xref: /openbmc/qemu/target/riscv/op_helper.c (revision 831734cc) 
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 "qemu/log.h"
22 #include "cpu.h"
23 #include "qemu/main-loop.h"
24 #include "exec/exec-all.h"
25 #include "exec/helper-proto.h"
26 
27 /* Exceptions processing helpers */
28 void QEMU_NORETURN riscv_raise_exception(CPURISCVState *env,
29                                           uint32_t exception, uintptr_t pc)
30 {
31     CPUState *cs = env_cpu(env);
32     cs->exception_index = exception;
33     cpu_loop_exit_restore(cs, pc);
34 }
35 
36 void helper_raise_exception(CPURISCVState *env, uint32_t exception)
37 {
38     riscv_raise_exception(env, exception, 0);
39 }
40 
41 target_ulong helper_csrrw(CPURISCVState *env, target_ulong src,
42         target_ulong csr)
43 {
44     target_ulong val = 0;
45     int ret = riscv_csrrw(env, csr, &val, src, -1);
46 
47     if (ret < 0) {
48         riscv_raise_exception(env, -ret, GETPC());
49     }
50     return val;
51 }
52 
53 target_ulong helper_csrrs(CPURISCVState *env, target_ulong src,
54         target_ulong csr, target_ulong rs1_pass)
55 {
56     target_ulong val = 0;
57     int ret = riscv_csrrw(env, csr, &val, -1, rs1_pass ? src : 0);
58 
59     if (ret < 0) {
60         riscv_raise_exception(env, -ret, GETPC());
61     }
62     return val;
63 }
64 
65 target_ulong helper_csrrc(CPURISCVState *env, target_ulong src,
66         target_ulong csr, target_ulong rs1_pass)
67 {
68     target_ulong val = 0;
69     int ret = riscv_csrrw(env, csr, &val, 0, rs1_pass ? src : 0);
70 
71     if (ret < 0) {
72         riscv_raise_exception(env, -ret, GETPC());
73     }
74     return val;
75 }
76 
77 #ifndef CONFIG_USER_ONLY
78 
79 target_ulong helper_sret(CPURISCVState *env, target_ulong cpu_pc_deb)
80 {
81     uint64_t mstatus;
82     target_ulong prev_priv, prev_virt;
83 
84     if (!(env->priv >= PRV_S)) {
85         riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
86     }
87 
88     target_ulong retpc = env->sepc;
89     if (!riscv_has_ext(env, RVC) && (retpc & 0x3)) {
90         riscv_raise_exception(env, RISCV_EXCP_INST_ADDR_MIS, GETPC());
91     }
92 
93     if (get_field(env->mstatus, MSTATUS_TSR) && !(env->priv >= PRV_M)) {
94         riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
95     }
96 
97     if (riscv_has_ext(env, RVH) && riscv_cpu_virt_enabled(env) &&
98         get_field(env->hstatus, HSTATUS_VTSR)) {
99         riscv_raise_exception(env, RISCV_EXCP_VIRT_INSTRUCTION_FAULT, GETPC());
100     }
101 
102     mstatus = env->mstatus;
103 
104     if (riscv_has_ext(env, RVH) && !riscv_cpu_virt_enabled(env)) {
105         /* We support Hypervisor extensions and virtulisation is disabled */
106         target_ulong hstatus = env->hstatus;
107 
108         prev_priv = get_field(mstatus, MSTATUS_SPP);
109         prev_virt = get_field(hstatus, HSTATUS_SPV);
110 
111         hstatus = set_field(hstatus, HSTATUS_SPV, 0);
112         mstatus = set_field(mstatus, MSTATUS_SPP, 0);
113         mstatus = set_field(mstatus, SSTATUS_SIE,
114                             get_field(mstatus, SSTATUS_SPIE));
115         mstatus = set_field(mstatus, SSTATUS_SPIE, 1);
116 
117         env->mstatus = mstatus;
118         env->hstatus = hstatus;
119 
120         if (prev_virt) {
121             riscv_cpu_swap_hypervisor_regs(env);
122         }
123 
124         riscv_cpu_set_virt_enabled(env, prev_virt);
125     } else {
126         prev_priv = get_field(mstatus, MSTATUS_SPP);
127 
128         mstatus = set_field(mstatus, MSTATUS_SIE,
129                             get_field(mstatus, MSTATUS_SPIE));
130         mstatus = set_field(mstatus, MSTATUS_SPIE, 1);
131         mstatus = set_field(mstatus, MSTATUS_SPP, PRV_U);
132         env->mstatus = mstatus;
