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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: linux-kernel@vger.kernel.org
Cc: 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>,
	"Sebastian Andrzej Siewior" <bigeasy@linutronix.de>
Subject: [RFC PATCH 05/10] x86/pkeys: Drop the preempt-disable section
Date: Wed, 12 Sep 2018 15:33:48 +0200	[thread overview]
Message-ID: <20180912133353.20595-6-bigeasy@linutronix.de> (raw)
In-Reply-To: <20180912133353.20595-1-bigeasy@linutronix.de>

From: Rik van Riel <riel@surriel.com>

The fpu->initialized flag should not be changed underneath us. This might be a
fallout during the removal of the LazyFPU support. The FPU is marked
initialized as soon as the state has been set to an initial value. It does not
signal if the CPU's FPU registers are loaded.

Signed-off-by: Rik van Riel <riel@surriel.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 arch/x86/mm/pkeys.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/arch/x86/mm/pkeys.c b/arch/x86/mm/pkeys.c
index c7a7b6bd64009..6e91529fe2a30 100644
--- a/arch/x86/mm/pkeys.c
+++ b/arch/x86/mm/pkeys.c
@@ -53,17 +53,13 @@ int __execute_only_pkey(struct mm_struct *mm)
 	 * dance to set PKRU if we do not need to.  Check it
 	 * first and assume that if the execute-only pkey is
 	 * write-disabled that we do not have to set it
-	 * ourselves.  We need preempt off so that nobody
-	 * can make fpregs inactive.
+	 * ourselves.
 	 */
-	preempt_disable();
 	if (!need_to_set_mm_pkey &&
 	    current->thread.fpu.initialized &&
 	    !__pkru_allows_read(read_pkru(), execute_only_pkey)) {
-		preempt_enable();
 		return execute_only_pkey;
 	}
-	preempt_enable();
 
 	/*
 	 * Set up PKRU so that it denies access for everything
-- 
2.19.0


  parent reply	other threads:[~2018-09-12 13:36 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-12 13:33 [RFC PATCH] x86: load FPU registers on return to userland Sebastian Andrzej Siewior
2018-09-12 13:33 ` [RFC PATCH 01/10] x86/entry: remove _TIF_ALLWORK_MASK Sebastian Andrzej Siewior
2018-09-27 14:21   ` Sebastian Andrzej Siewior
2018-09-12 13:33 ` [RFC PATCH 02/10] kvm: x86: make kvm_{load|put}_guest_fpu() static Sebastian Andrzej Siewior
2018-09-12 13:33 ` [RFC PATCH 03/10] x86/fpu: add (__)make_fpregs_active helpers Sebastian Andrzej Siewior
2018-09-12 13:33 ` [RFC PATCH 04/10] x86/fpu: eager switch PKRU state Sebastian Andrzej Siewior
2018-09-12 14:18   ` Paolo Bonzini
2018-09-12 15:24     ` Andy Lutomirski
2018-09-12 15:30       ` Paolo Bonzini
2018-09-14 20:35     ` [RFC PATCH 04/10 v2 ] " Sebastian Andrzej Siewior
2018-09-17  8:37       ` Paolo Bonzini
2018-09-18 14:27         ` Sebastian Andrzej Siewior
2018-09-18 15:07           ` Paolo Bonzini
2018-09-18 15:11             ` Rik van Riel
2018-09-18 15:29               ` Paolo Bonzini
2018-09-18 16:04                 ` Sebastian Andrzej Siewior
2018-09-18 17:29                   ` Rik van Riel
2018-09-19  5:55                     ` Paolo Bonzini
2018-09-19 16:57                       ` Sebastian Andrzej Siewior
2018-09-19 17:00                         ` Paolo Bonzini
2018-09-19 17:19                           ` Sebastian Andrzej Siewior
2018-09-19 19:38                           ` Rik van Riel
2018-09-19 19:49                           ` Andy Lutomirski
2018-09-12 15:20   ` [RFC PATCH 04/10] " Andy Lutomirski
2018-09-12 15:30     ` Rik van Riel
2018-09-12 15:49       ` Andy Lutomirski
2018-09-19 16:58         ` Sebastian Andrzej Siewior
2018-09-12 13:33 ` Sebastian Andrzej Siewior [this message]
2018-09-12 13:33 ` [RFC PATCH 06/10] x86/fpu: Always store the registers in copy_fpstate_to_sigframe() Sebastian Andrzej Siewior
2018-09-12 13:33 ` [RFC PATCH 07/10] x86/entry: add TIF_LOAD_FPU Sebastian Andrzej Siewior
2018-09-12 13:33 ` [RFC PATCH 08/10] x86/fpu: prepare copy_fpstate_to_sigframe for TIF_LOAD_FPU Sebastian Andrzej Siewior
2018-09-12 13:33 ` [RFC PATCH 09/10] x86/fpu: copy non-resident FPU state at fork time Sebastian Andrzej Siewior
2018-09-12 13:33 ` [RFC PATCH 10/10] x86/fpu: defer FPU state load until return to userspace Sebastian Andrzej Siewior
2018-09-12 15:47   ` Andy Lutomirski
2018-09-19 17:05     ` Sebastian Andrzej Siewior
2018-09-21  3:45       ` Andy Lutomirski
2018-09-21  4:15         ` Andy Lutomirski
2018-09-26 11:12           ` Sebastian Andrzej Siewior
2018-09-26 14:34             ` Andy Lutomirski
2018-09-26 15:32               ` Sebastian Andrzej Siewior
2018-09-26 16:24                 ` Andy Lutomirski

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