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Commit 7f124aaf authored by Lorenzo Pieralisi's avatar Lorenzo Pieralisi
Browse files

ARM: kernel: add logical mappings look-up 



In ARM SMP systems the MPIDR register ([23:0] bits) is used to uniquely
identify CPUs.

In order to retrieve the logical CPU index corresponding to a given
MPIDR value and guarantee a consistent translation throughout the kernel,
this patch adds a look-up based on the MPIDR[23:0] so that kernel subsystems
can use it whenever the logical cpu index corresponding to a given MPIDR
value is needed.

Signed-off-by: default avatarLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: default avatarWill Deacon <will.deacon@arm.com>
Acked-by: default avatarNicolas Pitre <nico@linaro.org>
parent 5587164e

arch/arm/include/asm/smp_plat.h

+17 −0
Original line number Original line Diff line number Diff line
@@ -5,6 +5,9 @@ 
#ifndef __ASMARM_SMP_PLAT_H

#ifndef __ASMARM_SMP_PLAT_H

#define __ASMARM_SMP_PLAT_H

#define __ASMARM_SMP_PLAT_H





#include <linux/cpumask.h>

#include <linux/err.h>



#include <asm/cputype.h>

#include <asm/cputype.h>





/*

/*
@@ -48,5 +51,19 @@ static inline int cache_ops_need_broadcast(void) 
 */

 */

extern int __cpu_logical_map[];

extern int __cpu_logical_map[];

#define cpu_logical_map(cpu)	__cpu_logical_map[cpu]

#define cpu_logical_map(cpu)	__cpu_logical_map[cpu]

/*

 * Retrieve logical cpu index corresponding to a given MPIDR[23:0]

 *  - mpidr: MPIDR[23:0] to be used for the look-up

 *

 * Returns the cpu logical index or -EINVAL on look-up error

 */

static inline int get_logical_index(u32 mpidr)

{

	int cpu;

	for (cpu = 0; cpu < nr_cpu_ids; cpu++)

		if (cpu_logical_map(cpu) == mpidr)

			return cpu;

	return -EINVAL;

}





#endif
 
#endif