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45 lines
826 B
45 lines
826 B
// 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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