1 // SPDX-License-Identifier: GPL-2.0-only 1
2 /*
3 * linux/arch/arm/mm/copypage-v4wt.S
4 *
5 * Copyright (C) 1995-1999 Russell King
6 *
7 * This is for CPUs with a writethrough cache
8 * the only supported cache operation.
9 */
10 #include <linux/init.h>
11 #include <linux/highmem.h>
12
13 /*
14 * ARMv4 optimised copy_user_highpage
15 *
16 * Since we have writethrough caches, we don't
17 * dirty data in the cache. However, we do ha
18 * subsequent reads are up to date.
19 */
20 static void v4wt_copy_user_page(void *kto, con
21 {
22 int tmp;
23
24 asm volatile ("\
25 .syntax unified\n\
26 ldmia %1!, {r3, r4, ip, lr}
27 1: stmia %0!, {r3, r4, ip, lr}
28 ldmia %1!, {r3, r4, ip, lr}
29 stmia %0!, {r3, r4, ip, lr}
30 ldmia %1!, {r3, r4, ip, lr}
31 stmia %0!, {r3, r4, ip, lr}
32 ldmia %1!, {r3, r4, ip, lr}
33 subs %2, %2, #1
34 stmia %0!, {r3, r4, ip, lr}
35 ldmiane %1!, {r3, r4, ip, lr}
36 bne 1b
37 mcr p15, 0, %2, c7, c7, 0
38 : "+&r" (kto), "+&r" (kfrom), "=&r" (t
39 : "2" (PAGE_SIZE / 64)
40 : "r3", "r4", "ip", "lr");
41 }
42
43 void v4wt_copy_user_highpage(struct page *to,
44 unsigned long vaddr, struct vm_area_st
45 {
46 void *kto, *kfrom;
47
48 kto = kmap_atomic(to);
49 kfrom = kmap_atomic(from);
50 v4wt_copy_user_page(kto, kfrom);
51 kunmap_atomic(kfrom);
52 kunmap_atomic(kto);
53 }
54
55 /*
56 * ARMv4 optimised clear_user_page
57 *
58 * Same story as above.
59 */
60 void v4wt_clear_user_highpage(struct page *pag
61 {
62 void *ptr, *kaddr = kmap_atomic(page);
63 asm volatile("\
64 mov r1, %2
65 mov r2, #0
66 mov r3, #0
67 mov ip, #0
68 mov lr, #0
69 1: stmia %0!, {r2, r3, ip, lr}
70 stmia %0!, {r2, r3, ip, lr}
71 stmia %0!, {r2, r3, ip, lr}
72 stmia %0!, {r2, r3, ip, lr}
73 subs r1, r1, #1
74 bne 1b
75 mcr p15, 0, r2, c7, c7, 0
76 : "=r" (ptr)
77 : "" (kaddr), "I" (PAGE_SIZE / 64)
78 : "r1", "r2", "r3", "ip", "lr");
79 kunmap_atomic(kaddr);
80 }
81
82 struct cpu_user_fns v4wt_user_fns __initdata =
83 .cpu_clear_user_highpage = v4wt_clear_
84 .cpu_copy_user_highpage = v4wt_copy_us
85 };
86
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