From: Yu-cheng Yu <yu-cheng.yu@intel.com>
To: Dave Hansen <dave.hansen@linux.intel.com>
Cc: x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org, Andy Lutomirski <luto@kernel.org>,
Borislav Petkov <bp@suse.de>,
Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>,
"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
Fenghua Yu <fenghua.yu@intel.com>
Subject: Re: [PATCH v4 04/10] x86/xsaves: Introduce a new check that allows correct xstates copy from kernel to user directly
Date: Mon, 2 May 2016 09:34:10 -0700 [thread overview]
Message-ID: <20160502163410.GA21734@test-lenovo> (raw)
In-Reply-To: <57277B11.9080802@linux.intel.com>
On Mon, May 02, 2016 at 09:06:41AM -0700, Dave Hansen wrote:
> On 05/02/2016 08:57 AM, Yu-cheng Yu wrote:
> > On Fri, Apr 29, 2016 at 05:36:48PM -0700, Dave Hansen wrote:
> >> If may_copy_fpregs_to_sigframe() were called from a slightly different
> >> context, or if we change the call-site, what breaks?
> >>
> >> In other words. if we can still "may_copy_fpregs_to_sigframe()" no
> >> matter the state of fpu.fpstate_active, then I don't think we should be
> >> checking it in may_copy_fpregs_to_sigframe().
> >
> > Do you mean, don't check fpu.fpstate_active here?
>
> Not really. I'm asking *why* the check is there.
If (fpu.fpstate_active == 0), then the task does not use FPU; we don't
want to save these registers, right?
next prev parent reply other threads:[~2016-05-02 16:38 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-04 18:12 [PATCH v4 0/10] x86/xsaves: Fix XSAVES known issues Yu-cheng Yu
2016-03-04 18:12 ` [PATCH v4 01/10] x86/xsaves: Define and use user_xstate_size for xstate size in signal context Yu-cheng Yu
2016-03-04 18:12 ` [PATCH v4 02/10] x86/xsaves: Rename xstate_size to kernel_xstate_size to explicitly distinguish xstate size in kernel from user space Yu-cheng Yu
2016-03-04 18:12 ` [PATCH v4 03/10] x86/xsaves: Keep init_fpstate.xsave.header.xfeatures as zero for init optimization Yu-cheng Yu
2016-03-04 18:12 ` [PATCH v4 04/10] x86/xsaves: Introduce a new check that allows correct xstates copy from kernel to user directly Yu-cheng Yu
2016-04-29 20:09 ` Dave Hansen
2016-04-29 22:43 ` Yu-cheng Yu
2016-04-30 0:36 ` Dave Hansen
2016-05-02 15:57 ` Yu-cheng Yu
2016-05-02 16:06 ` Dave Hansen
2016-05-02 16:34 ` Yu-cheng Yu [this message]
2016-05-02 16:43 ` Dave Hansen
2016-05-02 17:19 ` Yu-cheng Yu
2016-05-02 17:33 ` Dave Hansen
2016-05-02 21:18 ` Yu-cheng Yu
2016-05-02 21:24 ` Yu-cheng Yu
2016-05-02 21:32 ` Dave Hansen
2016-05-02 22:17 ` Yu-cheng Yu
2016-05-02 22:37 ` Dave Hansen
2016-03-04 18:12 ` [PATCH v4 05/10] x86/xsaves: Align xstate components according to CPUID Yu-cheng Yu
2016-04-29 20:11 ` Dave Hansen
2016-03-04 18:12 ` [PATCH v4 06/10] x86/xsaves: Supervisor state component offset Yu-cheng Yu
2016-03-04 18:12 ` [PATCH v4 07/10] x86/xsaves: Fix PTRACE frames for XSAVES Yu-cheng Yu
2016-04-29 20:16 ` Dave Hansen
2016-04-29 20:38 ` Borislav Petkov
2016-04-29 20:40 ` Dave Hansen
2016-04-29 20:46 ` Borislav Petkov
2016-04-29 20:25 ` Dave Hansen
2016-04-29 22:30 ` Yu-cheng Yu
2016-04-29 22:36 ` Dave Hansen
2016-04-29 22:38 ` Yu-cheng Yu
2016-03-04 18:12 ` [PATCH v4 08/10] x86/xsaves: Fix XSTATE component offset print out Yu-cheng Yu
2016-04-29 20:26 ` Dave Hansen
2016-03-04 18:12 ` [PATCH v4 09/10] x86/xsaves: Fix xstate_offsets, xstate_sizes for legacy components Yu-cheng Yu
2016-04-29 20:28 ` Dave Hansen
2016-04-29 22:07 ` Yu-cheng Yu
2016-04-29 22:13 ` Dave Hansen
2016-04-29 22:15 ` Yu-cheng Yu
2016-03-04 18:12 ` [PATCH v4 10/10] x86/xsaves: Re-enable XSAVES Yu-cheng Yu
2016-04-29 20:32 ` Dave Hansen
2016-04-29 23:12 ` Yu-cheng Yu
2016-04-30 0:40 ` Dave Hansen
2016-05-02 16:11 ` Yu-cheng Yu
2016-05-04 22:15 ` Dave Hansen
2016-05-04 22:21 ` Yu-cheng Yu
2016-05-04 22:41 ` Dave Hansen
2016-05-04 22:46 ` Yu-cheng Yu
2016-05-04 22:46 ` Dave Hansen
2016-04-29 18:09 ` [PATCH v4 0/10] x86/xsaves: Fix XSAVES known issues Dave Hansen
2016-04-29 19:43 ` Ingo Molnar
2016-04-29 19:57 ` Yu-cheng Yu
2016-04-29 20:03 ` Dave Hansen
2016-04-29 20:07 ` Yu-cheng Yu
2016-04-29 20:25 ` Andy Lutomirski
2016-04-29 20:40 ` Dave Hansen
2016-04-29 20:49 ` Andy Lutomirski
2016-04-29 22:42 ` Dave Hansen
2016-04-30 7:53 ` Ingo Molnar
2016-05-02 16:28 ` Dave Hansen
2016-05-02 18:32 ` Ingo Molnar
2016-04-29 20:37 ` Dave Hansen
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