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/arch/alpha/lib/copy_user.S

http://github.com/mirrors/linux
Assembly | 121 lines | 121 code | 0 blank | 0 comment | 0 complexity | 4364e2f400d1626f4215ec637c42eeb8 MD5 | raw file
  1/* SPDX-License-Identifier: GPL-2.0 */
  2/*
  3 * arch/alpha/lib/copy_user.S
  4 *
  5 * Copy to/from user space, handling exceptions as we go..  This
  6 * isn't exactly pretty.
  7 *
  8 * This is essentially the same as "memcpy()", but with a few twists.
  9 * Notably, we have to make sure that $0 is always up-to-date and
 10 * contains the right "bytes left to copy" value (and that it is updated
 11 * only _after_ a successful copy). There is also some rather minor
 12 * exception setup stuff..
 13 */
 14
 15#include <asm/export.h>
 16
 17/* Allow an exception for an insn; exit if we get one.  */
 18#define EXI(x,y...)			\
 19	99: x,##y;			\
 20	.section __ex_table,"a";	\
 21	.long 99b - .;			\
 22	lda $31, $exitin-99b($31);	\
 23	.previous
 24
 25#define EXO(x,y...)			\
 26	99: x,##y;			\
 27	.section __ex_table,"a";	\
 28	.long 99b - .;			\
 29	lda $31, $exitout-99b($31);	\
 30	.previous
 31
 32	.set noat
 33	.align 4
 34	.globl __copy_user
 35	.ent __copy_user
 36__copy_user:
 37	.prologue 0
 38	mov $18,$0
 39	and $16,7,$3
 40	beq $0,$35
 41	beq $3,$36
 42	subq $3,8,$3
 43	.align 4
 44$37:
 45	EXI( ldq_u $1,0($17) )
 46	EXO( ldq_u $2,0($16) )
 47	extbl $1,$17,$1
 48	mskbl $2,$16,$2
 49	insbl $1,$16,$1
 50	addq $3,1,$3
 51	bis $1,$2,$1
 52	EXO( stq_u $1,0($16) )
 53	subq $0,1,$0
 54	addq $16,1,$16
 55	addq $17,1,$17
 56	beq $0,$41
 57	bne $3,$37
 58$36:
 59	and $17,7,$1
 60	bic $0,7,$4
 61	beq $1,$43
 62	beq $4,$48
 63	EXI( ldq_u $3,0($17) )
 64	.align 4
 65$50:
 66	EXI( ldq_u $2,8($17) )
 67	subq $4,8,$4
 68	extql $3,$17,$3
 69	extqh $2,$17,$1
 70	bis $3,$1,$1
 71	EXO( stq $1,0($16) )
 72	addq $17,8,$17
 73	subq $0,8,$0
 74	addq $16,8,$16
 75	bis $2,$2,$3
 76	bne $4,$50
 77$48:
 78	beq $0,$41
 79	.align 4
 80$57:
 81	EXI( ldq_u $1,0($17) )
 82	EXO( ldq_u $2,0($16) )
 83	extbl $1,$17,$1
 84	mskbl $2,$16,$2
 85	insbl $1,$16,$1
 86	bis $1,$2,$1
 87	EXO( stq_u $1,0($16) )
 88	subq $0,1,$0
 89	addq $16,1,$16
 90	addq $17,1,$17
 91	bne $0,$57
 92	br $31,$41
 93	.align 4
 94$43:
 95	beq $4,$65
 96	.align 4
 97$66:
 98	EXI( ldq $1,0($17) )
 99	subq $4,8,$4
100	EXO( stq $1,0($16) )
101	addq $17,8,$17
102	subq $0,8,$0
103	addq $16,8,$16
104	bne $4,$66
105$65:
106	beq $0,$41
107	EXI( ldq $2,0($17) )
108	EXO( ldq $1,0($16) )
109	mskql $2,$0,$2
110	mskqh $1,$0,$1
111	bis $2,$1,$2
112	EXO( stq $2,0($16) )
113	bis $31,$31,$0
114$41:
115$35:
116$exitin:
117$exitout:
118	ret $31,($26),1
119
120	.end __copy_user
121EXPORT_SYMBOL(__copy_user)