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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright 2012 Calxeda, Inc.
*/
#ifndef _ASM_ARM_PERCPU_H_
#define _ASM_ARM_PERCPU_H_
#include <asm/insn.h>
register unsigned long current_stack_pointer asm ("sp");
/*
* Same as asm-generic/percpu.h, except that we store the per cpu offset
* in the TPIDRPRW. TPIDRPRW only exists on V6K and V7
*/
#ifdef CONFIG_SMP
static inline void set_my_cpu_offset(unsigned long off)
{
extern unsigned int smp_on_up;
if (IS_ENABLED(CONFIG_CPU_V6) && !smp_on_up)
return;
/* 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("0: mrc p15, 0, %0, c13, c0, 4 \n\t"
#ifdef CONFIG_CPU_V6
"1: \n\t"
" .subsection 1 \n\t"
#if defined(CONFIG_ARM_HAS_GROUP_RELOCS) && \
!(defined(MODULE) && defined(CONFIG_ARM_MODULE_PLTS))
"2: " LOAD_SYM_ARMV6(%0, __per_cpu_offset) " \n\t"
" b 1b \n\t"
#else
"2: ldr %0, 3f \n\t"
" ldr %0, [%0] \n\t"
" b 1b \n\t"
"3: .long __per_cpu_offset \n\t"
#endif
" .previous \n\t"
" .pushsection \".alt.smp.init\", \"a\" \n\t"
" .long 0b - . \n\t"
" b . + (2b - 0b) \n\t"
" .popsection \n\t"
#endif
: "=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_ */
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