linux-user/s390x/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 #define __NUM_GPRS 16
  25 #define __NUM_FPRS 16
  26 #define __NUM_ACRS 16
  27
  28 #define __SIGNAL_FRAMESIZE      160 /* FIXME: 31-bit mode -> 96 */
  29
  30 #define _SIGCONTEXT_NSIG        64
  31 #define _SIGCONTEXT_NSIG_BPW    64 /* FIXME: 31-bit mode -> 32 */
  32 #define _SIGCONTEXT_NSIG_WORDS  (_SIGCONTEXT_NSIG / _SIGCONTEXT_NSIG_BPW)
  33 #define _SIGMASK_COPY_SIZE    (sizeof(unsigned long)*_SIGCONTEXT_NSIG_WORDS)
  34 #define S390_SYSCALL_OPCODE ((uint16_t)0x0a00)
  35
  36 typedef struct {
  37     target_psw_t psw;
  38     abi_ulong gprs[__NUM_GPRS];
  39     abi_uint acrs[__NUM_ACRS];
  40 } target_s390_regs_common;
  41
  42 typedef struct {
  43     uint32_t fpc;
  44     uint32_t pad;
  45     uint64_t fprs[__NUM_FPRS];
  46 } target_s390_fp_regs;
  47
  48 typedef struct {
  49     target_s390_regs_common regs;
  50     target_s390_fp_regs     fpregs;
  51 } target_sigregs;
  52
  53 typedef struct {
  54     abi_ulong oldmask[_SIGCONTEXT_NSIG_WORDS];
  55     abi_ulong sregs;
  56 } target_sigcontext;
  57
  58 typedef struct {
  59     uint8_t callee_used_stack[__SIGNAL_FRAMESIZE];
  60     target_sigcontext sc;
  61     target_sigregs sregs;
  62     int signo;
  63     uint16_t retcode;
  64 } sigframe;
  65
  66 struct target_ucontext {
  67     abi_ulong tuc_flags;
  68     abi_ulong tuc_link;
  69     target_stack_t tuc_stack;
  70     target_sigregs tuc_mcontext;
  71     target_sigset_t tuc_sigmask;   /* mask last for extensibility */
  72 };
  73
  74 typedef struct {
  75     uint8_t callee_used_stack[__SIGNAL_FRAMESIZE];
  76     uint16_t retcode;
  77     struct target_siginfo info;
  78     struct target_ucontext uc;
  79 } rt_sigframe;
  80
  81 static inline abi_ulong
  82 get_sigframe(struct target_sigaction *ka, CPUS390XState *env, size_t frame_size)
  83 {
  84     abi_ulong sp;
  85
  86     /* Default to using normal stack */
  87     sp = get_sp_from_cpustate(env);
  88
  89     /* This is the X/Open sanctioned signal stack switching.  */
  90     if (ka->sa_flags & TARGET_SA_ONSTACK) {
  91         sp = target_sigsp(sp, ka);
  92     }
  93
  94     /* This is the legacy signal stack switching. */
  95     else if (/* FIXME !user_mode(regs) */ 0 &&
  96              !(ka->sa_flags & TARGET_SA_RESTORER) &&
  97              ka->sa_restorer) {
  98         sp = (abi_ulong) ka->sa_restorer;
  99     }
 100
 101     return (sp - frame_size) & -8ul;
 102 }
 103
 104 static void save_sigregs(CPUS390XState *env, target_sigregs *sregs)
 105 {
 106     int i;
 107
 108     /*
 109      * Copy a 'clean' PSW mask to the user to avoid leaking
 110      * information about whether PER is currently on.
 111      */
 112     __put_user(env->psw.mask, &sregs->regs.psw.mask);
 113     __put_user(env->psw.addr, &sregs->regs.psw.addr);
 114
 115     for (i = 0; i < 16; i++) {
 116         __put_user(env->regs[i], &sregs->regs.gprs[i]);
 117     }
 118     for (i = 0; i < 16; i++) {
 119         __put_user(env->aregs[i], &sregs->regs.acrs[i]);
 120     }
 121
 122     /*
 123      * We have to store the fp registers to current->thread.fp_regs
 124      * to merge them with the emulated registers.
