xref: /openbmc/qemu/target/arm/arm-powerctl.c (revision fcf5ef2a)
1 /*
2  * QEMU support -- ARM Power Control specific functions.
3  *
4  * Copyright (c) 2016 Jean-Christophe Dubois
5  *
6  * This work is licensed under the terms of the GNU GPL, version 2 or later.
7  * See the COPYING file in the top-level directory.
8  *
9  */
10 
11 #include "qemu/osdep.h"
12 #include "cpu.h"
13 #include "cpu-qom.h"
14 #include "internals.h"
15 #include "arm-powerctl.h"
16 #include "qemu/log.h"
17 #include "exec/exec-all.h"
18 
19 #ifndef DEBUG_ARM_POWERCTL
20 #define DEBUG_ARM_POWERCTL 0
21 #endif
22 
23 #define DPRINTF(fmt, args...) \
24     do { \
25         if (DEBUG_ARM_POWERCTL) { \
26             fprintf(stderr, "[ARM]%s: " fmt , __func__, ##args); \
27         } \
28     } while (0)
29 
30 CPUState *arm_get_cpu_by_id(uint64_t id)
31 {
32     CPUState *cpu;
33 
34     DPRINTF("cpu %" PRId64 "\n", id);
35 
36     CPU_FOREACH(cpu) {
37         ARMCPU *armcpu = ARM_CPU(cpu);
38 
39         if (armcpu->mp_affinity == id) {
40             return cpu;
41         }
42     }
43 
44     qemu_log_mask(LOG_GUEST_ERROR,
45                   "[ARM]%s: Requesting unknown CPU %" PRId64 "\n",
46                   __func__, id);
47 
48     return NULL;
49 }
50 
51 int arm_set_cpu_on(uint64_t cpuid, uint64_t entry, uint64_t context_id,
52                    uint32_t target_el, bool target_aa64)
53 {
54     CPUState *target_cpu_state;
55     ARMCPU *target_cpu;
56 
57     DPRINTF("cpu %" PRId64 " (EL %d, %s) @ 0x%" PRIx64 " with R0 = 0x%" PRIx64
58             "\n", cpuid, target_el, target_aa64 ? "aarch64" : "aarch32", entry,
59             context_id);
60 
61     /* requested EL level need to be in the 1 to 3 range */
62     assert((target_el > 0) && (target_el < 4));
63 
64     if (target_aa64 && (entry & 3)) {
65         /*
66          * if we are booting in AArch64 mode then "entry" needs to be 4 bytes
67          * aligned.
68          */
69         return QEMU_ARM_POWERCTL_INVALID_PARAM;
70     }
71 
72     /* Retrieve the cpu we are powering up */
73     target_cpu_state = arm_get_cpu_by_id(cpuid);
74     if (!target_cpu_state) {
75         /* The cpu was not found */
76         return QEMU_ARM_POWERCTL_INVALID_PARAM;
77     }
78 
79     target_cpu = ARM_CPU(target_cpu_state);
80     if (!target_cpu->powered_off) {
81         qemu_log_mask(LOG_GUEST_ERROR,
82                       "[ARM]%s: CPU %" PRId64 " is already on\n",
83                       __func__, cpuid);
84         return QEMU_ARM_POWERCTL_ALREADY_ON;
85     }
86 
87     /*
88      * The newly brought CPU is requested to enter the exception level
89      * "target_el" and be in the requested mode (AArch64 or AArch32).
