/* 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 __always_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_ */