LXR linux/arch/arm64/include/asm/smp.h

   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
  38DECLARE_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
  49struct seq_file;
  50
  51/*
  52 * generate IPI list text
  53 */
  54extern void show_ipi_list(struct seq_file *p, int prec);
  55
  56/*
  57 * Called from C code, this handles an IPI.
  58 */
  59extern 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 */
  65extern void smp_init_cpus(void);
  66
  67/*
  68 * Provide a function to raise an IPI cross call on CPUs in callmap.
  69 */
  70extern void set_smp_cross_call(void (*)(const struct cpumask *, unsigned int));
  71
  72extern 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 */
  77asmlinkage 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 */
  85struct secondary_data {
  86        void *stack;
  87        struct task_struct *task;
  88        long status;
  89};
  90
  91extern struct secondary_data secondary_data;
  92extern long __early_cpu_boot_status;
  93extern void secondary_entry(void);
  94
  95extern void arch_send_call_function_single_ipi(int cpu);
  96extern void arch_send_call_function_ipi_mask(const struct cpumask *mask);
  97
  98#ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL
  99extern void arch_send_wakeup_ipi_mask(const struct cpumask *mask);
 100#else
 101static inline void arch_send_wakeup_ipi_mask(const struct cpumask *mask)
 102{
 103        BUILD_BUG();
 104}
 105#endif
 106
 107extern int __cpu_disable(void);
 108
 109extern void __cpu_die(unsigned int cpu);
 110extern void cpu_die(void);
 111extern void cpu_die_early(void);
 112
 113static inline void cpu_park_loop(void)
 114{
 115        for (;;) {
 116                wfe();
 117                wfi();
 118        }
 119}
 120
 121static 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 */
 133static 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 */
 149bool cpus_are_stuck_in_kernel(void);
 150
 151extern void smp_send_crash_stop(void);
 152extern bool smp_crash_stop_failed(void);
 153
 154#endif /* ifndef __ASSEMBLY__ */
 155
 156#endif /* ifndef __ASM_SMP_H */
 157