LXR linux/arch/arm/mm/copypage-v4wt.c

   1/*
   2 *  linux/arch/arm/mm/copypage-v4wt.S
   3 *
   4 *  Copyright (C) 1995-1999 Russell King
   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 *  This is for CPUs with a writethrough cache and 'flush ID cache' is
  11 *  the only supported cache operation.
  12 */
  13#include <linux/init.h>
  14#include <linux/highmem.h>
  15
  16/*
  17 * ARMv4 optimised copy_user_highpage
  18 *
  19 * Since we have writethrough caches, we don't have to worry about
  20 * dirty data in the cache.  However, we do have to ensure that
  21 * subsequent reads are up to date.
  22 */
  23static void __naked
  24v4wt_copy_user_page(void *kto, const void *kfrom)
  25{
  26        asm("\
  27        stmfd   sp!, {r4, lr}                   @ 2\n\
  28        mov     r2, %2                          @ 1\n\
  29        ldmia   r1!, {r3, r4, ip, lr}           @ 4\n\
  301:      stmia   r0!, {r3, r4, ip, lr}           @ 4\n\
  31        ldmia   r1!, {r3, r4, ip, lr}           @ 4+1\n\
  32        stmia   r0!, {r3, r4, ip, lr}           @ 4\n\
  33        ldmia   r1!, {r3, r4, ip, lr}           @ 4\n\
  34        stmia   r0!, {r3, r4, ip, lr}           @ 4\n\
  35        ldmia   r1!, {r3, r4, ip, lr}           @ 4\n\
  36        subs    r2, r2, #1                      @ 1\n\
  37        stmia   r0!, {r3, r4, ip, lr}           @ 4\n\
  38        ldmneia r1!, {r3, r4, ip, lr}           @ 4\n\
  39        bne     1b                              @ 1\n\
  40        mcr     p15, 0, r2, c7, c7, 0           @ flush ID cache\n\
  41        ldmfd   sp!, {r4, pc}                   @ 3"
  42        :
  43        : "r" (kto), "r" (kfrom), "I" (PAGE_SIZE / 64));
  44}
  45
  46void v4wt_copy_user_highpage(struct page *to, struct page *from,
  47        unsigned long vaddr, struct vm_area_struct *vma)
  48{
  49        void *kto, *kfrom;
  50
  51        kto = kmap_atomic(to);
  52        kfrom = kmap_atomic(from);
  53        v4wt_copy_user_page(kto, kfrom);
  54        kunmap_atomic(kfrom);
  55        kunmap_atomic(kto);
  56}
  57
  58/*
  59 * ARMv4 optimised clear_user_page
  60 *
  61 * Same story as above.
  62 */
  63void v4wt_clear_user_highpage(struct page *page, unsigned long vaddr)
  64{
  65        void *ptr, *kaddr = kmap_atomic(page);
  66        asm volatile("\
  67        mov     r1, %2                          @ 1\n\
  68        mov     r2, #0                          @ 1\n\
  69        mov     r3, #0                          @ 1\n\
  70        mov     ip, #0                          @ 1\n\
  71        mov     lr, #0                          @ 1\n\
  721:      stmia   %0!, {r2, r3, ip, lr}           @ 4\n\
  73        stmia   %0!, {r2, r3, ip, lr}           @ 4\n\
  74        stmia   %0!, {r2, r3, ip, lr}           @ 4\n\
  75        stmia   %0!, {r2, r3, ip, lr}           @ 4\n\
  76        subs    r1, r1, #1                      @ 1\n\
  77        bne     1b                              @ 1\n\
  78        mcr     p15, 0, r2, c7, c7, 0           @ flush ID cache"
  79        : "=r" (ptr)
  80        : "0" (kaddr), "I" (PAGE_SIZE / 64)
  81        : "r1", "r2", "r3", "ip", "lr");
  82        kunmap_atomic(kaddr);
  83}
  84
  85struct cpu_user_fns v4wt_user_fns __initdata = {
  86        .cpu_clear_user_highpage = v4wt_clear_user_highpage,
  87        .cpu_copy_user_highpage = v4wt_copy_user_highpage,
  88};
  89