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// SPDX-License-Identifier: GPL-2.0-only
/*
* Fast user context implementation of getcpu()
*/
#include <asm/vdso.h>
#include <linux/getcpu.h>
static __always_inline int read_cpu_id(void)
{
int cpu_id;
__asm__ __volatile__(
" rdtime.d $zero, %0\n"
: "=r" (cpu_id)
:
: "memory");
return cpu_id;
}
static __always_inline const struct vdso_pcpu_data *get_pcpu_data(void)
{
return (struct vdso_pcpu_data *)(get_vdso_base() - VDSO_DATA_SIZE);
}
int __vdso_getcpu(unsigned int *cpu, unsigned int *node, struct getcpu_cache *unused)
{
int cpu_id;
const struct vdso_pcpu_data *data;
cpu_id = read_cpu_id();
if (cpu)
*cpu = cpu_id;
if (node) {
data = get_pcpu_data();
*node = data[cpu_id].node;
}
return 0;
}
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