linux_dsm_epyc7002/arch/arm/include/asm/percpu.h
Mark Charlebois ccbd2da50d ARM: 8174/1: Use global stack register variable for percpu
Using global current_stack_pointer works on both clang and gcc.
current_stack_pointer is an unsigned long and needs to be cast
as a pointer to dereference.

Signed-off-by: Mark Charlebois <charlebm@gmail.com>
Signed-off-by: Behan Webster <behanw@converseincode.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-11-13 23:58:06 +00:00

53 lines
1.5 KiB
C

/*
* Copyright 2012 Calxeda, Inc.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope 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_ARM_PERCPU_H_
#define _ASM_ARM_PERCPU_H_
/*
* Same as asm-generic/percpu.h, except that we store the per cpu offset
* in the TPIDRPRW. TPIDRPRW only exists on V6K and V7
*/
#if defined(CONFIG_SMP) && !defined(CONFIG_CPU_V6)
static inline void set_my_cpu_offset(unsigned long off)
{
/* Set TPIDRPRW */
asm volatile("mcr p15, 0, %0, c13, c0, 4" : : "r" (off) : "memory");
}
static inline unsigned long __my_cpu_offset(void)
{
unsigned long off;
/*
* Read TPIDRPRW.
* We want to allow caching the value, so avoid using volatile and
* instead use a fake stack read to hazard against barrier().
*/
asm("mrc p15, 0, %0, c13, c0, 4" : "=r" (off)
: "Q" (*(const unsigned long *)current_stack_pointer));
return off;
}
#define __my_cpu_offset __my_cpu_offset()
#else
#define set_my_cpu_offset(x) do {} while(0)
#endif /* CONFIG_SMP */
#include <asm-generic/percpu.h>
#endif /* _ASM_ARM_PERCPU_H_ */