write in 30M

hc

2024-02-20 ea08eeccae9297f7aabd2ef7f0c2517ac4549acc

 kernel/arch/powerpc/lib/checksum_32.S
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@@ -1,13 +1,9 @@
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+/* SPDX-License-Identifier: GPL-2.0-or-later */
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 /*
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  * This file contains assembly-language implementations
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  * of IP-style 1's complement checksum routines.
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  *	
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  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
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- *
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- *  This program is free software; you can redistribute it and/or
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- *  modify it under the terms of the GNU General Public License
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- *  as published by the Free Software Foundation; either version
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- *  2 of the License, or (at your option) any later version.
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  *
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  * Severely hacked about by Paul Mackerras (paulus@cs.anu.edu.au).
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  */
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@@ -82,12 +78,10 @@
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78
 
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 /*
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  * Computes the checksum of a memory block at src, length len,
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- * and adds in "sum" (32-bit), while copying the block to dst.
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- * If an access exception occurs on src or dst, it stores -EFAULT
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- * to *src_err or *dst_err respectively, and (for an error on
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- * src) zeroes the rest of dst.
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+ * and adds in 0xffffffff, while copying the block to dst.
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+ * If an access exception occurs it returns zero.
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  *
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- * csum_partial_copy_generic(src, dst, len, sum, src_err, dst_err)
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+ * csum_partial_copy_generic(src, dst, len)
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  */
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 #define CSUM_COPY_16_BYTES_WITHEX(n)	\
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 8 ## n ## 0:			\
..
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@@ -112,14 +106,14 @@
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 	adde	r12,r12,r10
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 #define CSUM_COPY_16_BYTES_EXCODE(n)		\
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-	EX_TABLE(8 ## n ## 0b, src_error);	\
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-	EX_TABLE(8 ## n ## 1b, src_error);	\
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-	EX_TABLE(8 ## n ## 2b, src_error);	\
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-	EX_TABLE(8 ## n ## 3b, src_error);	\
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-	EX_TABLE(8 ## n ## 4b, dst_error);	\
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-	EX_TABLE(8 ## n ## 5b, dst_error);	\
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-	EX_TABLE(8 ## n ## 6b, dst_error);	\
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-	EX_TABLE(8 ## n ## 7b, dst_error);
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+	EX_TABLE(8 ## n ## 0b, fault);	\
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+	EX_TABLE(8 ## n ## 1b, fault);	\
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+	EX_TABLE(8 ## n ## 2b, fault);	\
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+	EX_TABLE(8 ## n ## 3b, fault);	\
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+	EX_TABLE(8 ## n ## 4b, fault);	\
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+	EX_TABLE(8 ## n ## 5b, fault);	\
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+	EX_TABLE(8 ## n ## 6b, fault);	\
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+	EX_TABLE(8 ## n ## 7b, fault);
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117
 
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 	.text
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 	.stabs	"arch/powerpc/lib/",N_SO,0,0,0f
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@@ -131,11 +125,8 @@
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 CACHELINE_MASK = (L1_CACHE_BYTES-1)
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 _GLOBAL(csum_partial_copy_generic)
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-	stwu	r1,-16(r1)
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-	stw	r7,12(r1)
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-	stw	r8,8(r1)
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-
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-	addic	r12,r6,0
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+	li	r12,-1
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+	addic	r0,r0,0			/* clear carry */
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 	addi	r6,r4,-4
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 	neg	r0,r4
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 	addi	r4,r3,-4
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@@ -245,39 +236,23 @@
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 	slwi	r0,r0,8
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 	adde	r12,r12,r0
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 66:	addze	r3,r12
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-	addi	r1,r1,16
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 	beqlr+	cr7
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 	rlwinm	r3,r3,8,0,31	/* odd destination address: rotate one byte */
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 	blr
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-/* read fault */
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-src_error:
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-	lwz	r7,12(r1)
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-	addi	r1,r1,16
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-	cmpwi	cr0,r7,0
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-	beqlr
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-	li	r0,-EFAULT
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-	stw	r0,0(r7)
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-	blr
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-/* write fault */
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-dst_error:
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-	lwz	r8,8(r1)
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-	addi	r1,r1,16
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-	cmpwi	cr0,r8,0
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-	beqlr
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-	li	r0,-EFAULT
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-	stw	r0,0(r8)
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+fault:
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+	li	r3,0
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 	blr
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246
 
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-	EX_TABLE(70b, src_error);
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-	EX_TABLE(71b, dst_error);
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-	EX_TABLE(72b, src_error);
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-	EX_TABLE(73b, dst_error);
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-	EX_TABLE(54b, dst_error);
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+	EX_TABLE(70b, fault);
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+	EX_TABLE(71b, fault);
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+	EX_TABLE(72b, fault);
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+	EX_TABLE(73b, fault);
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+	EX_TABLE(54b, fault);
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 /*
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  * this stuff handles faults in the cacheline loop and branches to either
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- * src_error (if in read part) or dst_error (if in write part)
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+ * fault (if in read part) or fault (if in write part)
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  */
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 	CSUM_COPY_16_BYTES_EXCODE(0)
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 #if L1_CACHE_BYTES >= 32
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@@ -294,12 +269,12 @@
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 #endif
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 #endif
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-	EX_TABLE(30b, src_error);
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-	EX_TABLE(31b, dst_error);
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-	EX_TABLE(40b, src_error);
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-	EX_TABLE(41b, dst_error);
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-	EX_TABLE(50b, src_error);
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-	EX_TABLE(51b, dst_error);
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+	EX_TABLE(30b, fault);
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+	EX_TABLE(31b, fault);
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+	EX_TABLE(40b, fault);
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+	EX_TABLE(41b, fault);
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+	EX_TABLE(50b, fault);
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+	EX_TABLE(51b, fault);
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 EXPORT_SYMBOL(csum_partial_copy_generic)
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