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 */ 23 static void v4wt_copy_user_page(void *kto, const void *kfrom) 24 { 25 int tmp; 26 27 asm volatile ("\ 28 ldmia %1!, {r3, r4, ip, lr} @ 4\n\ 29 1: stmia %0!, {r3, r4, ip, lr} @ 4\n\ 30 ldmia %1!, {r3, r4, ip, lr} @ 4+1\n\ 31 stmia %0!, {r3, r4, ip, lr} @ 4\n\ 32 ldmia %1!, {r3, r4, ip, lr} @ 4\n\ 33 stmia %0!, {r3, r4, ip, lr} @ 4\n\ 34 ldmia %1!, {r3, r4, ip, lr} @ 4\n\ 35 subs %2, %2, #1 @ 1\n\ 36 stmia %0!, {r3, r4, ip, lr} @ 4\n\ 37 ldmneia %1!, {r3, r4, ip, lr} @ 4\n\ 38 bne 1b @ 1\n\ 39 mcr p15, 0, %2, c7, c7, 0 @ flush ID cache" 40 : "+&r" (kto), "+&r" (kfrom), "=&r" (tmp) 41 : "2" (PAGE_SIZE / 64) 42 : "r3", "r4", "ip", "lr"); 43 } 44 45 void v4wt_copy_user_highpage(struct page *to, struct page *from, 46 unsigned long vaddr, struct vm_area_struct *vma) 47 { 48 void *kto, *kfrom; 49 50 kto = kmap_atomic(to); 51 kfrom = kmap_atomic(from); 52 v4wt_copy_user_page(kto, kfrom); 53 kunmap_atomic(kfrom); 54 kunmap_atomic(kto); 55 } 56 57 /* 58 * ARMv4 optimised clear_user_page 59 * 60 * Same story as above. 61 */ 62 void v4wt_clear_user_highpage(struct page *page, unsigned long vaddr) 63 { 64 void *ptr, *kaddr = kmap_atomic(page); 65 asm volatile("\ 66 mov r1, %2 @ 1\n\ 67 mov r2, #0 @ 1\n\ 68 mov r3, #0 @ 1\n\ 69 mov ip, #0 @ 1\n\ 70 mov lr, #0 @ 1\n\ 71 1: stmia %0!, {r2, r3, ip, lr} @ 4\n\ 72 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 subs r1, r1, #1 @ 1\n\ 76 bne 1b @ 1\n\ 77 mcr p15, 0, r2, c7, c7, 0 @ flush ID cache" 78 : "=r" (ptr) 79 : "0" (kaddr), "I" (PAGE_SIZE / 64) 80 : "r1", "r2", "r3", "ip", "lr"); 81 kunmap_atomic(kaddr); 82 } 83 84 struct cpu_user_fns v4wt_user_fns __initdata = { 85 .cpu_clear_user_highpage = v4wt_clear_user_highpage, 86 .cpu_copy_user_highpage = v4wt_copy_user_highpage, 87 }; 88