linux-kernel - Re: [PATCH v5 5/5] Auto-detect whether a FPU exists

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Date:   Thu, 9 Aug 2018 14:43:36 +0800
From:   Alan Kao <alankao@...estech.com>
To:     Christoph Hellwig <hch@...radead.org>
CC:     <vincentc@...estech.com>, Andrew Waterman <andrew@...ive.com>,
        "Arnd Bergmann" <arnd@...db.de>, <greentime@...estech.com>,
        <zong@...estech.com>, Darius Rad <darius@...espec.com>,
        Palmer Dabbelt <palmer@...ive.com>,
        <linux-kernel@...r.kernel.org>, Albert Ou <albert@...ive.com>,
        <linux-riscv@...ts.infradead.org>, <nickhu@...estech.com>
Subject: Re: [PATCH v5 5/5] Auto-detect whether a FPU exists

On Wed, Aug 08, 2018 at 11:31:24PM -0700, Christoph Hellwig wrote:
> >  extern unsigned long elf_hwcap;
> > +extern bool has_fpu;
> >  #endif
> 
> Doesn't this conflict with the !CONFIG_CPU stub in switch_to.h?

switch_to.h did include asm/hwcap.h, but the !CONFIG_FPU stub

+#define has_fpu false

always shows later than

+extern bool has fpu

so actually no warning during compilation.
> 
> It seems like we should only have this definition in one place to start
> with.

It does look a little bit weird.  Should I send a v6 for this?
> 
> Otherwise this looks fine to me:
> 
> Reviewed-by: Christoph Hellwig <hch@....de>
> 

Thanks for all the feedback.

Alan