diff options
Diffstat (limited to 'arch/arc/include/asm/smp.h')
| -rw-r--r-- | arch/arc/include/asm/smp.h | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/arch/arc/include/asm/smp.h b/arch/arc/include/asm/smp.h index 4341f3ba7d92..f91f1946272f 100644 --- a/arch/arc/include/asm/smp.h +++ b/arch/arc/include/asm/smp.h @@ -9,6 +9,69 @@ #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 __init first_lines_of_secondary(void); + +/* + * API expected BY platform smp code (FROM arch smp code) + * + * smp_ipi_irq_setup: + * Takes @cpu and @irq to which the arch-common ISR is hooked up + */ +extern int smp_ipi_irq_setup(int cpu, int irq); + +/* + * APIs expected FROM platform smp code + * + * arc_platform_smp_cpuinfo: + * returns a string containing info for /proc/cpuinfo + * + * arc_platform_smp_init_cpu: + * Called from start_kernel_secondary to do any CPU local setup + * such as starting a timer, setting up IPI etc + * + * arc_platform_smp_wait_to_boot: + * Called from early bootup code for non-Master CPUs to "park" them + * + * arc_platform_smp_wakeup_cpu: + * Called from __cpu_up (Master CPU) to kick start another one + * + * arc_platform_ipi_send: + * Takes @cpumask to which IPI(s) would be sent. + * The actual msg-id/buffer is manager in arch-common code + * + * arc_platform_ipi_clear: + * Takes @cpu which got IPI at @irq to do any IPI clearing + */ +extern const char *arc_platform_smp_cpuinfo(void); +extern void arc_platform_smp_init_cpu(void); +extern void arc_platform_smp_wait_to_boot(int cpu); +extern void arc_platform_smp_wakeup_cpu(int cpu, unsigned long pc); +extern void arc_platform_ipi_send(const struct cpumask *callmap); +extern void arc_platform_ipi_clear(int cpu, int irq); + +#endif /* CONFIG_SMP */ + /* * ARC700 doesn't support atomic Read-Modify-Write ops. * Originally Interrupts had to be disabled around code to gaurantee atomicity. @@ -18,10 +81,52 @@ * * (1) These insn were introduced only in 4.10 release. So for older released * support needed. + * + * (2) In a SMP setup, the LLOCK/SCOND atomiticity 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) @@ -29,6 +134,8 @@ #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 |