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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 | /* SPDX-License-Identifier: GPL-2.0-only */ /* * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) */ #ifndef __ASM_ARC_SMP_H #define __ASM_ARC_SMP_H #ifdef CONFIG_SMP #include <linux/types.h> #include <linux/init.h> #include <linux/threads.h> #define raw_smp_processor_id() (current_thread_info()->cpu) /* including cpumask.h leads to cyclic deps hence this Forward declaration */ struct cpumask; /* * APIs provided by arch SMP code to generic code */ extern void arch_send_call_function_single_ipi(int cpu); extern void arch_send_call_function_ipi_mask(const struct cpumask *mask); /* * APIs provided by arch SMP code to rest of arch code */ extern void __init smp_init_cpus(void); extern void first_lines_of_secondary(void); extern const char *arc_platform_smp_cpuinfo(void); /* * API expected BY platform smp code (FROM arch smp code) * * smp_ipi_irq_setup: * Takes @cpu and @hwirq to which the arch-common ISR is hooked up */ extern int smp_ipi_irq_setup(int cpu, irq_hw_number_t hwirq); /* * struct plat_smp_ops - SMP callbacks provided by platform to ARC SMP * * @info: SoC SMP specific info for /proc/cpuinfo etc * @init_early_smp: A SMP specific h/w block can init itself * Could be common across platforms so not covered by * mach_desc->init_early() * @init_per_cpu: Called for each core so SMP h/w block driver can do * any needed setup per cpu (e.g. IPI request) * @cpu_kick: For Master to kickstart a cpu (optionally at a PC) * @ipi_send: To send IPI to a @cpu * @ips_clear: To clear IPI received at @irq */ struct plat_smp_ops { const char *info; void (*init_early_smp)(void); void (*init_per_cpu)(int cpu); void (*cpu_kick)(int cpu, unsigned long pc); void (*ipi_send)(int cpu); void (*ipi_clear)(int irq); }; /* TBD: stop exporting it for direct population by platform */ extern struct plat_smp_ops plat_smp_ops; #else /* CONFIG_SMP */ static inline void smp_init_cpus(void) {} static inline const char *arc_platform_smp_cpuinfo(void) { return ""; } #endif /* !CONFIG_SMP */ /* * ARC700 doesn't support atomic Read-Modify-Write ops. * Originally Interrupts had to be disabled around code to gaurantee atomicity. * The LLOCK/SCOND insns allow writing interrupt-hassle-free based atomic ops * based on retry-if-irq-in-atomic (with hardware assist). * However despite these, we provide the IRQ disabling variant * * (1) These insn were introduced only in 4.10 release. So for older released * support needed. * * (2) In a SMP setup, the LLOCK/SCOND atomicity across CPUs needs to be * gaurantted by the platform (not something which core handles). * Assuming a platform won't, SMP Linux needs to use spinlocks + local IRQ * disabling for atomicity. * * However exported spinlock API is not usable due to cyclic hdr deps * (even after system.h disintegration upstream) * asm/bitops.h -> linux/spinlock.h -> linux/preempt.h * -> linux/thread_info.h -> linux/bitops.h -> asm/bitops.h * * So the workaround is to use the lowest level arch spinlock API. * The exported spinlock API is smart enough to be NOP for !CONFIG_SMP, * but same is not true for ARCH backend, hence the need for 2 variants */ #ifndef CONFIG_ARC_HAS_LLSC #include <linux/irqflags.h> #ifdef CONFIG_SMP #include <asm/spinlock.h> extern arch_spinlock_t smp_atomic_ops_lock; #define atomic_ops_lock(flags) do { \ local_irq_save(flags); \ arch_spin_lock(&smp_atomic_ops_lock); \ } while (0) #define atomic_ops_unlock(flags) do { \ arch_spin_unlock(&smp_atomic_ops_lock); \ local_irq_restore(flags); \ } while (0) #else /* !CONFIG_SMP */ #define atomic_ops_lock(flags) local_irq_save(flags) #define atomic_ops_unlock(flags) local_irq_restore(flags) #endif /* !CONFIG_SMP */ #endif /* !CONFIG_ARC_HAS_LLSC */ #endif |