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copypage-xsc3.c

/*
 *  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 (matthew.m.gilbert@intel.com)
 */
#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, %0                        \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}"
      :
      : "I" (PAGE_SIZE / 64 - 1));
}

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

      kto = kmap_atomic(to, KM_USER0);
      kfrom = kmap_atomic(from, KM_USER1);
      xsc3_mc_copy_user_page(kto, kfrom);
      kunmap_atomic(kfrom, KM_USER1);
      kunmap_atomic(kto, KM_USER0);
}

/*
 * 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, KM_USER0);
      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, KM_USER0);
}

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,
};

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