1 /* SPDX-License-Identifier: GPL-2.0 */
3 * include/linux/cpu.h - generic cpu definition
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.
9 * Basic handling of the devices is done in drivers/base/cpu.c
11 * CPUs are exported via sysfs in the devices/system/cpu
17 #include <linux/node.h>
18 #include <linux/compiler.h>
19 #include <linux/cpumask.h>
20 #include <linux/cpuhotplug.h>
24 struct attribute_group;
27 int node_id; /* The node which contains the CPU */
28 int hotpluggable; /* creates sysfs control file if hotpluggable */
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);
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);
44 extern int cpu_add_dev_attr(struct device_attribute *attr);
45 extern void cpu_remove_dev_attr(struct device_attribute *attr);
47 extern int cpu_add_dev_attr_group(struct attribute_group *attrs);
48 extern void cpu_remove_dev_attr_group(struct attribute_group *attrs);
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);
64 struct device *cpu_device_create(struct device *parent, void *drvdata,
65 const struct attribute_group **groups,
66 const char *fmt, ...);
67 #ifdef CONFIG_HOTPLUG_CPU
68 extern void unregister_cpu(struct cpu *cpu);
69 extern ssize_t arch_cpu_probe(const char *, size_t);
70 extern ssize_t arch_cpu_release(const char *, size_t);
74 * These states are not related to the core CPU hotplug mechanism. They are
75 * used by various (sub)architectures to track internal state
77 #define CPU_ONLINE 0x0002 /* CPU is up */
78 #define CPU_UP_PREPARE 0x0003 /* CPU coming up */
79 #define CPU_DEAD 0x0007 /* CPU dead */
80 #define CPU_DEAD_FROZEN 0x0008 /* CPU timed out on unplug */
81 #define CPU_POST_DEAD 0x0009 /* CPU successfully unplugged */
82 #define CPU_BROKEN 0x000B /* CPU did not die properly */
85 extern bool cpuhp_tasks_frozen;
86 int cpu_up(unsigned int cpu);
87 void notify_cpu_starting(unsigned int cpu);
88 extern void cpu_maps_update_begin(void);
89 extern void cpu_maps_update_done(void);
91 #else /* CONFIG_SMP */
92 #define cpuhp_tasks_frozen 0
94 static inline void cpu_maps_update_begin(void)
98 static inline void cpu_maps_update_done(void)
102 #endif /* CONFIG_SMP */
103 extern struct bus_type cpu_subsys;
105 #ifdef CONFIG_HOTPLUG_CPU
106 extern void cpus_write_lock(void);
107 extern void cpus_write_unlock(void);
108 extern void cpus_read_lock(void);
109 extern void cpus_read_unlock(void);
110 extern int cpus_read_trylock(void);
111 extern void lockdep_assert_cpus_held(void);
112 extern void cpu_hotplug_disable(void);
113 extern void cpu_hotplug_enable(void);
114 void clear_tasks_mm_cpumask(int cpu);
115 int cpu_down(unsigned int cpu);
117 #else /* CONFIG_HOTPLUG_CPU */
119 static inline void cpus_write_lock(void) { }
120 static inline void cpus_write_unlock(void) { }
121 static inline void cpus_read_lock(void) { }
122 static inline void cpus_read_unlock(void) { }
123 static inline int cpus_read_trylock(void) { return true; }
124 static inline void lockdep_assert_cpus_held(void) { }
125 static inline void cpu_hotplug_disable(void) { }
126 static inline void cpu_hotplug_enable(void) { }
127 #endif /* !CONFIG_HOTPLUG_CPU */
129 /* Wrappers which go away once all code is converted */
130 static inline void cpu_hotplug_begin(void) { cpus_write_lock(); }
131 static inline void cpu_hotplug_done(void) { cpus_write_unlock(); }
132 static inline void get_online_cpus(void) { cpus_read_lock(); }
133 static inline void put_online_cpus(void) { cpus_read_unlock(); }
135 #ifdef CONFIG_PM_SLEEP_SMP
136 extern int freeze_secondary_cpus(int primary);
137 static inline int disable_nonboot_cpus(void)
139 return freeze_secondary_cpus(0);
141 extern void enable_nonboot_cpus(void);
143 static inline int suspend_disable_secondary_cpus(void)
147 if (IS_ENABLED(CONFIG_PM_SLEEP_SMP_NONZERO_CPU))
150 return freeze_secondary_cpus(cpu);
152 static inline void suspend_enable_secondary_cpus(void)
154 return enable_nonboot_cpus();
157 #else /* !CONFIG_PM_SLEEP_SMP */
158 static inline int disable_nonboot_cpus(void) { return 0; }
159 static inline void enable_nonboot_cpus(void) {}
160 static inline int suspend_disable_secondary_cpus(void) { return 0; }
161 static inline void suspend_enable_secondary_cpus(void) { }
162 #endif /* !CONFIG_PM_SLEEP_SMP */
164 void cpu_startup_entry(enum cpuhp_state state);
166 void cpu_idle_poll_ctrl(bool enable);
168 /* Attach to any functions which should be considered cpuidle. */
169 #define __cpuidle __attribute__((__section__(".cpuidle.text")))
171 bool cpu_in_idle(unsigned long pc);
173 void arch_cpu_idle(void);
174 void arch_cpu_idle_prepare(void);
175 void arch_cpu_idle_enter(void);
176 void arch_cpu_idle_exit(void);
177 void arch_cpu_idle_dead(void);
179 int cpu_report_state(int cpu);
180 int cpu_check_up_prepare(int cpu);
181 void cpu_set_state_online(int cpu);
182 void play_idle(unsigned long duration_ms);
184 #ifdef CONFIG_HOTPLUG_CPU
185 bool cpu_wait_death(unsigned int cpu, int seconds);
186 bool cpu_report_death(void);
187 void cpuhp_report_idle_dead(void);
189 static inline void cpuhp_report_idle_dead(void) { }
190 #endif /* #ifdef CONFIG_HOTPLUG_CPU */
192 enum cpuhp_smt_control {
195 CPU_SMT_FORCE_DISABLED,
196 CPU_SMT_NOT_SUPPORTED,
197 CPU_SMT_NOT_IMPLEMENTED,
200 #if defined(CONFIG_SMP) && defined(CONFIG_HOTPLUG_SMT)
201 extern enum cpuhp_smt_control cpu_smt_control;
202 extern void cpu_smt_disable(bool force);
203 extern void cpu_smt_check_topology(void);
204 extern int cpuhp_smt_enable(void);
205 extern int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval);
207 # define cpu_smt_control (CPU_SMT_NOT_IMPLEMENTED)
208 static inline void cpu_smt_disable(bool force) { }
209 static inline void cpu_smt_check_topology(void) { }
210 static inline int cpuhp_smt_enable(void) { return 0; }
211 static inline int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval) { return 0; }
215 * These are used for a global "mitigations=" cmdline option for toggling
216 * optional CPU mitigations.
218 enum cpu_mitigations {
220 CPU_MITIGATIONS_AUTO,
221 CPU_MITIGATIONS_AUTO_NOSMT,
224 extern enum cpu_mitigations cpu_mitigations;
226 /* mitigations=off */
227 static inline bool cpu_mitigations_off(void)
229 return cpu_mitigations == CPU_MITIGATIONS_OFF;
232 /* mitigations=auto,nosmt */
233 static inline bool cpu_mitigations_auto_nosmt(void)
235 return cpu_mitigations == CPU_MITIGATIONS_AUTO_NOSMT;
238 #endif /* _LINUX_CPU_H_ */