linux/arch/arm/lib/csumpartialcopyuser.S
Russell King 4609a179c9 ARM: Fix csum_partial_copy_from_user()
Using the parent functions frame pointer to access our arguments is
completely wrong, whether or not we're building with frame pointers
or not.  What we should be using is the stack pointer to get at the
word above the registers we stacked ourselves.

Reported-by: Bosko Radivojevic <bosko.radivojevic@gmail.com>
Tested-by: Bosko Radivojevic <bosko.radivojevic@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-07-26 12:18:16 +01:00

84 lines
1.9 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
.macro save_regs
stmfd sp!, {r1, r2, r4 - r8, lr}
.endm
.macro load_regs
ldmfd sp!, {r1, r2, r4 - r8, pc}
.endm
.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 .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