On 01/23/2017 01:43 AM, tip-bot for Kevin Hao wrote:
> diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
> index 1d77704..e287b90 100644
> --- a/arch/x86/kernel/fpu/xstate.c
> +++ b/arch/x86/kernel/fpu/xstate.c
> @@ -1070,6 +1070,7 @@ int copyin_to_xsaves(const void *kbuf, co
* Kevin Hao wrote:
> > other than helping to hide bugs?
>
> Why do you think it hide the bug? In contrast, I think my patch fixes what
> the
> bug really is. The memory area we fake up is bug, we should fix it there.
The intention is to have a single FPU format set at bootup and xcomp_bv is
On Mon, Jan 23, 2017 at 06:38:42PM -0800, Dave Hansen wrote:
> On 01/23/2017 06:09 PM, Kevin Hao wrote:
> > On Mon, Jan 23, 2017 at 06:01:10PM -0800, Dave Hansen wrote:
> >> On 01/23/2017 05:50 PM, Kevin Hao wrote:
> >>> According to the ISA manual, XSAVES also set the XCOMP_BV[62:0]. My code
> >>
On 01/23/2017 06:09 PM, Kevin Hao wrote:
> On Mon, Jan 23, 2017 at 06:01:10PM -0800, Dave Hansen wrote:
>> On 01/23/2017 05:50 PM, Kevin Hao wrote:
>>> According to the ISA manual, XSAVES also set the XCOMP_BV[62:0]. My code
>>> only
>>> try to be compatible with what the cpu does when excuting XS
On Mon, Jan 23, 2017 at 06:01:10PM -0800, Dave Hansen wrote:
> On 01/23/2017 05:50 PM, Kevin Hao wrote:
> > According to the ISA manual, XSAVES also set the XCOMP_BV[62:0]. My code
> > only
> > try to be compatible with what the cpu does when excuting XSAVES. The
> > following
> > is quoted from
On 01/23/2017 05:50 PM, Kevin Hao wrote:
> According to the ISA manual, XSAVES also set the XCOMP_BV[62:0]. My code only
> try to be compatible with what the cpu does when excuting XSAVES. The
> following
> is quoted from 325462-sdm-vol-1-2abcd-3abcd.pdf.
> The XSAVES instructions sets bit 63 of
On Mon, Jan 23, 2017 at 04:53:25PM -0800, Dave Hansen wrote:
> >> The fix I am proposing is...
> >>
> >>state->xsave.header.xcomp_bv = XCOMP_BV_COMPACTED_FORMAT |
> >> xfeatures_mask;
> >
> > Actually I thought about this change before I made this patch, but I
>> The fix I am proposing is...
>>
>> state->xsave.header.xcomp_bv = XCOMP_BV_COMPACTED_FORMAT |
>> xfeatures_mask;
>
> Actually I thought about this change before I made this patch, but I don't
> this
> is the right fix. It is always error prone to init t
On Mon, Jan 23, 2017 at 01:16:40PM -0800, Yu-cheng Yu wrote:
> On Mon, Jan 23, 2017 at 01:10:20PM -0800, Dave Hansen wrote:
> > The code is:
> >
> > > void fpstate_init(union fpregs_state *state)
> > > {
> > > if (!static_cpu_has(X86_FEATURE_FPU)) {
> > > fpstate_init_soft(
On 01/23/2017 01:16 PM, Yu-cheng Yu wrote:
> On Mon, Jan 23, 2017 at 01:10:20PM -0800, Dave Hansen wrote:
>> The code is:
>>
>>> void fpstate_init(union fpregs_state *state)
>>> {
>>> if (!static_cpu_has(X86_FEATURE_FPU)) {
>>> fpstate_init_soft(&state->soft);
>>>
On Mon, Jan 23, 2017 at 01:10:20PM -0800, Dave Hansen wrote:
> The code is:
>
> > void fpstate_init(union fpregs_state *state)
> > {
> > if (!static_cpu_has(X86_FEATURE_FPU)) {
> > fpstate_init_soft(&state->soft);
> > return;
> > }
> >
> > m
On 01/23/2017 12:57 PM, Yu-cheng Yu wrote:
> On Mon, Jan 23, 2017 at 09:23:06AM -0800, Dave Hansen wrote:
>> On 01/23/2017 08:55 AM, Yu-cheng Yu wrote:
The best fix here would be not to paper over the issue in the copy
function but find where it got clobbered, or where some initialization
On Mon, Jan 23, 2017 at 09:23:06AM -0800, Dave Hansen wrote:
> On 01/23/2017 08:55 AM, Yu-cheng Yu wrote:
> >> The best fix here would be not to paper over the issue in the copy
> >> function but find where it got clobbered, or where some initialization
> >> code failed to set it.
> >
> > Someone
On 01/23/2017 08:55 AM, Yu-cheng Yu wrote:
> On Mon, Jan 23, 2017 at 07:36:20AM -0800, Dave Hansen wrote:
>> The kernel xsave buffer should *ALWAYS* have the
>> XCOMP_BV_COMPACTED_FORMAT bit set. It should have been set before the
>> copyin and it should be set when it's finished.
>>
>> The best f
On Mon, Jan 23, 2017 at 07:36:20AM -0800, Dave Hansen wrote:
> The kernel xsave buffer should *ALWAYS* have the
> XCOMP_BV_COMPACTED_FORMAT bit set. It should have been set before the
> copyin and it should be set when it's finished.
>
> The best fix here would be not to paper over the issue in t
On 01/23/2017 12:28 AM, tip-bot for Kevin Hao wrote:
> x86/fpu: Set the xcomp_bv when we fake up a XSAVES area
>
> I got the following calltrace on a Apollo Lake SoC with 32-bit kernel:
...
> --- a/arch/x86/kernel/fpu/xstate.c
> +++ b/arch/x86/kernel/fpu/xstate.c
> @@ -1070,6 +1070,7 @@ int copyi
Commit-ID: 4c833368f0bf748d4147bf301b1f95bc8eccb3c0
Gitweb: http://git.kernel.org/tip/4c833368f0bf748d4147bf301b1f95bc8eccb3c0
Author: Kevin Hao
AuthorDate: Sun, 22 Jan 2017 16:50:23 +0800
Committer: Thomas Gleixner
CommitDate: Mon, 23 Jan 2017 10:40:18 +0100
x86/fpu: Set the xcomp_bv
Commit-ID: 5fa356458b5c918bdf8307b070a3d74bc015d910
Gitweb: http://git.kernel.org/tip/5fa356458b5c918bdf8307b070a3d74bc015d910
Author: Kevin Hao
AuthorDate: Sun, 22 Jan 2017 16:50:23 +0800
Committer: Ingo Molnar
CommitDate: Mon, 23 Jan 2017 09:03:03 +0100
x86/fpu: Set the xcomp_bv when
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