linux/arch/arm/lib/clear_user.S
Thomas Gleixner d2912cb15b treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500
Based on 2 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-19 17:09:55 +02:00

56 lines
1.3 KiB
ArmAsm

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* linux/arch/arm/lib/clear_user.S
*
* Copyright (C) 1995, 1996,1997,1998 Russell King
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/unwind.h>
.text
/* Prototype: unsigned long arm_clear_user(void *addr, size_t sz)
* Purpose : clear some user memory
* Params : addr - user memory address to clear
* : sz - number of bytes to clear
* Returns : number of bytes NOT cleared
*/
ENTRY(__clear_user_std)
WEAK(arm_clear_user)
UNWIND(.fnstart)
UNWIND(.save {r1, lr})
stmfd sp!, {r1, lr}
mov r2, #0
cmp r1, #4
blt 2f
ands ip, r0, #3
beq 1f
cmp ip, #2
strusr r2, r0, 1
strusr r2, r0, 1, le
strusr r2, r0, 1, lt
rsb ip, ip, #4
sub r1, r1, ip @ 7 6 5 4 3 2 1
1: subs r1, r1, #8 @ -1 -2 -3 -4 -5 -6 -7
strusr r2, r0, 4, pl, rept=2
bpl 1b
adds r1, r1, #4 @ 3 2 1 0 -1 -2 -3
strusr r2, r0, 4, pl
2: tst r1, #2 @ 1x 1x 0x 0x 1x 1x 0x
strusr r2, r0, 1, ne, rept=2
tst r1, #1 @ x1 x0 x1 x0 x1 x0 x1
it ne @ explicit IT needed for the label
USER( strbtne r2, [r0])
mov r0, #0
ldmfd sp!, {r1, pc}
UNWIND(.fnend)
ENDPROC(arm_clear_user)
ENDPROC(__clear_user_std)
.pushsection .text.fixup,"ax"
.align 0
9001: ldmfd sp!, {r0, pc}
.popsection