/*
 * Based on arch/arm/include/asm/assembler.h, arch/arm/mm/proc-macros.S
 *
 * 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/asm-offsets.h>
#include <asm/cpufeature.h>
#include <asm/debug-monitors.h>
#include <asm/page.h>
#include <asm/pgtable-hwdef.h>
#include <asm/ptrace.h>
#include <asm/thread_info.h>

        .macro save_and_disable_daif, flags
        mrs     \flags, daif
        msr     daifset, #0xf
        .endm

        .macro disable_daif
        msr     daifset, #0xf
        .endm

        .macro enable_daif
        msr     daifclr, #0xf
        .endm

        .macro  restore_daif, flags:req
        msr     daif, \flags
        .endm

        /* Only on aarch64 pstate, PSR_D_BIT is different for aarch32 */
        .macro  inherit_daif, pstate:req, tmp:req
        and     \tmp, \pstate, #(PSR_D_BIT | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT)
        msr     daif, \tmp
        .endm

        /* IRQ is the lowest priority flag, unconditionally unmask the rest. */
        .macro enable_da_f
        msr     daifclr, #(8 | 4 | 1)
        .endm

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

        .macro  enable_irq
        msr     daifclr, #2
        .endm

        .macro  save_and_disable_irq, flags
        mrs     \flags, daif
        msr     daifset, #2
        .endm

        .macro  restore_irq, flags
        msr     daif, \flags
        .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, #DBG_MDSCR_SS
        msr     mdscr_el1, \tmp
        isb     // Synchronise with enable_dbg
9990:
        .endm

        /* call with daif masked */
        .macro  enable_step_tsk, flgs, tmp
        tbz     \flgs, #TIF_SINGLESTEP, 9990f
        mrs     \tmp, mdscr_el1
        orr     \tmp, \tmp, #DBG_MDSCR_SS
        msr     mdscr_el1, \tmp
9990:
        .endm

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

/*
 * RAS Error Synchronization barrier
 */
        .macro  esb
        hint    #16
        .endm

/*
 * Value prediction barrier
 */
        .macro  csdb
        hint    #20
        .endm

/*
 * Sanitise a 64-bit bounded index wrt speculation, returning zero if out
 * of bounds.
 */
        .macro  mask_nospec64, idx, limit, tmp
        sub     \tmp, \idx, \limit
        bic     \tmp, \tmp, \idx
        and     \idx, \idx, \tmp, asr #63
        csdb
        .endm

/*
 * NOP sequence
 */
        .macro  nops, num
        .rept   \num
        nop
        .endr
        .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
         */
        .macro  adr_l, dst, sym
        adrp    \dst, \sym
        add     \dst, \dst, :lo12:\sym
        .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

        /*
         * @dst: Result of per_cpu(sym, smp_processor_id()) (can be SP)
         * @sym: The name of the per-cpu variable
         * @tmp: scratch register
         */
        .macro adr_this_cpu, dst, sym, tmp
        adrp    \tmp, \sym
        add     \dst, \tmp, #:lo12:\sym
alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
        mrs     \tmp, tpidr_el1
alternative_else
        mrs     \tmp, tpidr_el2
alternative_endif
        add     \dst, \dst, \tmp
        .endm

        /*
         * @dst: Result of READ_ONCE(per_cpu(sym, smp_processor_id()))
         * @sym: The name of the per-cpu variable
         * @tmp: scratch register
         */
        .macro ldr_this_cpu dst, sym, tmp
        adr_l   \dst, \sym
alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
        mrs     \tmp, tpidr_el1
alternative_else
        mrs     \tmp, tpidr_el2
alternative_endif
        ldr     \dst, [\dst, \tmp]
        .endm

/*
 * vma_vm_mm - get mm pointer from vma pointer (vma->vm_mm)
 */
        .macro  vma_vm_mm, rd, rn
        ldr     \rd, [\rn, #VMA_VM_MM]
        .endm

/*
 * mmid - get context id from mm pointer (mm->context.id)
 */
        .macro  mmid, rd, rn
        ldr     \rd, [\rn, #MM_CONTEXT_ID]
        .endm
/*
 * read_ctr - read CTR_EL0. If the system has mismatched
 * cache line sizes, provide the system wide safe value
 * from arm64_ftr_reg_ctrel0.sys_val
 */
        .macro  read_ctr, reg
alternative_if_not ARM64_MISMATCHED_CACHE_LINE_SIZE
        mrs     \reg, ctr_el0                   // read CTR
        nop
alternative_else
        ldr_l   \reg, arm64_ftr_reg_ctrel0 + ARM64_FTR_SYSVAL
alternative_endif
        .endm


