mirror of https://lore.kernel.org/lkml/
 help / color / mirror / Atom feed
From: Krzysztof Mazur <krzysiek@podlesie.net>
To: Andy Lutomirski <luto@kernel.org>
Cc: x86@kernel.org, LKML <linux-kernel@vger.kernel.org>,
	"Krzysztof Olędzki" <ole@ans.pl>, "Arnd Bergmann" <arnd@arndb.de>,
	stable@vger.kernel.org
Subject: Re: [PATCH v3 2/4] x86/mmx: Use KFPU_387 for MMX string operations
Date: Thu, 21 Jan 2021 12:29:57 +0100	[thread overview]
Message-ID: <20210121112957.GA16586@shrek.podlesie.net> (raw)
In-Reply-To: <e7bf21855fe99e5f3baa27446e32623358f69e8d.1611205691.git.luto@kernel.org>

On Wed, Jan 20, 2021 at 09:09:49PM -0800, Andy Lutomirski wrote:
> The default kernel_fpu_begin() doesn't work on systems that support XMM but
> haven't yet enabled CR4.OSFXSR.  This causes crashes when _mmx_memcpy() is
> called too early because LDMXCSR generates #UD when the aforementioned bit
> is clear.
> 
> Fix it by using kernel_fpu_begin_mask(KFPU_387) explicitly.
> 
> Fixes: 7ad816762f9b ("x86/fpu: Reset MXCSR to default in kernel_fpu_begin()")
> Cc: <stable@vger.kernel.org>
> Reported-by: Krzysztof Mazur <krzysiek@podlesie.net>
> Signed-off-by: Andy Lutomirski <luto@kernel.org>
> ---
>  arch/x86/lib/mmx_32.c | 20 +++++++++++++++-----
>  1 file changed, 15 insertions(+), 5 deletions(-)

Thanks, 5.10 + this patch series boots on K7 with SSE.

Tested-by: Krzysztof Mazur <krzysiek@podlesie.net>

Regards,
Krzysiek

  reply	other threads:[~2021-01-21 11:32 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-21  5:09 [PATCH v3 0/4] x86/fpu: Reduce unnecessary FNINIT and MXCSR usage Andy Lutomirski
2021-01-21  5:09 ` [PATCH v3 1/4] x86/fpu: Add kernel_fpu_begin_mask() to selectively initialize state Andy Lutomirski
2021-01-21 14:26   ` [tip: x86/urgent] " tip-bot2 for Andy Lutomirski
2021-01-21  5:09 ` [PATCH v3 2/4] x86/mmx: Use KFPU_387 for MMX string operations Andy Lutomirski
2021-01-21 11:29   ` Krzysztof Mazur [this message]
2021-01-21 14:26   ` [tip: x86/urgent] " tip-bot2 for Andy Lutomirski
2021-01-21  5:09 ` [PATCH v3 3/4] x86/fpu: Make the EFI FPU calling convention explicit Andy Lutomirski
2021-01-21  5:09 ` [PATCH v3 4/4] x86/fpu/64: Don't FNINIT in kernel_fpu_begin() Andy Lutomirski
2021-01-21  9:29 ` [PATCH v3 0/4] x86/fpu: Reduce unnecessary FNINIT and MXCSR usage Krzysztof Olędzki

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210121112957.GA16586@shrek.podlesie.net \
    --to=krzysiek@podlesie.net \
    --cc=arnd@arndb.de \
    --cc=linux-kernel@vger.kernel.org \
    --cc=luto@kernel.org \
    --cc=ole@ans.pl \
    --cc=stable@vger.kernel.org \
    --cc=x86@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®