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authorRussell King <rmk@dyn-67.arm.linux.org.uk>2005-05-10 09:23:01 -0400
committerRussell King <rmk@dyn-67.arm.linux.org.uk>2005-05-10 09:23:01 -0400
commitd2bab05ac1f9a2f5ddcd2f3256237e5c47fc127f (patch)
treea330a8ac155d82bae9a500d28533888dedad4d1e /arch/arm
parentc4e1f6f6bf82af89994a0ee760fc5e036c4d3c1f (diff)
[PATCH] ARM: Move copy/clear user_page locking into implementation
Move the locking for copy_user_page() and clear_user_page() into the implementations which require locking. For simple memcpy/ memset based implementations, the locking is extra overhead which is not necessary, and prevents preemption occuring. Signed-off-by: Russell King <rmk@arm.linux.org.uk>
Diffstat (limited to 'arch/arm')
-rw-r--r--arch/arm/mm/copypage-v4mc.S80
-rw-r--r--arch/arm/mm/copypage-v4mc.c111
2 files changed, 111 insertions, 80 deletions
diff --git a/arch/arm/mm/copypage-v4mc.S b/arch/arm/mm/copypage-v4mc.S
deleted file mode 100644
index 305af3dab3d8..000000000000
--- a/arch/arm/mm/copypage-v4mc.S
+++ /dev/null
@@ -1,80 +0,0 @@
1/*
2 * linux/arch/arm/lib/copy_page-armv4mc.S
3 *
4 * Copyright (C) 1995-2001 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 * ASM optimised string functions
11 */
12#include <linux/linkage.h>
13#include <linux/init.h>
14#include <asm/constants.h>
15
16 .text
17 .align 5
18/*
19 * ARMv4 mini-dcache optimised copy_user_page
20 *
21 * We flush the destination cache lines just before we write the data into the
22 * corresponding address. Since the Dcache is read-allocate, this removes the
23 * Dcache aliasing issue. The writes will be forwarded to the write buffer,
24 * and merged as appropriate.
25 *
26 * Note: We rely on all ARMv4 processors implementing the "invalidate D line"
27 * instruction. If your processor does not supply this, you have to write your
28 * own copy_user_page that does the right thing.
29 */
30ENTRY(v4_mc_copy_user_page)
31 stmfd sp!, {r4, lr} @ 2
32 mov r4, r0
33 mov r0, r1
34 bl map_page_minicache
35 mov r1, #PAGE_SZ/64 @ 1
36 ldmia r0!, {r2, r3, ip, lr} @ 4
371: mcr p15, 0, r4, c7, c6, 1 @ 1 invalidate D line
38 stmia r4!, {r2, r3, ip, lr} @ 4
39 ldmia r0!, {r2, r3, ip, lr} @ 4+1
40 stmia r4!, {r2, r3, ip, lr} @ 4
41 ldmia r0!, {r2, r3, ip, lr} @ 4
42 mcr p15, 0, r4, c7, c6, 1 @ 1 invalidate D line
43 stmia r4!, {r2, r3, ip, lr} @ 4
44 ldmia r0!, {r2, r3, ip, lr} @ 4
45 subs r1, r1, #1 @ 1
46 stmia r4!, {r2, r3, ip, lr} @ 4
47 ldmneia r0!, {r2, r3, ip, lr} @ 4
48 bne 1b @ 1
49 ldmfd sp!, {r4, pc} @ 3
50
51 .align 5
52/*
53 * ARMv4 optimised clear_user_page
54 *
55 * Same story as above.
56 */
57ENTRY(v4_mc_clear_user_page)
58 str lr, [sp, #-4]!
59 mov r1, #PAGE_SZ/64 @ 1
60 mov r2, #0 @ 1
61 mov r3, #0 @ 1
62 mov ip, #0 @ 1
63 mov lr, #0 @ 1
641: mcr p15, 0, r0, c7, c6, 1 @ 1 invalidate D line
65 stmia r0!, {r2, r3, ip, lr} @ 4
66 stmia r0!, {r2, r3, ip, lr} @ 4
67 mcr p15, 0, r0, c7, c6, 1 @ 1 invalidate D line
68 stmia r0!, {r2, r3, ip, lr} @ 4
69 stmia r0!, {r2, r3, ip, lr} @ 4
70 subs r1, r1, #1 @ 1
71 bne 1b @ 1
72 ldr pc, [sp], #4
73
74 __INITDATA
75
76 .type v4_mc_user_fns, #object
77ENTRY(v4_mc_user_fns)
78 .long v4_mc_clear_user_page
79 .long v4_mc_copy_user_page
80 .size v4_mc_user_fns, . - v4_mc_user_fns
diff --git a/arch/arm/mm/copypage-v4mc.c b/arch/arm/mm/copypage-v4mc.c
new file mode 100644
index 000000000000..16384a7600a1
--- /dev/null
+++ b/arch/arm/mm/copypage-v4mc.c
@@ -0,0 +1,111 @@
1/*
2 * linux/arch/arm/lib/copypage-armv4mc.S
3 *
4 * Copyright (C) 1995-2005 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 handles the mini data cache, as found on SA11x0 and XScale
11 * processors. When we copy a user page page, we map it in such a way
12 * that accesses to this page will not touch the main data cache, but
13 * will be cached in the mini data cache. This prevents us thrashing
14 * the main data cache on page faults.
