linux-kernel - Re: [RESEND PATCH 0/2] crypto: sunxi-ss: fix 64-bit compilation

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Message-ID: <20160118101511.GD12644@pd.tnic>
Date:	Mon, 18 Jan 2016 11:15:11 +0100
From:	Borislav Petkov <bp@...en8.de>
To:	Andre Przywara <andre.przywara@....com>
Cc:	Corentin LABBE <clabbe.montjoie@...il.com>,
	Maxime Ripard <maxime.ripard@...e-electrons.com>,
	Chen-Yu Tsai <wens@...e.org>, Arnd Bergmann <arnd@...db.de>,
	Herbert Xu <herbert@...dor.apana.org.au>,
	"David S . Miller" <davem@...emloft.net>,
	linux-sunxi@...glegroups.com, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org, linux-crypto@...r.kernel.org,
	x86-ml <x86@...nel.org>
Subject: Re: [RESEND PATCH 0/2] crypto: sunxi-ss: fix 64-bit compilation

On Mon, Jan 18, 2016 at 10:01:55AM +0000, Andre Przywara wrote:
> Hi Corentin,
> 
> (CC:ing Boris for the x86 parts)
> 
> thanks for looking at this and your answer.
> 
> On 16/01/16 20:32, Corentin LABBE wrote:
> > Le 08/01/2016 12:24, Andre Przywara a écrit :
> >> (resending to add linux-crypto, patches unchanged)
> >>
> >> Hi,
> >>
> >> these two patches provide a different approach to an issue I tried
> >> to fix lately [1].
> >> Instead of casting everything I now promote local types to size_t, so
> >> that the min3() arguments naturally match in type.
> >> As size_t is defined as "unsigned int" on 32-bit architectures
> >> anyway, that actually does not change anything there, but instead
> >> provides a clean approach to get it compiled for arm64.
> >>
> >> I split this up because 1/2 seems much cleaner to me than 2/2, so we
> >> can have a separate discussion/merge process on this.
> >>
> >> Cheers,
> >> Andre.
> >>
> >> [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2015-December/395689.html
> >>
> >> Andre Przywara (2):
> >>   crypto: sunxi-ss-cipher: promote variables to match types in min3()
> >>     calls
> >>   crypto: sunxi-ss-hash: promote variables to match types in min3()
> >>     calls
> >>
> >>  drivers/crypto/sunxi-ss/sun4i-ss-cipher.c | 20 ++++++++++----------
> >>  drivers/crypto/sunxi-ss/sun4i-ss-hash.c   | 12 ++++++------
> >>  drivers/crypto/sunxi-ss/sun4i-ss.h        |  2 +-
> >>  3 files changed, 17 insertions(+), 17 deletions(-)
> >>
> > 
> > Hello
> > 
> > Sorry for this late answer.
> > 
> > I am in trouble with those patch, so we have with Andre a long conversation about it.
> > Basically, sun4i-ss will never be available on 64bits platform. (A64 will have a totally new crypto engine).
> > So letting it to compile under 64bit arch is only useful when goal is to add COMPILE_TEST for it.
> 
> OK, but actually I don't see the strict requirement for having
> COMPILE_TEST here. Usually those warnings point to portability issues in
> the code and should be fixed, regardless of it being usable for a
> particular architecture or not. Since it got enabled with ARCH_SUNXI on
> arm64 without further ado, I took this as a sufficient reason to fix
> those issues.
> 
> But I see your point in it being useless outside of arm(32) (unless
> Allwinner comes up with a ARMv8 SoC using the "old" crypto engine ;-)
> 
> > But COMPILE_TEST cannot simply be added with those patch since some arches (x86/x86_64 at least) does not have writesl/readsl available.
> 
> So for the records (and interested x86 readers):
> The sunxi-ss driver uses writesl/readsl, which _are_ defined in
> include/asm-generic/io.h. But x86 does not include this header (probably
> for historic reasons). So I added the #include in
> arch/x86/include/asm/io.h, this required to dummy define a lot of
> implemented functions, like:
> #define readb readb
> basically for all MMIO and IO port accessors. After that it worked, I
> could use COMPILE_TEST on the driver and found the same issues as with
> arm64 (which were fixed by my patch).
> 
> Now adding a number of hideous #defines to a core header in an unrelated
> architecture to enable COMPILE_TEST for a single driver seems a bit of a
> stretch to me, so I refrain from sending this out - unless people ask
> for it.
> 
> Boris, do you recall any discussions about asm-generic/io.h on x86 in
> the past?

Bah, I don't remember what I did last week. :-)

Let's CC tip people. I'm leaving in the rest of the mail for reference.

> > The conclusion is that it is simpler to block 64bit build for sun4i-ss.
> 
> OK, I am fine with just adding "&& !64BIT" to the Kconfig entry.
> Actually that was my first impulse on finding this issue, but then I
> felt it a bit cowardly to paper over the problem instead of fixing it.
> 
> So if no-one disagrees, I will include the !64bit dependency in the A64
> enablement series I plan to send out later this week.
> 
> Cheers,
> Andre.
> 

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.