arm64/lib/clear_user.S

1 /* SPDX-License-Identifier: GPL-2.0-only */
7 #include <asm/asm-uaccess.h>
13  * Params   : addr - user memory address to clear
14  *          : sz   - number of bytes to clear
29 USER(9f, setpt	[x0]!, x1!, xzr)
30 USER(6f, setmt	[x0]!, x1!, xzr)
31 USER(6f, setet	[x0]!, x1!, xzr)
38 	b.mi	2f
40 1:	.p2align 4
41 USER(9f, sttr	xzr, [x0])
44 	b.hi	1b
45 USER(9f, sttr	xzr, [x2, #-8])
49 2:	tbz	x1, #2, 3f
50 USER(9f, sttr	wzr, [x0])
51 USER(8f, sttr	wzr, [x2, #-4])
55 3:	tbz	x1, #1, 4f
56 USER(9f, sttrh	wzr, [x0])
57 4:	tbz	x1, #0, 5f
58 USER(7f, sttrb	wzr, [x2, #-1])
63 6:	b.cs	9f
64 	// Registers are in Option A format
66 	b	9f
68 8:	add	x0, x0, #4	// ...or the second word of the 4-7 byte case
69 9:	sub	x0, x2, x0