/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Copyright (C) 2012 ARM Ltd.
 */
#ifndef __ASM_IRQFLAGS_H
#define __ASM_IRQFLAGS_H

#include <asm/alternative.h>
#include <asm/barrier.h>
#include <asm/ptrace.h>
#include <asm/sysreg.h>

/*
 * Aarch64 has flags for masking: Debug, Asynchronous (serror), Interrupts and
 * FIQ exceptions, in the 'daif' register. We mask and unmask them in 'daif'
 * order:
 * Masking debug exceptions causes all other exceptions to be masked too/
 * Masking SError masks IRQ/FIQ, but not debug exceptions. IRQ and FIQ are
 * always masked and unmasked together, and have no side effects for other
 * flags. Keeping to this order makes it easier for entry.S to know which
 * exceptions should be unmasked.
 */

static __always_inline bool __irqflags_uses_pmr(void)
{
    return IS_ENABLED(CONFIG_ARM64_PSEUDO_NMI) &&
           alternative_has_cap_unlikely(ARM64_HAS_GIC_PRIO_MASKING);
}

static __always_inline void __daif_local_irq_enable(void)
{
    barrier();
    asm volatile("msr daifclr, #3");
    barrier();
}

static __always_inline void __pmr_local_irq_enable(void)
{
    if (IS_ENABLED(CONFIG_ARM64_DEBUG_PRIORITY_MASKING)) {
        u32 pmr = read_sysreg_s(SYS_ICC_PMR_EL1);
        WARN_ON_ONCE(pmr != GIC_PRIO_IRQON && pmr != GIC_PRIO_IRQOFF);
    }

    barrier();
    write_sysreg_s(GIC_PRIO_IRQON, SYS_ICC_PMR_EL1);
    pmr_sync();
    barrier();
}

static inline void arch_local_irq_enable(void)
{
    if (__irqflags_uses_pmr()) {
        __pmr_local_irq_enable();
    } else {
        __daif_local_irq_enable();
    }
}

static __always_inline void __daif_local_irq_disable(void)
{
    barrier();
    asm volatile("msr daifset, #3");
    barrier();
}

static __always_inline void __pmr_local_irq_disable(void)
{
    if (IS_ENABLED(CONFIG_ARM64_DEBUG_PRIORITY_MASKING)) {
        u32 pmr = read_sysreg_s(SYS_ICC_PMR_EL1);
        WARN_ON_ONCE(pmr != GIC_PRIO_IRQON && pmr != GIC_PRIO_IRQOFF);
    }

    barrier();
    write_sysreg_s(GIC_PRIO_IRQOFF, SYS_ICC_PMR_EL1);
    barrier();
}

static inline void arch_local_irq_disable(void)
{
    if (__irqflags_uses_pmr()) {
        __pmr_local_irq_disable();
    } else {
        __daif_local_irq_disable();
    }
}

static __always_inline unsigned long __daif_local_save_flags(void)
{
    return read_sysreg(daif);
}

static __always_inline unsigned long __pmr_local_save_flags(void)
{
    return read_sysreg_s(SYS_ICC_PMR_EL1);
}

/*
 * Save the current interrupt enable state.
 */
static inline unsigned long arch_local_save_flags(void)
{
    if (__irqflags_uses_pmr()) {
        return __pmr_local_save_flags();
    } else {
        return __daif_local_save_flags();
    }
}

static __always_inline bool __daif_irqs_disabled_flags(unsigned long flags)
{
    return flags & PSR_I_BIT;
}

static __always_inline bool __pmr_irqs_disabled_flags(unsigned long flags)
{
    return flags != GIC_PRIO_IRQON;
}

static inline bool arch_irqs_disabled_flags(unsigned long flags)
{
    if (__irqflags_uses_pmr()) {
        return __pmr_irqs_disabled_flags(flags);
    } else {
        return __daif_irqs_disabled_flags(flags);
    }
}

static __always_inline bool __daif_irqs_disabled(void)
{
    return __daif_irqs_disabled_flags(__daif_local_save_flags());
}

static __always_inline bool __pmr_irqs_disabled(void)
{
    return __pmr_irqs_disabled_flags(__pmr_local_save_flags());
}

static inline bool arch_irqs_disabled(void)
{
    if (__irqflags_uses_pmr()) {
        return __pmr_irqs_disabled();
    } else {
        return __daif_irqs_disabled();
    }
}

static __always_inline unsigned long __daif_local_irq_save(void)
{
    unsigned long flags = __daif_local_save_flags();

    __daif_local_irq_disable();

    return flags;
}

static __always_inline unsigned long __pmr_local_irq_save(void)
{
    unsigned long flags = __pmr_local_save_flags();

    /*
     * There are too many states with IRQs disabled, just keep the current
     * state if interrupts are already disabled/masked.
     */
    if (!__pmr_irqs_disabled_flags(flags))
        __pmr_local_irq_disable();

    return flags;
}

static inline unsigned long arch_local_irq_save(void)
{
    if (__irqflags_uses_pmr()) {
        return __pmr_local_irq_save();
    } else {
        return __daif_local_irq_save();
    }
}

static __always_inline void __daif_local_irq_restore(unsigned long flags)
{
    barrier();
    write_sysreg(flags, daif);
    barrier();
}

static __always_inline void __pmr_local_irq_restore(unsigned long flags)
{
    barrier();
    write_sysreg_s(flags, SYS_ICC_PMR_EL1);
    pmr_sync();
    barrier();
}

/*
 * restore saved IRQ state
 */
static inline void arch_local_irq_restore(unsigned long flags)
{
    if (__irqflags_uses_pmr()) {
        __pmr_local_irq_restore(flags);
    } else {
        __daif_local_irq_restore(flags);
    }
}

#endif /* __ASM_IRQFLAGS_H */