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befb7447 LV |
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 | */ | |
9c3221c1 LV |
19 | #include "qemu/osdep.h" |
20 | #include "qemu.h" | |
9c3221c1 LV |
21 | #include "signal-common.h" |
22 | #include "linux-user/trace.h" | |
23 | ||
24 | /* Signal handler invocation must be transparent for the code being | |
25 | interrupted. Complete CPU (hart) state is saved on entry and restored | |
26 | before returning from the handler. Process sigmask is also saved to block | |
27 | signals while the handler is running. The handler gets its own stack, | |
28 | which also doubles as storage for the CPU state and sigmask. | |
29 | ||
30 | The code below is qemu re-implementation of arch/riscv/kernel/signal.c */ | |
31 | ||
32 | struct target_sigcontext { | |
33 | abi_long pc; | |
34 | abi_long gpr[31]; /* x0 is not present, so all offsets must be -1 */ | |
35 | uint64_t fpr[32]; | |
36 | uint32_t fcsr; | |
37 | }; /* cf. riscv-linux:arch/riscv/include/uapi/asm/ptrace.h */ | |
38 | ||
39 | struct target_ucontext { | |
40 | unsigned long uc_flags; | |
41 | struct target_ucontext *uc_link; | |
42 | target_stack_t uc_stack; | |
43 | struct target_sigcontext uc_mcontext; | |
44 | target_sigset_t uc_sigmask; | |
45 | }; | |
46 | ||
47 | struct target_rt_sigframe { | |
48 | uint32_t tramp[2]; /* not in kernel, which uses VDSO instead */ | |
49 | struct target_siginfo info; | |
50 | struct target_ucontext uc; | |
51 | }; | |
52 | ||
53 | static abi_ulong get_sigframe(struct target_sigaction *ka, | |
54 | CPURISCVState *regs, size_t framesize) | |
55 | { | |
465e237b | 56 | abi_ulong sp = get_sp_from_cpustate(regs); |
9c3221c1 LV |
57 | |
58 | /* If we are on the alternate signal stack and would overflow it, don't. | |
59 | Return an always-bogus address instead so we will die with SIGSEGV. */ | |
465e237b | 60 | if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize))) { |
9c3221c1 LV |
61 | return -1L; |
62 | } | |
63 | ||
465e237b LV |
64 | /* This is the X/Open sanctioned signal stack switching. */ |
65 | sp = target_sigsp(sp, ka) - framesize; | |
66 | ||
67 | /* XXX: kernel aligns with 0xf ? */ | |
68 | sp &= ~3UL; /* align sp on 4-byte boundary */ | |
69 | ||
9c3221c1 LV |
70 | return sp; |
71 | } | |
72 | ||
73 | static void setup_sigcontext(struct target_sigcontext *sc, CPURISCVState *env) | |
74 | { | |
75 | int i; | |
76 | ||
77 | __put_user(env->pc, &sc->pc); | |
78 | ||
79 | for (i = 1; i < 32; i++) { | |
80 | __put_user(env->gpr[i], &sc->gpr[i - 1]); | |
81 | } | |
82 | for (i = 0; i < 32; i++) { | |
83 | __put_user(env->fpr[i], &sc->fpr[i]); | |
84 | } | |
85 | ||
fb738839 | 86 | uint32_t fcsr = riscv_csr_read(env, CSR_FCSR); |
9c3221c1 LV |
87 | __put_user(fcsr, &sc->fcsr); |
88 | } | |
89 | ||
90 | static void setup_ucontext(struct target_ucontext *uc, | |
91 | CPURISCVState *env, target_sigset_t *set) | |
92 | { | |
9c3221c1 LV |
93 | __put_user(0, &(uc->uc_flags)); |
94 | __put_user(0, &(uc->uc_link)); | |
95 | ||
465e237b | 96 | target_save_altstack(&uc->uc_stack, env); |
9c3221c1 LV |
97 | |
98 | int i; | |
99 | for (i = 0; i < TARGET_NSIG_WORDS; i++) { | |
100 | __put_user(set->sig[i], &(uc->uc_sigmask.sig[i])); | |
101 | } | |
102 | ||
103 | setup_sigcontext(&uc->uc_mcontext, env); | |
104 | } | |
105 | ||
106 | static inline void install_sigtramp(uint32_t *tramp) | |
