cregit-Linux how code gets into the kernel

Release 4.14 arch/arc/include/asm/smp.h

/*
 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#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) {}

Contributors

PersonTokensPropCommitsCommitProp
Vineet Gupta8100.00%1100.00%
Total8100.00%1100.00%


static inline const char *arc_platform_smp_cpuinfo(void) { return ""; }

Contributors

PersonTokensPropCommitsCommitProp
Vineet Gupta14100.00%1100.00%
Total14100.00%1100.00%

#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; extern arch_spinlock_t smp_bitops_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) #define bitops_lock(flags) do { \ local_irq_save(flags); \ arch_spin_lock(&smp_bitops_lock); \ } while (0) #define bitops_unlock(flags) do { \ arch_spin_unlock(&smp_bitops_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) #define bitops_lock(flags) local_irq_save(flags) #define bitops_unlock(flags) local_irq_restore(flags) #endif /* !CONFIG_SMP */ #endif /* !CONFIG_ARC_HAS_LLSC */ #endif

Overall Contributors

PersonTokensPropCommitsCommitProp
Vineet Gupta26597.79%770.00%
Yuriy Kolerov31.11%110.00%
Noam Camus20.74%110.00%
Andrea Gelmini10.37%110.00%
Total271100.00%10100.00%
Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.
Created with cregit.