Re: [PATCH v3 4/8] powerpc/pseries/svm: Add a powerpc version of cc_platform_has()

From: Michael Ellerman <mpe@ellerman.id.au>
To: Borislav Petkov <bp@alien8.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>,
	linux-kernel@vger.kernel.org, x86@kernel.org,
	linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org,
	iommu@lists.linux-foundation.org, kvm@vger.kernel.org,
	linux-efi@vger.kernel.org, platform-driver-x86@vger.kernel.org,
	linux-graphics-maintainer@vmware.com,
	amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
	kexec@lists.infradead.org, linux-fsdevel@vger.kernel.org,
	Brijesh Singh <brijesh.singh@amd.com>,
	Joerg Roedel <joro@8bytes.org>, Andi Kleen <ak@linux.intel.com>,
	Sathyanarayanan Kuppuswamy 
	<sathyanarayanan.kuppuswamy@linux.intel.com>,
	Tianyu Lan <Tianyu.Lan@microsoft.com>,
	Christoph Hellwig <hch@infradead.org>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>
Subject: Re: [PATCH v3 4/8] powerpc/pseries/svm: Add a powerpc version of cc_platform_has()
Date: Wed, 15 Sep 2021 10:28:59 +1000	[thread overview]
Message-ID: <87lf3yk7g4.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <YUCOTIPPsJJpLO/d@zn.tnic>

Borislav Petkov <bp@alien8.de> writes:
> On Wed, Sep 08, 2021 at 05:58:35PM -0500, Tom Lendacky wrote:
>> Introduce a powerpc version of the cc_platform_has() function. This will
>> be used to replace the powerpc mem_encrypt_active() implementation, so
>> the implementation will initially only support the CC_ATTR_MEM_ENCRYPT
>> attribute.
>> 
>> Cc: Michael Ellerman <mpe@ellerman.id.au>
>> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
>> Cc: Paul Mackerras <paulus@samba.org>
>> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
>> ---
>>  arch/powerpc/platforms/pseries/Kconfig       |  1 +
>>  arch/powerpc/platforms/pseries/Makefile      |  2 ++
>>  arch/powerpc/platforms/pseries/cc_platform.c | 26 ++++++++++++++++++++
>>  3 files changed, 29 insertions(+)
>>  create mode 100644 arch/powerpc/platforms/pseries/cc_platform.c
>
> Michael,
>
> can I get an ACK for the ppc bits to carry them through the tip tree
> pls?

Yeah.

I don't love it, a new C file and an out-of-line call to then call back
to a static inline that for most configuration will return false ... but
whatever :)

Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)

> Btw, on a related note, cross-compiling this throws the following error here:
>
> $ make CROSS_COMPILE=/home/share/src/crosstool/gcc-9.4.0-nolibc/powerpc64-linux/bin/powerpc64-linux- V=1 ARCH=powerpc
>
> ...
>
> /home/share/src/crosstool/gcc-9.4.0-nolibc/powerpc64-linux/bin/powerpc64-linux-gcc -Wp,-MD,arch/powerpc/boot/.crt0.o.d -D__ASSEMBLY__ -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing -O2 -msoft-float -mno-altivec -mno-vsx -pipe -fomit-frame-pointer -fno-builtin -fPIC -nostdinc -include ./include/linux/compiler_attributes.h -I./arch/powerpc/include -I./arch/powerpc/include/generated  -I./include -I./arch/powerpc/include/uapi -I./arch/powerpc/include/generated/uapi -I./include/uapi -I./include/generated/uapi -include ./include/linux/compiler-version.h -include ./include/linux/kconfig.h -m32 -isystem /home/share/src/crosstool/gcc-9.4.0-nolibc/powerpc64-linux/bin/../lib/gcc/powerpc64-linux/9.4.0/include -mbig-endian -nostdinc -c -o arch/powerpc/boot/crt0.o arch/powerpc/boot/crt0.S
> In file included from <command-line>:
> ././include/linux/compiler_attributes.h:62:5: warning: "__has_attribute" is not defined, evaluates to 0 [-Wundef]
>    62 | #if __has_attribute(__assume_aligned__)
>       |     ^~~~~~~~~~~~~~~
> ././include/linux/compiler_attributes.h:62:20: error: missing binary operator before token "("
>    62 | #if __has_attribute(__assume_aligned__)
>       |                    ^
> ././include/linux/compiler_attributes.h:88:5: warning: "__has_attribute" is not defined, evaluates to 0 [-Wundef]
>    88 | #if __has_attribute(__copy__)
>       |     ^~~~~~~~~~~~~~~
> ...
>
> Known issue?

Yeah, fixed in mainline today, thanks for trying to cross compile :)

cheers