remarkable-linux/arch/arm/lib/csumpartialcopyuser.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

98 lines
2.1 KiB
ArmAsm

/*
* linux/arch/arm/lib/csumpartialcopyuser.S
*
* Copyright (C) 1995-1998 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.
*
* 27/03/03 Ian Molton Clean up CONFIG_CPU
*
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/errno.h>
#include <asm/asm-offsets.h>
.text
#ifdef CONFIG_CPU_SW_DOMAIN_PAN
.macro save_regs
mrc p15, 0, ip, c3, c0, 0
stmfd sp!, {r1, r2, r4 - r8, ip, lr}
uaccess_enable ip
.endm
.macro load_regs
ldmfd sp!, {r1, r2, r4 - r8, ip, lr}
mcr p15, 0, ip, c3, c0, 0
ret lr
.endm
#else
.macro save_regs
stmfd sp!, {r1, r2, r4 - r8, lr}
.endm
.macro load_regs
ldmfd sp!, {r1, r2, r4 - r8, pc}
.endm
#endif
.macro load1b, reg1
ldrusr \reg1, r0, 1
.endm
.macro load2b, reg1, reg2
ldrusr \reg1, r0, 1
ldrusr \reg2, r0, 1
.endm
.macro load1l, reg1
ldrusr \reg1, r0, 4
.endm
.macro load2l, reg1, reg2
ldrusr \reg1, r0, 4
ldrusr \reg2, r0, 4
.endm
.macro load4l, reg1, reg2, reg3, reg4
ldrusr \reg1, r0, 4
ldrusr \reg2, r0, 4
ldrusr \reg3, r0, 4
ldrusr \reg4, r0, 4
.endm
/*
* unsigned int
* csum_partial_copy_from_user(const char *src, char *dst, int len, int sum, int *err_ptr)
* r0 = src, r1 = dst, r2 = len, r3 = sum, [sp] = *err_ptr
* Returns : r0 = checksum, [[sp, #0], #0] = 0 or -EFAULT
*/
#define FN_ENTRY ENTRY(csum_partial_copy_from_user)
#define FN_EXIT ENDPROC(csum_partial_copy_from_user)
#include "csumpartialcopygeneric.S"
/*
* FIXME: minor buglet here
* We don't return the checksum for the data present in the buffer. To do
* so properly, we would have to add in whatever registers were loaded before
* the fault, which, with the current asm above is not predictable.
*/
.pushsection .text.fixup,"ax"
.align 4
9001: mov r4, #-EFAULT
ldr r5, [sp, #8*4] @ *err_ptr
str r4, [r5]
ldmia sp, {r1, r2} @ retrieve dst, len
add r2, r2, r1
mov r0, #0 @ zero the buffer
9002: teq r2, r1
strneb r0, [r1], #1
bne 9002b
load_regs
.popsection