133     }
134 
135     riscv_cpu_set_mode(env, prev_priv);
136 
137     return retpc;
138 }
139 
140 target_ulong helper_mret(CPURISCVState *env, target_ulong cpu_pc_deb)
141 {
142     if (!(env->priv >= PRV_M)) {
143         riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
144     }
145 
146     target_ulong retpc = env->mepc;
147     if (!riscv_has_ext(env, RVC) && (retpc & 0x3)) {
148         riscv_raise_exception(env, RISCV_EXCP_INST_ADDR_MIS, GETPC());
149     }
150 
151     uint64_t mstatus = env->mstatus;
152     target_ulong prev_priv = get_field(mstatus, MSTATUS_MPP);
153 
154     if (!pmp_get_num_rules(env) && (prev_priv != PRV_M)) {
155         riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
156     }
157 
158     target_ulong prev_virt = get_field(env->mstatus, MSTATUS_MPV);
159     mstatus = set_field(mstatus, MSTATUS_MIE,
160                         get_field(mstatus, MSTATUS_MPIE));
161     mstatus = set_field(mstatus, MSTATUS_MPIE, 1);
162     mstatus = set_field(mstatus, MSTATUS_MPP, PRV_U);
163     mstatus = set_field(mstatus, MSTATUS_MPV, 0);
164     env->mstatus = mstatus;
165     riscv_cpu_set_mode(env, prev_priv);
166 
167     if (riscv_has_ext(env, RVH)) {
168         if (prev_virt) {
169             riscv_cpu_swap_hypervisor_regs(env);
170         }
171 
172         riscv_cpu_set_virt_enabled(env, prev_virt);
173     }
174 
175     return retpc;
176 }
177 
178 void helper_wfi(CPURISCVState *env)
179 {
180     CPUState *cs = env_cpu(env);
181 
182     if ((env->priv == PRV_S &&
183         get_field(env->mstatus, MSTATUS_TW)) ||
184         riscv_cpu_virt_enabled(env)) {
185         riscv_raise_exception(env, RISCV_EXCP_VIRT_INSTRUCTION_FAULT, GETPC());
186     } else {
187         cs->halted = 1;
188         cs->exception_index = EXCP_HLT;
189         cpu_loop_exit(cs);
190     }
191 }
192 
193 void helper_tlb_flush(CPURISCVState *env)
194 {
195     CPUState *cs = env_cpu(env);
196     if (!(env->priv >= PRV_S) ||
197         (env->priv == PRV_S &&
198          get_field(env->mstatus, MSTATUS_TVM))) {
199         riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
200     } else if (riscv_has_ext(env, RVH) && riscv_cpu_virt_enabled(env) &&
201                get_field(env->hstatus, HSTATUS_VTVM)) {
202         riscv_raise_exception(env, RISCV_EXCP_VIRT_INSTRUCTION_FAULT, GETPC());
203     } else {
204         tlb_flush(cs);
205     }
206 }
207 
208 void helper_hyp_tlb_flush(CPURISCVState *env)
209 {
210     CPUState *cs = env_cpu(env);
211 
212     if (env->priv == PRV_S && riscv_cpu_virt_enabled(env)) {
213         riscv_raise_exception(env, RISCV_EXCP_VIRT_INSTRUCTION_FAULT, GETPC());
214     }
215 
216     if (env->priv == PRV_M ||
217         (env->priv == PRV_S && !riscv_cpu_virt_enabled(env))) {
218         tlb_flush(cs);
219         return;
220     }
221 
222     riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
223 }
224 
225 void helper_hyp_gvma_tlb_flush(CPURISCVState *env)
226 {
227     if (env->priv == PRV_S && !riscv_cpu_virt_enabled(env) &&
228         get_field(env->mstatus, MSTATUS_TVM)) {
229         riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
230     }
231 
232     helper_hyp_tlb_flush(env);
233 }
234 
235 target_ulong helper_hyp_hlvx_hu(CPURISCVState *env, target_ulong address)
236 {
237     int mmu_idx = cpu_mmu_index(env, true) | TB_FLAGS_PRIV_HYP_ACCESS_MASK;
238 
239     return cpu_lduw_mmuidx_ra(env, address, mmu_idx, GETPC());
240 }
241 
242 target_ulong helper_hyp_hlvx_wu(CPURISCVState *env, target_ulong address)
243 {
244     int mmu_idx = cpu_mmu_index(env, true) | TB_FLAGS_PRIV_HYP_ACCESS_MASK;
245 
246     return cpu_ldl_mmuidx_ra(env, address, mmu_idx, GETPC());
247 }
248 
249 #endif /* !CONFIG_USER_ONLY */
250