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 "user-internals.h"
  22 #include "signal-common.h"
  23 #include "linux-user/trace.h"
  24
  25 /*
  26  * code and data structures from linux kernel:
  27  * include/asm-sh/sigcontext.h
  28  * arch/sh/kernel/signal.c
  29  */
  30
  31 struct target_sigcontext {
  32     target_ulong  oldmask;
  33
  34     /* CPU registers */
  35     target_ulong  sc_gregs[16];
  36     target_ulong  sc_pc;
  37     target_ulong  sc_pr;
  38     target_ulong  sc_sr;
  39     target_ulong  sc_gbr;
  40     target_ulong  sc_mach;
  41     target_ulong  sc_macl;
  42
  43     /* FPU registers */
  44     target_ulong  sc_fpregs[16];
  45     target_ulong  sc_xfpregs[16];
  46     unsigned int sc_fpscr;
  47     unsigned int sc_fpul;
  48     unsigned int sc_ownedfp;
  49 };
  50
  51 struct target_sigframe
  52 {
  53     struct target_sigcontext sc;
  54     target_ulong extramask[TARGET_NSIG_WORDS-1];
  55     uint16_t retcode[3];
  56 };
  57
  58
  59 struct target_ucontext {
  60     target_ulong tuc_flags;
  61     struct target_ucontext *tuc_link;
  62     target_stack_t tuc_stack;
  63     struct target_sigcontext tuc_mcontext;
  64     target_sigset_t tuc_sigmask;        /* mask last for extensibility */
  65 };
  66
  67 struct target_rt_sigframe
  68 {
  69     struct target_siginfo info;
  70     struct target_ucontext uc;
  71     uint16_t retcode[3];
  72 };
  73
  74
  75 #define MOVW(n)  (0x9300|((n)-2)) /* Move mem word at PC+n to R3 */
  76 #define TRAP_NOARG 0xc310         /* Syscall w/no args (NR in R3) SH3/4 */
  77
  78 static abi_ulong get_sigframe(struct target_sigaction *ka,
  79                               unsigned long sp, size_t frame_size)
  80 {
  81     sp = target_sigsp(sp, ka);
  82
  83     return (sp - frame_size) & -8ul;
  84 }
  85
  86 /*
  87  * Notice when we're in the middle of a gUSA region and reset.
  88  * Note that this will only occur when #CF_PARALLEL is unset, as we
  89  * will translate such sequences differently in a parallel context.
  90  */
  91 static void unwind_gusa(CPUSH4State *regs)
  92 {
  93     /* If the stack pointer is sufficiently negative, and we haven't
  94        completed the sequence, then reset to the entry to the region.  */
  95     /* ??? The SH4 kernel checks for and address above 0xC0000000.
  96        However, the page mappings in qemu linux-user aren't as restricted
  97        and we wind up with the normal stack mapped above 0xF0000000.
  98        That said, there is no reason why the kernel should be allowing
  99        a gUSA region that spans 1GB.  Use a tighter check here, for what
 100        can actually be enabled by the immediate move.  */
 101     if (regs->gregs[15] >= -128u && regs->pc < regs->gregs[0]) {
 102         /* Reset the PC to before the gUSA region, as computed from
 103            R0 = region end, SP = -(region size), plus one more for the
 104            insn that actually initializes SP to the region size.  */
 105         regs->pc = regs->gregs[0] + regs->gregs[15] - 2;
 106
 107         /* Reset the SP to the saved version in R1.  */
 108         regs->gregs[15] = regs->gregs[1];
 109     }
 110 }
 111
 112 static void setup_sigcontext(struct target_sigcontext *sc,
 113                              CPUSH4State *regs, unsigned long mask)
 114 {
 115     int i;
 116
 117 #define COPY(x)         __put_user(regs->x, &sc->sc_##x)
 118     COPY(gregs[0]); COPY(gregs[1]);
 119     COPY(gregs[2]); COPY(gregs[3]);
 120     COPY(gregs[4]); COPY(gregs[5]);
 121     COPY(gregs[6]); COPY(gregs[7]);
 122     COPY(gregs[8]); COPY(gregs[9]);
 123     COPY(gregs[10]); COPY(gregs[11]);
 124     COPY(gregs[12]); COPY(gregs[13]);
