Commit | Line | Data |
---|---|---|
a0c6fdb9 NP |
1 | /* |
2 | * linux/arch/arm/lib/clear_user.S | |
3 | * | |
4 | * Copyright (C) 1995, 1996,1997,1998 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 | #include <linux/linkage.h> | |
11 | #include <asm/assembler.h> | |
6f56a68d | 12 | #include <asm/unwind.h> |
a0c6fdb9 NP |
13 | |
14 | .text | |
15 | ||
3fba7e23 | 16 | /* Prototype: unsigned long arm_clear_user(void *addr, size_t sz) |
a0c6fdb9 NP |
17 | * Purpose : clear some user memory |
18 | * Params : addr - user memory address to clear | |
19 | * : sz - number of bytes to clear | |
20 | * Returns : number of bytes NOT cleared | |
21 | */ | |
a1f98849 | 22 | ENTRY(__clear_user_std) |
3fba7e23 | 23 | WEAK(arm_clear_user) |
6f56a68d SB |
24 | UNWIND(.fnstart) |
25 | UNWIND(.save {r1, lr}) | |
a0c6fdb9 NP |
26 | stmfd sp!, {r1, lr} |
27 | mov r2, #0 | |
28 | cmp r1, #4 | |
29 | blt 2f | |
30 | ands ip, r0, #3 | |
31 | beq 1f | |
32 | cmp ip, #2 | |
8b592783 CM |
33 | strusr r2, r0, 1 |
34 | strusr r2, r0, 1, le | |
35 | strusr r2, r0, 1, lt | |
a0c6fdb9 NP |
36 | rsb ip, ip, #4 |
37 | sub r1, r1, ip @ 7 6 5 4 3 2 1 | |
38 | 1: subs r1, r1, #8 @ -1 -2 -3 -4 -5 -6 -7 | |
8b592783 | 39 | strusr r2, r0, 4, pl, rept=2 |
a0c6fdb9 NP |
40 | bpl 1b |
41 | adds r1, r1, #4 @ 3 2 1 0 -1 -2 -3 | |
8b592783 | 42 | strusr r2, r0, 4, pl |
a0c6fdb9 | 43 | 2: tst r1, #2 @ 1x 1x 0x 0x 1x 1x 0x |
8b592783 | 44 | strusr r2, r0, 1, ne, rept=2 |
a0c6fdb9 | 45 | tst r1, #1 @ x1 x0 x1 x0 x1 x0 x1 |
8b592783 | 46 | it ne @ explicit IT needed for the label |
9c23e5fe | 47 | USER( strnebt r2, [r0]) |
a0c6fdb9 | 48 | mov r0, #0 |
1b93a717 | 49 | ldmfd sp!, {r1, pc} |
6f56a68d | 50 | UNWIND(.fnend) |
3fba7e23 | 51 | ENDPROC(arm_clear_user) |
e814d826 | 52 | ENDPROC(__clear_user_std) |
a0c6fdb9 | 53 | |
c4a84ae3 | 54 | .pushsection .text.fixup,"ax" |
a0c6fdb9 | 55 | .align 0 |
1b93a717 | 56 | 9001: ldmfd sp!, {r0, pc} |
4260415f | 57 | .popsection |
a0c6fdb9 | 58 |