspace.  If provided, use a stub
 188        already in userspace.  */
 189     if (ka->sa_flags & TARGET_SA_RESTORER) {
 190         regs->pr = (unsigned long) ka->sa_restorer;
 191     } else {
 192         /* Generate return code (system call to sigreturn) */
 193         abi_ulong retcode_addr = frame_addr +
 194                                  offsetof(struct target_sigframe, retcode);
 195         __put_user(MOVW(2), &frame->retcode[0]);
 196         __put_user(TRAP_NOARG, &frame->retcode[1]);
 197         __put_user((TARGET_NR_sigreturn), &frame->retcode[2]);
 198         regs->pr = (unsigned long) retcode_addr;
 199     }
 200
 201     /* Set up registers for signal handler */
 202     regs->gregs[15] = frame_addr;
 203     regs->gregs[4] = sig; /* Arg for signal handler */
 204     regs->gregs[5] = 0;
 205     regs->gregs[6] = frame_addr += offsetof(typeof(*frame), sc);
 206     regs->pc = (unsigned long) ka->_sa_handler;
 207     regs->flags &= ~(DELAY_SLOT_MASK | GUSA_MASK);
 208
 209     unlock_user_struct(frame, frame_addr, 1);
 210     return;
 211
 212 give_sigsegv:
 213     unlock_user_struct(frame, frame_addr, 1);
 214     force_sigsegv(sig);
 215 }
 216
 217 void setup_rt_frame(int sig, struct target_sigaction *ka,
 218                     target_siginfo_t *info,
 219                     target_sigset_t *set, CPUSH4State *regs)
 220 {
 221     struct target_rt_sigframe *frame;
 222     abi_ulong frame_addr;
 223     int i;
 224
 225     unwind_gusa(regs);
 226
 227     frame_addr = get_sigframe(ka, regs->gregs[15], sizeof(*frame));
 228     trace_user_setup_rt_frame(regs, frame_addr);
 229     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
 230         goto give_sigsegv;
 231     }
 232
 233     tswap_siginfo(&frame->info, info);
 234
 235     /* Create the ucontext.  */
 236     __put_user(0, &frame->uc.tuc_flags);
 237     __put_user(0, (unsigned long *)&frame->uc.tuc_link);
 238     target_save_altstack(&frame->uc.tuc_stack, regs);
 239     setup_sigcontext(&frame->uc.tuc_mcontext,
 240                      regs, set->sig[0]);
 241     for(i = 0; i < TARGET_NSIG_WORDS; i++) {
 242         __put_user(set->sig[i], &frame->uc.tuc_sigmask.sig[i]);
 243     }
 244
 245     /* Set up to return from userspace.  If provided, use a stub
 246        already in userspace.  */
 247     if (ka->sa_flags & TARGET_SA_RESTORER) {
 248         regs->pr = (unsigned long) ka->sa_restorer;
 249     } else {
 250         /* Generate return code (system call to sigreturn) */
 251         abi_ulong retcode_addr = frame_addr +
 252                                  offsetof(struct target_rt_sigframe, retcode);
 253         __put_user(MOVW(2), &frame->retcode[0]);
 254         __put_user(TRAP_NOARG, &frame->retcode[1]);
 255         __put_user((TARGET_NR_rt_sigreturn), &frame->retcode[2]);
 256         regs->pr = (unsigned long) retcode_addr;
 257     }
 258
 259     /* Set up registers for signal handler */
 260     regs->gregs[15] = frame_addr;
 261     regs->gregs[4] = sig; /* Arg for signal handler */
 262     regs->gregs[5] = frame_addr + offsetof(typeof(*frame), info);
 263     regs->gregs[6] = frame_addr + offsetof(typeof(*frame), uc);
 264     regs->pc = (unsigned long) ka->_sa_handler;
 265     regs->flags &= ~(DELAY_SLOT_MASK | GUSA_MASK);
 266
 267     unlock_user_struct(frame, frame_addr, 1);
 268     return;
 269
 270 give_sigsegv:
 271     unlock_user_struct(frame, frame_addr, 1);
 272     force_sigsegv(sig);
 273 }
 274
 275 long do_sigreturn(CPUSH4State *regs)
 276 {
 277     struct target_sigframe *frame;
 278     abi_ulong frame_addr;
 279     sigset_t blocked;
 280     target_sigset_t target_set;
 281     int i;
 282
 283     frame_addr = regs->gregs[15];
 284     trace_user_do_sigreturn(regs, frame_addr);
 285     if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
 286         goto badframe;
 287     }
 288
 289     __get_user(target_set.sig[0], &frame->sc.oldmask);
 290     for(i = 1; i < TARGET_NSIG_WORDS; i++) {
 291         __get_user(target_set.sig[i], &frame->extramask[i - 1]);
 292     }
 293
 294     target_to_host_sigset_internal(&blocked, &target_set);
 295     set_sigmask(&blocked);
 296
 297     restore_sigcontext(regs, &frame->sc);
 298
 299     unlock_user_struct(frame, frame_addr, 0);
 300     return -TARGET_QEMU_ESIGRETURN;
 301
 302 badframe:
 303     unlock_user_struct(frame, frame_addr, 0);
 304     force_sig(TARGET_SIGSEGV);
 305     return -TARGET_QEMU_ESIGRETURN;
 306 }
 307
 308 long do_rt_sigreturn(CPUSH4State *regs)
 309 {
 310     struct target_rt_sigframe *frame;
 311     abi_ulong frame_addr;
 312     sigset_t blocked;
 313
 314     frame_addr = regs->gregs[15];
 315     trace_user_do_rt_sigreturn(regs, frame_addr);
 316     if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
 317         goto badframe;
 318     }
 319
 320     target_to_host_sigset(&blocked, &frame->uc.tuc_sigmask);
 321     set_sigmask(&blocked);
 322
 323     restore_sigcontext(regs, &frame->uc.tuc_mcontext);
 324
 325     if (do_sigaltstack(frame_addr +
 326                        offsetof(struct target_rt_sigframe, uc.tuc_stack),
 327                        0, get_sp_from_cpustate(regs)) == -EFAULT) {
 328         goto badframe;
 329     }
 330
 331     unlock_user_struct(frame, frame_addr, 0);
 332     return -TARGET_QEMU_ESIGRETURN;
 333
 334 badframe:
 335     unlock_user_struct(frame, frame_addr, 0);
 336     force_sig(TARGET_SIGSEGV);
 337     return -TARGET_QEMU_ESIGRETURN;
 338 }