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/* SPDX-License-Identifier: GPL-2.0-only */
* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (
#ifndef __ASM_ARC_SMP_H
#define __ASM_ARC_SMP_H
#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
#include <linux/irqflags.h>
#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 */