xref: /openbmc/qemu/target/riscv/op_helper.c (revision e2abbeac) 
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_csrrw(CPURISCVState *env, target_ulong src,
41         target_ulong csr)
42 {
43     target_ulong val = 0;
44     RISCVException ret = riscv_csrrw(env, csr, &val, src, -1);
45 
46     if (ret != RISCV_EXCP_NONE) {
47         riscv_raise_exception(env, ret, GETPC());
48     }
49     return val;
50 }
51 
52 target_ulong helper_csrrs(CPURISCVState *env, target_ulong src,
53         target_ulong csr, target_ulong rs1_pass)
54 {
55     target_ulong val = 0;
56     RISCVException ret = riscv_csrrw(env, csr, &val, -1, rs1_pass ? src : 0);
57 
58     if (ret != RISCV_EXCP_NONE) {
59         riscv_raise_exception(env, ret, GETPC());
60     }
61     return val;
62 }
63 
64 target_ulong helper_csrrc(CPURISCVState *env, target_ulong src,
65         target_ulong csr, target_ulong rs1_pass)
66 {
67     target_ulong val = 0;
68     RISCVException ret = riscv_csrrw(env, csr, &val, 0, rs1_pass ? src : 0);
69 
70     if (ret != RISCV_EXCP_NONE) {
71         riscv_raise_exception(env, ret, GETPC());
72     }
73     return val;
74 }
75 
76 #ifndef CONFIG_USER_ONLY
77 
78 target_ulong helper_sret(CPURISCVState *env, target_ulong cpu_pc_deb)
79 {
80     uint64_t mstatus;
81     target_ulong prev_priv, prev_virt;
82 
83     if (!(env->priv >= PRV_S)) {
84         riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
85     }
86 
87     target_ulong retpc = env->sepc;
88     if (!riscv_has_ext(env, RVC) && (retpc & 0x3)) {
89         riscv_raise_exception(env, RISCV_EXCP_INST_ADDR_MIS, GETPC());
90     }
91 
92     if (get_field(env->mstatus, MSTATUS_TSR) && !(env->priv >= PRV_M)) {
93         riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
94     }
95 
96     if (riscv_has_ext(env, RVH) && riscv_cpu_virt_enabled(env) &&
97         get_field(env->hstatus, HSTATUS_VTSR)) {
98         riscv_raise_exception(env, RISCV_EXCP_VIRT_INSTRUCTION_FAULT, GETPC());
99     }
100 
101     mstatus = env->mstatus;
102 
103     if (riscv_has_ext(env, RVH) && !riscv_cpu_virt_enabled(env)) {
104         /* We support Hypervisor extensions and virtulisation is disabled */
105         target_ulong hstatus = env->hstatus;
106 
107         prev_priv = get_field(mstatus, MSTATUS_SPP);
108         prev_virt = get_field(hstatus, HSTATUS_SPV);
109 
110         hstatus = set_field(hstatus, HSTATUS_SPV, 0);
111         mstatus = set_field(mstatus, MSTATUS_SPP, 0);
112         mstatus = set_field(mstatus, SSTATUS_SIE,
113                             get_field(mstatus, SSTATUS_SPIE));
114         mstatus = set_field(mstatus, SSTATUS_SPIE, 1);
115 
116         env->mstatus = mstatus;
117         env->hstatus = hstatus;
118 
119         if (prev_virt) {
120             riscv_cpu_swap_hypervisor_regs(env);
121         }
122 
123         riscv_cpu_set_virt_enabled(env, prev_virt);
124     } else {
125         prev_priv = get_field(mstatus, MSTATUS_SPP);
126 
127         mstatus = set_field(mstatus, MSTATUS_SIE,
128                             get_field(mstatus, MSTATUS_SPIE));
129         mstatus = set_field(mstatus, MSTATUS_SPIE, 1);
130         mstatus = set_field(mstatus, MSTATUS_SPP, PRV_U);
131         env->mstatus = mstatus;
132     }
133 
134     riscv_cpu_set_mode(env, prev_priv);
135 
136     return retpc;
137 }
138 
139 target_ulong helper_mret(CPURISCVState *env, target_ulong cpu_pc_deb)
140 {
141     if (!(env->priv >= PRV_M)) {
142         riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
143     }
144 
145     target_ulong retpc = env->mepc;
146     if (!riscv_has_ext(env, RVC) && (retpc & 0x3)) {
