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Subject: Re: [PATCH 2/2] Enable 'make CONFIG_FOO=y oldconfig'
From: David Woodhouse <dwmw2@infradead.org>
To: Randy Dunlap <rdunlap@xenotime.net>
Cc: Arnaud Lacombe <lacombar@gmail.com>, "H. Peter Anvin" <hpa@zytor.com>,
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        Roman Zippel <zippel@linux-m68k.org>
Date: Sun, 31 Jul 2011 17:57:46 +0100
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On Sun, 2011-07-31 at 09:37 -0700, Randy Dunlap wrote:
> Simple question:  what does "ARCH=x86" mean?
> 
> It doesn't mean anything to me without SUBARCH or nnBIT specified.

SUBARCH is meaningless for a native build; it's only for ARCH=um. So I
don't know why that would make anything more meaningful to you.

And why would CONFIG_64BIT make a difference either? Or conversely: why
do CONFIG_PAE, CONFIG_LITTLE_ENDIAN, etc. *not* make a difference to
your understanding?

ARCH=x86 means exactly what it says: "build a kernel for the x86
architecture".

Just like ARCH=mips means "build a kernel for MIPS" and ARCH=sparc means
"build a kernel for SPARC", and ARCH=parisc means "build a kernel for
PARISC", and ARCH=powerpc means "build a kernel for PowerPC". and
ARCH=s390 means "build a kernel for S390".

In *all* of those cases, CONFIG_64BIT is just one more configuration
option; one of *many* that define what actual hardware the kernel
supports.

-- 
dwmw2