/*
 * raw_dcache_line_size - get the minimum D-cache line size on this CPU
 * from the CTR register.
 */
        .macro  raw_dcache_line_size, reg, tmp
        mrs     \tmp, ctr_el0                   // read CTR
        ubfm    \tmp, \tmp, #16, #19            // cache line size encoding
        mov     \reg, #4                        // bytes per word
        lsl     \reg, \reg, \tmp                // actual cache line size
        .endm

/*
 * dcache_line_size - get the safe D-cache line size across all CPUs
 */
        .macro  dcache_line_size, reg, tmp
        read_ctr        \tmp
        ubfm            \tmp, \tmp, #16, #19    // cache line size encoding
        mov             \reg, #4                // bytes per word
        lsl             \reg, \reg, \tmp        // actual cache line size
        .endm

/*
 * raw_icache_line_size - get the minimum I-cache line size on this CPU
 * from the CTR register.
 */
        .macro  raw_icache_line_size, reg, tmp
        mrs     \tmp, ctr_el0                   // read CTR
        and     \tmp, \tmp, #0xf                // cache line size encoding
        mov     \reg, #4                        // bytes per word
        lsl     \reg, \reg, \tmp                // actual cache line size
        .endm

/*
 * icache_line_size - get the safe I-cache line size across all CPUs
 */
        .macro  icache_line_size, reg, tmp
        read_ctr        \tmp
        and             \tmp, \tmp, #0xf        // cache line size encoding
        mov             \reg, #4                // bytes per word
        lsl             \reg, \reg, \tmp        // actual cache line size
        .endm

/*
 * tcr_set_idmap_t0sz - update TCR.T0SZ so that we can load the ID map
 */
        .macro  tcr_set_idmap_t0sz, valreg, tmpreg
        ldr_l   \tmpreg, idmap_t0sz
        bfi     \valreg, \tmpreg, #TCR_T0SZ_OFFSET, #TCR_TxSZ_WIDTH
        .endm

/*
 * tcr_compute_pa_size - set TCR.(I)PS to the highest supported
 * ID_AA64MMFR0_EL1.PARange value
 *
 *      tcr:            register with the TCR_ELx value to be updated
 *      pos:            IPS or PS bitfield position
 *      tmp{0,1}:       temporary registers
 */
        .macro  tcr_compute_pa_size, tcr, pos, tmp0, tmp1
        mrs     \tmp0, ID_AA64MMFR0_EL1
        // Narrow PARange to fit the PS field in TCR_ELx
        ubfx    \tmp0, \tmp0, #ID_AA64MMFR0_PARANGE_SHIFT, #3
        mov     \tmp1, #ID_AA64MMFR0_PARANGE_MAX
        cmp     \tmp0, \tmp1
        csel    \tmp0, \tmp1, \tmp0, hi
        bfi     \tcr, \tmp0, \pos, #3
        .endm

/*
 * Macro to perform a data cache maintenance for the interval
 * [kaddr, kaddr + size)
 *
 *      op:             operation passed to dc instruction
 *      domain:         domain used in dsb instruciton
 *      kaddr:          starting virtual address of the region
 *      size:           size of the region
 *      Corrupts:       kaddr, size, tmp1, tmp2
 */
        .macro dcache_by_line_op op, domain, kaddr, size, tmp1, tmp2
        dcache_line_size \tmp1, \tmp2
        add     \size, \kaddr, \size
        sub     \tmp2, \tmp1, #1
        bic     \kaddr, \kaddr, \tmp2
9998:
        .if     (\op == cvau || \op == cvac)
alternative_if_not ARM64_WORKAROUND_CLEAN_CACHE
        dc      \op, \kaddr
alternative_else
        dc      civac, \kaddr
alternative_endif
        .elseif (\op == cvap)
alternative_if ARM64_HAS_DCPOP
        sys 3, c7, c12, 1, \kaddr       // dc cvap
alternative_else
        dc      cvac, \kaddr
alternative_endif
        .else
        dc      \op, \kaddr
        .endif
        add     \kaddr, \kaddr, \tmp1
        cmp     \kaddr, \size
        b.lo    9998b
        dsb     \domain
        .endm

/*
 * Macro to perform an instruction cache maintenance for the interval
 * [start, end)
 *
 *      start, end:     virtual addresses describing the region
 *      label:          A label to branch to on user fault.
 *      Corrupts:       tmp1, tmp2
 */
        .macro invalidate_icache_by_line start, end, tmp1, tmp2, label
        icache_line_size \tmp1, \tmp2
        sub     \tmp2, \tmp1, #1
        bic     \tmp2, \start, \tmp2
9997:
USER(\label, ic ivau, \tmp2)                    // invalidate I line PoU
        add     \tmp2, \tmp2, \tmp1
        cmp     \tmp2, \end
        b.lo    9997b
        dsb     ish
        isb
        .endm

