linux/arch/arm64/include/asm/percpu.h
Will Deacon 7158627686 arm64: percpu: implement optimised pcpu access using tpidr_el1
This patch implements optimised percpu variable accesses using the
el1 r/w thread register (tpidr_el1) along the same lines as arch/arm/.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2013-12-19 17:43:06 +00:00

42 lines
1.2 KiB
C

/*
* Copyright (C) 2013 ARM Ltd.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef __ASM_PERCPU_H
#define __ASM_PERCPU_H
static inline void set_my_cpu_offset(unsigned long off)
{
asm volatile("msr tpidr_el1, %0" :: "r" (off) : "memory");
}
static inline unsigned long __my_cpu_offset(void)
{
unsigned long off;
register unsigned long *sp asm ("sp");
/*
* We want to allow caching the value, so avoid using volatile and
* instead use a fake stack read to hazard against barrier().
*/
asm("mrs %0, tpidr_el1" : "=r" (off) : "Q" (*sp));
return off;
}
#define __my_cpu_offset __my_cpu_offset()
#include <asm-generic/percpu.h>
#endif /* __ASM_PERCPU_H */