xref: /openbmc/qemu/target/riscv/op_helper.c (revision b3e02049) 
1 /*
2  * RISC-V Emulation Helpers for QEMU.
3  *
4  * Copyright (c) 2016-2017 Sagar Karandikar, sagark@eecs.berkeley.edu
5  * Copyright (c) 2017-2018 SiFive, Inc.
6  *
7  * This program is free software; you can redistribute it and/or modify it
8  * under the terms and conditions of the GNU General Public License,
9  * version 2 or later, as published by the Free Software Foundation.
10  *
11  * This program is distributed in the hope it will be useful, but WITHOUT
12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
14  * more details.
15  *
16  * You should have received a copy of the GNU General Public License along with
17  * this program.  If not, see <http://www.gnu.org/licenses/>.
18  */
19 
20 #include "qemu/osdep.h"
21 #include "cpu.h"
22 #include "qemu/main-loop.h"
23 #include "exec/exec-all.h"
24 #include "exec/helper-proto.h"
25 
26 /* Exceptions processing helpers */
27 void QEMU_NORETURN riscv_raise_exception(CPURISCVState *env,
28                                           uint32_t exception, uintptr_t pc)
29 {
30     CPUState *cs = env_cpu(env);
31     cs->exception_index = exception;
32     cpu_loop_exit_restore(cs, pc);
33 }
34 
35 void helper_raise_exception(CPURISCVState *env, uint32_t exception)
36 {
37     riscv_raise_exception(env, exception, 0);
38 }
39 
40 target_ulong helper_csrr(CPURISCVState *env, int csr)
41 {
42     target_ulong val = 0;
43     RISCVException ret = riscv_csrrw(env, csr, &val, 0, 0);
44 
45     if (ret != RISCV_EXCP_NONE) {
46         riscv_raise_exception(env, ret, GETPC());
47     }
48     return val;
49 }
50 
51 void helper_csrw(CPURISCVState *env, int csr, target_ulong src)
52 {
53     RISCVException ret = riscv_csrrw(env, csr, NULL, src, -1);
54 
55     if (ret != RISCV_EXCP_NONE) {
56         riscv_raise_exception(env, ret, GETPC());
57     }
58 }
59 
60 target_ulong helper_csrrw(CPURISCVState *env, int csr,
61                           target_ulong src, target_ulong write_mask)
62 {
63     target_ulong val = 0;
64     RISCVException ret = riscv_csrrw(env, csr, &val, src, write_mask);
65 
66     if (ret != RISCV_EXCP_NONE) {
67         riscv_raise_exception(env, ret, GETPC());
68     }
69     return val;
70 }
71 
72 #ifndef CONFIG_USER_ONLY
73 
74 target_ulong helper_sret(CPURISCVState *env, target_ulong cpu_pc_deb)
75 {
76     uint64_t mstatus;
77     target_ulong prev_priv, prev_virt;
78 
79     if (!(env->priv >= PRV_S)) {
80         riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
81     }
82 
83     target_ulong retpc = env->sepc;
84     if (!riscv_has_ext(env, RVC) && (retpc & 0x3)) {
85         riscv_raise_exception(env, RISCV_EXCP_INST_ADDR_MIS, GETPC());
86     }
87 
88     if (get_field(env->mstatus, MSTATUS_TSR) && !(env->priv >= PRV_M)) {
89         riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
90     }
91 
92     if (riscv_has_ext(env, RVH) && riscv_cpu_virt_enabled(env) &&
93         get_field(env->hstatus, HSTATUS_VTSR)) {
94         riscv_raise_exception(env, RISCV_EXCP_VIRT_INSTRUCTION_FAULT, GETPC());
95     }
96 
97     mstatus = env->mstatus;
98 
99     if (riscv_has_ext(env, RVH) && !riscv_cpu_virt_enabled(env)) {
100         /* We support Hypervisor extensions and virtulisation is disabled */
101         target_ulong hstatus = env->hstatus;
102 
103         prev_priv = get_field(mstatus, MSTATUS_SPP);
104         prev_virt = get_field(hstatus, HSTATUS_SPV);
105 
106         hstatus = set_field(hstatus, HSTATUS_SPV, 0);
107         mstatus = set_field(mstatus, MSTATUS_SPP, 0);
108         mstatus = set_field(mstatus, SSTATUS_SIE,
109                             get_field(mstatus, SSTATUS_SPIE));
110         mstatus = set_field(mstatus, SSTATUS_SPIE, 1);
111 
112         env->mstatus = mstatus;
113         env->hstatus = hstatus;
114 
115         if (prev_virt) {
116             riscv_cpu_swap_hypervisor_regs(env);
117         }
118 
119         riscv_cpu_set_virt_enabled(env, prev_virt);
120     } else {
121         prev_priv = get_field(mstatus, MSTATUS_SPP);
122 
123         mstatus = set_field(mstatus, MSTATUS_SIE,
124                             get_field(mstatus, MSTATUS_SPIE));
125         mstatus = set_field(mstatus, MSTATUS_SPIE, 1);
