[PATCH] MIPS: Remove unused and erroneous div64.h

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There are many errors in div64.h caused by commit c21004cd5b4cb7d479514
("MIPS: Rewrite <asm/div64.h> to work with gcc 4.4.0."):

1, Only 32bit kernel need __div64_32(), but the above commit makes it
   depend on 64bit kernel by mistake. So div64.h is unused in fact.

2, asm-generic/div64.h should be included after __div64_32() definition.

3, __n should be initialized as *n before use (and "*__n >> 32" should
   be "__n >> 32") in __div64_32() definition.

4, linux/types.h should be included at the first place, otherwise BITS_
   PER_LONG is not defined.

5, As Nikolaus, Yunqiang Su and Yanjie Zhou said, the MIPS-specific
   __div64_32() sometimes produces wrong results, which makes 32bit
   kernel boot fails.

I have tried to fix theses errors but I have failed with the last one.
Yunqiang's tests show that the MIPS-specific __div64_32() has no obvious
advantage than the C version, so I just simply remove div64.h.

Fixes: c21004cd5b4cb7d479514 ("MIPS: Rewrite <asm/div64.h> to work with gcc 4.4.0.")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
---
 arch/mips/include/asm/div64.h | 68 -----------------------------------
 1 file changed, 68 deletions(-)
 delete mode 100644 arch/mips/include/asm/div64.h

diff --git a/arch/mips/include/asm/div64.h b/arch/mips/include/asm/div64.h
deleted file mode 100644
index dc5ea5736440..000000000000
--- a/arch/mips/include/asm/div64.h
+++ /dev/null
@@ -1,68 +0,0 @@
-/*
- * Copyright (C) 2000, 2004  Maciej W. Rozycki
- * Copyright (C) 2003, 07 Ralf Baechle (ralf@xxxxxxxxxxxxxx)
- *
- * This file is subject to the terms and conditions of the GNU General Public
- * License.  See the file "COPYING" in the main directory of this archive
- * for more details.
- */
-#ifndef __ASM_DIV64_H
-#define __ASM_DIV64_H
-
-#include <asm-generic/div64.h>
-
-#if BITS_PER_LONG == 64
-
-#include <linux/types.h>
-
-/*
- * No traps on overflows for any of these...
- */
-
-#define __div64_32(n, base)						\
-({									\
-	unsigned long __cf, __tmp, __tmp2, __i;				\
-	unsigned long __quot32, __mod32;				\
-	unsigned long __high, __low;					\
-	unsigned long long __n;						\
-									\
-	__high = *__n >> 32;						\
-	__low = __n;							\
-	__asm__(							\
-	"	.set	push					\n"	\
-	"	.set	noat					\n"	\
-	"	.set	noreorder				\n"	\
-	"	move	%2, $0					\n"	\
-	"	move	%3, $0					\n"	\
-	"	b	1f					\n"	\
-	"	 li	%4, 0x21				\n"	\
-	"0:							\n"	\
-	"	sll	$1, %0, 0x1				\n"	\
-	"	srl	%3, %0, 0x1f				\n"	\
-	"	or	%0, $1, %5				\n"	\
-	"	sll	%1, %1, 0x1				\n"	\
-	"	sll	%2, %2, 0x1				\n"	\
-	"1:							\n"	\
-	"	bnez	%3, 2f					\n"	\
-	"	 sltu	%5, %0, %z6				\n"	\
-	"	bnez	%5, 3f					\n"	\
-	"2:							\n"	\
-	"	 addiu	%4, %4, -1				\n"	\
-	"	subu	%0, %0, %z6				\n"	\
-	"	addiu	%2, %2, 1				\n"	\
-	"3:							\n"	\
-	"	bnez	%4, 0b\n\t"					\
-	"	 srl	%5, %1, 0x1f\n\t"				\
-	"	.set	pop"						\
-	: "=&r" (__mod32), "=&r" (__tmp),				\
-	  "=&r" (__quot32), "=&r" (__cf),				\
-	  "=&r" (__i), "=&r" (__tmp2)					\
-	: "Jr" (base), "0" (__high), "1" (__low));			\
-									\
-	(__n) = __quot32;						\
-	__mod32;							\
-})
-
-#endif /* BITS_PER_LONG == 64 */
-
-#endif /* __ASM_DIV64_H */
-- 
2.27.0




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