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 };
  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 };
  71
  72
  73 #define MOVW(n)  (0x9300|((n)-2)) /* Move mem word at PC+n to R3 */
  74 #define TRAP_NOARG 0xc310         /* Syscall w/no args (NR in R3) SH3/4 */
  75
  76 static abi_ulong get_sigframe(struct target_sigaction *ka,
  77                               unsigned long sp, size_t frame_size)
  78 {
  79     sp = target_sigsp(sp, ka);
  80
  81     return (sp - frame_size) & -8ul;
  82 }
  83
  84 /*
  85  * Notice when we're in the middle of a gUSA region and reset.
  86  * Note that this will only occur when #CF_PARALLEL is unset, as we
  87  * will translate such sequences differently in a parallel context.
  88  */
  89 static void unwind_gusa(CPUSH4State *regs)
  90 {
  91     /* If the stack pointer is sufficiently negative, and we haven't
  92        completed the sequence, then reset to the entry to the region.  */
  93     /* ??? The SH4 kernel checks for and address above 0xC0000000.
  94        However, the page mappings in qemu linux-user aren't as restricted
  95        and we wind up with the normal stack mapped above 0xF0000000.
  96        That said, there is no reason why the kernel should be allowing
  97        a gUSA region that spans 1GB.  Use a tighter check here, for what
  98        can actually be enabled by the immediate move.  */
  99     if (regs->gregs[15] >= -128u && regs->pc < regs->gregs[0]) {
 100         /* Reset the PC to before the gUSA region, as computed from
 101            R0 = region end, SP = -(region size), plus one more for the
 102            insn that actually initializes SP to the region size.  */
 103         regs->pc = regs->gregs[0] + regs->gregs[15] - 2;
 104
 105         /* Reset the SP to the saved version in R1.  */
 106         regs->gregs[15] = regs->gregs[1];
 107     } else if (regs->gregs[15] >= -128u && regs->pc == regs->gregs[0]) {
 108         /* If we are on the last instruction of a gUSA region, we must reset
 109            the SP, otherwise we would be pushing the signal context to
 110            invalid memory.  */
 111         regs->gregs[15] = regs->gregs[1];
 112     } else if (regs->flags & TB_FLAG_DELAY_SLOT) {
 113         /* If we are in a delay slot, push the previous instruction.  */
 114         regs->pc -= 2;
 115     }
 116 }
 117
 118 static void setup_sigcontext(struct target_sigcontext *sc,
 119                              CPUSH4State *regs, unsigned long mask)
 120 {
 121     int i;
 122
 123 #define COPY(x)         __put_user(regs->x, &sc->sc_##x)
 124     COPY(gregs[0]); COPY(gregs[1]);
 125     COPY(gregs[2]); COPY(gregs[3]);
 126     COPY(gregs[4]); COPY(gregs[5]);
 127     COPY(gregs[6]); COPY(gregs[7]);
 128     COPY(gregs[8]); COPY(gregs[9]);
 129     COPY(gregs[10]); COPY(gregs[11]);
 130     COPY(gregs[12]); COPY(gregs[13]);
 131     COPY(gregs[14]); COPY(gregs[15]);
 132     COPY(gbr); COPY(mach);
 133     COPY(macl); COPY(pr);
 134     COPY(sr); COPY(pc);
 135 #undef COPY
 136
 137     for (i=0; i<16; i++) {
 138         __put_user(regs->fregs[i], &sc->sc_fpregs[i]);
 139     }
 140     __put_user(regs->fpscr, &sc->sc_fpscr);
 141     __put_user(regs->fpul, &sc->sc_fpul);
 142
 143     /* non-iBCS2 extensions.. */
 144     __put_user(mask, &sc->oldmask);
 145 }
 146
 147 static void restore_sigcontext(CPUSH4State *regs, struct target_sigcontext *sc)
 148 {
 149     int i;
 150
 151 #define COPY(x)         __get_user(regs->x, &sc->sc_##x)
 152     COPY(gregs[0]); COPY(gregs[1]);
 153     COPY(gregs[2]); COPY(gregs[3]);
 154     COPY(gregs[4]); COPY(gregs[5]);
 155     COPY(gregs[6]); COPY(gregs[7]);
 156     COPY(gregs[8]); COPY(gregs[9]);
 157     COPY(gregs[10]); COPY(gregs[11]);
 158     COPY(gregs[12]); COPY(gregs[13]);
 159     COPY(gregs[14]); COPY(gregs[15]);
 160     COPY(gbr); COPY(mach);
 161     COPY(macl); COPY(pr);
 162     COPY(sr); COPY(pc);
 163 #undef COPY
 164
 165     for (i=0; i<16; i++) {
 166         __get_user(regs->fregs[i], &sc->sc_fpregs[i]);
 167     }
 168     __get_user(regs->fpscr, &sc->sc_fpscr);
 169     __get_user(regs->fpul, &sc->sc_fpul);
 170
 171     regs->tra = -1;         /* disable syscall checks */
 172     regs->flags = 0;
