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 typedef struct target_sigcontext {
  25     struct target_pt_regs regs;
  26     abi_ulong oldmask;
  27 } target_sigcontext;
  28
  29 typedef struct target_ucontext {
  30     abi_ulong tuc_flags;
  31     abi_ulong tuc_link;
  32     target_stack_t tuc_stack;
  33     target_sigcontext tuc_mcontext;
  34     target_sigset_t tuc_sigmask;   /* mask last for extensibility */
  35 } target_ucontext;
  36
  37 typedef struct target_rt_sigframe {
  38     struct target_siginfo info;
  39     target_ucontext uc;
  40     uint32_t retcode[4];  /* trampoline code */
  41 } target_rt_sigframe;
  42
  43 static void restore_sigcontext(CPUOpenRISCState *env, target_sigcontext *sc)
  44 {
  45     int i;
  46     abi_ulong v;
  47
  48     for (i = 0; i < 32; ++i) {
  49         __get_user(v, &sc->regs.gpr[i]);
  50         cpu_set_gpr(env, i, v);
  51     }
  52     __get_user(env->pc, &sc->regs.pc);
  53
  54     /* Make sure the supervisor flag is clear.  */
  55     __get_user(v, &sc->regs.sr);
  56     cpu_set_sr(env, v & ~SR_SM);
  57 }
  58
  59 /* Set up a signal frame.  */
  60
  61 static void setup_sigcontext(target_sigcontext *sc, CPUOpenRISCState *env)
  62 {
  63     int i;
  64
  65     for (i = 0; i < 32; ++i) {
  66         __put_user(cpu_get_gpr(env, i), &sc->regs.gpr[i]);
  67     }
  68
  69     __put_user(env->pc, &sc->regs.pc);
  70     __put_user(cpu_get_sr(env), &sc->regs.sr);
  71 }
  72
  73 static inline abi_ulong get_sigframe(struct target_sigaction *ka,
  74                                      CPUOpenRISCState *env,
  75                                      size_t frame_size)
  76 {
  77     target_ulong sp = get_sp_from_cpustate(env);
  78
  79     /* Honor redzone now.  If we swap to signal stack, no need to waste
  80      * the 128 bytes by subtracting afterward.
  81      */
  82     sp -= 128;
  83
  84     sp = target_sigsp(sp, ka);
  85     sp -= frame_size;
  86     sp = QEMU_ALIGN_DOWN(sp, 4);
  87
  88     return sp;
  89 }
  90
  91 void setup_rt_frame(int sig, struct target_sigaction *ka,
  92                     target_siginfo_t *info,
  93                     target_sigset_t *set, CPUOpenRISCState *env)
  94 {
  95     abi_ulong frame_addr;
  96     target_rt_sigframe *frame;
  97     int i;
  98
  99     frame_addr = get_sigframe(ka, env, sizeof(*frame));
 100     trace_user_setup_rt_frame(env, frame_addr);
 101     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
 102         goto give_sigsegv;
 103     }
 104
 105     if (ka->sa_flags & SA_SIGINFO) {
 106         tswap_siginfo(&frame->info, info);
 107     }
 108
 109     __put_user(0, &frame->uc.tuc_flags);
 110     __put_user(0, &frame->uc.tuc_link);
 111
 112     target_save_altstack(&frame->uc.tuc_stack, env);
 113     setup_sigcontext(&frame->uc.tuc_mcontext, env);
 114     for (i = 0; i < TARGET_NSIG_WORDS; ++i) {
 115         __put_user(set->sig[i], &frame->uc.tuc_sigmask.sig[i]);
 116     }
 117
 118     /* This is l.ori r11,r0,__NR_sigreturn; l.sys 1; l.nop; l.nop */
 119     __put_user(0xa9600000 | TARGET_NR_rt_sigreturn, frame->retcode + 0);
 120     __put_user(0x20000001, frame->retcode + 1);
 121     __put_user(0x15000000, frame->retcode + 2);
 122     __put_user(0x15000000, frame->retcode + 3);
 123
 124     /* Set up registers for signal handler */
 125     cpu_set_gpr(env, 9, frame_addr + offsetof(target_rt_sigframe, retcode));
 126     cpu_set_gpr(env, 3, sig);
 127     cpu_set_gpr(env, 4, frame_addr + offsetof(target_rt_sigframe, info));
 128     cpu_set_gpr(env, 5, frame_addr + offsetof(target_rt_sigframe, uc));
 129     cpu_set_gpr(env, 1, frame_addr);
 130
 131     /* For debugging convenience, set ppc to the insn that faulted.  */
 132     env->ppc = env->pc;
 133     /* When setting the PC for the signal handler, exit delay slot.  */
 134     env->pc = ka->_sa_handler;
 135     env->dflag = 0;
 136     return;
 137
 138 give_sigsegv:
 139     unlock_user_struct(frame, frame_addr, 1);
 140     force_sigsegv(sig);
 141 }
 142
 143 long do_rt_sigreturn(CPUOpenRISCState *env)
 144 {
 145     abi_ulong frame_addr = get_sp_from_cpustate(env);
 146     target_rt_sigframe *frame;
 147     sigset_t set;
 148
 149     trace_user_do_rt_sigreturn(env, 0);
 150     if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
 151         goto badframe;
 152     }
 153     if (frame_addr & 3) {
 154         goto badframe;
 155     }
 156
 157     target_to_host_sigset(&set, &frame->uc.tuc_sigmask);
 158     set_sigmask(&set);
 159
 160     restore_sigcontext(env, &frame->uc.tuc_mcontext);
 161     if (do_sigaltstack(frame_addr + offsetof(target_rt_sigframe, uc.tuc_stack),
 162                        0, frame_addr) == -EFAULT) {
 163         goto badframe;
 164     }
 165
 166     unlock_user_struct(frame, frame_addr, 0);
 167     return cpu_get_gpr(env, 11);
 168
 169  badframe:
 170     unlock_user_struct(frame, frame_addr, 0);
 171     force_sig(TARGET_SIGSEGV);
 172     return 0;
 173 }