arch/arm/mm/copypage-xsc3.c

   1 /*
   2  *  linux/arch/arm/mm/copypage-xsc3.S
   3  *
   4  *  Copyright (C) 2004 Intel Corp.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * Adapted for 3rd gen XScale core, no more mini-dcache
  11  * Author: Matt Gilbert (matthew.m.gilbert@intel.com)
  12  */
  13 #include <linux/init.h>
  14 #include <linux/highmem.h>
  15
  16 /*
  17  * General note:
  18  *  We don't really want write-allocate cache behaviour for these functions
  19  *  since that will just eat through 8K of the cache.
  20  */
  21
  22 /*
  23  * XSC3 optimised copy_user_highpage
  24  *  r0 = destination
  25  *  r1 = source
  26  *
  27  * The source page may have some clean entries in the cache already, but we
  28  * can safely ignore them - break_cow() will flush them out of the cache
  29  * if we eventually end up using our copied page.
  30  *
  31  */
  32 static void __naked
  33 xsc3_mc_copy_user_page(void *kto, const void *kfrom)
  34 {
  35         asm("\
  36         stmfd   sp!, {r4, r5, lr}               \n\
  37         mov     lr, %0                          \n\
  38                                                 \n\
  39         pld     [r1, #0]                        \n\
  40         pld     [r1, #32]                       \n\
  41 1:      pld     [r1, #64]                       \n\
  42         pld     [r1, #96]                       \n\
  43                                                 \n\
  44 2:      ldrd    r2, [r1], #8                    \n\
  45         mov     ip, r0                          \n\
  46         ldrd    r4, [r1], #8                    \n\
  47         mcr     p15, 0, ip, c7, c6, 1           @ invalidate\n\
  48         strd    r2, [r0], #8                    \n\
  49         ldrd    r2, [r1], #8                    \n\
  50         strd    r4, [r0], #8                    \n\
  51         ldrd    r4, [r1], #8                    \n\
  52         strd    r2, [r0], #8                    \n\
  53         strd    r4, [r0], #8                    \n\
  54         ldrd    r2, [r1], #8                    \n\
  55         mov     ip, r0                          \n\
  56         ldrd    r4, [r1], #8                    \n\
  57         mcr     p15, 0, ip, c7, c6, 1           @ invalidate\n\
  58         strd    r2, [r0], #8                    \n\
  59         ldrd    r2, [r1], #8                    \n\
  60         subs    lr, lr, #1                      \n\
  61         strd    r4, [r0], #8                    \n\
  62         ldrd    r4, [r1], #8                    \n\
  63         strd    r2, [r0], #8                    \n\
  64         strd    r4, [r0], #8                    \n\
  65         bgt     1b                              \n\
  66         beq     2b                              \n\
  67                                                 \n\
  68         ldmfd   sp!, {r4, r5, pc}"
  69         :
  70         : "I" (PAGE_SIZE / 64 - 1));
  71 }
  72
  73 void xsc3_mc_copy_user_highpage(struct page *to, struct page *from,
  74         unsigned long vaddr)
  75 {
  76         void *kto, *kfrom;
  77
  78         kto = kmap_atomic(to, KM_USER0);
  79         kfrom = kmap_atomic(from, KM_USER1);
  80         xsc3_mc_copy_user_page(kto, kfrom);
  81         kunmap_atomic(kfrom, KM_USER1);
  82         kunmap_atomic(kto, KM_USER0);
  83 }
  84
  85 /*
  86  * XScale optimised clear_user_page
  87  *  r0 = destination
  88  *  r1 = virtual user address of ultimate destination page
  89  */
  90 void xsc3_mc_clear_user_highpage(struct page *page, unsigned long vaddr)
  91 {
  92         void *ptr, *kaddr = kmap_atomic(page, KM_USER0);
  93         asm volatile ("\
  94         mov     r1, %2                          \n\
  95         mov     r2, #0                          \n\
  96         mov     r3, #0                          \n\
  97 1:      mcr     p15, 0, %0, c7, c6, 1           @ invalidate line\n\
  98         strd    r2, [%0], #8                    \n\
  99         strd    r2, [%0], #8                    \n\
 100         strd    r2, [%0], #8                    \n\
 101         strd    r2, [%0], #8                    \n\
 102         subs    r1, r1, #1                      \n\
 103         bne     1b"
 104         : "=r" (ptr)
 105         : "0" (kaddr), "I" (PAGE_SIZE / 32)
 106         : "r1", "r2", "r3");
 107         kunmap_atomic(kaddr, KM_USER0);
 108 }
 109
 110 struct cpu_user_fns xsc3_mc_user_fns __initdata = {
 111         .cpu_clear_user_highpage = xsc3_mc_clear_user_highpage,
 112         .cpu_copy_user_highpage = xsc3_mc_copy_user_highpage,
 113 };