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];
  49extern u64 cpu_logical_map(int cpu);
  50
  51static inline void set_cpu_logical_map(int cpu, u64 hwid)
  52{
  53        __cpu_logical_map[cpu] = hwid;
  54}
  55
  56struct seq_file;
  57
  58/*
  59 * generate IPI list text
  60 */
  61extern void show_ipi_list(struct seq_file *p, int prec);
  62
  63/*
  64 * Called from C code, this handles an IPI.
  65 */
  66extern void handle_IPI(int ipinr, struct pt_regs *regs);
  67
  68/*
  69 * Discover the set of possible CPUs and determine their
  70 * SMP operations.
  71 */
  72extern void smp_init_cpus(void);
  73
  74/*
  75 * Provide a function to raise an IPI cross call on CPUs in callmap.
  76 */
  77extern void set_smp_cross_call(void (*)(const struct cpumask *, unsigned int));
  78
  79extern void (*__smp_cross_call)(const struct cpumask *, unsigned int);
  80
  81/*
  82 * Called from the secondary holding pen, this is the secondary CPU entry point.
  83 */
  84asmlinkage void secondary_start_kernel(void);
  85
  86/*
  87 * Initial data for bringing up a secondary CPU.
  88 * @stack  - sp for the secondary CPU
  89 * @status - Result passed back from the secondary CPU to
  90 *           indicate failure.
  91 */
  92struct secondary_data {
  93        void *stack;
  94        struct task_struct *task;
  95        long status;
  96};
  97
  98extern struct secondary_data secondary_data;
  99extern long __early_cpu_boot_status;
 100extern void secondary_entry(void);
 101
 102extern void arch_send_call_function_single_ipi(int cpu);
 103extern void arch_send_call_function_ipi_mask(const struct cpumask *mask);
 104
 105#ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL
 106extern void arch_send_wakeup_ipi_mask(const struct cpumask *mask);
 107#else
 108static inline void arch_send_wakeup_ipi_mask(const struct cpumask *mask)
 109{
 110        BUILD_BUG();
 111}
 112#endif
 113
 114extern int __cpu_disable(void);
 115
 116extern void __cpu_die(unsigned int cpu);
 117extern void cpu_die(void);
 118extern void cpu_die_early(void);
 119
 120static inline void cpu_park_loop(void)
 121{
 122        for (;;) {
 123                wfe();
 124                wfi();
 125        }
 126}
 127
 128static inline void update_cpu_boot_status(int val)
 129{
 130        WRITE_ONCE(secondary_data.status, val);
 131        /* Ensure the visibility of the status update */
 132        dsb(ishst);
 133}
 134
 135/*
 136 * The calling secondary CPU has detected serious configuration mismatch,
 137 * which calls for a kernel panic. Update the boot status and park the calling
 138 * CPU.
 139 */
 140static inline void cpu_panic_kernel(void)
 141{
 142        update_cpu_boot_status(CPU_PANIC_KERNEL);
 143        cpu_park_loop();
 144}
 145
 146/*
 147 * If a secondary CPU enters the kernel but fails to come online,
 148 * (e.g. due to mismatched features), and cannot exit the kernel,
 149 * we increment cpus_stuck_in_kernel and leave the CPU in a
 150 * quiesecent loop within the kernel text. The memory containing
 151 * this loop must not be re-used for anything else as the 'stuck'
 152 * core is executing it.
 153 *
 154 * This function is used to inhibit features like kexec and hibernate.
 155 */
 156bool cpus_are_stuck_in_kernel(void);
 157
 158extern void crash_smp_send_stop(void);
 159extern bool smp_crash_stop_failed(void);
 160
 161#endif /* ifndef __ASSEMBLY__ */
 162
 163#endif /* ifndef __ASM_SMP_H */
 164