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