/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_POWERPC_KUP_BOOKE_H_
#define _ASM_POWERPC_KUP_BOOKE_H_

#include <asm/bug.h>
#include <asm/mmu.h>

#ifdef CONFIG_PPC_KUAP

#ifdef __ASSEMBLER__

.macro kuap_check_amr   gpr1, gpr2
.endm

#else

#include <linux/sched.h>

#include <asm/reg.h>

static __always_inline void __kuap_lock(void)
{
        mtspr(SPRN_PID, 0);
        isync();
}
#define __kuap_lock __kuap_lock

static __always_inline void __kuap_save_and_lock(struct pt_regs *regs)
{
        regs->kuap = mfspr(SPRN_PID);
        mtspr(SPRN_PID, 0);
        isync();
}
#define __kuap_save_and_lock __kuap_save_and_lock

static __always_inline void kuap_user_restore(struct pt_regs *regs)
{
        if (kuap_is_disabled())
                return;

        mtspr(SPRN_PID, current->thread.pid);

        /* Context synchronisation is performed by rfi */
}

static __always_inline void __kuap_kernel_restore(struct pt_regs *regs, unsigned long kuap)
{
        if (regs->kuap)
                mtspr(SPRN_PID, current->thread.pid);

        /* Context synchronisation is performed by rfi */
}

#ifdef CONFIG_PPC_KUAP_DEBUG
static __always_inline unsigned long __kuap_get_and_assert_locked(void)
{
        WARN_ON_ONCE(mfspr(SPRN_PID));

        return 0;
}
#define __kuap_get_and_assert_locked __kuap_get_and_assert_locked
#endif

static __always_inline void uaccess_begin_booke(unsigned long val)
{
        asm(ASM_MMU_FTR_IFSET("mtspr %0, %1; isync", "", %2) : :
            "i"(SPRN_PID), "r"(val), "i"(MMU_FTR_KUAP) : "memory");
}

static __always_inline void uaccess_end_booke(void)
{
        asm(ASM_MMU_FTR_IFSET("mtspr %0, %1; isync", "", %2) : :
            "i"(SPRN_PID), "r"(0), "i"(MMU_FTR_KUAP) : "memory");
}

static __always_inline void allow_user_access(void __user *to, unsigned long dir)
{
        uaccess_begin_booke(current->thread.pid);
}

static __always_inline void prevent_user_access(unsigned long dir)
{
        uaccess_end_booke();
}

static __always_inline unsigned long prevent_user_access_return(void)
{
        unsigned long flags = mfspr(SPRN_PID);

        uaccess_end_booke();

        return flags;
}

static __always_inline void restore_user_access(unsigned long flags)
{
        if (flags)
                uaccess_begin_booke(current->thread.pid);
}

static __always_inline bool
__bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write)
{
        return !regs->kuap;
}

#endif /* !__ASSEMBLER__ */

#endif /* CONFIG_PPC_KUAP */

#endif /* _ASM_POWERPC_KUP_BOOKE_H_ */