/*
 * reset_pmuserenr_el0 - reset PMUSERENR_EL0 if PMUv3 present
 */
        .macro  reset_pmuserenr_el0, tmpreg
        mrs     \tmpreg, id_aa64dfr0_el1        // Check ID_AA64DFR0_EL1 PMUVer
        sbfx    \tmpreg, \tmpreg, #8, #4
        cmp     \tmpreg, #1                     // Skip if no PMU present
        b.lt    9000f
        msr     pmuserenr_el0, xzr              // Disable PMU access from EL0
9000:
        .endm

/*
 * copy_page - copy src to dest using temp registers t1-t8
 */
        .macro copy_page dest:req src:req t1:req t2:req t3:req t4:req t5:req t6:req t7:req t8:req
9998:   ldp     \t1, \t2, [\src]
        ldp     \t3, \t4, [\src, #16]
        ldp     \t5, \t6, [\src, #32]
        ldp     \t7, \t8, [\src, #48]
        add     \src, \src, #64
        stnp    \t1, \t2, [\dest]
        stnp    \t3, \t4, [\dest, #16]
        stnp    \t5, \t6, [\dest, #32]
        stnp    \t7, \t8, [\dest, #48]
        add     \dest, \dest, #64
        tst     \src, #(PAGE_SIZE - 1)
        b.ne    9998b
        .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)

/*
 * Annotate a function as being unsuitable for kprobes.
 */
#ifdef CONFIG_KPROBES
#define NOKPROBE(x)                             \
        .pushsection "_kprobe_blacklist", "aw"; \
        .quad   x;                              \
        .popsection;
#else
#define NOKPROBE(x)
#endif
        /*
         * 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

        /*
         * mov_q - move an immediate constant into a 64-bit register using
         *         between 2 and 4 movz/movk instructions (depending on the
         *         magnitude and sign of the operand)
         */
        .macro  mov_q, reg, val
        .if (((\val) >> 31) == 0 || ((\val) >> 31) == 0x1ffffffff)
        movz    \reg, :abs_g1_s:\val
        .else
        .if (((\val) >> 47) == 0 || ((\val) >> 47) == 0x1ffff)
        movz    \reg, :abs_g2_s:\val
        .else
        movz    \reg, :abs_g3:\val
        movk    \reg, :abs_g2_nc:\val
        .endif
        movk    \reg, :abs_g1_nc:\val
        .endif
        movk    \reg, :abs_g0_nc:\val
        .endm

/*
 * Return the current thread_info.
 */
        .macro  get_thread_info, rd
        mrs     \rd, sp_el0
        .endm

/*
 * Arrange a physical address in a TTBR register, taking care of 52-bit
 * addresses.
 *
 *      phys:   physical address, preserved
 *      ttbr:   returns the TTBR value
 */
        .macro  phys_to_ttbr, ttbr, phys
#ifdef CONFIG_ARM64_PA_BITS_52
        orr     \ttbr, \phys, \phys, lsr #46
        and     \ttbr, \ttbr, #TTBR_BADDR_MASK_52
#else
        mov     \ttbr, \phys
#endif
        .endm

        .macro  phys_to_pte, pte, phys
#ifdef CONFIG_ARM64_PA_BITS_52
        /*
         * We assume \phys is 64K aligned and this is guaranteed by only
         * supporting this configuration with 64K pages.
         */
        orr     \pte, \phys, \phys, lsr #36
        and     \pte, \pte, #PTE_ADDR_MASK
#else
        mov     \pte, \phys
#endif
        .endm

        .macro  pte_to_phys, phys, pte
#ifdef CONFIG_ARM64_PA_BITS_52
        ubfiz   \phys, \pte, #(48 - 16 - 12), #16
        bfxil   \phys, \pte, #16, #32
        lsl     \phys, \phys, #16
#else
        and     \phys, \pte, #PTE_ADDR_MASK
#endif
        .endm

/**
 * Errata workaround prior to disable MMU. Insert an ISB immediately prior
 * to executing the MSR that will change SCTLR_ELn[M] from a value of 1 to 0.
 */
        .macro pre_disable_mmu_workaround
#ifdef CONFIG_QCOM_FALKOR_ERRATUM_E1041
        isb
#endif
        .endm

        /*
         * frame_push - Push @regcount callee saved registers to the stack,
         *              starting at x19, as well as x29/x30, and set x29 to
         *              the new value of sp. Add @extra bytes of stack space
         *              for locals.
         */
        .macro          frame_push, regcount:req, extra
        __frame         st, \regcount, \extra
        .endm