 125      */
 126     for (i = 0; i < 16; i++) {
 127         __put_user(*get_freg(env, i), &sregs->fpregs.fprs[i]);
 128     }
 129 }
 130
 131 void setup_frame(int sig, struct target_sigaction *ka,
 132                  target_sigset_t *set, CPUS390XState *env)
 133 {
 134     sigframe *frame;
 135     abi_ulong frame_addr;
 136
 137     frame_addr = get_sigframe(ka, env, sizeof(*frame));
 138     trace_user_setup_frame(env, frame_addr);
 139     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
 140         force_sigsegv(sig);
 141         return;
 142     }
 143
 144     __put_user(set->sig[0], &frame->sc.oldmask[0]);
 145
 146     save_sigregs(env, &frame->sregs);
 147
 148     __put_user(frame_addr + offsetof(sigframe, sregs), &frame->sc.sregs);
 149
 150     /* Set up to return from userspace.  If provided, use a stub
 151        already in userspace.  */
 152     if (ka->sa_flags & TARGET_SA_RESTORER) {
 153         env->regs[14] = ka->sa_restorer;
 154     } else {
 155         env->regs[14] = frame_addr + offsetof(sigframe, retcode);
 156         __put_user(S390_SYSCALL_OPCODE | TARGET_NR_sigreturn,
 157                    &frame->retcode);
 158     }
 159
 160     /* Set up backchain. */
 161     __put_user(env->regs[15], (abi_ulong *) frame);
 162
 163     /* Set up registers for signal handler */
 164     env->regs[15] = frame_addr;
 165     /* Force default amode and default user address space control. */
 166     env->psw.mask = PSW_MASK_64 | PSW_MASK_32 | PSW_ASC_PRIMARY
 167                   | (env->psw.mask & ~PSW_MASK_ASC);
 168     env->psw.addr = ka->_sa_handler;
 169
 170     env->regs[2] = sig;
 171     env->regs[3] = frame_addr += offsetof(typeof(*frame), sc);
 172
 173     /*
 174      * We forgot to include these in the sigcontext.
 175      * To avoid breaking binary compatibility, they are passed as args.
 176      */
 177     env->regs[4] = 0; /* FIXME: regs->int_code & 127 */
 178     env->regs[5] = 0; /* FIXME: regs->int_parm_long */
 179     env->regs[6] = 0; /* FIXME: current->thread.last_break */
 180
 181     /* Place signal number on stack to allow backtrace from handler.  */
 182     __put_user(env->regs[2], &frame->signo);
 183     unlock_user_struct(frame, frame_addr, 1);
 184 }
 185
 186 void setup_rt_frame(int sig, struct target_sigaction *ka,
 187                     target_siginfo_t *info,
 188                     target_sigset_t *set, CPUS390XState *env)
 189 {
 190     rt_sigframe *frame;
 191     abi_ulong frame_addr;
 192
 193     frame_addr = get_sigframe(ka, env, sizeof *frame);
 194     trace_user_setup_rt_frame(env, frame_addr);
 195     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
 196         force_sigsegv(sig);
 197         return;
 198     }
 199
 200     tswap_siginfo(&frame->info, info);
 201
 202     /* Create the ucontext.  */
 203     __put_user(0, &frame->uc.tuc_flags);
 204     __put_user((abi_ulong)0, (abi_ulong *)&frame->uc.tuc_link);
 205     target_save_altstack(&frame->uc.tuc_stack, env);
 206     save_sigregs(env, &frame->uc.tuc_mcontext);
 207     tswap_sigset(&frame->uc.tuc_sigmask, set);
 208
 209     /* Set up to return from userspace.  If provided, use a stub
