linux/arch/arm/lib/clear_user.S
Russell King 8478132a87 Revert "arm: move exports to definitions"
This reverts commit 4dd1837d75.

Moving the exports for assembly code into the assembly files breaks
KSYM trimming, but also breaks modversions.

While fixing the KSYM trimming is trivial, fixing modversions brings
us to a technically worse position that we had prior to the above
change:

- We end up with the prototype definitions divorsed from everything
  else, which means that adding or removing assembly level ksyms
  become more fragile:
  * if adding a new assembly ksyms export, a missed prototype in
    asm-prototypes.h results in a successful build if no module in
    the selected configuration makes use of the symbol.
  * when removing a ksyms export, asm-prototypes.h will get forgotten,
    with armksyms.c, you'll get a build error if you forget to touch
    the file.

- We end up with the same amount of include files and prototypes,
  they're just in a header file instead of a .c file with their
  exports.

As for lines of code, we don't get much of a size reduction:
 (original commit)
 47 files changed, 131 insertions(+), 208 deletions(-)
 (fix for ksyms trimming)
 7 files changed, 18 insertions(+), 5 deletions(-)
 (two fixes for modversions)
 1 file changed, 34 insertions(+)
 3 files changed, 7 insertions(+), 2 deletions(-)
which results in a net total of only 25 lines deleted.

As there does not seem to be much benefit from this change of approach,
revert the change.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2016-11-23 10:00:03 +00:00

59 lines
1.4 KiB
ArmAsm

/*
* linux/arch/arm/lib/clear_user.S
*
* Copyright (C) 1995, 1996,1997,1998 Russell King
*
* 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.
*/
#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( strnebt 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