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Date: Thu, 18 Feb 2016 15:02:00 +0100 From: Arnd Bergmann <arnd@...db.de> To: Russell King <linux@....linux.org.uk> Cc: linux-arm-kernel@...ts.infradead.org, Arnd Bergmann <arnd@...db.de>, Ard Biesheuvel <ard.biesheuvel@...aro.org>, Nicolas Pitre <nico@...aro.org>, Jon Medhurst <tixy@...aro.org>, Marc Zyngier <marc.zyngier@....com>, Nicolas Pitre <nicolas.pitre@...aro.org>, linux-kernel@...r.kernel.org Subject: [PATCH 8/9] ARM: do not use optimized do_div for ARMv3 The gcc-4.9 optimization goes wrong while building target_core_iblock.c for ARMv3 and leaves a bogus reference to __aeabi_uldivmod in the output: ERROR: "__aeabi_uldivmod" [drivers/target/target_core_iblock.ko] undefined! I could not find anyone who is interested in fixing it in gcc, so as a workaround this disables the do_div magic, just like we do for old compilers and for OABI. Signed-off-by: Arnd Bergmann <arnd@...db.de> --- arch/arm/include/asm/div64.h | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/arm/include/asm/div64.h b/arch/arm/include/asm/div64.h index 7d919a9b32e5..958fdc2363f5 100644 --- a/arch/arm/include/asm/div64.h +++ b/arch/arm/include/asm/div64.h @@ -58,6 +58,14 @@ static inline uint32_t __div64_32(uint64_t *n, uint32_t base) */ #define do_div(n, base) __div64_32(&(n), base) +#elif defined(CONFIG_CPU_32v3) + +/* + * modern compiler versions (>= gcc-4.9) tend to misoptimize + * the code for ARMv3, and this is not getting fixed any more. + */ +#define do_div(n, base) __div64_32(&(n), base) + #else /* -- 2.7.0
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