 173 }
 174
 175 void setup_frame(int sig, struct target_sigaction *ka,
 176                  target_sigset_t *set, CPUSH4State *regs)
 177 {
 178     struct target_sigframe *frame;
 179     abi_ulong frame_addr;
 180     int i;
 181
 182     unwind_gusa(regs);
 183
 184     frame_addr = get_sigframe(ka, regs->gregs[15], sizeof(*frame));
 185     trace_user_setup_frame(regs, frame_addr);
 186     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
 187         goto give_sigsegv;
 188     }
 189
 190     setup_sigcontext(&frame->sc, regs, set->sig[0]);
 191
 192     for (i = 0; i < TARGET_NSIG_WORDS - 1; i++) {
 193         __put_user(set->sig[i + 1], &frame->extramask[i]);
 194     }
 195
 196     /* Set up to return from userspace.  If provided, use a stub
 197        already in userspace.  */
 198     if (ka->sa_flags & TARGET_SA_RESTORER) {
 199         regs->pr = ka->sa_restorer;
 200     } else {
 201         regs->pr = default_sigreturn;
 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 &= ~(TB_FLAG_DELAY_SLOT_MASK | TB_FLAG_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 = ka->sa_restorer;
 252     } else {
 253         regs->pr = default_rt_sigreturn;
 254     }
 255
 256     /* Set up registers for signal handler */
 257     regs->gregs[15] = frame_addr;
 258     regs->gregs[4] = sig; /* Arg for signal handler */
 259     regs->gregs[5] = frame_addr + offsetof(typeof(*frame), info);
 260     regs->gregs[6] = frame_addr + offsetof(typeof(*frame), uc);
 261     regs->pc = (unsigned long) ka->_sa_handler;
 262     regs->flags &= ~(TB_FLAG_DELAY_SLOT_MASK | TB_FLAG_GUSA_MASK);
 263
 264     unlock_user_struct(frame, frame_addr, 1);
 265     return;
 266
 267 give_sigsegv:
 268     unlock_user_struct(frame, frame_addr, 1);
 269     force_sigsegv(sig);
 270 }
 271
 272 long do_sigreturn(CPUSH4State *regs)
 273 {
 274     struct target_sigframe *frame;
 275     abi_ulong frame_addr;
 276     sigset_t blocked;
 277     target_sigset_t target_set;
 278     int i;
 279
 280     frame_addr = regs->gregs[15];
 281     trace_user_do_sigreturn(regs, frame_addr);
 282     if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
 283         goto badframe;
 284     }
 285
 286     __get_user(target_set.sig[0], &frame->sc.oldmask);
 287     for(i = 1; i < TARGET_NSIG_WORDS; i++) {
 288         __get_user(target_set.sig[i], &frame->extramask[i - 1]);
 289     }
 290
 291     target_to_host_sigset_internal(&blocked, &target_set);
 292     set_sigmask(&blocked);
 293
 294     restore_sigcontext(regs, &frame->sc);
 295
 296     unlock_user_struct(frame, frame_addr, 0);
 297     return -QEMU_ESIGRETURN;
 298
 299 badframe:
 300     unlock_user_struct(frame, frame_addr, 0);
 301     force_sig(TARGET_SIGSEGV);
 302     return -QEMU_ESIGRETURN;
 303 }
 304
 305 long do_rt_sigreturn(CPUSH4State *regs)
 306 {
 307     struct target_rt_sigframe *frame;
 308     abi_ulong frame_addr;
 309     sigset_t blocked;
 310
 311     frame_addr = regs->gregs[15];
 312     trace_user_do_rt_sigreturn(regs, frame_addr);
 313     if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
 314         goto badframe;
 315     }
 316
 317     target_to_host_sigset(&blocked, &frame->uc.tuc_sigmask);
 318     set_sigmask(&blocked);
 319
 320     restore_sigcontext(regs, &frame->uc.tuc_mcontext);
 321     target_restore_altstack(&frame->uc.tuc_stack, regs);
 322
 323     unlock_user_struct(frame, frame_addr, 0);
 324     return -QEMU_ESIGRETURN;
 325
 326 badframe:
 327     unlock_user_struct(frame, frame_addr, 0);
 328     force_sig(TARGET_SIGSEGV);
 329     return -QEMU_ESIGRETURN;
 330 }
 331
 332 void setup_sigtramp(abi_ulong sigtramp_page)
 333 {
 334     uint16_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 2 * 6, 0);
 335     assert(tramp != NULL);
 336
 337     default_sigreturn = sigtramp_page;
 338     __put_user(MOVW(2), &tramp[0]);
 339     __put_user(TRAP_NOARG, &tramp[1]);
 340     __put_user(TARGET_NR_sigreturn, &tramp[2]);
 341
 342     default_rt_sigreturn = sigtramp_page + 6;
 343     __put_user(MOVW(2), &tramp[3]);
 344     __put_user(TRAP_NOARG, &tramp[4]);
 345     __put_user(TARGET_NR_rt_sigreturn, &tramp[5]);
 346
 347     unlock_user(tramp, sigtramp_page, 2 * 6);
 348 }