blob: 2c3dd0b5656ced04b9ccfd7eeaea593d56c45ed7 [file] [log] [blame]
/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copy to/from user space, handling exceptions as we go.. This
* isn't exactly pretty.
*
* This is essentially the same as "memcpy()", but with a few twists.
* Notably, we have to make sure that $0 is always up-to-date and
* contains the right "bytes left to copy" value (and that it is updated
* only _after_ a successful copy). There is also some rather minor
* exception setup stuff..
*/
#include <asm/export.h>
/* Allow an exception for an insn; exit if we get one. */
#define EXI(x,y...) \
99: x,##y; \
.section __ex_table, "a"; \
.long 99b - .; \
ldi $31, $exitin-99b($31); \
.previous
#define EXO(x,y...) \
99: x, ##y; \
.section __ex_table, "a"; \
.long 99b - .; \
ldi $31, $exitout-99b($31); \
.previous
.set noat
.align 4
.globl __copy_user
.ent __copy_user
__copy_user:
.prologue 0
and $18, $18, $0
and $16, 7, $3
beq $0, $35
beq $3, $36
subl $3, 8, $3
.align 4
$37:
EXI(ldbu $1, 0($17))
EXO(stb $1, 0($16))
addl $3, 1, $3
subl $0, 1, $0
addl $16, 1, $16
addl $17, 1, $17
beq $0, $41
bne $3, $37
$36:
and $17, 7, $1
bic $0, 7, $4
beq $1, $43
beq $4, $48
EXI(ldl_u $3, 0($17))
.align 4
$50:
EXI(ldl_u $2, 8($17))
subl $4, 8, $4
extll $3, $17, $3
exthl $2, $17, $1
bis $3, $1, $1
EXO(stl $1,0($16))
addl $17, 8, $17
subl $0, 8, $0
addl $16, 8, $16
bis $2, $2, $3
bne $4, $50
$48:
beq $0, $41
.align 4
$57:
EXI(ldbu $1, 0($17))
EXO(stb $1, 0($16))
subl $0, 1, $0
addl $16, 1, $16
addl $17, 1, $17
bne $0, $57
br $31, $41
.align 4
$43:
beq $4, $65
.align 4
$66:
EXI(ldl $1, 0($17))
subl $4, 8, $4
EXO(stl $1,0($16))
addl $17, 8, $17
subl $0, 8, $0
addl $16, 8, $16
bne $4, $66
$65:
beq $0, $41
EXI(ldbu $1, 0($17))
EXO(stb $1, 0($16))
addl $17, 1, $17
addl $16, 1, $16
subl $0, 1, $0
br $31, $65
$41:
$35:
$exitin:
$exitout:
ret $31, ($26), 1
.end __copy_user
EXPORT_SYMBOL(__copy_user)