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-rw-r--r--arch/alpha/lib/copy_user.S121
1 files changed, 121 insertions, 0 deletions
diff --git a/arch/alpha/lib/copy_user.S b/arch/alpha/lib/copy_user.S
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+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * arch/alpha/lib/copy_user.S
+ *
+ * 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 <linux/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 - .; \
+ lda $31, $exitin-99b($31); \
+ .previous
+
+#define EXO(x,y...) \
+ 99: x,##y; \
+ .section __ex_table,"a"; \
+ .long 99b - .; \
+ lda $31, $exitout-99b($31); \
+ .previous
+
+ .set noat
+ .align 4
+ .globl __copy_user
+ .ent __copy_user
+__copy_user:
+ .prologue 0
+ mov $18,$0
+ and $16,7,$3
+ beq $0,$35
+ beq $3,$36
+ subq $3,8,$3
+ .align 4
+$37:
+ EXI( ldq_u $1,0($17) )
+ EXO( ldq_u $2,0($16) )
+ extbl $1,$17,$1
+ mskbl $2,$16,$2
+ insbl $1,$16,$1
+ addq $3,1,$3
+ bis $1,$2,$1
+ EXO( stq_u $1,0($16) )
+ subq $0,1,$0
+ addq $16,1,$16
+ addq $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( ldq_u $3,0($17) )
+ .align 4
+$50:
+ EXI( ldq_u $2,8($17) )
+ subq $4,8,$4
+ extql $3,$17,$3
+ extqh $2,$17,$1
+ bis $3,$1,$1
+ EXO( stq $1,0($16) )
+ addq $17,8,$17
+ subq $0,8,$0
+ addq $16,8,$16
+ bis $2,$2,$3
+ bne $4,$50
+$48:
+ beq $0,$41
+ .align 4
+$57:
+ EXI( ldq_u $1,0($17) )
+ EXO( ldq_u $2,0($16) )
+ extbl $1,$17,$1
+ mskbl $2,$16,$2
+ insbl $1,$16,$1
+ bis $1,$2,$1
+ EXO( stq_u $1,0($16) )
+ subq $0,1,$0
+ addq $16,1,$16
+ addq $17,1,$17
+ bne $0,$57
+ br $31,$41
+ .align 4
+$43:
+ beq $4,$65
+ .align 4
+$66:
+ EXI( ldq $1,0($17) )
+ subq $4,8,$4
+ EXO( stq $1,0($16) )
+ addq $17,8,$17
+ subq $0,8,$0
+ addq $16,8,$16
+ bne $4,$66
+$65:
+ beq $0,$41
+ EXI( ldq $2,0($17) )
+ EXO( ldq $1,0($16) )
+ mskql $2,$0,$2
+ mskqh $1,$0,$1
+ bis $2,$1,$2
+ EXO( stq $2,0($16) )
+ bis $31,$31,$0
+$41:
+$35:
+$exitin:
+$exitout:
+ ret $31,($26),1
+
+ .end __copy_user
+EXPORT_SYMBOL(__copy_user)