arch/arm64/lib/copy_page.S

   1 /*
   2  * Copyright (C) 2012 ARM Ltd.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15  */
  16
  17 #include <linux/linkage.h>
  18 #include <linux/const.h>
  19 #include <asm/assembler.h>
  20 #include <asm/page.h>
  21 #include <asm/cpufeature.h>
  22 #include <asm/alternative.h>
  23
  24 /*
  25  * Copy a page from src to dest (both are page aligned)
  26  *
  27  * Parameters:
  28  *      x0 - dest
  29  *      x1 - src
  30  */
  31 ENTRY(copy_page)
  32 alternative_if_not ARM64_HAS_NO_HW_PREFETCH
  33         nop
  34         nop
  35 alternative_else
  36         # Prefetch two cache lines ahead.
  37         prfm    pldl1strm, [x1, #128]
  38         prfm    pldl1strm, [x1, #256]
  39 alternative_endif
  40
  41         ldp     x2, x3, [x1]
  42         ldp     x4, x5, [x1, #16]
  43         ldp     x6, x7, [x1, #32]
  44         ldp     x8, x9, [x1, #48]
  45         ldp     x10, x11, [x1, #64]
  46         ldp     x12, x13, [x1, #80]
  47         ldp     x14, x15, [x1, #96]
  48         ldp     x16, x17, [x1, #112]
  49
  50         mov     x18, #(PAGE_SIZE - 128)
  51         add     x1, x1, #128
  52 1:
  53         subs    x18, x18, #128
  54
  55 alternative_if_not ARM64_HAS_NO_HW_PREFETCH
  56         nop
  57 alternative_else
  58         prfm    pldl1strm, [x1, #384]
  59 alternative_endif
  60
  61         stnp    x2, x3, [x0]
  62         ldp     x2, x3, [x1]
  63         stnp    x4, x5, [x0, #16]
  64         ldp     x4, x5, [x1, #16]
  65         stnp    x6, x7, [x0, #32]
  66         ldp     x6, x7, [x1, #32]
  67         stnp    x8, x9, [x0, #48]
  68         ldp     x8, x9, [x1, #48]
  69         stnp    x10, x11, [x0, #64]
  70         ldp     x10, x11, [x1, #64]
  71         stnp    x12, x13, [x0, #80]
  72         ldp     x12, x13, [x1, #80]
  73         stnp    x14, x15, [x0, #96]
  74         ldp     x14, x15, [x1, #96]
  75         stnp    x16, x17, [x0, #112]
  76         ldp     x16, x17, [x1, #112]
  77
  78         add     x0, x0, #128
  79         add     x1, x1, #128
  80
  81         b.gt    1b
  82
  83         stnp    x2, x3, [x0]
  84         stnp    x4, x5, [x0, #16]
  85         stnp    x6, x7, [x0, #32]
  86         stnp    x8, x9, [x0, #48]
  87         stnp    x10, x11, [x0, #64]
  88         stnp    x12, x13, [x0, #80]
  89         stnp    x14, x15, [x0, #96]
  90         stnp    x16, x17, [x0, #112]
  91
  92         ret
  93 ENDPROC(copy_page)