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