From: Rik van Riel <riel@surriel.com>
To: Sebastian Gottschall <s.gottschall@newmedia-net.de>,
Ingo Molnar <mingo@kernel.org>, Jiri Kosina <jikos@kernel.org>
Cc: "Sebastian Andrzej Siewior" <bigeasy@linutronix.de>,
"Andy Lutomirski" <luto@kernel.org>,
"Greg KH" <gregkh@linuxfoundation.org>,
LKML <linux-kernel@vger.kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
"Jason A. Donenfeld" <Jason@zx2c4.com>,
"Ard Biesheuvel" <ard.biesheuvel@linaro.org>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
"Ingo Molnar" <mingo@redhat.com>,
"Nicolai Stange" <nstange@suse.de>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
x86@kernel.org, stable@vger.kernel.org,
"Jiri Kosina" <jikos@jikos.cz>
Subject: Re: [PATCH] x86/fpu: Remove the _GPL from the kernel_fpu_begin/end() export
Date: Sun, 05 May 2019 12:05:32 -0400 [thread overview]
Message-ID: <86b8d81d760ac1f6e622f1c873a5f9aad7862734.camel@surriel.com> (raw)
In-Reply-To: <2238f6ed-9338-903c-760c-6200e73b1599@newmedia-net.de>
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On Sat, 2019-05-04 at 04:28 +0200, Sebastian Gottschall wrote:
> Using fpu code in kernel space in a kernel module is a derived work
> of
> the kernel itself?
> dont get me wrong, but this is absurd. i mean you limit the use of
> cpu
> instructions. the use
> of cpu instructions should be free of any licensing issue. i would
> even
> argument you are violating
> the license of the cpu ower given to the kernel by executing it, by
> restricting its use for no reason
Using FPU code in kernel space in a kernel module
does not require the use of kernel_fpu_begin/end().
The kernel module could simply disable preemption,
save the FPU registers, use the FPU, restore the
FPU registers, and reenable preemption.
However, using kernel_fpu_begin/end() does get that
module some nice optimizations that are specific to
Linux.
--
All Rights Reversed.
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next prev parent reply other threads:[~2019-05-05 16:05 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-02 14:42 Andy Lutomirski
2019-05-02 15:40 ` Sebastian Andrzej Siewior
2019-05-02 16:29 ` Andy Lutomirski
2019-05-02 16:55 ` Borislav Petkov
2019-05-03 17:21 ` Paolo Bonzini
2019-05-03 18:07 ` Borislav Petkov
2019-05-03 18:54 ` Andy Lutomirski
2019-05-03 19:07 ` Borislav Petkov
2019-05-03 18:49 ` Jiri Kosina
2019-05-04 0:47 ` Ingo Molnar
2019-05-04 2:28 ` Sebastian Gottschall
2019-05-04 6:40 ` Greg KH
2019-05-05 16:05 ` Rik van Riel [this message]
2019-05-05 19:09 ` Jiri Kosina
2019-05-04 7:26 ` Jiri Kosina
2019-05-07 10:31 ` David Laight
2019-05-08 12:28 ` Sebastian Gottschall
2019-05-08 12:51 ` Greg KH
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