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