xref: /openbmc/qemu/target/riscv/op_helper.c (revision d695918f) 
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 G_NORETURN void 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     /*
43      * The seed CSR must be accessed with a read-write instruction. A
44      * read-only instruction such as CSRRS/CSRRC with rs1=x0 or CSRRSI/
45      * CSRRCI with uimm=0 will raise an illegal instruction exception.
46      */
47     if (csr == CSR_SEED) {
48         riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
49     }
50 
51     target_ulong val = 0;
52     RISCVException ret = riscv_csrrw(env, csr, &val, 0, 0);
53 
54     if (ret != RISCV_EXCP_NONE) {
55         riscv_raise_exception(env, ret, GETPC());
56     }
57     return val;
58 }
59 
60 void helper_csrw(CPURISCVState *env, int csr, target_ulong src)
61 {
62     target_ulong mask = env->xl == MXL_RV32 ? UINT32_MAX : (target_ulong)-1;
63     RISCVException ret = riscv_csrrw(env, csr, NULL, src, mask);
64 
65     if (ret != RISCV_EXCP_NONE) {
66         riscv_raise_exception(env, ret, GETPC());
67     }
68 }
69 
70 target_ulong helper_csrrw(CPURISCVState *env, int csr,
71                           target_ulong src, target_ulong write_mask)
72 {
73     target_ulong val = 0;
74     RISCVException ret = riscv_csrrw(env, csr, &val, src, write_mask);
75 
76     if (ret != RISCV_EXCP_NONE) {
77         riscv_raise_exception(env, ret, GETPC());
78     }
79     return val;
80 }
81 
82 target_ulong helper_csrr_i128(CPURISCVState *env, int csr)
83 {
84     Int128 rv = int128_zero();
85     RISCVException ret = riscv_csrrw_i128(env, csr, &rv,
86                                           int128_zero(),
87                                           int128_zero());
88 
89     if (ret != RISCV_EXCP_NONE) {
90         riscv_raise_exception(env, ret, GETPC());
91     }
92 
93     env->retxh = int128_gethi(rv);
94     return int128_getlo(rv);
95 }
96 
97 void helper_csrw_i128(CPURISCVState *env, int csr,
98                       target_ulong srcl, target_ulong srch)
99 {
100     RISCVException ret = riscv_csrrw_i128(env, csr, NULL,
101                                           int128_make128(srcl, srch),
102                                           UINT128_MAX);
103 
104     if (ret != RISCV_EXCP_NONE) {
105         riscv_raise_exception(env, ret, GETPC());
106     }
107 }
108 
109 target_ulong helper_csrrw_i128(CPURISCVState *env, int csr,
110                        target_ulong srcl, target_ulong srch,
111                        target_ulong maskl, target_ulong maskh)
112 {
113     Int128 rv = int128_zero();
114     RISCVException ret = riscv_csrrw_i128(env, csr, &rv,
115                                           int128_make128(srcl, srch),
116                                           int128_make128(maskl, maskh));
117 
118     if (ret != RISCV_EXCP_NONE) {
119         riscv_raise_exception(env, ret, GETPC());
120     }
121 
122     env->retxh = int128_gethi(rv);
123     return int128_getlo(rv);
124 }
125 
126 #ifndef CONFIG_USER_ONLY
127 
128 target_ulong helper_sret(CPURISCVState *env)
129 {
130     uint64_t mstatus;
131     target_ulong prev_priv, prev_virt;
132 
133     if (!(env->priv >= PRV_S)) {
134         riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
135     }
136 
137     target_ulong retpc = env->sepc;
138     if (!riscv_has_ext(env, RVC) && (retpc & 0x3)) {
139         riscv_raise_exception(env, RISCV_EXCP_INST_ADDR_MIS, GETPC());
140     }
141 
142     if (get_field(env->mstatus, MSTATUS_TSR) && !(env->priv >= PRV_M)) {
143         riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
144     }
145 
146     if (riscv_has_ext(env, RVH) && riscv_cpu_virt_enabled(env) &&
147         get_field(env->hstatus, HSTATUS_VTSR)) {
148         riscv_raise_exception(env, RISCV_EXCP_VIRT_INSTRUCTION_FAULT, GETPC());
149     }
150 
151     mstatus = env->mstatus;
152 
153     if (riscv_has_ext(env, RVH) && !riscv_cpu_virt_enabled(env)) {
154         /* We support Hypervisor extensions and virtulisation is disabled */
155         target_ulong hstatus = env->hstatus;
156 
157         prev_priv = get_field(mstatus, MSTATUS_SPP);
158         prev_virt = get_field(hstatus, HSTATUS_SPV);
159 
160         hstatus = set_field(hstatus, HSTATUS_SPV, 0);
161         mstatus = set_field(mstatus, MSTATUS_SPP, 0);
162         mstatus = set_field(mstatus, SSTATUS_SIE,
163                             get_field(mstatus, SSTATUS_SPIE));
164         mstatus = set_field(mstatus, SSTATUS_SPIE, 1);
165 
166         env->mstatus = mstatus;
167         env->hstatus = hstatus;
168 
169         if (prev_virt) {
