linux-user/openrisc/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 struct target_sigcontext {
  25     struct target_pt_regs regs;
  26     abi_ulong oldmask;
  27     abi_ulong usp;
  28 };
  29
  30 struct target_ucontext {
  31     abi_ulong tuc_flags;
  32     abi_ulong tuc_link;
  33     target_stack_t tuc_stack;
  34     struct target_sigcontext tuc_mcontext;
  35     target_sigset_t tuc_sigmask;   /* mask last for extensibility */
  36 };
  37
  38 struct target_rt_sigframe {
  39     abi_ulong pinfo;
  40     uint64_t puc;
  41     struct target_siginfo info;
  42     struct target_sigcontext sc;
  43     struct target_ucontext uc;
  44     unsigned char retcode[16];  /* trampoline code */
  45 };
  46
  47 /* This is the asm-generic/ucontext.h version */
  48 #if 0
  49 static int restore_sigcontext(CPUOpenRISCState *regs,
  50                               struct target_sigcontext *sc)
  51 {
  52     unsigned int err = 0;
  53     unsigned long old_usp;
  54
  55     /* Alwys make any pending restarted system call return -EINTR */
  56     current_thread_info()->restart_block.fn = do_no_restart_syscall;
  57
  58     /* restore the regs from &sc->regs (same as sc, since regs is first)
  59      * (sc is already checked for VERIFY_READ since the sigframe was
  60      *  checked in sys_sigreturn previously)
  61      */
  62
  63     if (copy_from_user(regs, &sc, sizeof(struct target_pt_regs))) {
  64         goto badframe;
  65     }
  66
  67     /* make sure the U-flag is set so user-mode cannot fool us */
  68
  69     regs->sr &= ~SR_SM;
  70
  71     /* restore the old USP as it was before we stacked the sc etc.
  72      * (we cannot just pop the sigcontext since we aligned the sp and
  73      *  stuff after pushing it)
  74      */
  75
  76     __get_user(old_usp, &sc->usp);
  77     phx_signal("old_usp 0x%lx", old_usp);
  78
  79     __PHX__ REALLY           /* ??? */
  80     wrusp(old_usp);
  81     regs->gpr[1] = old_usp;
  82
  83     /* TODO: the other ports use regs->orig_XX to disable syscall checks
  84      * after this completes, but we don't use that mechanism. maybe we can
  85      * use it now ?
  86      */
  87
  88     return err;
  89
  90 badframe:
  91     return 1;
  92 }
  93 #endif
  94
  95 /* Set up a signal frame.  */
  96
  97 static void setup_sigcontext(struct target_sigcontext *sc,
  98                              CPUOpenRISCState *regs,
  99                              unsigned long mask)
 100 {
 101     unsigned long usp = cpu_get_gpr(regs, 1);
 102
 103     /* copy the regs. they are first in sc so we can use sc directly */
 104
 105     /*copy_to_user(&sc, regs, sizeof(struct target_pt_regs));*/
 106
 107     /* Set the frametype to CRIS_FRAME_NORMAL for the execution of
 108        the signal handler. The frametype will be restored to its previous
 109        value in restore_sigcontext. */
 110     /*regs->frametype = CRIS_FRAME_NORMAL;*/
 111
 112     /* then some other stuff */
 113     __put_user(mask, &sc->oldmask);
 114     __put_user(usp, &sc->usp);
 115 }
 116
 117 static inline unsigned long align_sigframe(unsigned long sp)
 118 {
 119     return sp & ~3UL;
 120 }
 121
 122 static inline abi_ulong get_sigframe(struct target_sigaction *ka,
 123                                      CPUOpenRISCState *regs,
 124                                      size_t frame_size)
 125 {
 126     unsigned long sp = get_sp_from_cpustate(regs);
 127     int onsigstack = on_sig_stack(sp);
 128
 129     /* redzone */
 130     sp = target_sigsp(sp, ka);
 131
 132     sp = align_sigframe(sp - frame_size);
 133
 134     /*
 135      * If we are on the alternate signal stack and would overflow it, don't.
