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 #endif /* ifndef __ASSEMBLY__ */ 152 153 #endif /* ifndef __ASM_SMP_H */ 154