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 "target_signal.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 /* Notice when we're in the middle of a gUSA region and reset.
  87    Note that this will only occur for !parallel_cpus, as we will
  88    translate such sequences differently in a parallel context.  */
  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     }
 108 }
 109
 110 static void setup_sigcontext(struct target_sigcontext *sc,
 111                              CPUSH4State *regs, unsigned long mask)
 112 {
 113     int i;
 114
 115 #define COPY(x)         __put_user(regs->x, &sc->sc_##x)
 116     COPY(gregs[0]); COPY(gregs[1]);
 117     COPY(gregs[2]); COPY(gregs[3]);
 118     COPY(gregs[4]); COPY(gregs[5]);
 119     COPY(gregs[6]); COPY(gregs[7]);
 120     COPY(gregs[8]); COPY(gregs[9]);
 121     COPY(gregs[10]); COPY(gregs[11]);
 122     COPY(gregs[12]); COPY(gregs[13]);
 123     COPY(gregs[14]); COPY(gregs[15]);
 124     COPY(gbr); COPY(mach);
 125     COPY(macl); COPY(pr);
 126     COPY(sr); COPY(pc);
 127 #undef COPY
 128
 129     for (i=0; i<16; i++) {
 130         __put_user(regs->fregs[i], &sc->sc_fpregs[i]);
 131     }
 132     __put_user(regs->fpscr, &sc->sc_fpscr);
 133     __put_user(regs->fpul, &sc->sc_fpul);
 134
 135     /* non-iBCS2 extensions.. */
 136     __put_user(mask, &sc->oldmask);
 137 }
 138
 139 static void restore_sigcontext(CPUSH4State *regs, struct target_sigcontext *sc)
 140 {
 141     int i;
 142
 143 #define COPY(x)         __get_user(regs->x, &sc->sc_##x)
 144     COPY(gregs[0]); COPY(gregs[1]);
 145     COPY(gregs[2]); COPY(gregs[3]);
 146     COPY(gregs[4]); COPY(gregs[5]);
 147     COPY(gregs[6]); COPY(gregs[7]);
 148     COPY(gregs[8]); COPY(gregs[9]);
 149     COPY(gregs[10]); COPY(gregs[11]);
 150     COPY(gregs[12]); COPY(gregs[13]);
 151     COPY(gregs[14]); COPY(gregs[15]);
 152     COPY(gbr); COPY(mach);
 153     COPY(macl); COPY(pr);
 154     COPY(sr); COPY(pc);
 155 #undef COPY
 156
 157     for (i=0; i<16; i++) {
 158         __get_user(regs->fregs[i], &sc->sc_fpregs[i]);
 159     }
 160     __get_user(regs->fpscr, &sc->sc_fpscr);
 161     __get_user(regs->fpul, &sc->sc_fpul);
 162
 163     regs->tra = -1;         /* disable syscall checks */
 164     regs->flags &= ~(DELAY_SLOT_MASK | GUSA_MASK);
 165 }
 166
 167 void setup_frame(int sig, struct target_sigaction *ka,
 168                  target_sigset_t *set, CPUSH4State *regs)
 169 {
 170     struct target_sigframe *frame;
 171     abi_ulong frame_addr;
 172     int i;
 173
 174     unwind_gusa(regs);
 175
 176     frame_addr = get_sigframe(ka, regs->gregs[15], sizeof(*frame));
 177     trace_user_setup_frame(regs, frame_addr);
 178     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
 179         goto give_sigsegv;
 180     }
 181
 182     setup_sigcontext(&frame->sc, regs, set->sig[0]);
 183
 184     for (i = 0; i < TARGET_NSIG_WORDS - 1; i++) {
 185         __put_user(set->sig[i + 1], &frame->extramask[i]);
 186     }
 187
 188     /* Set up to return from userspace.  If provided, use a stub
 189        already in userspace.  */
 190     if (ka->sa_flags & TARGET_SA_RESTORER) {
 191         regs->pr = (unsigned long) ka->sa_restorer;
 192     } else {
 193         /* Generate return code (system call to sigreturn) */
 194         abi_ulong retcode_addr = frame_addr +
 195                                  offsetof(struct target_sigframe, retcode);
 196         __put_user(MOVW(2), &frame->retcode[0]);
 197         __put_user(TRAP_NOARG, &frame->retcode[1]);
 198         __put_user((TARGET_NR_sigreturn), &frame->retcode[2]);
 199         regs->pr = (unsigned long) retcode_addr;
 200     }
 201
 202     /* Set up registers for signal handler */
 203     regs->gregs[15] = frame_addr;
 204     regs->gregs[4] = sig; /* Arg for signal handler */
 205     regs->gregs[5] = 0;
 206     regs->gregs[6] = frame_addr += offsetof(typeof(*frame), sc);
 207     regs->pc = (unsigned long) ka->_sa_handler;
 208     regs->flags &= ~(DELAY_SLOT_MASK | GUSA_MASK);
 209
 210     unlock_user_struct(frame, frame_addr, 1);
 211     return;
 212
 213 give_sigsegv:
