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 __naked 24 v4wt_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\ 30 1: 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 46 void 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 */ 63 void 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\ 72 1: 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 85 struct 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