147         riscv_raise_exception(env, RISCV_EXCP_INST_ADDR_MIS, GETPC());
148     }
149 
150     uint64_t mstatus = env->mstatus;
151     target_ulong prev_priv = get_field(mstatus, MSTATUS_MPP);
152 
153     if (!pmp_get_num_rules(env) && (prev_priv != PRV_M)) {
154         riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
155     }
156 
157     target_ulong prev_virt = get_field(env->mstatus, MSTATUS_MPV);
158     mstatus = set_field(mstatus, MSTATUS_MIE,
159                         get_field(mstatus, MSTATUS_MPIE));
160     mstatus = set_field(mstatus, MSTATUS_MPIE, 1);
161     mstatus = set_field(mstatus, MSTATUS_MPP, PRV_U);
162     mstatus = set_field(mstatus, MSTATUS_MPV, 0);
163     env->mstatus = mstatus;
164     riscv_cpu_set_mode(env, prev_priv);
165 
166     if (riscv_has_ext(env, RVH)) {
167         if (prev_virt) {
168             riscv_cpu_swap_hypervisor_regs(env);
169         }
170 
171         riscv_cpu_set_virt_enabled(env, prev_virt);
172     }
173 
174     return retpc;
175 }
176 
177 void helper_wfi(CPURISCVState *env)
178 {
179     CPUState *cs = env_cpu(env);
180     bool rvs = riscv_has_ext(env, RVS);
181     bool prv_u = env->priv == PRV_U;
182     bool prv_s = env->priv == PRV_S;
183 
184     if (((prv_s || (!rvs && prv_u)) && get_field(env->mstatus, MSTATUS_TW)) ||
185         (rvs && prv_u && !riscv_cpu_virt_enabled(env))) {
186         riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
187     } else if (riscv_cpu_virt_enabled(env) && (prv_u ||
188         (prv_s && get_field(env->hstatus, HSTATUS_VTW)))) {
189         riscv_raise_exception(env, RISCV_EXCP_VIRT_INSTRUCTION_FAULT, GETPC());
190     } else {
191         cs->halted = 1;
192         cs->exception_index = EXCP_HLT;
193         cpu_loop_exit(cs);
194     }
195 }
196 
197 void helper_tlb_flush(CPURISCVState *env)
198 {
199     CPUState *cs = env_cpu(env);
200     if (!(env->priv >= PRV_S) ||
201         (env->priv == PRV_S &&
202          get_field(env->mstatus, MSTATUS_TVM))) {
203         riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
204     } else if (riscv_has_ext(env, RVH) && riscv_cpu_virt_enabled(env) &&
205                get_field(env->hstatus, HSTATUS_VTVM)) {
206         riscv_raise_exception(env, RISCV_EXCP_VIRT_INSTRUCTION_FAULT, GETPC());
207     } else {
208         tlb_flush(cs);
209     }
210 }
211 
212 void helper_hyp_tlb_flush(CPURISCVState *env)
213 {
214     CPUState *cs = env_cpu(env);
215 
216     if (env->priv == PRV_S && riscv_cpu_virt_enabled(env)) {
217         riscv_raise_exception(env, RISCV_EXCP_VIRT_INSTRUCTION_FAULT, GETPC());
218     }
219 
220     if (env->priv == PRV_M ||
221         (env->priv == PRV_S && !riscv_cpu_virt_enabled(env))) {
222         tlb_flush(cs);
223         return;
224     }
225 
226     riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
227 }
228 
229 void helper_hyp_gvma_tlb_flush(CPURISCVState *env)
230 {
231     if (env->priv == PRV_S && !riscv_cpu_virt_enabled(env) &&
232         get_field(env->mstatus, MSTATUS_TVM)) {
233         riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
234     }
235 
236     helper_hyp_tlb_flush(env);
237 }
238 
239 target_ulong helper_hyp_hlvx_hu(CPURISCVState *env, target_ulong address)
240 {
241     int mmu_idx = cpu_mmu_index(env, true) | TB_FLAGS_PRIV_HYP_ACCESS_MASK;
242 
243     return cpu_lduw_mmuidx_ra(env, address, mmu_idx, GETPC());
244 }
245 
246 target_ulong helper_hyp_hlvx_wu(CPURISCVState *env, target_ulong address)
247 {
248     int mmu_idx = cpu_mmu_index(env, true) | TB_FLAGS_PRIV_HYP_ACCESS_MASK;
249 
250     return cpu_ldl_mmuidx_ra(env, address, mmu_idx, GETPC());
251 }
252 
253 #endif /* !CONFIG_USER_ONLY */
254