xref: /openbmc/linux/arch/arm64/include/asm/smp.h (revision 4f205687)
1 /*
2  * Copyright (C) 2012 ARM Ltd.
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License version 2 as
6  * published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11  * GNU General Public License for more details.
12  *
13  * You should have received a copy of the GNU General Public License
14  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
15  */
16 #ifndef __ASM_SMP_H
17 #define __ASM_SMP_H
18 
19 /* Values for secondary_data.status */
20 
21 #define CPU_MMU_OFF		(-1)
22 #define CPU_BOOT_SUCCESS	(0)
23 /* The cpu invoked ops->cpu_die, synchronise it with cpu_kill */
24 #define CPU_KILL_ME		(1)
25 /* The cpu couldn't die gracefully and is looping in the kernel */
26 #define CPU_STUCK_IN_KERNEL	(2)
27 /* Fatal system error detected by secondary CPU, crash the system */
28 #define CPU_PANIC_KERNEL	(3)
29 
30 #ifndef __ASSEMBLY__
31 
32 #include <linux/threads.h>
33 #include <linux/cpumask.h>
34 #include <linux/thread_info.h>
35 
36 #define raw_smp_processor_id() (current_thread_info()->cpu)
37 
38 struct seq_file;
39 
40 /*
41  * generate IPI list text
42  */
43 extern void show_ipi_list(struct seq_file *p, int prec);
44 
45 /*
46  * Called from C code, this handles an IPI.
47  */
48 extern void handle_IPI(int ipinr, struct pt_regs *regs);
49 
50 /*
51  * Discover the set of possible CPUs and determine their
52  * SMP operations.
53  */
54 extern void smp_init_cpus(void);
55 
56 /*
57  * Provide a function to raise an IPI cross call on CPUs in callmap.
58  */
59 extern void set_smp_cross_call(void (*)(const struct cpumask *, unsigned int));
60 
61 extern void (*__smp_cross_call)(const struct cpumask *, unsigned int);
62 
63 /*
64  * Called from the secondary holding pen, this is the secondary CPU entry point.
65  */
66 asmlinkage void secondary_start_kernel(void);
67 
68 /*
69  * Initial data for bringing up a secondary CPU.
70  * @stack  - sp for the secondary CPU
71  * @status - Result passed back from the secondary CPU to
72  *           indicate failure.
73  */
74 struct secondary_data {
75 	void *stack;
76 	long status;
77 };
78 
79 extern struct secondary_data secondary_data;
80 extern long __early_cpu_boot_status;
81 extern void secondary_entry(void);
82 
83 extern void arch_send_call_function_single_ipi(int cpu);
84 extern void arch_send_call_function_ipi_mask(const struct cpumask *mask);
85 
86 #ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL
87 extern void arch_send_wakeup_ipi_mask(const struct cpumask *mask);
88 #else
89 static inline void arch_send_wakeup_ipi_mask(const struct cpumask *mask)
90 {
91 	BUILD_BUG();
92 }
93 #endif
94 
95 extern int __cpu_disable(void);
96 
97 extern void __cpu_die(unsigned int cpu);
98 extern void cpu_die(void);
99 extern void cpu_die_early(void);
100 
101 static inline void cpu_park_loop(void)
102 {
103 	for (;;) {
104 		wfe();
105 		wfi();
106 	}
107 }
108 
109 static inline void update_cpu_boot_status(int val)
110 {
111 	WRITE_ONCE(secondary_data.status, val);
112 	/* Ensure the visibility of the status update */
113 	dsb(ishst);
114 }
115 
116 /*
117  * The calling secondary CPU has detected serious configuration mismatch,
118  * which calls for a kernel panic. Update the boot status and park the calling
119  * CPU.
120  */
121 static inline void cpu_panic_kernel(void)
122 {
123 	update_cpu_boot_status(CPU_PANIC_KERNEL);
124 	cpu_park_loop();
125 }
126 
127 /*
128  * If a secondary CPU enters the kernel but fails to come online,
129  * (e.g. due to mismatched features), and cannot exit the kernel,
130  * we increment cpus_stuck_in_kernel and leave the CPU in a
131  * quiesecent loop within the kernel text. The memory containing
132  * this loop must not be re-used for anything else as the 'stuck'
133  * core is executing it.
134  *
135  * This function is used to inhibit features like kexec and hibernate.
136  */
137 bool cpus_are_stuck_in_kernel(void);
138 
139 #endif /* ifndef __ASSEMBLY__ */
140 
141 #endif /* ifndef __ASM_SMP_H */
142