 210        already in userspace.  */
 211     if (ka->sa_flags & TARGET_SA_RESTORER) {
 212         env->regs[14] = ka->sa_restorer;
 213     } else {
 214         env->regs[14] = frame_addr + offsetof(typeof(*frame), retcode);
 215         __put_user(S390_SYSCALL_OPCODE | TARGET_NR_rt_sigreturn,
 216                    &frame->retcode);
 217     }
 218
 219     /* Set up backchain. */
 220     __put_user(env->regs[15], (abi_ulong *) frame);
 221
 222     /* Set up registers for signal handler */
 223     env->regs[15] = frame_addr;
 224     /* Force default amode and default user address space control. */
 225     env->psw.mask = PSW_MASK_64 | PSW_MASK_32 | PSW_ASC_PRIMARY
 226                   | (env->psw.mask & ~PSW_MASK_ASC);
 227     env->psw.addr = ka->_sa_handler;
 228
 229     env->regs[2] = sig;
 230     env->regs[3] = frame_addr + offsetof(typeof(*frame), info);
 231     env->regs[4] = frame_addr + offsetof(typeof(*frame), uc);
 232     env->regs[5] = 0; /* FIXME: current->thread.last_break */
 233 }
 234
 235 static void restore_sigregs(CPUS390XState *env, target_sigregs *sc)
 236 {
 237     target_ulong prev_addr;
 238     int i;
 239
 240     for (i = 0; i < 16; i++) {
 241         __get_user(env->regs[i], &sc->regs.gprs[i]);
 242     }
 243
 244     prev_addr = env->psw.addr;
 245     __get_user(env->psw.mask, &sc->regs.psw.mask);
 246     __get_user(env->psw.addr, &sc->regs.psw.addr);
 247     trace_user_s390x_restore_sigregs(env, env->psw.addr, prev_addr);
 248
 249     for (i = 0; i < 16; i++) {
 250         __get_user(env->aregs[i], &sc->regs.acrs[i]);
 251     }
 252     for (i = 0; i < 16; i++) {
 253         __get_user(*get_freg(env, i), &sc->fpregs.fprs[i]);
 254     }
 255 }
 256
 257 long do_sigreturn(CPUS390XState *env)
 258 {
 259     sigframe *frame;
 260     abi_ulong frame_addr = env->regs[15];
 261     target_sigset_t target_set;
 262     sigset_t set;
 263
 264     trace_user_do_sigreturn(env, frame_addr);
 265     if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
 266         force_sig(TARGET_SIGSEGV);
 267         return -TARGET_QEMU_ESIGRETURN;
 268     }
 269     __get_user(target_set.sig[0], &frame->sc.oldmask[0]);
 270
 271     target_to_host_sigset_internal(&set, &target_set);
 272     set_sigmask(&set); /* ~_BLOCKABLE? */
 273
 274     restore_sigregs(env, &frame->sregs);
 275
 276     unlock_user_struct(frame, frame_addr, 0);
 277     return -TARGET_QEMU_ESIGRETURN;
 278 }
 279
 280 long do_rt_sigreturn(CPUS390XState *env)
 281 {
 282     rt_sigframe *frame;
 283     abi_ulong frame_addr = env->regs[15];
 284     sigset_t set;
 285
 286     trace_user_do_rt_sigreturn(env, frame_addr);
 287     if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
 288         force_sig(TARGET_SIGSEGV);
 289         return -TARGET_QEMU_ESIGRETURN;
 290     }
 291     target_to_host_sigset(&set, &frame->uc.tuc_sigmask);
 292
 293     set_sigmask(&set); /* ~_BLOCKABLE? */
 294
 295     restore_sigregs(env, &frame->uc.tuc_mcontext);
 296
 297     target_restore_altstack(&frame->uc.tuc_stack, env);
 298
 299     unlock_user_struct(frame, frame_addr, 0);
 300     return -TARGET_QEMU_ESIGRETURN;
 301 }