copypage-xsc3.c

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/*
 *  linux/arch/arm/mm/copypage-xsc3.S
 *
 *  Copyright (C) 2004 Intel Corp.
 *
 * 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.
 *
 * Adapted for 3rd gen XScale core, no more mini-dcache
 * Author: Matt Gilbert ([email protected])
 */
#include <linux/init.h>
#include <linux/highmem.h>

/*
 * General note:
 *  We don't really want write-allocate cache behaviour for these functions
 *  since that will just eat through 8K of the cache.
 */

/*
 * XSC3 optimised copy_user_highpage
 *  r0 = destination
 *  r1 = source
 *
 * The source page may have some clean entries in the cache already, but we
 * can safely ignore them - break_cow() will flush them out of the cache
 * if we eventually end up using our copied page.
 *
 */
static void __naked
xsc3_mc_copy_user_page(void *kto, const void *kfrom)
{
    asm("\
    stmfd   sp!, {r4, r5, lr}       \n\
    mov lr, %2              \n\
                        \n\
    pld [r1, #0]            \n\
    pld [r1, #32]           \n\
1:  pld [r1, #64]           \n\
    pld [r1, #96]           \n\
                        \n\
2:  ldrd    r2, [r1], #8            \n\
    mov ip, r0              \n\
    ldrd    r4, [r1], #8            \n\
    mcr p15, 0, ip, c7, c6, 1       @ invalidate\n\
    strd    r2, [r0], #8            \n\
    ldrd    r2, [r1], #8            \n\
    strd    r4, [r0], #8            \n\
    ldrd    r4, [r1], #8            \n\
    strd    r2, [r0], #8            \n\
    strd    r4, [r0], #8            \n\
    ldrd    r2, [r1], #8            \n\
    mov ip, r0              \n\
    ldrd    r4, [r1], #8            \n\
    mcr p15, 0, ip, c7, c6, 1       @ invalidate\n\
    strd    r2, [r0], #8            \n\
    ldrd    r2, [r1], #8            \n\
    subs    lr, lr, #1          \n\
    strd    r4, [r0], #8            \n\
    ldrd    r4, [r1], #8            \n\
    strd    r2, [r0], #8            \n\
    strd    r4, [r0], #8            \n\
    bgt 1b              \n\
    beq 2b              \n\
                        \n\
    ldmfd   sp!, {r4, r5, pc}"
    :
    : "r" (kto), "r" (kfrom), "I" (PAGE_SIZE / 64 - 1));
}

void xsc3_mc_copy_user_highpage(struct page *to, struct page *from,
    unsigned long vaddr, struct vm_area_struct *vma)
{
    void *kto, *kfrom;

    kto = kmap_atomic(to);
    kfrom = kmap_atomic(from);
    flush_cache_page(vma, vaddr, page_to_pfn(from));
    xsc3_mc_copy_user_page(kto, kfrom);
    kunmap_atomic(kfrom);
    kunmap_atomic(kto);
}

/*
 * XScale optimised clear_user_page
 *  r0 = destination
 *  r1 = virtual user address of ultimate destination page
 */
void xsc3_mc_clear_user_highpage(struct page *page, unsigned long vaddr)
{
    void *ptr, *kaddr = kmap_atomic(page);
    asm volatile ("\
    mov r1, %2              \n\
    mov r2, #0              \n\
    mov r3, #0              \n\
1:  mcr p15, 0, %0, c7, c6, 1       @ invalidate line\n\
    strd    r2, [%0], #8            \n\
    strd    r2, [%0], #8            \n\
    strd    r2, [%0], #8            \n\
    strd    r2, [%0], #8            \n\
    subs    r1, r1, #1          \n\
    bne 1b"
    : "=r" (ptr)
    : "0" (kaddr), "I" (PAGE_SIZE / 32)
    : "r1", "r2", "r3");
    kunmap_atomic(kaddr);
}

struct cpu_user_fns xsc3_mc_user_fns __initdata = {
    .cpu_clear_user_highpage = xsc3_mc_clear_user_highpage,
    .cpu_copy_user_highpage = xsc3_mc_copy_user_highpage,
};