@samitouri / QOSamiQemu
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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 typedef struct target_sigcontext {
27 struct target_user_regs_struct regs;
28 abi_ulong oldmask;
29 } target_sigcontext;
30
31 typedef struct target_ucontext {
32 abi_ulong tuc_flags;
33 abi_ulong tuc_link;
34 target_stack_t tuc_stack;
35 target_sigcontext tuc_mcontext;
36 target_sigset_t tuc_sigmask; /* mask last for extensibility */
37 } target_ucontext;
38
39 typedef struct target_rt_sigframe {
40 struct target_siginfo info;
41 target_ucontext uc;
42 } target_rt_sigframe;
43
44 static void restore_sigcontext(CPUOpenRISCState *env, target_sigcontext *sc)
45 {
46 int i;
47 abi_ulong v;
48
49 for (i = 0; i < 32; ++i) {
50 __get_user(v, &sc->regs.gpr[i]);
51 cpu_set_gpr(env, i, v);
52 }
53 __get_user(env->pc, &sc->regs.pc);
54
55 /* Make sure the supervisor flag is clear. */
56 __get_user(v, &sc->regs.sr);
57 cpu_set_sr(env, v & ~SR_SM);
58 }
59
60 /* Set up a signal frame. */
61
62 static void setup_sigcontext(target_sigcontext *sc, CPUOpenRISCState *env)
63 {
64 int i;
65
66 for (i = 0; i < 32; ++i) {
67 __put_user(cpu_get_gpr(env, i), &sc->regs.gpr[i]);
68 }
69
70 __put_user(env->pc, &sc->regs.pc);
71 __put_user(cpu_get_sr(env), &sc->regs.sr);
72 }
73
74 static inline abi_ulong get_sigframe(struct target_sigaction *ka,
75 CPUOpenRISCState *env,
76 size_t frame_size)
77 {
78 target_ulong sp = get_sp_from_cpustate(env);
79
80 /* Honor redzone now. If we swap to signal stack, no need to waste
81 * the 128 bytes by subtracting afterward.
82 */
83 sp -= 128;
84
85 sp = target_sigsp(sp, ka);
86 sp -= frame_size;
87 sp = QEMU_ALIGN_DOWN(sp, 4);
88
89 return sp;
90 }
91
92 void setup_rt_frame(int sig, struct target_sigaction *ka,
93 target_siginfo_t *info,
94 target_sigset_t *set, CPUOpenRISCState *env)
95 {
96 abi_ulong frame_addr;
97 target_rt_sigframe *frame;
98 int i;
99
100 frame_addr = get_sigframe(ka, env, sizeof(*frame));
101 trace_user_setup_rt_frame(env, frame_addr);
102 if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
103 goto give_sigsegv;
104 }
105
106 if (ka->sa_flags & SA_SIGINFO) {
107 frame->info = *info;
108 }
109
110 __put_user(0, &frame->uc.tuc_flags);
111 __put_user(0, &frame->uc.tuc_link);
112
113 target_save_altstack(&frame->uc.tuc_stack, env);
114 setup_sigcontext(&frame->uc.tuc_mcontext, env);
115 for (i = 0; i < TARGET_NSIG_WORDS; ++i) {
116 __put_user(set->sig[i], &frame->uc.tuc_sigmask.sig[i]);
117 }
118
119 /* Set up registers for signal handler */
120 cpu_set_gpr(env, 9, default_rt_sigreturn);
121 cpu_set_gpr(env, 3, sig);
122 cpu_set_gpr(env, 4, frame_addr + offsetof(target_rt_sigframe, info));
123 cpu_set_gpr(env, 5, frame_addr + offsetof(target_rt_sigframe, uc));
124 cpu_set_gpr(env, 1, frame_addr);
125
126 /* For debugging convenience, set ppc to the insn that faulted. */
127 env->ppc = env->pc;
128 /* When setting the PC for the signal handler, exit delay slot. */
129 env->pc = ka->_sa_handler;
130 env->dflag = 0;
131 return;
132
133 give_sigsegv:
134 unlock_user_struct(frame, frame_addr, 1);
135 force_sigsegv(sig);
136 }
137
138 long do_rt_sigreturn(CPUOpenRISCState *env)
139 {
140 abi_ulong frame_addr = get_sp_from_cpustate(env);
141 target_rt_sigframe *frame;
142 sigset_t set;
143
144 trace_user_do_rt_sigreturn(env, 0);
145 if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
146 goto badframe;
147 }
148 if (frame_addr & 3) {
149 goto badframe;
150 }
151
152 target_to_host_sigset(&set, &frame->uc.tuc_sigmask);
153 set_sigmask(&set);
154
155 restore_sigcontext(env, &frame->uc.tuc_mcontext);
156 target_restore_altstack(&frame->uc.tuc_stack, env);
157
158 unlock_user_struct(frame, frame_addr, 0);
159 return cpu_get_gpr(env, 11);
160
161 badframe:
162 unlock_user_struct(frame, frame_addr, 0);
163 force_sig(TARGET_SIGSEGV);
164 return 0;
165 }
166
167 void setup_sigtramp(abi_ulong sigtramp_page)
168 {
169 uint32_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 8, 0);
170 assert(tramp != NULL);
171
172 /* This is l.ori r11,r0,__NR_sigreturn; l.sys 1 */
173 __put_user(0xa9600000 | TARGET_NR_rt_sigreturn, tramp + 0);
174 __put_user(0x20000001, tramp + 1);
175
176 default_rt_sigreturn = sigtramp_page;
177 unlock_user(tramp, sigtramp_page, 8);
178 }