// 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); } extern int __vdso_getcpu(unsigned int *cpu, unsigned int *node, struct getcpu_cache *unused); 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; }