arch/arm64/include/asm/smp.h

   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
  34 DECLARE_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  */
  48 extern u64 __cpu_logical_map[NR_CPUS];
  49 #define cpu_logical_map(cpu)    __cpu_logical_map[cpu]
  50
  51 struct seq_file;
  52
  53 /*
  54  * generate IPI list text
  55  */
  56 extern void show_ipi_list(struct seq_file *p, int prec);
  57
  58 /*
  59  * Called from C code, this handles an IPI.
  60  */
  61 extern 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  */
  67 extern void smp_init_cpus(void);
  68
  69 /*
  70  * Provide a function to raise an IPI cross call on CPUs in callmap.
  71  */
  72 extern void set_smp_cross_call(void (*)(const struct cpumask *, unsigned int));
  73
  74 extern 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  */
  79 asmlinkage 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  */
  87 struct secondary_data {
  88         void *stack;
  89         struct task_struct *task;
  90         long status;
  91 };
  92
  93 extern struct secondary_data secondary_data;
  94 extern long __early_cpu_boot_status;
  95 extern void secondary_entry(void);
  96
  97 extern void arch_send_call_function_single_ipi(int cpu);
  98 extern void arch_send_call_function_ipi_mask(const struct cpumask *mask);
  99
 100 #ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL
 101 extern void arch_send_wakeup_ipi_mask(const struct cpumask *mask);
 102 #else
 103 static inline void arch_send_wakeup_ipi_mask(const struct cpumask *mask)
 104 {
 105         BUILD_BUG();
 106 }
 107 #endif
 108
 109 extern int __cpu_disable(void);
 110
 111 extern void __cpu_die(unsigned int cpu);
 112 extern void cpu_die(void);
 113 extern void cpu_die_early(void);
 114
 115 static inline void cpu_park_loop(void)
 116 {
 117         for (;;) {
 118                 wfe();
 119                 wfi();
 120         }
 121 }
 122
 123 static 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  */
 135 static 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  */
 151 bool cpus_are_stuck_in_kernel(void);
 152
 153 extern void crash_smp_send_stop(void);
 154 extern bool smp_crash_stop_failed(void);
 155
 156 #endif /* ifndef __ASSEMBLY__ */
 157
 158 #endif /* ifndef __ASM_SMP_H */