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d2912cb1 | 1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
a0c6fdb9 NP |
2 | /* |
3 | * linux/arch/arm/lib/clear_user.S | |
4 | * | |
5 | * Copyright (C) 1995, 1996,1997,1998 Russell King | |
a0c6fdb9 NP |
6 | */ |
7 | #include <linux/linkage.h> | |
8 | #include <asm/assembler.h> | |
6f56a68d | 9 | #include <asm/unwind.h> |
a0c6fdb9 NP |
10 | |
11 | .text | |
12 | ||
3fba7e23 | 13 | /* Prototype: unsigned long arm_clear_user(void *addr, size_t sz) |
a0c6fdb9 NP |
14 | * Purpose : clear some user memory |
15 | * Params : addr - user memory address to clear | |
16 | * : sz - number of bytes to clear | |
17 | * Returns : number of bytes NOT cleared | |
18 | */ | |
a1f98849 | 19 | ENTRY(__clear_user_std) |
3fba7e23 | 20 | WEAK(arm_clear_user) |
6f56a68d SB |
21 | UNWIND(.fnstart) |
22 | UNWIND(.save {r1, lr}) | |
a0c6fdb9 NP |
23 | stmfd sp!, {r1, lr} |
24 | mov r2, #0 | |
25 | cmp r1, #4 | |
26 | blt 2f | |
27 | ands ip, r0, #3 | |
28 | beq 1f | |
29 | cmp ip, #2 | |
8b592783 CM |
30 | strusr r2, r0, 1 |
31 | strusr r2, r0, 1, le | |
32 | strusr r2, r0, 1, lt | |
a0c6fdb9 NP |
33 | rsb ip, ip, #4 |
34 | sub r1, r1, ip @ 7 6 5 4 3 2 1 | |
35 | 1: subs r1, r1, #8 @ -1 -2 -3 -4 -5 -6 -7 | |
8b592783 | 36 | strusr r2, r0, 4, pl, rept=2 |
a0c6fdb9 NP |
37 | bpl 1b |
38 | adds r1, r1, #4 @ 3 2 1 0 -1 -2 -3 | |
8b592783 | 39 | strusr r2, r0, 4, pl |
a0c6fdb9 | 40 | 2: tst r1, #2 @ 1x 1x 0x 0x 1x 1x 0x |
8b592783 | 41 | strusr r2, r0, 1, ne, rept=2 |
a0c6fdb9 | 42 | tst r1, #1 @ x1 x0 x1 x0 x1 x0 x1 |
8b592783 | 43 | it ne @ explicit IT needed for the label |
e44fc388 | 44 | USER( strbtne r2, [r0]) |
a0c6fdb9 | 45 | mov r0, #0 |
1b93a717 | 46 | ldmfd sp!, {r1, pc} |
6f56a68d | 47 | UNWIND(.fnend) |
3fba7e23 | 48 | ENDPROC(arm_clear_user) |
e814d826 | 49 | ENDPROC(__clear_user_std) |
a0c6fdb9 | 50 | |
c4a84ae3 | 51 | .pushsection .text.fixup,"ax" |
a0c6fdb9 | 52 | .align 0 |
1b93a717 | 53 | 9001: ldmfd sp!, {r0, pc} |
4260415f | 54 | .popsection |
a0c6fdb9 | 55 |