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Sender: Guenter Roeck <groeck7@gmail.com>
Date: Mon, 22 Jan 2024 08:40:25 -0800
From: Guenter Roeck <linux@roeck-us.net>
To: Charlie Jenkins <charlie@rivosinc.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>, Conor Dooley <conor@kernel.org>,
	Samuel Holland <samuel.holland@sifive.com>,
	David Laight <David.Laight@aculab.com>,
	Xiao Wang <xiao.w.wang@intel.com>, Evan Green <evan@rivosinc.com>,
	Guo Ren <guoren@kernel.org>, linux-riscv@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Albert Ou <aou@eecs.berkeley.edu>, Arnd Bergmann <arnd@arndb.de>
Subject: Re: [PATCH v15 5/5] kunit: Add tests for csum_ipv6_magic and
 ip_fast_csum
Message-ID: <2c8e98b6-336e-4bc7-81ba-5a4d35ac868a@roeck-us.net>
References: <20240108-optimize_checksum-v15-0-1c50de5f2167@rivosinc.com>
 <20240108-optimize_checksum-v15-5-1c50de5f2167@rivosinc.com>
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In-Reply-To: <20240108-optimize_checksum-v15-5-1c50de5f2167@rivosinc.com>

Hi,

On Mon, Jan 08, 2024 at 03:57:06PM -0800, Charlie Jenkins wrote:
> Supplement existing checksum tests with tests for csum_ipv6_magic and
> ip_fast_csum.
> 
> Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
> ---

With this patch in the tree, the arm:mps2-an385 qemu emulation gets a bad hiccup.

[    1.839556] Unhandled exception: IPSR = 00000006 LR = fffffff1
[    1.839804] CPU: 0 PID: 164 Comm: kunit_try_catch Tainted: G                 N 6.8.0-rc1 #1
[    1.839948] Hardware name: Generic DT based system
[    1.840062] PC is at __csum_ipv6_magic+0x8/0xb4
[    1.840408] LR is at test_csum_ipv6_magic+0x3d/0xa4
[    1.840493] pc : [<21212f34>]    lr : [<21117fd5>]    psr: 0100020b
[    1.840586] sp : 2180bebc  ip : 46c7f0d2  fp : 21275b38
[    1.840664] r10: 21276b60  r9 : 21275b28  r8 : 21465cfc
[    1.840751] r7 : 00003085  r6 : 21275b4e  r5 : 2138702c  r4 : 00000001
[    1.840847] r3 : 2c000000  r2 : 1ac7f0d2  r1 : 21275b39  r0 : 21275b29
[    1.840942] xPSR: 0100020b

This translates to:

PC is at __csum_ipv6_magic (arch/arm/lib/csumipv6.S:15)
LR is at test_csum_ipv6_magic (./arch/arm/include/asm/checksum.h:60 ./arch/arm/include/asm/checksum.h:163 lib/checksum_kunit.c:617)

Obviously I can not say if this is a problem with qemu or a problem with
the Linux kernel. Given that, and the presumably low interest in
running mps2-an385 with Linux, I'll simply disable that test. Just take
it as a heads up that there _may_ be a problem with this on arm
nommu systems.

Thanks,
Guenter