LXR qemu/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
  24typedef struct target_sigcontext {
  25    struct target_pt_regs regs;
  26    abi_ulong oldmask;
  27} target_sigcontext;
  28
  29typedef 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
  37typedef 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
  43static 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
  61static 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
  73static 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
  91void 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
 138give_sigsegv:
 139    unlock_user_struct(frame, frame_addr, 1);
 140    force_sigsegv(sig);
 141}
 142
 143long 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}
 174