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
  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
 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
 113 static inline void cpu_park_loop(void)
 114 {
 115         for (;;) {
 116                 wfe();
 117                 wfi();
 118         }
 119 }
 120
 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  */
 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 */