LXR linux/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
  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 */
 159