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

#include <asm/alternative-macros.h>
#include <asm/asm-extable.h>
#include <asm/assembler.h>
#include <asm/kernel-pgtable.h>
#include <asm/mmu.h>
#include <asm/sysreg.h>

/*
 * User access enabling/disabling macros.
 */
#ifdef CONFIG_ARM64_SW_TTBR0_PAN
        .macro  __uaccess_ttbr0_disable, tmp1
        mrs     \tmp1, ttbr1_el1                        // swapper_pg_dir
        bic     \tmp1, \tmp1, #TTBR_ASID_MASK
        sub     \tmp1, \tmp1, #RESERVED_SWAPPER_OFFSET  // reserved_pg_dir
        msr     ttbr0_el1, \tmp1                        // set reserved TTBR0_EL1
        add     \tmp1, \tmp1, #RESERVED_SWAPPER_OFFSET
        msr     ttbr1_el1, \tmp1                // set reserved ASID
        isb
        .endm

        .macro  __uaccess_ttbr0_enable, tmp1, tmp2
        get_current_task \tmp1
        ldr     \tmp1, [\tmp1, #TSK_TI_TTBR0]   // load saved TTBR0_EL1
        mrs     \tmp2, ttbr1_el1
        extr    \tmp2, \tmp2, \tmp1, #48
        ror     \tmp2, \tmp2, #16
        msr     ttbr1_el1, \tmp2                // set the active ASID
        msr     ttbr0_el1, \tmp1                // set the non-PAN TTBR0_EL1
        isb
        .endm

        .macro  uaccess_ttbr0_disable, tmp1, tmp2
alternative_if_not ARM64_HAS_PAN
        save_and_disable_irq \tmp2              // avoid preemption
        __uaccess_ttbr0_disable \tmp1
        restore_irq \tmp2
alternative_else_nop_endif
        .endm

        .macro  uaccess_ttbr0_enable, tmp1, tmp2, tmp3
alternative_if_not ARM64_HAS_PAN
        save_and_disable_irq \tmp3              // avoid preemption
        __uaccess_ttbr0_enable \tmp1, \tmp2
        restore_irq \tmp3
alternative_else_nop_endif
        .endm
#else
        .macro  uaccess_ttbr0_disable, tmp1, tmp2
        .endm

        .macro  uaccess_ttbr0_enable, tmp1, tmp2, tmp3
        .endm
#endif

#define USER(l, x...)                           \
9999:   x;                                      \
        _asm_extable_uaccess    9999b, l

#define USER_CPY(l, uaccess_is_write, x...)     \
9999:   x;                                      \
        _asm_extable_uaccess_cpy 9999b, l, uaccess_is_write

/*
 * Generate the assembly for LDTR/STTR with exception table entries.
 * This is complicated as there is no post-increment or pair versions of the
 * unprivileged instructions, and USER() only works for single instructions.
 */
        .macro user_ldp l, reg1, reg2, addr, post_inc
8888:           ldtr    \reg1, [\addr];
8889:           ldtr    \reg2, [\addr, #8];
                add     \addr, \addr, \post_inc;

                _asm_extable_uaccess    8888b, \l;
                _asm_extable_uaccess    8889b, \l;
        .endm

        .macro user_stp l, reg1, reg2, addr, post_inc
8888:           sttr    \reg1, [\addr];
8889:           sttr    \reg2, [\addr, #8];
                add     \addr, \addr, \post_inc;

                _asm_extable_uaccess    8888b,\l;
                _asm_extable_uaccess    8889b,\l;
        .endm

        .macro user_ldst l, inst, reg, addr, post_inc
8888:           \inst           \reg, [\addr];
                add             \addr, \addr, \post_inc;

                _asm_extable_uaccess    8888b, \l;
        .endm
#endif