        /*
         * frame_pop  - Pop the callee saved registers from the stack that were
         *              pushed in the most recent call to frame_push, as well
         *              as x29/x30 and any extra stack space that may have been
         *              allocated.
         */
        .macro          frame_pop
        __frame         ld
        .endm

        .macro          __frame_regs, reg1, reg2, op, num
        .if             .Lframe_regcount == \num
        \op\()r         \reg1, [sp, #(\num + 1) * 8]
        .elseif         .Lframe_regcount > \num
        \op\()p         \reg1, \reg2, [sp, #(\num + 1) * 8]
        .endif
        .endm

        .macro          __frame, op, regcount, extra=0
        .ifc            \op, st
        .if             (\regcount) < 0 || (\regcount) > 10
        .error          "regcount should be in the range [0 ... 10]"
        .endif
        .if             ((\extra) % 16) != 0
        .error          "extra should be a multiple of 16 bytes"
        .endif
        .ifdef          .Lframe_regcount
        .if             .Lframe_regcount != -1
        .error          "frame_push/frame_pop may not be nested"
        .endif
        .endif
        .set            .Lframe_regcount, \regcount
        .set            .Lframe_extra, \extra
        .set            .Lframe_local_offset, ((\regcount + 3) / 2) * 16
        stp             x29, x30, [sp, #-.Lframe_local_offset - .Lframe_extra]!
        mov             x29, sp
        .endif

        __frame_regs    x19, x20, \op, 1
        __frame_regs    x21, x22, \op, 3
        __frame_regs    x23, x24, \op, 5
        __frame_regs    x25, x26, \op, 7
        __frame_regs    x27, x28, \op, 9

        .ifc            \op, ld
        .if             .Lframe_regcount == -1
        .error          "frame_push/frame_pop may not be nested"
        .endif
        ldp             x29, x30, [sp], #.Lframe_local_offset + .Lframe_extra
        .set            .Lframe_regcount, -1
        .endif
        .endm

/*
 * Check whether to yield to another runnable task from kernel mode NEON code
 * (which runs with preemption disabled).
 *
 * if_will_cond_yield_neon
 *        // pre-yield patchup code
 * do_cond_yield_neon
 *        // post-yield patchup code
 * endif_yield_neon    <label>
 *
 * where <label> is optional, and marks the point where execution will resume
 * after a yield has been performed. If omitted, execution resumes right after
 * the endif_yield_neon invocation. Note that the entire sequence, including
 * the provided patchup code, will be omitted from the image if CONFIG_PREEMPT
 * is not defined.
 *
 * As a convenience, in the case where no patchup code is required, the above
 * sequence may be abbreviated to
 *
 * cond_yield_neon <label>
 *
 * Note that the patchup code does not support assembler directives that change
 * the output section, any use of such directives is undefined.
 *
 * The yield itself consists of the following:
 * - Check whether the preempt count is exactly 1, in which case disabling
 *   preemption once will make the task preemptible. If this is not the case,
 *   yielding is pointless.
 * - Check whether TIF_NEED_RESCHED is set, and if so, disable and re-enable
 *   kernel mode NEON (which will trigger a reschedule), and branch to the
 *   yield fixup code.
 *
 * This macro sequence may clobber all CPU state that is not guaranteed by the
 * AAPCS to be preserved across an ordinary function call.
 */

        .macro          cond_yield_neon, lbl
        if_will_cond_yield_neon
        do_cond_yield_neon
        endif_yield_neon        \lbl
        .endm

        .macro          if_will_cond_yield_neon
#ifdef CONFIG_PREEMPT
        get_thread_info x0
        ldr             w1, [x0, #TSK_TI_PREEMPT]
        ldr             x0, [x0, #TSK_TI_FLAGS]
        cmp             w1, #PREEMPT_DISABLE_OFFSET
        csel            x0, x0, xzr, eq
        tbnz            x0, #TIF_NEED_RESCHED, .Lyield_\@       // needs rescheduling?
        /* fall through to endif_yield_neon */
        .subsection     1
.Lyield_\@ :
#else
        .section        ".discard.cond_yield_neon", "ax"
#endif
        .endm

        .macro          do_cond_yield_neon
        bl              kernel_neon_end
        bl              kernel_neon_begin
        .endm

        .macro          endif_yield_neon, lbl
        .ifnb           \lbl
        b               \lbl
        .else
        b               .Lyield_out_\@
        .endif
        .previous
.Lyield_out_\@ :
        .endm

#endif  /* __ASM_ASSEMBLER_H */