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Subject: Re: [PATCH] ARM: ep93xx: don't use clang IAS for crunch
From:   Alexander Sverdlin <alexander.sverdlin@gmail.com>
To:     Arnd Bergmann <arnd@kernel.org>,
        Hartley Sweeten <hsweeten@visionengravers.com>
Cc:     soc@kernel.org, Arnd Bergmann <arnd@arndb.de>,
        Russell King <linux@armlinux.org.uk>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        clang-built-linux@googlegroups.com
Date:   Fri, 26 Feb 2021 20:23:24 +0100
In-Reply-To: <20210226164345.3889993-1-arnd@kernel.org>
References: <20210226164345.3889993-1-arnd@kernel.org>
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Hi!

On Fri, 2021-02-26 at 17:43 +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> Randconfig builds with ep93xx fail with the clang integrated
> assembler that does not understand the maverick crunch extensions:
> 
> arch/arm/mach-ep93xx/crunch-bits.S:94:2: error: invalid instruction
>  cfstr64 mvdx0, [r1, #0] @ save 64b registers
> 
> It is unclear if anyone is still using support for crunch: gcc-4.8 dropped
> it in 2012 when it was already too broken to be used reliabled. glibc
> support existed as an external patch but was never merged upstream.
> We could consider removing the last bits of the kernel support as well.

This was my impression already in 2006, that Cirrus is not going to work
on Crunch support. From my PoV it's OK to remove the support in the
kernel completely.

> Turn off the integrated assembler for this file for now.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  arch/arm/mach-ep93xx/Makefile | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm/mach-ep93xx/Makefile b/arch/arm/mach-ep93xx/Makefile
> index 86768495f61d..f686577ba059 100644
> --- a/arch/arm/mach-ep93xx/Makefile
> +++ b/arch/arm/mach-ep93xx/Makefile
> @@ -7,7 +7,7 @@ obj-y                   := core.o clock.o timer-ep93xx.o
>  obj-$(CONFIG_EP93XX_DMA)       += dma.o
>  
>  obj-$(CONFIG_CRUNCH)           += crunch.o crunch-bits.o
> -AFLAGS_crunch-bits.o           := -Wa,-mcpu=ep9312
> +AFLAGS_crunch-bits.o           := -Wa,-mcpu=ep9312 $(cc-option, -fno-integrated-as)
>  
>  obj-$(CONFIG_MACH_ADSSPHERE)   += adssphere.o
>  obj-$(CONFIG_MACH_EDB93XX)     += edb93xx.o

-- 
Alexander Sverdlin.