Re: [RFC PATCH v2 09/31] kvx: Add build infrastructure

From: Jules Maselbas <jmaselbas@kalray.eu>
To: Arnd Bergmann <arnd@arndb.de>
Cc: "Yann Sionneau" <ysionneau@kalray.eu>,
	"Jonathan Corbet" <corbet@lwn.net>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Marc Zyngier" <maz@kernel.org>,
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Subject: Re: [RFC PATCH v2 09/31] kvx: Add build infrastructure
Date: Fri, 20 Jan 2023 16:03:40 +0100	[thread overview]
Message-ID: <20230120150340.GA5952@tellis.lin.mbt.kalray.eu> (raw)
In-Reply-To: <9965e2d1-bae8-4ce7-911c-783c772e9ff1@app.fastmail.com>

On Fri, Jan 20, 2023 at 04:01:11PM +0100, Arnd Bergmann wrote:
> On Fri, Jan 20, 2023, at 15:53, Jules Maselbas wrote:
> > On Fri, Jan 20, 2023 at 03:39:22PM +0100, Arnd Bergmann wrote:
> >> On Fri, Jan 20, 2023, at 15:09, Yann Sionneau wrote:
> >> >      - Fix clean target raising an error from gcc (LIBGCC)
> >> 
> >> I had not noticed this on v1 but:
> >> 
> >> > +# Link with libgcc to get __div* builtins.
> >> > +LIBGCC	:= $(shell $(CC) $(DEFAULT_OPTS) --print-libgcc-file-name)
> >> 
> >> It's better to copy the bits of libgcc that you actually need
> >> than to include the whole thing. The kernel is in a weird
> > It was initialy using KCONFIG_CFLAGS which do not contains valid options
> > when invoking the clean target.
> >
> > I am not exactly sure what's needed by gcc for --print-libgcc-file-name,
> > my guess is that only the -march option matters, I will double check
> > internally with compiler peoples.
> >
> >> state that is neither freestanding nor the normal libc based
> >> environment, so we generally want full control over what is
> >> used. This is particularly important for 32-bit architectures
> >> that do not want the 64-bit division, but there are probably
> >> enough other cases as well.
> 
> To clarify: I meant you should not include libgcc.a at all but
> add the minimum set of required files as arch/kvx/lib/*.S.
Thanks for clarifying :)


-- Jules