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
