1 /* 2 * Copyright 2012 Calxeda, Inc. 3 * 4 * This program is free software; you can redistribute it and/or modify it 5 * under the terms and conditions of the GNU General Public License, 6 * version 2, as published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope it will be useful, but WITHOUT 9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 11 * more details. 12 * 13 * You should have received a copy of the GNU General Public License along with 14 * this program. If not, see <http://www.gnu.org/licenses/>. 15 */ 16 #ifndef _ASM_ARM_PERCPU_H_ 17 #define _ASM_ARM_PERCPU_H_ 18 19 /* 20 * Same as asm-generic/percpu.h, except that we store the per cpu offset 21 * in the TPIDRPRW. TPIDRPRW only exists on V6K and V7 22 */ 23 #if defined(CONFIG_SMP) && !defined(CONFIG_CPU_V6) 24 static inline void set_my_cpu_offset(unsigned long off) 25 { 26 /* Set TPIDRPRW */ 27 asm volatile("mcr p15, 0, %0, c13, c0, 4" : : "r" (off) : "memory"); 28 } 29 30 static inline unsigned long __my_cpu_offset(void) 31 { 32 unsigned long off; 33 register unsigned long *sp asm ("sp"); 34 35 /* 36 * Read TPIDRPRW. 37 * We want to allow caching the value, so avoid using volatile and 38 * instead use a fake stack read to hazard against barrier(). 39 */ 40 asm("mrc p15, 0, %0, c13, c0, 4" : "=r" (off) : "Q" (*sp)); 41 42 return off; 43 } 44 #define __my_cpu_offset __my_cpu_offset() 45 #else 46 #define set_my_cpu_offset(x) do {} while(0) 47 48 #endif /* CONFIG_SMP */ 49 50 #include <asm-generic/percpu.h> 51 52 #endif /* _ASM_ARM_PERCPU_H_ */ 53