90      */
91 
92     if (((target_el == 3) && !arm_feature(&target_cpu->env, ARM_FEATURE_EL3)) ||
93         ((target_el == 2) && !arm_feature(&target_cpu->env, ARM_FEATURE_EL2))) {
94         /*
95          * The CPU does not support requested level
96          */
97         return QEMU_ARM_POWERCTL_INVALID_PARAM;
98     }
99 
100     if (!target_aa64 && arm_feature(&target_cpu->env, ARM_FEATURE_AARCH64)) {
101         /*
102          * For now we don't support booting an AArch64 CPU in AArch32 mode
103          * TODO: We should add this support later
104          */
105         qemu_log_mask(LOG_UNIMP,
106                       "[ARM]%s: Starting AArch64 CPU %" PRId64
107                       " in AArch32 mode is not supported yet\n",
108                       __func__, cpuid);
109         return QEMU_ARM_POWERCTL_INVALID_PARAM;
110     }
111 
112     /* Initialize the cpu we are turning on */
113     cpu_reset(target_cpu_state);
114     target_cpu->powered_off = false;
115     target_cpu_state->halted = 0;
116 
117     if (target_aa64) {
118         if ((target_el < 3) && arm_feature(&target_cpu->env, ARM_FEATURE_EL3)) {
119             /*
120              * As target mode is AArch64, we need to set lower
121              * exception level (the requested level 2) to AArch64
122              */
123             target_cpu->env.cp15.scr_el3 |= SCR_RW;
124         }
125 
126         if ((target_el < 2) && arm_feature(&target_cpu->env, ARM_FEATURE_EL2)) {
127             /*
128              * As target mode is AArch64, we need to set lower
129              * exception level (the requested level 1) to AArch64
130              */
131             target_cpu->env.cp15.hcr_el2 |= HCR_RW;
132         }
133 
134         target_cpu->env.pstate = aarch64_pstate_mode(target_el, true);
135     } else {
136         /* We are requested to boot in AArch32 mode */
137         static uint32_t mode_for_el[] = { 0,
138                                           ARM_CPU_MODE_SVC,
139                                           ARM_CPU_MODE_HYP,
140                                           ARM_CPU_MODE_SVC };
141 
142         cpsr_write(&target_cpu->env, mode_for_el[target_el], CPSR_M,
143                    CPSRWriteRaw);
144     }
145 
146     if (target_el == 3) {
147         /* Processor is in secure mode */
148         target_cpu->env.cp15.scr_el3 &= ~SCR_NS;
149     } else {
150         /* Processor is not in secure mode */
151         target_cpu->env.cp15.scr_el3 |= SCR_NS;
152     }
153 
154     /* We check if the started CPU is now at the correct level */
155     assert(target_el == arm_current_el(&target_cpu->env));
156 
157     if (target_aa64) {
158         target_cpu->env.xregs[0] = context_id;
159         target_cpu->env.thumb = false;
160     } else {
161         target_cpu->env.regs[0] = context_id;
162         target_cpu->env.thumb = entry & 1;
163         entry &= 0xfffffffe;
164     }
165 
166     /* Start the new CPU at the requested address */
167     cpu_set_pc(target_cpu_state, entry);
168 
169     qemu_cpu_kick(target_cpu_state);
170 
171     /* We are good to go */
172     return QEMU_ARM_POWERCTL_RET_SUCCESS;
173 }
174 
175 int arm_set_cpu_off(uint64_t cpuid)
176 {
177     CPUState *target_cpu_state;
178     ARMCPU *target_cpu;
179 
180     DPRINTF("cpu %" PRId64 "\n", cpuid);
181 
182     /* change to the cpu we are powering up */
183     target_cpu_state = arm_get_cpu_by_id(cpuid);
184     if (!target_cpu_state) {
185         return QEMU_ARM_POWERCTL_INVALID_PARAM;
186     }
187     target_cpu = ARM_CPU(target_cpu_state);
188     if (target_cpu->powered_off) {
189         qemu_log_mask(LOG_GUEST_ERROR,
190                       "[ARM]%s: CPU %" PRId64 " is already off\n",
191                       __func__, cpuid);
192         return QEMU_ARM_POWERCTL_IS_OFF;
193     }
194 
195     target_cpu->powered_off = true;
196     target_cpu_state->halted = 1;
197     target_cpu_state->exception_index = EXCP_HLT;
198     cpu_loop_exit(target_cpu_state);
199     /* notreached */
200 
201     return QEMU_ARM_POWERCTL_RET_SUCCESS;
202 }
203 
204 int arm_reset_cpu(uint64_t cpuid)
205 {
206     CPUState *target_cpu_state;
207     ARMCPU *target_cpu;
208 
209     DPRINTF("cpu %" PRId64 "\n", cpuid);
210 
211     /* change to the cpu we are resetting */
212     target_cpu_state = arm_get_cpu_by_id(cpuid);
213     if (!target_cpu_state) {
214         return QEMU_ARM_POWERCTL_INVALID_PARAM;
215     }
216     target_cpu = ARM_CPU(target_cpu_state);
217     if (target_cpu->powered_off) {
218         qemu_log_mask(LOG_GUEST_ERROR,
219                       "[ARM]%s: CPU %" PRId64 " is off\n",
220                       __func__, cpuid);
221         return QEMU_ARM_POWERCTL_IS_OFF;
222     }
223 
224     /* Reset the cpu */
225     cpu_reset(target_cpu_state);
226 
227     return QEMU_ARM_POWERCTL_RET_SUCCESS;
228 }
229