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MIPS: introduce cpu_coherent_mask

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Add a mask of CPUs which are currently known to be operating coherently.
This is setup initially to be all present CPUs, but in a subsequent
patch CPUs in a MIPS Coherent Processing System will be cleared in this
mask as they enter non-coherent idle states. This will be used in order
to determine when a CPU within a CPS system may need to be powered back
up, but may also be used in future to optimise away wakeups for cache
operations or TLB invalidations.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
This commit is contained in:
Paul Burton 2014-02-14 16:30:52 +00:00
parent cc7964af8f
commit 76306f4272
2 changed files with 7 additions and 0 deletions
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3
arch/mips/include/asm/smp.h
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@ -46,6 +46,9 @@ extern int __cpu_logical_map[NR_CPUS];
extern volatile cpumask_t cpu_callin_map;
/* Mask of CPUs which are currently definitely operating coherently */
extern cpumask_t cpu_coherent_mask;
extern void asmlinkage smp_bootstrap(void);
/*

4
arch/mips/kernel/smp.c
View file

@ -66,6 +66,8 @@ EXPORT_SYMBOL(cpu_sibling_map);
/* representing cpus for which sibling maps can be computed */
static cpumask_t cpu_sibling_setup_map;
cpumask_t cpu_coherent_mask;
static inline void set_cpu_sibling_map(int cpu)
{
int i;
@ -124,6 +126,7 @@ asmlinkage void start_secondary(void)
cpu = smp_processor_id();
cpu_data[cpu].udelay_val = loops_per_jiffy;
cpu_set(cpu, cpu_coherent_mask);
notify_cpu_starting(cpu);
set_cpu_online(cpu, true);
@ -186,6 +189,7 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
#ifndef CONFIG_HOTPLUG_CPU
init_cpu_present(cpu_possible_mask);
#endif
cpumask_copy(&cpu_coherent_mask, cpu_possible_mask);
}
/* preload SMP state for boot cpu */