Received-SPF: pass (google.com: domain of linux-kernel+bounces-195568-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) client-ip=2604:1380:4601:e00::3;
Message-ID: <f12ab64f-fd59-491e-a44a-6ae570a81ada@heusipp.de>
Date: Thu, 30 May 2024 17:05:33 +0200
Precedence: bulk
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
Subject: Re: [tip: x86/urgent] x86/cpu: Provide default cache line size if not
 enumerated
To: linux-kernel@vger.kernel.org, Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
 stable@vger.kernel.org, x86@kernel.org, Thomas Gleixner
 <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>,
 Borislav Petkov <bp@alien8.de>, Andy Lutomirski <luto@kernel.org>,
 Peter Zijlstra <peterz@infradead.org>, Adam Dunlap <acdunlap@google.com>
References: <171707898810.10875.17950546903678321366.tip-bot2@tip-bot2>
Content-Language: en-US
From: =?UTF-8?Q?J=C3=B6rn_Heusipp?= <osmanx@heusipp.de>
In-Reply-To: <171707898810.10875.17950546903678321366.tip-bot2@tip-bot2>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: quoted-printable
UI-OutboundReport: notjunk:1;M01:P0:bHyNZgwEtmQ=;ry7j9VPvrIDQ6l4YE8cO0qjgyHI
 1S7/s7sGiYENwZb401zw2Nsig162np+buJUBUNvQN2QoRdZcD0/QW2uj8ujdUpB0BOt+3qhvS
 ZCl0oPHW6UyBsA1vsvgqPrh31Y7NrpwmCHDqs9TFOkeNEIxelbLw93oaTMjGlUqUJe/h9eiCY
 wui3O/svluhwOafr1ln3bLyX86U9QjAH6WaB7DSpAGYYRqDX8WTYL9XEQ0sqskXgmxMUOav5d
 kw/YSBfDxlmhrHtmeEc0jxuGvPHMVq5jz6e5K+1macrr9dLvZfwp1hM61l0/KiJa7U/OOWBcB
 dtmzdN+iWaI6ksL9FCs+H8dD0yuils1EQ95Bh3JAImlV7c5rY8c08AyqHjY8yOWQKdkMD7NR7
 d5hY4IaEd0blkLMjEuV4Rzmprz0tSeUt+0pHIWKwOydqPurtdSqsn0hgQ7QOKi3pq598OsCKt
 4Q+yudpBUNG0wqzR0jPlOv+oSNgFRxtGtU5SrEJzuZn5pc9sRZkyOyyvBcUmeeyOjBVuxUwzY
 bUtcaRcy3F4+JTN/TOanST5+w+fq0GFZZHIUpYYlMV3yP8dC09QynEyk1i+4BJCTeaSK95mr1
 mL31lP/8BdQXEjRF4RfFI1HEc/HqlHDlX/st6W7HOAvqpQydYKXhUnpegXvlNCxJYgKPSCmSn
 6XWfwvdT5oLvrrN2/qOl16Rfr8SvX/2X5z0d7kObQfgJQcFIqUWQCe3fKf8P6AFeWzRk9Wr7q
 3PPeNVDF9wjYv63laKapQcfoY7ipu1Nw5Ru/QJhb0EWZ3u+JlAZLmo=


Hello Dave!

On 30/05/2024 16:23, tip-bot2 for Dave Hansen wrote:
> The following commit has been merged into the x86/urgent branch of tip:
>
> Commit-ID:     b9210e56d71d9deb1ad692e405f6b2394f7baa4d
> Gitweb:        https://git.kernel.org/tip/b9210e56d71d9deb1ad692e405f6b2=
394f7baa4d
> Author:        Dave Hansen <dave.hansen@linux.intel.com>
> AuthorDate:    Fri, 17 May 2024 13:05:34 -07:00
> Committer:     Dave Hansen <dave.hansen@linux.intel.com>
> CommitterDate: Thu, 30 May 2024 07:14:27 -07:00

> Tested-by: J=C3=B6rn Heusipp <osmanx@heusipp.de>

> diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
> index 2b170da..373b16b 100644
> --- a/arch/x86/kernel/cpu/common.c
> +++ b/arch/x86/kernel/cpu/common.c
> @@ -1070,6 +1070,10 @@ void get_cpu_address_sizes(struct cpuinfo_x86 *c)
>   			    cpu_has(c, X86_FEATURE_PSE36))
>   				c->x86_phys_bits =3D 36;
>   		}
> +
> +		/* Provide a sane default if not enumerated: */
> +		if (!c->x86_clflush_size)
> +			c->x86_clflush_size =3D 32;
>   	} else {
>   		cpuid(0x80000008, &eax, &ebx, &ecx, &edx);
>

That honestly looks like a mis-merge to me. This is not what I did test.
x86_clflush_size needs to get set in the top-level else branch in which
it is not already set. commit 95bfb35269b2e85cff0dd2c957b2d42ebf95ae5f
had switched the if branches around.

Best regards,
J=C3=B6rn