1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  * include/linux/cpu.h - generic cpu definition
4  *
5  * This is mainly for topological representation. We define the
6  * basic 'struct cpu' here, which can be embedded in per-arch
7  * definitions of processors.
8  *
9  * Basic handling of the devices is done in drivers/base/cpu.c
10  *
11  * CPUs are exported via sysfs in the devices/system/cpu
12  * directory.
13  */
14 #ifndef _LINUX_CPU_H_
15 #define _LINUX_CPU_H_
16 
17 #include <linux/node.h>
18 #include <linux/compiler.h>
19 #include <linux/cpumask.h>
20 #include <linux/cpuhotplug.h>
21 
22 struct device;
23 struct device_node;
24 struct attribute_group;
25 
26 struct cpu {
27 	int node_id;		/* The node which contains the CPU */
28 	int hotpluggable;	/* creates sysfs control file if hotpluggable */
29 	struct device dev;
30 };
31 
32 extern void boot_cpu_init(void);
33 extern void boot_cpu_hotplug_init(void);
34 extern void cpu_init(void);
35 extern void trap_init(void);
36 
37 extern int register_cpu(struct cpu *cpu, int num);
38 extern struct device *get_cpu_device(unsigned cpu);
39 extern bool cpu_is_hotpluggable(unsigned cpu);
40 extern bool arch_match_cpu_phys_id(int cpu, u64 phys_id);
41 extern bool arch_find_n_match_cpu_physical_id(struct device_node *cpun,
42 					      int cpu, unsigned int *thread);
43 
44 extern int cpu_add_dev_attr(struct device_attribute *attr);
45 extern void cpu_remove_dev_attr(struct device_attribute *attr);
46 
47 extern int cpu_add_dev_attr_group(struct attribute_group *attrs);
48 extern void cpu_remove_dev_attr_group(struct attribute_group *attrs);
49 
50 extern ssize_t cpu_show_meltdown(struct device *dev,
51 				 struct device_attribute *attr, char *buf);
52 extern ssize_t cpu_show_spectre_v1(struct device *dev,
53 				   struct device_attribute *attr, char *buf);
54 extern ssize_t cpu_show_spectre_v2(struct device *dev,
55 				   struct device_attribute *attr, char *buf);
56 extern ssize_t cpu_show_spec_store_bypass(struct device *dev,
57 					  struct device_attribute *attr, char *buf);
58 extern ssize_t cpu_show_l1tf(struct device *dev,
59 			     struct device_attribute *attr, char *buf);
60 extern ssize_t cpu_show_mds(struct device *dev,
61 			    struct device_attribute *attr, char *buf);
62 extern ssize_t cpu_show_tsx_async_abort(struct device *dev,
63 					struct device_attribute *attr,
64 					char *buf);
65 extern ssize_t cpu_show_itlb_multihit(struct device *dev,
66 				      struct device_attribute *attr, char *buf);
67 extern ssize_t cpu_show_srbds(struct device *dev, struct device_attribute *attr, char *buf);
68 
69 extern __printf(4, 5)
70 struct device *cpu_device_create(struct device *parent, void *drvdata,
71 				 const struct attribute_group **groups,
72 				 const char *fmt, ...);
73 #ifdef CONFIG_HOTPLUG_CPU
74 extern void unregister_cpu(struct cpu *cpu);
75 extern ssize_t arch_cpu_probe(const char *, size_t);
76 extern ssize_t arch_cpu_release(const char *, size_t);
77 #endif
78 
79 /*
80  * These states are not related to the core CPU hotplug mechanism. They are
81  * used by various (sub)architectures to track internal state
82  */
83 #define CPU_ONLINE		0x0002 /* CPU is up */
84 #define CPU_UP_PREPARE		0x0003 /* CPU coming up */
85 #define CPU_DEAD		0x0007 /* CPU dead */
86 #define CPU_DEAD_FROZEN		0x0008 /* CPU timed out on unplug */
87 #define CPU_POST_DEAD		0x0009 /* CPU successfully unplugged */
88 #define CPU_BROKEN		0x000B /* CPU did not die properly */
89 
90 #ifdef CONFIG_SMP
91 extern bool cpuhp_tasks_frozen;
92 int add_cpu(unsigned int cpu);
93 int cpu_device_up(struct device *dev);
94 void notify_cpu_starting(unsigned int cpu);
95 extern void cpu_maps_update_begin(void);
96 extern void cpu_maps_update_done(void);
97 int bringup_hibernate_cpu(unsigned int sleep_cpu);
98 void bringup_nonboot_cpus(unsigned int setup_max_cpus);
99 
100 #else	/* CONFIG_SMP */
101 #define cpuhp_tasks_frozen	0
102 
cpu_maps_update_begin(void)103 static inline void cpu_maps_update_begin(void)
104 {
105 }
106 
cpu_maps_update_done(void)107 static inline void cpu_maps_update_done(void)
108 {
109 }
110 
add_cpu(unsigned int cpu)111 static inline int add_cpu(unsigned int cpu) { return 0;}
112 
113 #endif /* CONFIG_SMP */
114 extern struct bus_type cpu_subsys;
115 
116 extern int lockdep_is_cpus_held(void);
117 
118 #ifdef CONFIG_HOTPLUG_CPU
119 extern void cpus_write_lock(void);
120 extern void cpus_write_unlock(void);
121 extern void cpus_read_lock(void);
122 extern void cpus_read_unlock(void);