 214     unlock_user_struct(frame, frame_addr, 1);
 215     force_sigsegv(sig);
 216 }
 217
 218 void setup_rt_frame(int sig, struct target_sigaction *ka,
 219                     target_siginfo_t *info,
 220                     target_sigset_t *set, CPUSH4State *regs)
 221 {
 222     struct target_rt_sigframe *frame;
 223     abi_ulong frame_addr;
 224     int i;
 225
 226     unwind_gusa(regs);
 227
 228     frame_addr = get_sigframe(ka, regs->gregs[15], sizeof(*frame));
 229     trace_user_setup_rt_frame(regs, frame_addr);
 230     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
 231         goto give_sigsegv;
 232     }
 233
 234     tswap_siginfo(&frame->info, info);
 235
 236     /* Create the ucontext.  */
 237     __put_user(0, &frame->uc.tuc_flags);
 238     __put_user(0, (unsigned long *)&frame->uc.tuc_link);
 239     target_save_altstack(&frame->uc.tuc_stack, regs);
 240     setup_sigcontext(&frame->uc.tuc_mcontext,
 241                      regs, set->sig[0]);
 242     for(i = 0; i < TARGET_NSIG_WORDS; i++) {
 243         __put_user(set->sig[i], &frame->uc.tuc_sigmask.sig[i]);
 244     }
 245
 246     /* Set up to return from userspace.  If provided, use a stub
 247        already in userspace.  */
 248     if (ka->sa_flags & TARGET_SA_RESTORER) {
 249         regs->pr = (unsigned long) ka->sa_restorer;
 250     } else {
 251         /* Generate return code (system call to sigreturn) */
 252         abi_ulong retcode_addr = frame_addr +
 253                                  offsetof(struct target_rt_sigframe, retcode);
 254         __put_user(MOVW(2), &frame->retcode[0]);
 255         __put_user(TRAP_NOARG, &frame->retcode[1]);
 256         __put_user((TARGET_NR_rt_sigreturn), &frame->retcode[2]);
 257         regs->pr = (unsigned long) retcode_addr;
 258     }
 259
 260     /* Set up registers for signal handler */
 261     regs->gregs[15] = frame_addr;
 262     regs->gregs[4] = sig; /* Arg for signal handler */
 263     regs->gregs[5] = frame_addr + offsetof(typeof(*frame), info);
 264     regs->gregs[6] = frame_addr + offsetof(typeof(*frame), uc);
 265     regs->pc = (unsigned long) ka->_sa_handler;
 266     regs->flags &= ~(DELAY_SLOT_MASK | GUSA_MASK);
 267
 268     unlock_user_struct(frame, frame_addr, 1);
 269     return;
 270
 271 give_sigsegv:
 272     unlock_user_struct(frame, frame_addr, 1);
 273     force_sigsegv(sig);
 274 }
 275
 276 long do_sigreturn(CPUSH4State *regs)
 277 {
 278     struct target_sigframe *frame;
 279     abi_ulong frame_addr;
 280     sigset_t blocked;
 281     target_sigset_t target_set;
 282     int i;
 283     int err = 0;
 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     if (err)
 297         goto badframe;
 298
 299     target_to_host_sigset_internal(&blocked, &target_set);
 300     set_sigmask(&blocked);
 301
 302     restore_sigcontext(regs, &frame->sc);
 303
 304     unlock_user_struct(frame, frame_addr, 0);
 305     return -TARGET_QEMU_ESIGRETURN;
 306
 307 badframe:
 308     unlock_user_struct(frame, frame_addr, 0);
 309     force_sig(TARGET_SIGSEGV);
 310     return -TARGET_QEMU_ESIGRETURN;
 311 }
 312
 313 long do_rt_sigreturn(CPUSH4State *regs)
 314 {
 315     struct target_rt_sigframe *frame;
 316     abi_ulong frame_addr;
 317     sigset_t blocked;
 318
 319     frame_addr = regs->gregs[15];
 320     trace_user_do_rt_sigreturn(regs, frame_addr);
 321     if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
 322         goto badframe;
 323     }
 324
 325     target_to_host_sigset(&blocked, &frame->uc.tuc_sigmask);
 326     set_sigmask(&blocked);
 327
 328     restore_sigcontext(regs, &frame->uc.tuc_mcontext);
 329
 330     if (do_sigaltstack(frame_addr +
 331                        offsetof(struct target_rt_sigframe, uc.tuc_stack),
 332                        0, get_sp_from_cpustate(regs)) == -EFAULT) {
 333         goto badframe;
 334     }
 335
 336     unlock_user_struct(frame, frame_addr, 0);
 337     return -TARGET_QEMU_ESIGRETURN;
 338
 339 badframe:
 340     unlock_user_struct(frame, frame_addr, 0);
 341     force_sig(TARGET_SIGSEGV);
 342     return -TARGET_QEMU_ESIGRETURN;
 343 }