From: Nate Eldredge <nate@thatsmathematics.com>
To: Suresh Siddha <sbsiddha@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
the arch/x86 maintainers <x86@kernel.org>,
stable <stable@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Maarten Baert <maarten-baert@hotmail.com>,
Jan Kara <jack@suse.cz>, George Spelvin <linux@horizon.com>,
Pekka Riikonen <priikone@iki.fi>
Subject: Re: [PATCH] Make math_state_restore() save and restore the interrupt flag
Date: Wed, 5 Feb 2014 22:26:24 -0700 (MST) [thread overview]
Message-ID: <alpine.DEB.2.10.1402052224200.2702@minerva.lan> (raw)
In-Reply-To: <1391410583.3801.6.camel@europa>
On Sun, 2 Feb 2014, Suresh Siddha wrote:
> Here is the second patch, which should fix the issue reported in this
> thread. Maarten, Nate, George, please give this patch a try as is and
> see if it helps address the issue you ran into. And please ack/review
> with your test results.
3.13 plus this patch: boots and fixes the testcase I reported (core dump
on ecrypt).
Tested-by: Nate Eldredge <nate@thatsmathematics.com>
> diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
> index 4e5f770..670bba1 100644
> --- a/arch/x86/kernel/i387.c
> +++ b/arch/x86/kernel/i387.c
> @@ -87,10 +87,19 @@ EXPORT_SYMBOL(__kernel_fpu_begin);
>
> void __kernel_fpu_end(void)
> {
> - if (use_eager_fpu())
> - math_state_restore();
> - else
> + if (use_eager_fpu()) {
> + /*
> + * For eager fpu, most the time, tsk_used_math() is true.
> + * Restore the user math as we are done with the kernel usage.
> + * At few instances during thread exit, signal handling etc,
> + * tsk_used_math() is false. Those few places will take proper
> + * actions, so we don't need to restore the math here.
> + */
> + if (likely(tsk_used_math(current)))
> + math_state_restore();
> + } else {
> stts();
> + }
> }
> EXPORT_SYMBOL(__kernel_fpu_end);
--
Nate Eldredge
nate@thatsmathematics.com
next prev parent reply other threads:[~2014-02-06 5:26 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-30 22:01 [PATCH] Make math_state_restore() save and restore the interrupt flag Nate Eldredge
2014-01-30 22:24 ` Linus Torvalds
2014-01-31 7:33 ` Suresh Siddha
2014-02-01 19:27 ` Linus Torvalds
2014-02-01 19:35 ` H. Peter Anvin
2014-02-01 19:46 ` Linus Torvalds
2014-02-01 20:00 ` H. Peter Anvin
2014-02-01 20:16 ` Linus Torvalds
2014-02-01 20:16 ` H. Peter Anvin
2014-02-01 21:17 ` George Spelvin
2014-02-01 21:36 ` H. Peter Anvin
2014-02-01 23:40 ` H. Peter Anvin
2014-02-02 0:17 ` Linus Torvalds
2014-02-02 1:19 ` George Spelvin
2014-02-02 1:25 ` H. Peter Anvin
2014-02-02 8:45 ` Pekka Riikonen
2014-02-02 1:06 ` Suresh Siddha
2014-02-02 1:26 ` H. Peter Anvin
2014-02-02 1:35 ` Suresh Siddha
2014-02-02 1:38 ` Linus Torvalds
2014-02-02 1:47 ` Suresh Siddha
2014-02-02 1:51 ` Linus Torvalds
2014-02-02 1:57 ` H. Peter Anvin
2014-02-02 2:05 ` Linus Torvalds
2014-02-02 2:12 ` H. Peter Anvin
2014-02-02 1:59 ` Suresh Siddha
2014-02-02 1:43 ` H. Peter Anvin
2014-02-02 1:47 ` Linus Torvalds
2014-02-02 7:19 ` Suresh Siddha
2014-02-02 19:15 ` Linus Torvalds
2014-02-03 6:56 ` Suresh Siddha
2014-02-03 18:20 ` Linus Torvalds
2014-02-04 6:03 ` Suresh Siddha
2014-02-06 5:26 ` Nate Eldredge [this message]
2014-02-06 5:34 ` George Spelvin
2014-02-13 15:45 ` Maarten Baert
2014-02-13 20:00 ` George Spelvin
2014-03-11 19:36 ` [tip:x86/urgent] x86, fpu: Check tsk_used_math() in kernel_fpu_end() for eager FPU tip-bot for Suresh Siddha
2014-02-27 23:44 ` [PATCH] Make math_state_restore() save and restore the interrupt flag H. Peter Anvin
2014-03-07 23:18 ` H. Peter Anvin
2014-03-08 6:18 ` Suresh Siddha
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