123 extern int  cpus_read_trylock(void);
124 extern void lockdep_assert_cpus_held(void);
125 extern void cpu_hotplug_disable(void);
126 extern void cpu_hotplug_enable(void);
127 void clear_tasks_mm_cpumask(int cpu);
128 int remove_cpu(unsigned int cpu);
129 int cpu_device_down(struct device *dev);
130 extern void smp_shutdown_nonboot_cpus(unsigned int primary_cpu);
131 
132 #else /* CONFIG_HOTPLUG_CPU */
133 
cpus_write_lock(void)134 static inline void cpus_write_lock(void) { }
cpus_write_unlock(void)135 static inline void cpus_write_unlock(void) { }
cpus_read_lock(void)136 static inline void cpus_read_lock(void) { }
cpus_read_unlock(void)137 static inline void cpus_read_unlock(void) { }
cpus_read_trylock(void)138 static inline int  cpus_read_trylock(void) { return true; }
lockdep_assert_cpus_held(void)139 static inline void lockdep_assert_cpus_held(void) { }
cpu_hotplug_disable(void)140 static inline void cpu_hotplug_disable(void) { }
cpu_hotplug_enable(void)141 static inline void cpu_hotplug_enable(void) { }
remove_cpu(unsigned int cpu)142 static inline int remove_cpu(unsigned int cpu) { return -EPERM; }
smp_shutdown_nonboot_cpus(unsigned int primary_cpu)143 static inline void smp_shutdown_nonboot_cpus(unsigned int primary_cpu) { }
144 #endif	/* !CONFIG_HOTPLUG_CPU */
145 
146 #ifdef CONFIG_PM_SLEEP_SMP
147 extern int freeze_secondary_cpus(int primary);
148 extern void thaw_secondary_cpus(void);
149 
suspend_disable_secondary_cpus(void)150 static inline int suspend_disable_secondary_cpus(void)
151 {
152 	int cpu = 0;
153 
154 	if (IS_ENABLED(CONFIG_PM_SLEEP_SMP_NONZERO_CPU))
155 		cpu = -1;
156 
157 	return freeze_secondary_cpus(cpu);
158 }
suspend_enable_secondary_cpus(void)159 static inline void suspend_enable_secondary_cpus(void)
160 {
161 	return thaw_secondary_cpus();
162 }
163 
164 #else /* !CONFIG_PM_SLEEP_SMP */
thaw_secondary_cpus(void)165 static inline void thaw_secondary_cpus(void) {}
suspend_disable_secondary_cpus(void)166 static inline int suspend_disable_secondary_cpus(void) { return 0; }
suspend_enable_secondary_cpus(void)167 static inline void suspend_enable_secondary_cpus(void) { }
168 #endif /* !CONFIG_PM_SLEEP_SMP */
169 
170 void cpu_startup_entry(enum cpuhp_state state);
171 
172 void cpu_idle_poll_ctrl(bool enable);
173 
174 /* Attach to any functions which should be considered cpuidle. */
175 #define __cpuidle	__section(".cpuidle.text")
176 
177 bool cpu_in_idle(unsigned long pc);
178 
179 void arch_cpu_idle(void);
180 void arch_cpu_idle_prepare(void);
181 void arch_cpu_idle_enter(void);
182 void arch_cpu_idle_exit(void);
183 void arch_cpu_idle_dead(void);
184 
185 int cpu_report_state(int cpu);
186 int cpu_check_up_prepare(int cpu);
187 void cpu_set_state_online(int cpu);
188 void play_idle_precise(u64 duration_ns, u64 latency_ns);
189 
play_idle(unsigned long duration_us)190 static inline void play_idle(unsigned long duration_us)
191 {
192 	play_idle_precise(duration_us * NSEC_PER_USEC, U64_MAX);
193 }
194 
195 #ifdef CONFIG_HOTPLUG_CPU
196 bool cpu_wait_death(unsigned int cpu, int seconds);
197 bool cpu_report_death(void);
198 void cpuhp_report_idle_dead(void);
199 #else
cpuhp_report_idle_dead(void)200 static inline void cpuhp_report_idle_dead(void) { }
201 #endif /* #ifdef CONFIG_HOTPLUG_CPU */
202 
203 enum cpuhp_smt_control {
204 	CPU_SMT_ENABLED,
205 	CPU_SMT_DISABLED,
206 	CPU_SMT_FORCE_DISABLED,
207 	CPU_SMT_NOT_SUPPORTED,
208 	CPU_SMT_NOT_IMPLEMENTED,
209 };
210 
211 #if defined(CONFIG_SMP) && defined(CONFIG_HOTPLUG_SMT)
212 extern enum cpuhp_smt_control cpu_smt_control;
213 extern void cpu_smt_disable(bool force);
214 extern void cpu_smt_check_topology(void);
215 extern bool cpu_smt_possible(void);
216 extern int cpuhp_smt_enable(void);
217 extern int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval);
218 #else
219 # define cpu_smt_control		(CPU_SMT_NOT_IMPLEMENTED)
cpu_smt_disable(bool force)220 static inline void cpu_smt_disable(bool force) { }
cpu_smt_check_topology(void)221 static inline void cpu_smt_check_topology(void) { }
cpu_smt_possible(void)222 static inline bool cpu_smt_possible(void) { return false; }
cpuhp_smt_enable(void)223 static inline int cpuhp_smt_enable(void) { return 0; }
cpuhp_smt_disable(enum cpuhp_smt_control ctrlval)224 static inline int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval) { return 0; }
225 #endif
226 
227 extern bool cpu_mitigations_off(void);
228 extern bool cpu_mitigations_auto_nosmt(void);
229 
230 #endif /* _LINUX_CPU_H_ */
231