/*
 * Based on arch/arm/include/asm/assembler.h
 *
 * Copyright (C) 1996-2000 Russell King
 * Copyright (C) 2012 ARM Ltd.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#ifndef __ASSEMBLY__
#error "Only include this from assembly code"
#endif

#ifndef __ASM_ASSEMBLER_H
#define __ASM_ASSEMBLER_H

#include <asm/ptrace.h>
#include <asm/thread_info.h>

/*
 * Stack pushing/popping (register pairs only). Equivalent to store decrement
 * before, load increment after.
 */
        .macro  push, xreg1, xreg2
        stp     \xreg1, \xreg2, [sp, #-16]!
        .endm

        .macro  pop, xreg1, xreg2
        ldp     \xreg1, \xreg2, [sp], #16
        .endm

/*
 * Enable and disable interrupts.
 */
        .macro  disable_irq
        msr     daifset, #2
        .endm

        .macro  enable_irq
        msr     daifclr, #2
        .endm

/*
 * Enable and disable debug exceptions.
 */
        .macro  disable_dbg
        msr     daifset, #8
        .endm

        .macro  enable_dbg
        msr     daifclr, #8
        .endm

        .macro  disable_step_tsk, flgs, tmp
        tbz     \flgs, #TIF_SINGLESTEP, 9990f
        mrs     \tmp, mdscr_el1
        bic     \tmp, \tmp, #1
        msr     mdscr_el1, \tmp
        isb     // Synchronise with enable_dbg
9990:
        .endm

        .macro  enable_step_tsk, flgs, tmp
        tbz     \flgs, #TIF_SINGLESTEP, 9990f
        disable_dbg
        mrs     \tmp, mdscr_el1
        orr     \tmp, \tmp, #1
        msr     mdscr_el1, \tmp
9990:
        .endm

/*
 * Enable both debug exceptions and interrupts. This is likely to be
 * faster than two daifclr operations, since writes to this register
 * are self-synchronising.
 */
        .macro  enable_dbg_and_irq
        msr     daifclr, #(8 | 2)
        .endm

/*
 * SMP data memory barrier
 */
        .macro  smp_dmb, opt
        dmb     \opt
        .endm

/*
 * Emit an entry into the exception table
 */
        .macro          _asm_extable, from, to
        .pushsection    __ex_table, "a"
        .align          3
        .long           (\from - .), (\to - .)
        .popsection
        .endm

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

/*
 * Register aliases.
 */
lr      .req    x30             // link register

/*
 * Vector entry
 */
         .macro ventry  label
        .align  7
        b       \label
        .endm

/*
 * Select code when configured for BE.
 */
#ifdef CONFIG_CPU_BIG_ENDIAN
#define CPU_BE(code...) code
#else
#define CPU_BE(code...)
#endif

/*
 * Select code when configured for LE.
 */
#ifdef CONFIG_CPU_BIG_ENDIAN
#define CPU_LE(code...)
#else
#define CPU_LE(code...) code
#endif

/*
 * Define a macro that constructs a 64-bit value by concatenating two
 * 32-bit registers. Note that on big endian systems the order of the
 * registers is swapped.
 */
#ifndef CONFIG_CPU_BIG_ENDIAN
        .macro  regs_to_64, rd, lbits, hbits
#else
        .macro  regs_to_64, rd, hbits, lbits
#endif
        orr     \rd, \lbits, \hbits, lsl #32
        .endm

/*
 * Pseudo-ops for PC-relative adr/ldr/str <reg>, <symbol> where
 * <symbol> is within the range +/- 4 GB of the PC.
 */
        /*
         * @dst: destination register (64 bit wide)
         * @sym: name of the symbol
         * @tmp: optional scratch register to be used if <dst> == sp, which
         *       is not allowed in an adrp instruction
         */
        .macro  adr_l, dst, sym, tmp=
        .ifb    \tmp
        adrp    \dst, \sym
        add     \dst, \dst, :lo12:\sym
        .else
        adrp    \tmp, \sym
        add     \dst, \tmp, :lo12:\sym
        .endif
        .endm

        /*
         * @dst: destination register (32 or 64 bit wide)
         * @sym: name of the symbol
         * @tmp: optional 64-bit scratch register to be used if <dst> is a
         *       32-bit wide register, in which case it cannot be used to hold
         *       the address
         */
        .macro  ldr_l, dst, sym, tmp=
        .ifb    \tmp
        adrp    \dst, \sym
        ldr     \dst, [\dst, :lo12:\sym]
        .else
        adrp    \tmp, \sym
        ldr     \dst, [\tmp, :lo12:\sym]
        .endif
        .endm

        /*
         * @src: source register (32 or 64 bit wide)
         * @sym: name of the symbol
         * @tmp: mandatory 64-bit scratch register to calculate the address
         *       while <src> needs to be preserved.
         */
        .macro  str_l, src, sym, tmp
        adrp    \tmp, \sym
        str     \src, [\tmp, :lo12:\sym]
        .endm

        /*
         * @sym: The name of the per-cpu variable
         * @reg: Result of per_cpu(sym, smp_processor_id())
         * @tmp: scratch register
         */
        .macro this_cpu_ptr, sym, reg, tmp
        adr_l   \reg, \sym
        mrs     \tmp, tpidr_el1
        add     \reg, \reg, \tmp
        .endm

/*
 * Annotate a function as position independent, i.e., safe to be called before
 * the kernel virtual mapping is activated.
 */
#define ENDPIPROC(x)                    \
        .globl  __pi_##x;               \
        .type   __pi_##x, %function;    \
        .set    __pi_##x, x;            \
        .size   __pi_##x, . - x;        \
        ENDPROC(x)

        /*
         * Emit a 64-bit absolute little endian symbol reference in a way that
         * ensures that it will be resolved at build time, even when building a
         * PIE binary. This requires cooperation from the linker script, which
         * must emit the lo32/hi32 halves individually.
         */
        .macro  le64sym, sym
        .long   \sym\()_lo32
        .long   \sym\()_hi32
        .endm

#endif  /* __ASM_ASSEMBLER_H */