 125     COPY(gregs[14]); COPY(gregs[15]);
 126     COPY(gbr); COPY(mach);
 127     COPY(macl); COPY(pr);
 128     COPY(sr); COPY(pc);
 129 #undef COPY
 130
 131     for (i=0; i<16; i++) {
 132         __put_user(regs->fregs[i], &sc->sc_fpregs[i]);
 133     }
 134     __put_user(regs->fpscr, &sc->sc_fpscr);
 135     __put_user(regs->fpul, &sc->sc_fpul);
 136
 137     /* non-iBCS2 extensions.. */
 138     __put_user(mask, &sc->oldmask);
 139 }
 140
 141 static void restore_sigcontext(CPUSH4State *regs, struct target_sigcontext *sc)
 142 {
 143     int i;
 144
 145 #define COPY(x)         __get_user(regs->x, &sc->sc_##x)
 146     COPY(gregs[0]); COPY(gregs[1]);
 147     COPY(gregs[2]); COPY(gregs[3]);
 148     COPY(gregs[4]); COPY(gregs[5]);
 149     COPY(gregs[6]); COPY(gregs[7]);
 150     COPY(gregs[8]); COPY(gregs[9]);
 151     COPY(gregs[10]); COPY(gregs[11]);
 152     COPY(gregs[12]); COPY(gregs[13]);
 153     COPY(gregs[14]); COPY(gregs[15]);
 154     COPY(gbr); COPY(mach);
 155     COPY(macl); COPY(pr);
 156     COPY(sr); COPY(pc);
 157 #undef COPY
 158
 159     for (i=0; i<16; i++) {
 160         __get_user(regs->fregs[i], &sc->sc_fpregs[i]);
 161     }
 162     __get_user(regs->fpscr, &sc->sc_fpscr);
 163     __get_user(regs->fpul, &sc->sc_fpul);
 164
 165     regs->tra = -1;         /* disable syscall checks */
 166     regs->flags &= ~(DELAY_SLOT_MASK | GUSA_MASK);
 167 }
 168
 169 void setup_frame(int sig, struct target_sigaction *ka,
 170                  target_sigset_t *set, CPUSH4State *regs)
 171 {
 172     struct target_sigframe *frame;
 173     abi_ulong frame_addr;
 174     int i;
 175
 176     unwind_gusa(regs);
 177
 178     frame_addr = get_sigframe(ka, regs->gregs[15], sizeof(*frame));
 179     trace_user_setup_frame(regs, frame_addr);
 180     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
 181         goto give_sigsegv;
 182     }
 183
 184     setup_sigcontext(&frame->sc, regs, set->sig[0]);
 185
 186     for (i = 0; i < TARGET_NSIG_WORDS - 1; i++) {
 187         __put_user(set->sig[i + 1], &frame->extramask[i]);
 188     }
 189
 190     /* Set up to return from userspace.  If provided, use a stub
 191        already in userspace.  */
 192     if (ka->sa_flags & TARGET_SA_RESTORER) {
 193         regs->pr = (unsigned long) ka->sa_restorer;
 194     } else {
 195         /* Generate return code (system call to sigreturn) */
 196         abi_ulong retcode_addr = frame_addr +
 197                                  offsetof(struct target_sigframe, retcode);
 198         __put_user(MOVW(2), &frame->retcode[0]);
 199         __put_user(TRAP_NOARG, &frame->retcode[1]);
 200         __put_user((TARGET_NR_sigreturn), &frame->retcode[2]);
 201         regs->pr = (unsigned long) retcode_addr;
 202     }
 203
 204     /* Set up registers for signal handler */
 205     regs->gregs[15] = frame_addr;
 206     regs->gregs[4] = sig; /* Arg for signal handler */
 207     regs->gregs[5] = 0;
 208     regs->gregs[6] = frame_addr += offsetof(typeof(*frame), sc);
 209     regs->pc = (unsigned long) ka->_sa_handler;
 210     regs->flags &= ~(DELAY_SLOT_MASK | GUSA_MASK);
 211
 212     unlock_user_struct(frame, frame_addr, 1);
 213     return;
 214
 215 give_sigsegv:
 216     unlock_user_struct(frame, frame_addr, 1);
 217     force_sigsegv(sig);
 218 }
 219
 220 void setup_rt_frame(int sig, struct target_sigaction *ka,
 221                     target_siginfo_t *info,
 222                     target_sigset_t *set, CPUSH4State *regs)
 223 {
 224     struct target_rt_sigframe *frame;
 225     abi_ulong frame_addr;
 226     int i;
 227
 228     unwind_gusa(regs);
 229
 230     frame_addr = get_sigframe(ka, regs->gregs[15], sizeof(*frame));
 231     trace_user_setup_rt_frame(regs, frame_addr);