126         mstatus = set_field(mstatus, MSTATUS_SPP, PRV_U);
127         env->mstatus = mstatus;
128     }
129 
130     riscv_cpu_set_mode(env, prev_priv);
131 
132     return retpc;
133 }
134 
135 target_ulong helper_mret(CPURISCVState *env, target_ulong cpu_pc_deb)
136 {
137     if (!(env->priv >= PRV_M)) {
138         riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
139     }
140 
141     target_ulong retpc = env->mepc;
142     if (!riscv_has_ext(env, RVC) && (retpc & 0x3)) {
143         riscv_raise_exception(env, RISCV_EXCP_INST_ADDR_MIS, GETPC());
144     }
145 
146     uint64_t mstatus = env->mstatus;
147     target_ulong prev_priv = get_field(mstatus, MSTATUS_MPP);
148 
149     if (riscv_feature(env, RISCV_FEATURE_PMP) &&
150         !pmp_get_num_rules(env) && (prev_priv != PRV_M)) {
151         riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
152     }
153 
154     target_ulong prev_virt = get_field(env->mstatus, MSTATUS_MPV);
155     mstatus = set_field(mstatus, MSTATUS_MIE,
156                         get_field(mstatus, MSTATUS_MPIE));
157     mstatus = set_field(mstatus, MSTATUS_MPIE, 1);
158     mstatus = set_field(mstatus, MSTATUS_MPP, PRV_U);
159     mstatus = set_field(mstatus, MSTATUS_MPV, 0);
160     env->mstatus = mstatus;
161     riscv_cpu_set_mode(env, prev_priv);
162 
163     if (riscv_has_ext(env, RVH)) {
164         if (prev_virt) {
165             riscv_cpu_swap_hypervisor_regs(env);
166         }
167 
168         riscv_cpu_set_virt_enabled(env, prev_virt);
169     }
170 
171     return retpc;
172 }
173 
174 void helper_wfi(CPURISCVState *env)
175 {
176     CPUState *cs = env_cpu(env);
177     bool rvs = riscv_has_ext(env, RVS);
178     bool prv_u = env->priv == PRV_U;
179     bool prv_s = env->priv == PRV_S;
180 
181     if (((prv_s || (!rvs && prv_u)) && get_field(env->mstatus, MSTATUS_TW)) ||
182         (rvs && prv_u && !riscv_cpu_virt_enabled(env))) {
183         riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
184     } else if (riscv_cpu_virt_enabled(env) && (prv_u ||
185         (prv_s && get_field(env->hstatus, HSTATUS_VTW)))) {
186         riscv_raise_exception(env, RISCV_EXCP_VIRT_INSTRUCTION_FAULT, GETPC());
187     } else {
188         cs->halted = 1;
189         cs->exception_index = EXCP_HLT;
190         cpu_loop_exit(cs);
191     }
192 }
193 
194 void helper_tlb_flush(CPURISCVState *env)
195 {
196     CPUState *cs = env_cpu(env);
197     if (!(env->priv >= PRV_S) ||
198         (env->priv == PRV_S &&
199          get_field(env->mstatus, MSTATUS_TVM))) {
200         riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
201     } else if (riscv_has_ext(env, RVH) && riscv_cpu_virt_enabled(env) &&
202                get_field(env->hstatus, HSTATUS_VTVM)) {
203         riscv_raise_exception(env, RISCV_EXCP_VIRT_INSTRUCTION_FAULT, GETPC());
204     } else {
205         tlb_flush(cs);
206     }
207 }
208 
209 void helper_hyp_tlb_flush(CPURISCVState *env)
210 {
211     CPUState *cs = env_cpu(env);
212 
213     if (env->priv == PRV_S && riscv_cpu_virt_enabled(env)) {
214         riscv_raise_exception(env, RISCV_EXCP_VIRT_INSTRUCTION_FAULT, GETPC());
215     }
216 
217     if (env->priv == PRV_M ||
218         (env->priv == PRV_S && !riscv_cpu_virt_enabled(env))) {
219         tlb_flush(cs);
220         return;
221     }
222 
223     riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
224 }
225 
226 void helper_hyp_gvma_tlb_flush(CPURISCVState *env)
227 {
228     if (env->priv == PRV_S && !riscv_cpu_virt_enabled(env) &&
229         get_field(env->mstatus, MSTATUS_TVM)) {
230         riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
231     }
232 
233     helper_hyp_tlb_flush(env);
234 }
235 
236 target_ulong helper_hyp_hlvx_hu(CPURISCVState *env, target_ulong address)
237 {
238     int mmu_idx = cpu_mmu_index(env, true) | TB_FLAGS_PRIV_HYP_ACCESS_MASK;
239 
240     return cpu_lduw_mmuidx_ra(env, address, mmu_idx, GETPC());
241 }
242 
243 target_ulong helper_hyp_hlvx_wu(CPURISCVState *env, target_ulong address)
244 {
245     int mmu_idx = cpu_mmu_index(env, true) | TB_FLAGS_PRIV_HYP_ACCESS_MASK;
246 
247     return cpu_ldl_mmuidx_ra(env, address, mmu_idx, GETPC());
248 }
249 
250 #endif /* !CONFIG_USER_ONLY */
251