107 | { | |
108 | __put_user(0x08b00893, tramp + 0); /* li a7, 139 = __NR_rt_sigreturn */ | |
109 | __put_user(0x00000073, tramp + 1); /* ecall */ | |
110 | } | |
111 | ||
112 | void setup_rt_frame(int sig, struct target_sigaction *ka, | |
113 | target_siginfo_t *info, | |
114 | target_sigset_t *set, CPURISCVState *env) | |
115 | { | |
116 | abi_ulong frame_addr; | |
117 | struct target_rt_sigframe *frame; | |
118 | ||
119 | frame_addr = get_sigframe(ka, env, sizeof(*frame)); | |
120 | trace_user_setup_rt_frame(env, frame_addr); | |
121 | ||
122 | if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) { | |
123 | goto badframe; | |
124 | } | |
125 | ||
126 | setup_ucontext(&frame->uc, env, set); | |
127 | tswap_siginfo(&frame->info, info); | |
128 | install_sigtramp(frame->tramp); | |
129 | ||
130 | env->pc = ka->_sa_handler; | |
131 | env->gpr[xSP] = frame_addr; | |
132 | env->gpr[xA0] = sig; | |
133 | env->gpr[xA1] = frame_addr + offsetof(struct target_rt_sigframe, info); | |
134 | env->gpr[xA2] = frame_addr + offsetof(struct target_rt_sigframe, uc); | |
135 | env->gpr[xRA] = frame_addr + offsetof(struct target_rt_sigframe, tramp); | |
136 | ||
137 | return; | |
138 | ||
139 | badframe: | |
140 | unlock_user_struct(frame, frame_addr, 1); | |
141 | if (sig == TARGET_SIGSEGV) { | |
142 | ka->_sa_handler = TARGET_SIG_DFL; | |
143 | } | |
144 | force_sig(TARGET_SIGSEGV); | |
145 | } | |
146 | ||
147 | static void restore_sigcontext(CPURISCVState *env, struct target_sigcontext *sc) | |
148 | { | |
149 | int i; | |
150 | ||
151 | __get_user(env->pc, &sc->pc); | |
152 | ||
153 | for (i = 1; i < 32; ++i) { | |
154 | __get_user(env->gpr[i], &sc->gpr[i - 1]); | |
155 | } | |
156 | for (i = 0; i < 32; ++i) { | |
157 | __get_user(env->fpr[i], &sc->fpr[i]); | |
158 | } | |
159 | ||
160 | uint32_t fcsr; | |
161 | __get_user(fcsr, &sc->fcsr); | |
fb738839 | 162 | riscv_csr_write(env, CSR_FCSR, fcsr); |
9c3221c1 LV |
163 | } |
164 | ||
165 | static void restore_ucontext(CPURISCVState *env, struct target_ucontext *uc) | |
166 | { | |
167 | sigset_t blocked; | |
168 | target_sigset_t target_set; | |
169 | int i; | |
170 | ||
171 | target_sigemptyset(&target_set); | |
172 | for (i = 0; i < TARGET_NSIG_WORDS; i++) { | |
173 | __get_user(target_set.sig[i], &(uc->uc_sigmask.sig[i])); | |
174 | } | |
175 | ||
176 | target_to_host_sigset_internal(&blocked, &target_set); | |
177 | set_sigmask(&blocked); | |
178 | ||
179 | restore_sigcontext(env, &uc->uc_mcontext); | |
180 | } | |
181 | ||
182 | long do_rt_sigreturn(CPURISCVState *env) | |
183 | { | |
184 | struct target_rt_sigframe *frame; | |
185 | abi_ulong frame_addr; | |
186 | ||
187 | frame_addr = env->gpr[xSP]; | |
188 | trace_user_do_sigreturn(env, frame_addr); | |
189 | if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) { | |
190 | goto badframe; | |
191 | } | |
192 | ||
193 | restore_ucontext(env, &frame->uc); | |
194 | ||
195 | if (do_sigaltstack(frame_addr + offsetof(struct target_rt_sigframe, | |
196 | uc.uc_stack), 0, get_sp_from_cpustate(env)) == -EFAULT) { | |
197 | goto badframe; | |
198 | } | |
199 | ||
200 | unlock_user_struct(frame, frame_addr, 0); | |
201 | return -TARGET_QEMU_ESIGRETURN; | |
202 | ||
203 | badframe: | |
204 | unlock_user_struct(frame, frame_addr, 0); | |
205 | force_sig(TARGET_SIGSEGV); | |
206 | return 0; | |
207 | } |