| 1 | // SPDX-License-Identifier: GPL-2.0-only |
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| 2 | /* |
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| 3 | * Fast user context implementation of getcpu() |
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| 4 | */ |
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| 5 | |
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| 6 | #include <asm/vdso.h> |
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| 7 | #include <linux/getcpu.h> |
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| 8 | |
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| 9 | static __always_inline int read_cpu_id(void) |
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| 10 | { |
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| 11 | int cpu_id; |
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| 12 | |
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| 13 | #ifdef CONFIG_64BIT |
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| 14 | __asm__ __volatile__( |
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| 15 | " rdtime.d $zero, %0\n" |
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| 16 | : "=r" (cpu_id) |
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| 17 | : |
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| 18 | : "memory" ); |
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| 19 | #else |
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| 20 | __asm__ __volatile__( |
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| 21 | " rdtimel.w $zero, %0\n" |
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| 22 | : "=r" (cpu_id) |
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| 23 | : |
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| 24 | : "memory" ); |
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| 25 | #endif |
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| 26 | |
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| 27 | return cpu_id; |
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| 28 | } |
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| 29 | |
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| 30 | extern |
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| 31 | int __vdso_getcpu(unsigned int *cpu, unsigned int *node, struct getcpu_cache *unused); |
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| 32 | int __vdso_getcpu(unsigned int *cpu, unsigned int *node, struct getcpu_cache *unused) |
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| 33 | { |
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| 34 | int cpu_id; |
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| 35 | |
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| 36 | cpu_id = read_cpu_id(); |
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| 37 | |
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| 38 | if (cpu) |
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| 39 | *cpu = cpu_id; |
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| 40 | |
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| 41 | if (node) |
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| 42 | *node = vdso_u_arch_data.pdata[cpu_id].node; |
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| 43 | |
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| 44 | return 0; |
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| 45 | } |
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| 46 | |
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