 232     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
 233         goto give_sigsegv;
 234     }
 235
 236     tswap_siginfo(&frame->info, info);
 237
 238     /* Create the ucontext.  */
 239     __put_user(0, &frame->uc.tuc_flags);
 240     __put_user(0, (unsigned long *)&frame->uc.tuc_link);
 241     target_save_altstack(&frame->uc.tuc_stack, regs);
 242     setup_sigcontext(&frame->uc.tuc_mcontext,
 243                      regs, set->sig[0]);
 244     for(i = 0; i < TARGET_NSIG_WORDS; i++) {
 245         __put_user(set->sig[i], &frame->uc.tuc_sigmask.sig[i]);
 246     }
 247
 248     /* Set up to return from userspace.  If provided, use a stub
 249        already in userspace.  */
 250     if (ka->sa_flags & TARGET_SA_RESTORER) {
 251         regs->pr = (unsigned long) ka->sa_restorer;
 252     } else {
 253         /* Generate return code (system call to sigreturn) */
 254         abi_ulong retcode_addr = frame_addr +
 255                                  offsetof(struct target_rt_sigframe, retcode);
 256         __put_user(MOVW(2), &frame->retcode[0]);
 257         __put_user(TRAP_NOARG, &frame->retcode[1]);
 258         __put_user((TARGET_NR_rt_sigreturn), &frame->retcode[2]);
 259         regs->pr = (unsigned long) retcode_addr;
 260     }
 261
 262     /* Set up registers for signal handler */
 263     regs->gregs[15] = frame_addr;
 264     regs->gregs[4] = sig; /* Arg for signal handler */
 265     regs->gregs[5] = frame_addr + offsetof(typeof(*frame), info);
 266     regs->gregs[6] = frame_addr + offsetof(typeof(*frame), uc);
 267     regs->pc = (unsigned long) ka->_sa_handler;
 268     regs->flags &= ~(DELAY_SLOT_MASK | GUSA_MASK);
 269
 270     unlock_user_struct(frame, frame_addr, 1);
 271     return;
 272
 273 give_sigsegv:
 274     unlock_user_struct(frame, frame_addr, 1);
 275     force_sigsegv(sig);
 276 }
 277
 278 long do_sigreturn(CPUSH4State *regs)
 279 {
 280     struct target_sigframe *frame;
 281     abi_ulong frame_addr;
 282     sigset_t blocked;
 283     target_sigset_t target_set;
 284     int i;
 285
 286     frame_addr = regs->gregs[15];
 287     trace_user_do_sigreturn(regs, frame_addr);
 288     if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
 289         goto badframe;
 290     }
 291
 292     __get_user(target_set.sig[0], &frame->sc.oldmask);
 293     for(i = 1; i < TARGET_NSIG_WORDS; i++) {
 294         __get_user(target_set.sig[i], &frame->extramask[i - 1]);
 295     }
 296
 297     target_to_host_sigset_internal(&blocked, &target_set);
 298     set_sigmask(&blocked);
 299
 300     restore_sigcontext(regs, &frame->sc);
 301
 302     unlock_user_struct(frame, frame_addr, 0);
 303     return -TARGET_QEMU_ESIGRETURN;
 304
 305 badframe:
 306     unlock_user_struct(frame, frame_addr, 0);
 307     force_sig(TARGET_SIGSEGV);
 308     return -TARGET_QEMU_ESIGRETURN;
 309 }
 310
 311 long do_rt_sigreturn(CPUSH4State *regs)
 312 {
 313     struct target_rt_sigframe *frame;
 314     abi_ulong frame_addr;
 315     sigset_t blocked;
 316
 317     frame_addr = regs->gregs[15];
 318     trace_user_do_rt_sigreturn(regs, frame_addr);
 319     if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
 320         goto badframe;
 321     }
 322
 323     target_to_host_sigset(&blocked, &frame->uc.tuc_sigmask);
 324     set_sigmask(&blocked);
 325
 326     restore_sigcontext(regs, &frame->uc.tuc_mcontext);
 327     target_restore_altstack(&frame->uc.tuc_stack, regs);
 328
 329     unlock_user_struct(frame, frame_addr, 0);
 330     return -TARGET_QEMU_ESIGRETURN;
 331
 332 badframe:
 333     unlock_user_struct(frame, frame_addr, 0);
 334     force_sig(TARGET_SIGSEGV);
 335     return -TARGET_QEMU_ESIGRETURN;
 336 }