 136      * Return an always-bogus address instead so we will die with SIGSEGV.
 137      */
 138
 139     if (onsigstack && !likely(on_sig_stack(sp))) {
 140         return -1L;
 141     }
 142
 143     return sp;
 144 }
 145
 146 void setup_rt_frame(int sig, struct target_sigaction *ka,
 147                     target_siginfo_t *info,
 148                     target_sigset_t *set, CPUOpenRISCState *env)
 149 {
 150     int err = 0;
 151     abi_ulong frame_addr;
 152     unsigned long return_ip;
 153     struct target_rt_sigframe *frame;
 154     abi_ulong info_addr, uc_addr;
 155
 156     frame_addr = get_sigframe(ka, env, sizeof(*frame));
 157     trace_user_setup_rt_frame(env, frame_addr);
 158     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
 159         goto give_sigsegv;
 160     }
 161
 162     info_addr = frame_addr + offsetof(struct target_rt_sigframe, info);
 163     __put_user(info_addr, &frame->pinfo);
 164     uc_addr = frame_addr + offsetof(struct target_rt_sigframe, uc);
 165     __put_user(uc_addr, &frame->puc);
 166
 167     if (ka->sa_flags & SA_SIGINFO) {
 168         tswap_siginfo(&frame->info, info);
 169     }
 170
 171     /*err |= __clear_user(&frame->uc, offsetof(ucontext_t, uc_mcontext));*/
 172     __put_user(0, &frame->uc.tuc_flags);
 173     __put_user(0, &frame->uc.tuc_link);
 174     target_save_altstack(&frame->uc.tuc_stack, env);
 175     setup_sigcontext(&frame->sc, env, set->sig[0]);
 176
 177     /*err |= copy_to_user(frame->uc.tuc_sigmask, set, sizeof(*set));*/
 178
 179     /* trampoline - the desired return ip is the retcode itself */
 180     return_ip = (unsigned long)&frame->retcode;
 181     /* This is l.ori r11,r0,__NR_sigreturn, l.sys 1 */
 182     __put_user(0xa960, (short *)(frame->retcode + 0));
 183     __put_user(TARGET_NR_rt_sigreturn, (short *)(frame->retcode + 2));
 184     __put_user(0x20000001, (unsigned long *)(frame->retcode + 4));
 185     __put_user(0x15000000, (unsigned long *)(frame->retcode + 8));
 186
 187     if (err) {
 188         goto give_sigsegv;
 189     }
 190
 191     /* TODO what is the current->exec_domain stuff and invmap ? */
 192
 193     /* Set up registers for signal handler */
 194     env->pc = (unsigned long)ka->_sa_handler; /* what we enter NOW */
 195     cpu_set_gpr(env, 9, (unsigned long)return_ip);     /* what we enter LATER */
 196     cpu_set_gpr(env, 3, (unsigned long)sig);           /* arg 1: signo */
 197     cpu_set_gpr(env, 4, (unsigned long)&frame->info);  /* arg 2: (siginfo_t*) */
 198     cpu_set_gpr(env, 5, (unsigned long)&frame->uc);    /* arg 3: ucontext */
 199
 200     /* actually move the usp to reflect the stacked frame */
 201     cpu_set_gpr(env, 1, (unsigned long)frame);
 202
 203     return;
 204
 205 give_sigsegv:
 206     unlock_user_struct(frame, frame_addr, 1);
 207     force_sigsegv(sig);
 208 }
 209
 210 long do_sigreturn(CPUOpenRISCState *env)
 211 {
 212     trace_user_do_sigreturn(env, 0);
 213     fprintf(stderr, "do_sigreturn: not implemented\n");
 214     return -TARGET_ENOSYS;
 215 }
 216
 217 long do_rt_sigreturn(CPUOpenRISCState *env)
 218 {
 219     trace_user_do_rt_sigreturn(env, 0);
 220     fprintf(stderr, "do_rt_sigreturn: not implemented\n");
 221     return -TARGET_ENOSYS;
 222 }