linux-kernel - Re: [PATCH 2/3] x86, fpu: always allow FPU in interrupt if use_eager

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20150220214805.GM19378@pd.tnic>
Date:	Fri, 20 Feb 2015 22:48:05 +0100
From:	Borislav Petkov <bp@...en8.de>
To:	Oleg Nesterov <oleg@...hat.com>
Cc:	Rik van Riel <riel@...hat.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Suresh Siddha <sbsiddha@...il.com>,
	linux-kernel@...r.kernel.org, mingo@...hat.com, hpa@...or.com,
	matt.fleming@...el.com, bp@...e.de, pbonzini@...hat.com,
	tglx@...utronix.de, luto@...capital.net
Subject: Re: [PATCH 2/3] x86, fpu: always allow FPU in interrupt if
 use_eager_fpu()

On Mon, Jan 19, 2015 at 07:51:51PM +0100, Oleg Nesterov wrote:
> The __thread_has_fpu() check in interrupted_kernel_fpu_idle() was needed
> to prevent the nested kernel_fpu_begin(). Now that we have in_kernel_fpu
> and !__thread_has_fpu() case in __kernel_fpu_begin() does not depend on
> use_eager_fpu() (except clts) we can remove it.
> 
> __thread_has_fpu() can be false even if use_eager_fpu(), but this case
> does not differ from !use_eager_fpu() case except we should not worry
> about X86_CR0_TS, __kernel_fpu_begin/end will not touch this bit.
> 
> Note: I think we can kill all irq_fpu_usable() checks except in_kernel_fpu,
> just we need to record the state of X86_CR0_TS in __kernel_fpu_begin() and
> conditionalize stts() in __kernel_fpu_end(), but this needs another patch.
> 
> Signed-off-by: Oleg Nesterov <oleg@...hat.com>

Applied, thanks.

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
--
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/