/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Author: Qi Hu <huqi@loongson.cn>
 *         Huacai Chen <chenhuacai@loongson.cn>
 *
 * Copyright (C) 2020-2023 Loongson Technology Corporation Limited
 */
#include <asm/asm.h>
#include <asm/asmmacro.h>
#include <asm/asm-extable.h>
#include <asm/asm-offsets.h>
#include <asm/errno.h>
#include <asm/regdef.h>
#include <asm/unwind_hints.h>

#define SCR_REG_WIDTH 8

        .macro  EX insn, reg, src, offs
.ex\@:  \insn   \reg, \src, \offs
        _asm_extable .ex\@, .L_lbt_fault
        .endm

/*
 * Save a thread's lbt context.
 */
SYM_FUNC_START(_save_lbt)
        movscr2gr       t1, $scr0               # save scr
        stptr.d         t1, a0, THREAD_SCR0
        movscr2gr       t1, $scr1
        stptr.d         t1, a0, THREAD_SCR1
        movscr2gr       t1, $scr2
        stptr.d         t1, a0, THREAD_SCR2
        movscr2gr       t1, $scr3
        stptr.d         t1, a0, THREAD_SCR3

        x86mfflag       t1, 0x3f                # save eflags
        stptr.d         t1, a0, THREAD_EFLAGS
        jr              ra
SYM_FUNC_END(_save_lbt)
EXPORT_SYMBOL(_save_lbt)

/*
 * Restore a thread's lbt context.
 */
SYM_FUNC_START(_restore_lbt)
        ldptr.d         t1, a0, THREAD_SCR0     # restore scr
        movgr2scr       $scr0, t1
        ldptr.d         t1, a0, THREAD_SCR1
        movgr2scr       $scr1, t1
        ldptr.d         t1, a0, THREAD_SCR2
        movgr2scr       $scr2, t1
        ldptr.d         t1, a0, THREAD_SCR3
        movgr2scr       $scr3, t1

        ldptr.d         t1, a0, THREAD_EFLAGS   # restore eflags
        x86mtflag       t1, 0x3f
        jr              ra
SYM_FUNC_END(_restore_lbt)
EXPORT_SYMBOL(_restore_lbt)

/*
 * Load scr/eflag with zero.
 */
SYM_FUNC_START(_init_lbt)
        movgr2scr       $scr0, zero
        movgr2scr       $scr1, zero
        movgr2scr       $scr2, zero
        movgr2scr       $scr3, zero

        x86mtflag       zero, 0x3f
        jr              ra
SYM_FUNC_END(_init_lbt)

/*
 * a0: scr
 * a1: eflag
 */
SYM_FUNC_START(_save_lbt_context)
        movscr2gr       t1, $scr0               # save scr
        EX      st.d    t1, a0, (0 * SCR_REG_WIDTH)
        movscr2gr       t1, $scr1
        EX      st.d    t1, a0, (1 * SCR_REG_WIDTH)
        movscr2gr       t1, $scr2
        EX      st.d    t1, a0, (2 * SCR_REG_WIDTH)
        movscr2gr       t1, $scr3
        EX      st.d    t1, a0, (3 * SCR_REG_WIDTH)

        x86mfflag       t1, 0x3f                # save eflags
        EX      st.w    t1, a1, 0
        li.w            a0, 0                   # success
        jr              ra
SYM_FUNC_END(_save_lbt_context)
EXPORT_SYMBOL_GPL(_save_lbt_context)

/*
 * a0: scr
 * a1: eflag
 */
SYM_FUNC_START(_restore_lbt_context)
        EX      ld.d    t1, a0, (0 * SCR_REG_WIDTH)     # restore scr
        movgr2scr       $scr0, t1
        EX      ld.d    t1, a0, (1 * SCR_REG_WIDTH)
        movgr2scr       $scr1, t1
        EX      ld.d    t1, a0, (2 * SCR_REG_WIDTH)
        movgr2scr       $scr2, t1
        EX      ld.d    t1, a0, (3 * SCR_REG_WIDTH)
        movgr2scr       $scr3, t1

        EX      ld.w    t1, a1, 0                       # restore eflags
        x86mtflag       t1, 0x3f
        li.w            a0, 0                   # success
        jr              ra
SYM_FUNC_END(_restore_lbt_context)
EXPORT_SYMBOL_GPL(_restore_lbt_context)

/*
 * a0: ftop
 */
SYM_FUNC_START(_save_ftop_context)
        x86mftop        t1
        st.w            t1, a0, 0
        li.w            a0, 0                   # success
        jr              ra
SYM_FUNC_END(_save_ftop_context)
EXPORT_SYMBOL_GPL(_save_ftop_context)

/*
 * a0: ftop
 */
SYM_FUNC_START(_restore_ftop_context)
        ld.w            t1, a0, 0
        andi            t1, t1, 0x7
        la.pcrel        a0, 1f
        alsl.d          a0, t1, a0, 3
        jr              a0
1:
        x86mttop        0
        b       2f
        x86mttop        1
        b       2f
        x86mttop        2
        b       2f
        x86mttop        3
        b       2f
        x86mttop        4
        b       2f
        x86mttop        5
        b       2f
        x86mttop        6
        b       2f
        x86mttop        7
2:
        li.w            a0, 0                   # success
        jr              ra
SYM_FUNC_END(_restore_ftop_context)
EXPORT_SYMBOL_GPL(_restore_ftop_context)

.L_lbt_fault:
        li.w            a0, -EFAULT             # failure
        jr              ra

STACK_FRAME_NON_STANDARD _restore_ftop_context