From: Borislav Petkov <bp@alien8.de>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org,
"Andy Lutomirski" <luto@kernel.org>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
kvm@vger.kernel.org, "Jason A. Donenfeld" <Jason@zx2c4.com>,
"Rik van Riel" <riel@surriel.com>,
"Dave Hansen" <dave.hansen@linux.intel.com>
Subject: Re: [PATCH 05/22] x86/fpu: Remove fpu->initialized usage in copy_fpstate_to_sigframe()
Date: Wed, 16 Jan 2019 20:36:03 +0100 [thread overview]
Message-ID: <20190116193603.GK15409@zn.tnic> (raw)
In-Reply-To: <20190109114744.10936-6-bigeasy@linutronix.de>
On Wed, Jan 09, 2019 at 12:47:27PM +0100, Sebastian Andrzej Siewior wrote:
> Since ->initialized is always true for user tasks and kernel threads
> don't get this far,
Yeah, this is commit message is too laconic. Don'g get this far "where"?
> we always save the registers directly to userspace.
We don't save registers to userspace - please write stuff out.
So from looking at what you're removing I can barely rhyme up what
you're doing but this needs a lot more explanation why it is OK to
remove the else case. Hell, why was the thing added in the first place
if ->initialized is always true?
And why is it ok to save registers directly to the user task's buffers?
So please be more verbose even at the risk of explaning the obvious.
This is the FPU code, remember? :)
Thx.
--
Regards/Gruss,
Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
next prev parent reply other threads:[~2019-01-16 19:36 UTC|newest]
Thread overview: 91+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-09 11:47 [PATCH v6] x86: load FPU registers on return to userland Sebastian Andrzej Siewior
2019-01-09 11:47 ` [PATCH 01/22] x86/fpu: Remove fpu->initialized usage in __fpu__restore_sig() Sebastian Andrzej Siewior
2019-01-14 16:24 ` Borislav Petkov
2019-02-05 10:08 ` Sebastian Andrzej Siewior
2019-01-09 11:47 ` [PATCH 02/22] x86/fpu: Remove fpu__restore() Sebastian Andrzej Siewior
2019-01-09 11:47 ` [PATCH 03/22] x86/fpu: Remove preempt_disable() in fpu__clear() Sebastian Andrzej Siewior
2019-01-14 18:55 ` Borislav Petkov
2019-01-09 11:47 ` [PATCH 04/22] x86/fpu: Always init the `state' " Sebastian Andrzej Siewior
2019-01-14 19:32 ` Borislav Petkov
2019-01-09 11:47 ` [PATCH 05/22] x86/fpu: Remove fpu->initialized usage in copy_fpstate_to_sigframe() Sebastian Andrzej Siewior
2019-01-16 19:36 ` Borislav Petkov [this message]
2019-01-16 22:40 ` Sebastian Andrzej Siewior
2019-01-17 12:22 ` Borislav Petkov
2019-01-18 21:14 ` Sebastian Andrzej Siewior
2019-01-18 21:17 ` Dave Hansen
2019-01-18 21:37 ` Sebastian Andrzej Siewior
2019-01-18 21:43 ` Dave Hansen
2019-01-21 11:21 ` Oleg Nesterov
2019-01-22 13:40 ` Borislav Petkov
2019-01-22 16:15 ` Oleg Nesterov
2019-01-22 17:00 ` Borislav Petkov
2019-02-05 11:34 ` Sebastian Andrzej Siewior
2019-02-05 11:17 ` Sebastian Andrzej Siewior
2019-02-26 16:38 ` Oleg Nesterov
2019-03-08 18:12 ` Sebastian Andrzej Siewior
2019-02-05 14:37 ` [PATCH 05/22 v2] " Sebastian Andrzej Siewior
2019-01-09 11:47 ` [PATCH 06/22] x86/fpu: Don't save fxregs for ia32 frames " Sebastian Andrzej Siewior
2019-01-24 11:17 ` Borislav Petkov
2019-02-05 16:43 ` [PATCH 06/22 v2] x86/fpu: Don't save fxregs for ia32 frames in Sebastian Andrzej Siewior
2019-01-09 11:47 ` [PATCH 07/22] x86/fpu: Remove fpu->initialized Sebastian Andrzej Siewior
2019-01-24 13:34 ` Borislav Petkov
2019-02-05 18:03 ` Sebastian Andrzej Siewior
2019-02-06 14:01 ` Borislav Petkov
2019-02-07 10:13 ` Sebastian Andrzej Siewior
2019-02-07 10:37 ` Borislav Petkov
