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@vger.kernel.org Signed-off-by: Huacai Chen chenhuacai@loongson.cn --- 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@linux-mips.org) - * - * 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 */