| 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 "user-internals.h" |
| 22 | #include "signal-common.h" |
| 23 | #include "linux-user/trace.h" |
| 24 | #include "target_ptrace.h" |
| 25 | |
| 26 | struct target_sigcontext { |
| 27 | struct target_pt_regs regs; /* needs to be first */ |
| 28 | uint32_t oldmask; |
| 29 | }; |
| 30 | |
| 31 | struct target_stack_t { |
| 32 | abi_ulong ss_sp; |
| 33 | int ss_flags; |
| 34 | unsigned int ss_size; |
| 35 | }; |
| 36 | |
| 37 | struct target_ucontext { |
| 38 | abi_ulong tuc_flags; |
| 39 | abi_ulong tuc_link; |
| 40 | target_stack_t tuc_stack; |
| 41 | struct target_sigcontext tuc_mcontext; |
| 42 | target_sigset_t tuc_sigmask; |
| 43 | }; |
| 44 | |
| 45 | /* Signal frames. */ |
| 46 | struct target_rt_sigframe { |
| 47 | target_siginfo_t info; |
| 48 | struct target_ucontext uc; |
| 49 | uint32_t tramp[2]; |
| 50 | }; |
| 51 | |
| 52 | static void setup_sigcontext(struct target_sigcontext *sc, CPUMBState *env) |
| 53 | { |
| 54 | for (int i = 0; i < 32; ++i) { |
| 55 | __put_user(env->regs[i], &sc->regs.r[i]); |
| 56 | } |
| 57 | __put_user(env->pc, &sc->regs.pc); |
| 58 | } |
| 59 | |
| 60 | static void restore_sigcontext(struct target_sigcontext *sc, CPUMBState *env) |
| 61 | { |
| 62 | for (int i = 0; i < 32; ++i) { |
| 63 | __get_user(env->regs[i], &sc->regs.r[i]); |
| 64 | } |
| 65 | __get_user(env->pc, &sc->regs.pc); |
| 66 | } |
| 67 | |
| 68 | static abi_ulong get_sigframe(struct target_sigaction *ka, |
| 69 | CPUMBState *env, int frame_size) |
| 70 | { |
| 71 | abi_ulong sp = env->regs[1]; |
| 72 | |
| 73 | sp = target_sigsp(sp, ka); |
| 74 | |
| 75 | return ((sp - frame_size) & -8UL); |
| 76 | } |
| 77 | |
| 78 | void setup_rt_frame(int sig, struct target_sigaction *ka, |
| 79 | target_siginfo_t *info, |
| 80 | target_sigset_t *set, CPUMBState *env) |
| 81 | { |
| 82 | struct target_rt_sigframe *frame; |
| 83 | abi_ulong frame_addr; |
| 84 | |
| 85 | frame_addr = get_sigframe(ka, env, sizeof *frame); |
| 86 | trace_user_setup_rt_frame(env, frame_addr); |
| 87 | |
| 88 | if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) { |
| 89 | force_sigsegv(sig); |
| 90 | return; |
| 91 | } |
| 92 | |
| 93 | frame->info = *info; |
| 94 | |
| 95 | __put_user(0, &frame->uc.tuc_flags); |
| 96 | __put_user(0, &frame->uc.tuc_link); |
| 97 | |
| 98 | target_save_altstack(&frame->uc.tuc_stack, env); |
| 99 | setup_sigcontext(&frame->uc.tuc_mcontext, env); |
| 100 | |
| 101 | for (int i = 0; i < TARGET_NSIG_WORDS; i++) { |
| 102 | __put_user(set->sig[i], &frame->uc.tuc_sigmask.sig[i]); |
| 103 | } |
| 104 | |
| 105 | /* Kernel does not use SA_RESTORER. */ |
| 106 | |
| 107 | /* |
| 108 | * Return from sighandler will jump to the tramp. |
| 109 | * Negative 8 offset because return is rtsd r15, 8 |
| 110 | */ |
| 111 | env->regs[15] = default_rt_sigreturn - 8; |
| 112 | |
| 113 | /* Set up registers for signal handler */ |
| 114 | env->regs[1] = frame_addr; |
| 115 | |
| 116 | /* Signal handler args: */ |
| 117 | env->regs[5] = sig; |
| 118 | env->regs[6] = frame_addr + offsetof(struct target_rt_sigframe, info); |
| 119 | env->regs[7] = frame_addr + offsetof(struct target_rt_sigframe, uc); |
| 120 | |
| 121 | /* Offset to handle microblaze rtid r14, 0 */ |
| 122 | env->pc = (unsigned long)ka->_sa_handler; |
| 123 | |
| 124 | unlock_user_struct(frame, frame_addr, 1); |
| 125 | } |
| 126 | |
| 127 | |
| 128 | long do_sigreturn(CPUMBState *env) |
| 129 | { |
| 130 | return -TARGET_ENOSYS; |
| 131 | } |
| 132 | |
| 133 | long do_rt_sigreturn(CPUMBState *env) |
| 134 | { |
| 135 | struct target_rt_sigframe *frame = NULL; |
| 136 | abi_ulong frame_addr = env->regs[1]; |
| 137 | sigset_t set; |
| 138 | |
| 139 | trace_user_do_rt_sigreturn(env, frame_addr); |
| 140 | |
| 141 | if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) { |
| 142 | goto badframe; |
| 143 | } |
| 144 | |
| 145 | target_to_host_sigset(&set, &frame->uc.tuc_sigmask); |
| 146 | set_sigmask(&set); |
| 147 | |
| 148 | restore_sigcontext(&frame->uc.tuc_mcontext, env); |
| 149 | |
| 150 | target_restore_altstack(&frame->uc.tuc_stack, env); |
| 151 | |
| 152 | unlock_user_struct(frame, frame_addr, 0); |
| 153 | return -QEMU_ESIGRETURN; |
| 154 | |
| 155 | badframe: |
| 156 | unlock_user_struct(frame, frame_addr, 0); |
| 157 | force_sig(TARGET_SIGSEGV); |
| 158 | return -QEMU_ESIGRETURN; |
| 159 | } |
| 160 | |
| 161 | void setup_sigtramp(abi_ulong sigtramp_page) |
| 162 | { |
| 163 | uint32_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 8, 0); |
| 164 | assert(tramp != NULL); |
| 165 | |
| 166 | /* |
| 167 | * addi r12, r0, __NR_rt_sigreturn |
| 168 | * brki r14, 0x8 |
| 169 | */ |
| 170 | __put_user(0x31800000U | TARGET_NR_rt_sigreturn, tramp); |
| 171 | __put_user(0xb9cc0008U, tramp + 1); |
| 172 | |
| 173 | default_rt_sigreturn = sigtramp_page; |
| 174 | unlock_user(tramp, sigtramp_page, 8); |
| 175 | } |