2019-02-05 18:06 ` [PATCH 07/22 v2] " Sebastian Andrzej Siewior
2019-01-09 11:47 ` [PATCH 08/22] x86/fpu: Remove user_fpu_begin() Sebastian Andrzej Siewior
2019-01-25 15:18 ` Borislav Petkov
2019-02-05 18:16 ` Sebastian Andrzej Siewior
2019-01-09 11:47 ` [PATCH 09/22] x86/fpu: Add (__)make_fpregs_active helpers Sebastian Andrzej Siewior
2019-01-28 18:23 ` Borislav Petkov
2019-02-07 10:43 ` Sebastian Andrzej Siewior
2019-02-13 9:30 ` Borislav Petkov
2019-02-14 14:51 ` Sebastian Andrzej Siewior
2019-01-09 11:47 ` [PATCH 10/22] x86/fpu: Make __raw_xsave_addr() use feature number instead of mask Sebastian Andrzej Siewior
2019-01-28 18:30 ` Borislav Petkov
2019-01-09 11:47 ` [PATCH 11/22] x86/fpu: Make get_xsave_field_ptr() and get_xsave_addr() " Sebastian Andrzej Siewior
2019-01-28 18:49 ` Borislav Petkov
2019-02-07 11:13 ` Sebastian Andrzej Siewior
2019-02-13 9:31 ` Borislav Petkov
2019-01-09 11:47 ` [PATCH 12/22] x86/fpu: Only write PKRU if it is different from current Sebastian Andrzej Siewior
2019-01-23 18:09 ` Dave Hansen
2019-02-07 11:27 ` Sebastian Andrzej Siewior
2019-01-09 11:47 ` [PATCH 13/22] x86/pkeys: Don't check if PKRU is zero before writting it Sebastian Andrzej Siewior
2019-01-09 11:47 ` [PATCH 14/22] x86/fpu: Eager switch PKRU state Sebastian Andrzej Siewior
2019-01-09 11:47 ` [PATCH 15/22] x86/entry: Add TIF_NEED_FPU_LOAD Sebastian Andrzej Siewior
2019-01-30 11:55 ` Borislav Petkov
2019-02-07 11:49 ` Sebastian Andrzej Siewior
2019-02-13 9:35 ` Borislav Petkov
2019-02-14 15:28 ` Sebastian Andrzej Siewior
2019-01-09 11:47 ` [PATCH 16/22] x86/fpu: Always store the registers in copy_fpstate_to_sigframe() Sebastian Andrzej Siewior
2019-01-30 11:43 ` Borislav Petkov
2019-02-07 13:28 ` Sebastian Andrzej Siewior
2019-01-09 11:47 ` [PATCH 17/22] x86/fpu: Prepare copy_fpstate_to_sigframe() for TIF_NEED_FPU_LOAD Sebastian Andrzej Siewior
2019-01-30 11:56 ` Borislav Petkov
2019-01-30 12:28 ` Sebastian Andrzej Siewior
2019-01-30 12:53 ` Borislav Petkov
2019-02-07 14:10 ` Sebastian Andrzej Siewior
2019-01-09 11:47 ` [PATCH 18/22] x86/fpu: Update xstate's PKRU value on write_pkru() Sebastian Andrzej Siewior
2019-01-23 17:28 ` Dave Hansen
2019-01-09 11:47 ` [PATCH 19/22] x86/fpu: Inline copy_user_to_fpregs_zeroing() Sebastian Andrzej Siewior
2019-01-09 11:47 ` [PATCH 20/22] x86/fpu: Let __fpu__restore_sig() restore the !32bit+fxsr frame from kernel memory Sebastian Andrzej Siewior
2019-01-30 21:29 ` Borislav Petkov
2019-01-09 11:47 ` [PATCH 21/22] x86/fpu: Merge the two code paths in __fpu__restore_sig() Sebastian Andrzej Siewior
2019-01-09 11:47 ` [PATCH 22/22] x86/fpu: Defer FPU state load until return to userspace Sebastian Andrzej Siewior
2019-01-31 9:16 ` Borislav Petkov
2019-01-15 12:44 ` [PATCH v6] x86: load FPU registers on return to userland David Laight
2019-01-15 13:15 ` 'Sebastian Andrzej Siewior'
2019-01-15 14:33 ` David Laight
2019-01-15 19:46 ` Dave Hansen
2019-01-15 20:26 ` Andy Lutomirski
2019-01-15 20:54 ` Dave Hansen
2019-01-15 21:11 ` Andy Lutomirski
2019-01-16 10:31 ` David Laight
2019-01-16 10:18 ` David Laight
2019-01-30 11:35 ` Borislav Petkov
2019-01-30 12:06 ` Sebastian Andrzej Siewior
2019-01-30 12:27 ` Borislav Petkov
2019-02-08 13:12 ` Sebastian Andrzej Siewior
2019-02-13 15:54 ` Sebastian Andrzej Siewior
2019-02-21 11:49 [PATCH v7] " Sebastian Andrzej Siewior
2019-02-21 11:50 ` [PATCH 05/22] x86/fpu: Remove fpu->initialized usage in copy_fpstate_to_sigframe() Sebastian Andrzej Siewior
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