15 */
16#include <linux/init.h>
17#include <linux/mm.h>
18
19#include <asm/page.h>
20#include <asm/pgtable.h>
21#include <asm/tlbflush.h>
22
23/*
24 * 0xffff8000 to 0xffffffff is reserved for any ARM architecture
25 * specific hacks for copying pages efficiently.
26 */
27#define minicache_pgprot __pgprot(L_PTE_PRESENT | L_PTE_YOUNG | \
28 L_PTE_CACHEABLE)
29
30#define TOP_PTE(x) pte_offset_kernel(top_pmd, x)
31
32static DEFINE_SPINLOCK(minicache_lock);
33
34/*
35 * ARMv4 mini-dcache optimised copy_user_page
36 *
37 * We flush the destination cache lines just before we write the data into the
38 * corresponding address. Since the Dcache is read-allocate, this removes the
39 * Dcache aliasing issue. The writes will be forwarded to the write buffer,
40 * and merged as appropriate.
41 *
42 * Note: We rely on all ARMv4 processors implementing the "invalidate D line"
43 * instruction. If your processor does not supply this, you have to write your
44 * own copy_user_page that does the right thing.
45 */
46static void __attribute__((naked))
47mc_copy_user_page(void *from, void *to)
48{
49 asm volatile(
50 "stmfd sp!, {r4, lr} @ 2\n\
51 mov r4, %2 @ 1\n\
52 ldmia %0!, {r2, r3, ip, lr} @ 4\n\
531: mcr p15, 0, %1, c7, c6, 1 @ 1 invalidate D line\n\
54 stmia %1!, {r2, r3, ip, lr} @ 4\n\
55 ldmia %0!, {r2, r3, ip, lr} @ 4+1\n\
56 stmia %1!, {r2, r3, ip, lr} @ 4\n\
57 ldmia %0!, {r2, r3, ip, lr} @ 4\n\
58 mcr p15, 0, %1, c7, c6, 1 @ 1 invalidate D line\n\
59 stmia %1!, {r2, r3, ip, lr} @ 4\n\
60 ldmia %0!, {r2, r3, ip, lr} @ 4\n\
61 subs r4, r4, #1 @ 1\n\
62 stmia %1!, {r2, r3, ip, lr} @ 4\n\
63 ldmneia %0!, {r2, r3, ip, lr} @ 4\n\
64 bne 1b @ 1\n\
65 ldmfd sp!, {r4, pc} @ 3"
66 :
67 : "r" (from), "r" (to), "I" (PAGE_SIZE / 64));
68}
69
70void v4_mc_copy_user_page(void *kto, const void *kfrom, unsigned long vaddr)
71{
72 spin_lock(&minicache_lock);
73
74 set_pte(TOP_PTE(COPYPAGE_MINICACHE), pfn_pte(__pa(kfrom) >> PAGE_SHIFT, minicache_pgprot));
75 flush_tlb_kernel_page(COPYPAGE_MINICACHE);
76
77 mc_copy_user_page((void *)COPYPAGE_MINICACHE, kto);
78
79 spin_unlock(&minicache_lock);
80}
81
82/*
83 * ARMv4 optimised clear_user_page
84 */
85void __attribute__((naked))
86v4_mc_clear_user_page(void *kaddr, unsigned long vaddr)
87{
88 asm volatile(
89 "str lr, [sp, #-4]!\n\
90 mov r1, %0 @ 1\n\
91 mov r2, #0 @ 1\n\
92 mov r3, #0 @ 1\n\
93 mov ip, #0 @ 1\n\
94 mov lr, #0 @ 1\n\
951: mcr p15, 0, r0, c7, c6, 1 @ 1 invalidate D line\n\
96 stmia r0!, {r2, r3, ip, lr} @ 4\n\
97 stmia r0!, {r2, r3, ip, lr} @ 4\n\
98 mcr p15, 0, r0, c7, c6, 1 @ 1 invalidate D line\n\
99 stmia r0!, {r2, r3, ip, lr} @ 4\n\
100 stmia r0!, {r2, r3, ip, lr} @ 4\n\
101 subs r1, r1, #1 @ 1\n\
102 bne 1b @ 1\n\
103 ldr pc, [sp], #4"
104 :
105 : "I" (PAGE_SIZE / 64));
106}
107
108struct cpu_user_fns v4_mc_user_fns __initdata = {
109 .cpu_clear_user_page = v4_mc_clear_user_page,
110 .cpu_copy_user_page = v4_mc_copy_user_page,
111};
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-13 19:08:26 -0500