170             riscv_cpu_swap_hypervisor_regs(env);
171         }
172 
173         riscv_cpu_set_virt_enabled(env, prev_virt);
174     } else {
175         prev_priv = get_field(mstatus, MSTATUS_SPP);
176 
177         mstatus = set_field(mstatus, MSTATUS_SIE,
178                             get_field(mstatus, MSTATUS_SPIE));
179         mstatus = set_field(mstatus, MSTATUS_SPIE, 1);
180         mstatus = set_field(mstatus, MSTATUS_SPP, PRV_U);
181         env->mstatus = mstatus;
182     }
183 
184     riscv_cpu_set_mode(env, prev_priv);
185 
186     return retpc;
187 }
188 
189 target_ulong helper_mret(CPURISCVState *env)
190 {
191     if (!(env->priv >= PRV_M)) {
192         riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
193     }
194 
195     target_ulong retpc = env->mepc;
196     if (!riscv_has_ext(env, RVC) && (retpc & 0x3)) {
197         riscv_raise_exception(env, RISCV_EXCP_INST_ADDR_MIS, GETPC());
198     }
199 
200     uint64_t mstatus = env->mstatus;
201     target_ulong prev_priv = get_field(mstatus, MSTATUS_MPP);
202 
203     if (riscv_feature(env, RISCV_FEATURE_PMP) &&
204         !pmp_get_num_rules(env) && (prev_priv != PRV_M)) {
205         riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
206     }
207 
208     target_ulong prev_virt = get_field(env->mstatus, MSTATUS_MPV);
209     mstatus = set_field(mstatus, MSTATUS_MIE,
210                         get_field(mstatus, MSTATUS_MPIE));
211     mstatus = set_field(mstatus, MSTATUS_MPIE, 1);
212     mstatus = set_field(mstatus, MSTATUS_MPP, PRV_U);
213     mstatus = set_field(mstatus, MSTATUS_MPV, 0);
214     env->mstatus = mstatus;
215     riscv_cpu_set_mode(env, prev_priv);
216 
217     if (riscv_has_ext(env, RVH)) {
218         if (prev_virt) {
219             riscv_cpu_swap_hypervisor_regs(env);
220         }
221 
222         riscv_cpu_set_virt_enabled(env, prev_virt);
223     }
224 
225     return retpc;
226 }
227 
228 void helper_wfi(CPURISCVState *env)
229 {
230     CPUState *cs = env_cpu(env);
231     bool rvs = riscv_has_ext(env, RVS);
232     bool prv_u = env->priv == PRV_U;
233     bool prv_s = env->priv == PRV_S;
234 
235     if (((prv_s || (!rvs && prv_u)) && get_field(env->mstatus, MSTATUS_TW)) ||
236         (rvs && prv_u && !riscv_cpu_virt_enabled(env))) {
237         riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
238     } else if (riscv_cpu_virt_enabled(env) && (prv_u ||
239         (prv_s && get_field(env->hstatus, HSTATUS_VTW)))) {
240         riscv_raise_exception(env, RISCV_EXCP_VIRT_INSTRUCTION_FAULT, GETPC());
241     } else {
242         cs->halted = 1;
243         cs->exception_index = EXCP_HLT;
244         cpu_loop_exit(cs);
245     }
246 }
247 
248 void helper_tlb_flush(CPURISCVState *env)
249 {
250     CPUState *cs = env_cpu(env);
251     if (!(env->priv >= PRV_S) ||
252         (env->priv == PRV_S &&
253          get_field(env->mstatus, MSTATUS_TVM))) {
254         riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
255     } else if (riscv_has_ext(env, RVH) && riscv_cpu_virt_enabled(env) &&
256                get_field(env->hstatus, HSTATUS_VTVM)) {
257         riscv_raise_exception(env, RISCV_EXCP_VIRT_INSTRUCTION_FAULT, GETPC());
258     } else {
259         tlb_flush(cs);
260     }
261 }
262 
263 void helper_hyp_tlb_flush(CPURISCVState *env)
264 {
265     CPUState *cs = env_cpu(env);
266 
267     if (env->priv == PRV_S && riscv_cpu_virt_enabled(env)) {
268         riscv_raise_exception(env, RISCV_EXCP_VIRT_INSTRUCTION_FAULT, GETPC());
269     }
270 
271     if (env->priv == PRV_M ||
272         (env->priv == PRV_S && !riscv_cpu_virt_enabled(env))) {
273         tlb_flush(cs);
274         return;
275     }
276 
277     riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
278 }
279 
280 void helper_hyp_gvma_tlb_flush(CPURISCVState *env)
281 {
282     if (env->priv == PRV_S && !riscv_cpu_virt_enabled(env) &&
283         get_field(env->mstatus, MSTATUS_TVM)) {
284         riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
285     }
286 
287     helper_hyp_tlb_flush(env);
288 }
289 
290 target_ulong helper_hyp_hlvx_hu(CPURISCVState *env, target_ulong address)
291 {
292     int mmu_idx = cpu_mmu_index(env, true) | TB_FLAGS_PRIV_HYP_ACCESS_MASK;
293 
294     return cpu_lduw_mmuidx_ra(env, address, mmu_idx, GETPC());
295 }
296 
297 target_ulong helper_hyp_hlvx_wu(CPURISCVState *env, target_ulong address)
298 {
299     int mmu_idx = cpu_mmu_index(env, true) | TB_FLAGS_PRIV_HYP_ACCESS_MASK;
300 
301     return cpu_ldl_mmuidx_ra(env, address, mmu_idx, GETPC());
302 }
303 
304 #endif /* !CONFIG_USER_ONLY */
305