tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * linux/arch/arm/lib/copy_from_user.S
3 *
4 * Author: Nicolas Pitre
5 * Created: Sep 29, 2005
6 * Copyright: MontaVista Software, Inc.
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12
13#include <linux/linkage.h>
14#include <asm/assembler.h>
15#include <asm/unwind.h>
16
17/*
18 * Prototype:
19 *
20 * size_t arm_copy_from_user(void *to, const void *from, size_t n)
21 *
22 * Purpose:
23 *
24 * copy a block to kernel memory from user memory
25 *
26 * Params:
27 *
28 * to = kernel memory
29 * from = user memory
30 * n = number of bytes to copy
31 *
32 * Return value:
33 *
34 * Number of bytes NOT copied.
35 */
36
37#ifndef CONFIG_THUMB2_KERNEL
38#define LDR1W_SHIFT 0
39#else
40#define LDR1W_SHIFT 1
41#endif
42#define STR1W_SHIFT 0
43
44 .macro ldr1w ptr reg abort
45 ldrusr \reg, \ptr, 4, abort=\abort
46 .endm
47
48 .macro ldr4w ptr reg1 reg2 reg3 reg4 abort
49 ldr1w \ptr, \reg1, \abort
50 ldr1w \ptr, \reg2, \abort
51 ldr1w \ptr, \reg3, \abort
52 ldr1w \ptr, \reg4, \abort
53 .endm
54
55 .macro ldr8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
56 ldr4w \ptr, \reg1, \reg2, \reg3, \reg4, \abort
57 ldr4w \ptr, \reg5, \reg6, \reg7, \reg8, \abort
58 .endm
59
60 .macro ldr1b ptr reg cond=al abort
61 ldrusr \reg, \ptr, 1, \cond, abort=\abort
62 .endm
63
64 .macro str1w ptr reg abort
65 W(str) \reg, [\ptr], #4
66 .endm
67
68 .macro str8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
69 stmia \ptr!, {\reg1, \reg2, \reg3, \reg4, \reg5, \reg6, \reg7, \reg8}
70 .endm
71
72 .macro str1b ptr reg cond=al abort
73 str\cond\()b \reg, [\ptr], #1
74 .endm
75
76 .macro enter reg1 reg2
77 mov r3, #0
78 stmdb sp!, {r0, r2, r3, \reg1, \reg2}
79 .endm
80
81 .macro usave reg1 reg2
82 UNWIND( .save {r0, r2, r3, \reg1, \reg2} )
83 .endm
84
85 .macro exit reg1 reg2
86 add sp, sp, #8
87 ldmfd sp!, {r0, \reg1, \reg2}
88 .endm
89
90 .text
91
92ENTRY(arm_copy_from_user)
93#ifdef CONFIG_CPU_SPECTRE
94 get_thread_info r3
95 ldr r3, [r3, #TI_ADDR_LIMIT]
96 adds ip, r1, r2 @ ip=addr+size
97 sub r3, r3, #1 @ addr_limit - 1
98 cmpcc ip, r3 @ if (addr+size > addr_limit - 1)
99 movcs r1, #0 @ addr = NULL
100 csdb
101#endif
102
103#include "copy_template.S"
104
105ENDPROC(arm_copy_from_user)
106
107 .pushsection .fixup,"ax"
108 .align 0
109 copy_abort_preamble
110 ldmfd sp!, {r1, r2, r3}
111 sub r0, r0, r1
112 rsb r0, r0, r2
113 copy_abort_end
114 .popsection
115