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Linux kernel mirror (for testing)
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1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Copyright (C) 2012 ARM Ltd.
4 */
5#ifndef __ASM_SMP_H
6#define __ASM_SMP_H
7
8#include <linux/const.h>
9
10/* Values for secondary_data.status */
11#define CPU_STUCK_REASON_SHIFT (8)
12#define CPU_BOOT_STATUS_MASK ((UL(1) << CPU_STUCK_REASON_SHIFT) - 1)
13
14#define CPU_MMU_OFF (-1)
15#define CPU_BOOT_SUCCESS (0)
16/* The cpu invoked ops->cpu_die, synchronise it with cpu_kill */
17#define CPU_KILL_ME (1)
18/* The cpu couldn't die gracefully and is looping in the kernel */
19#define CPU_STUCK_IN_KERNEL (2)
20/* Fatal system error detected by secondary CPU, crash the system */
21#define CPU_PANIC_KERNEL (3)
22
23#define CPU_STUCK_REASON_52_BIT_VA (UL(1) << CPU_STUCK_REASON_SHIFT)
24#define CPU_STUCK_REASON_NO_GRAN (UL(2) << CPU_STUCK_REASON_SHIFT)
25
26#ifndef __ASSEMBLY__
27
28#include <asm/percpu.h>
29
30#include <linux/threads.h>
31#include <linux/cpumask.h>
32#include <linux/thread_info.h>
33
34DECLARE_PER_CPU_READ_MOSTLY(int, cpu_number);
35
36/*
37 * We don't use this_cpu_read(cpu_number) as that has implicit writes to
38 * preempt_count, and associated (compiler) barriers, that we'd like to avoid
39 * the expense of. If we're preemptible, the value can be stale at use anyway.
40 * And we can't use this_cpu_ptr() either, as that winds up recursing back
41 * here under CONFIG_DEBUG_PREEMPT=y.
42 */
43#define raw_smp_processor_id() (*raw_cpu_ptr(&cpu_number))
44
45/*
46 * Logical CPU mapping.
47 */
48extern u64 __cpu_logical_map[NR_CPUS];
49#define cpu_logical_map(cpu) __cpu_logical_map[cpu]
50
51struct seq_file;
52
53/*
54 * generate IPI list text
55 */
56extern void show_ipi_list(struct seq_file *p, int prec);
57
58/*
59 * Called from C code, this handles an IPI.
60 */
61extern void handle_IPI(int ipinr, struct pt_regs *regs);
62
63/*
64 * Discover the set of possible CPUs and determine their
65 * SMP operations.
66 */
67extern void smp_init_cpus(void);
68
69/*
70 * Provide a function to raise an IPI cross call on CPUs in callmap.
71 */
72extern void set_smp_cross_call(void (*)(const struct cpumask *, unsigned int));
73
74extern void (*__smp_cross_call)(const struct cpumask *, unsigned int);
75
76/*
77 * Called from the secondary holding pen, this is the secondary CPU entry point.
78 */
79asmlinkage void secondary_start_kernel(void);
80
81/*
82 * Initial data for bringing up a secondary CPU.
83 * @stack - sp for the secondary CPU
84 * @status - Result passed back from the secondary CPU to
85 * indicate failure.
86 */
87struct secondary_data {
88 void *stack;
89 struct task_struct *task;
90 long status;
91};
92
93extern struct secondary_data secondary_data;
94extern long __early_cpu_boot_status;
95extern void secondary_entry(void);
96
97extern void arch_send_call_function_single_ipi(int cpu);
98extern void arch_send_call_function_ipi_mask(const struct cpumask *mask);
99
100#ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL
101extern void arch_send_wakeup_ipi_mask(const struct cpumask *mask);
102#else
103static inline void arch_send_wakeup_ipi_mask(const struct cpumask *mask)
104{
105 BUILD_BUG();
106}
107#endif
108
109extern int __cpu_disable(void);
110
111extern void __cpu_die(unsigned int cpu);
112extern void cpu_die(void);
113extern void cpu_die_early(void);
114
115static inline void cpu_park_loop(void)
116{
117 for (;;) {
118 wfe();
119 wfi();
120 }
121}
122
123static inline void update_cpu_boot_status(int val)
124{
125 WRITE_ONCE(secondary_data.status, val);
126 /* Ensure the visibility of the status update */
127 dsb(ishst);
128}
129
130/*
131 * The calling secondary CPU has detected serious configuration mismatch,
132 * which calls for a kernel panic. Update the boot status and park the calling
133 * CPU.
134 */
135static inline void cpu_panic_kernel(void)
136{
137 update_cpu_boot_status(CPU_PANIC_KERNEL);
138 cpu_park_loop();
139}
140
141/*
142 * If a secondary CPU enters the kernel but fails to come online,
143 * (e.g. due to mismatched features), and cannot exit the kernel,
144 * we increment cpus_stuck_in_kernel and leave the CPU in a
145 * quiesecent loop within the kernel text. The memory containing
146 * this loop must not be re-used for anything else as the 'stuck'
147 * core is executing it.
148 *
149 * This function is used to inhibit features like kexec and hibernate.
150 */
151bool cpus_are_stuck_in_kernel(void);
152
153extern void crash_smp_send_stop(void);
154extern bool smp_crash_stop_failed(void);
155
156#endif /* ifndef __ASSEMBLY__ */
157
158#endif /* ifndef __ASM_SMP_H */