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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>,
	"Dave Hansen" <dave.hansen@linux.intel.com>,
	"Sebastian Andrzej Siewior" <bigeasy@linutronix.de>
Subject: [PATCH 07/11] x86/pkeys: Drop the preempt-disable section
Date: Thu,  4 Oct 2018 16:05:43 +0200	[thread overview]
Message-ID: <20181004140547.13014-8-bigeasy@linutronix.de> (raw)
In-Reply-To: <20181004140547.13014-1-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 a150984171684..eeb03b0f0f514 100644
--- a/arch/x86/mm/pkeys.c
+++ b/arch/x86/mm/pkeys.c
@@ -40,17 +40,13 @@ 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:[~2018-10-04 14:06 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-04 14:05 [PATCH 00/11 v3] x86: load FPU registers on return to userland Sebastian Andrzej Siewior
2018-10-04 14:05 ` [PATCH 01/11] x86/entry: remove _TIF_ALLWORK_MASK Sebastian Andrzej Siewior
2018-10-11 16:27   ` Borislav Petkov
2018-10-04 14:05 ` [PATCH 02/11] x86/fpu: add (__)make_fpregs_active helpers Sebastian Andrzej Siewior
2018-10-04 14:05 ` [PATCH 03/11] x86/fpu: make __raw_xsave_addr() use feature number instead of mask Sebastian Andrzej Siewior
2018-10-11 17:30   ` Christophe de Dinechin
2018-10-18 11:19     ` Sebastian Andrzej Siewior
2018-10-12 15:52   ` Dave Hansen
2018-10-18 11:17     ` Sebastian Andrzej Siewior
2018-10-18 11:21       ` Sebastian Andrzej Siewior
2018-10-17 10:01   ` Borislav Petkov
2018-10-18 11:48     ` Sebastian Andrzej Siewior
2018-10-04 14:05 ` [PATCH 04/11] x86/fpu: eager switch PKRU state Sebastian Andrzej Siewior
2018-10-12 17:51   ` Dave Hansen
2018-10-12 18:09     ` Andy Lutomirski
2018-10-12 19:44       ` Dave Hansen
2018-10-18 16:13     ` Sebastian Andrzej Siewior
2018-10-18 17:50       ` Dave Hansen
2018-10-04 14:05 ` [PATCH 05/11] x86/fpu: set PKRU state for kernel threads Sebastian Andrzej Siewior
2018-10-12 17:54   ` Dave Hansen
2018-10-12 18:02     ` Andy Lutomirski
2018-10-18 16:26       ` Sebastian Andrzej Siewior
2018-10-18 16:48         ` Andy Lutomirski
2018-10-18 17:47           ` Dave Hansen
2018-10-18 18:25           ` Sebastian Andrzej Siewior
2018-10-18 20:46             ` Andy Lutomirski
2018-10-18 20:56               ` Dave Hansen
2018-10-18 21:24                 ` Sebastian Andrzej Siewior
2018-10-18 21:58                   ` Andy Lutomirski
2018-10-19  7:44               ` Paolo Bonzini
2018-10-19 16:59                 ` Andy Lutomirski
2018-10-19 17:01                   ` Dave Hansen
2018-10-19 17:37                     ` Andy Lutomirski
2018-10-19 18:26                       ` Dave Hansen
2018-10-04 14:05 ` [PATCH 06/11] x86/pkeys: make init_pkru_value static Sebastian Andrzej Siewior
2018-10-12 17:55   ` Dave Hansen
2018-10-04 14:05 ` Sebastian Andrzej Siewior [this message]
2018-10-12 17:58   ` [PATCH 07/11] x86/pkeys: Drop the preempt-disable section Dave Hansen
2018-10-12 18:07     ` Andy Lutomirski
2018-10-12 20:26       ` Sebastian Andrzej Siewior
2018-10-04 14:05 ` [PATCH 08/11] x86/fpu: Always store the registers in copy_fpstate_to_sigframe() Sebastian Andrzej Siewior
2018-10-11 17:50   ` Christophe de Dinechin
2018-10-11 21:18     ` Andy Lutomirski
2018-10-12 18:15   ` Dave Hansen
2018-11-02 14:42     ` Sebastian Andrzej Siewior
2018-10-04 14:05 ` [PATCH 09/11] x86/entry: add TIF_LOAD_FPU Sebastian Andrzej Siewior
2018-10-04 14:05 ` [PATCH 10/11] x86/fpu: prepare copy_fpstate_to_sigframe for TIF_LOAD_FPU Sebastian Andrzej Siewior
2018-10-12 19:40   ` Dave Hansen
2018-10-15 15:24     ` Borislav Petkov
2018-11-02 15:44       ` Sebastian Andrzej Siewior
2018-11-02 22:55     ` Sebastian Andrzej Siewior
2018-10-04 14:05 ` [PATCH 11/11] x86/fpu: defer FPU state load until return to userspace Sebastian Andrzej Siewior
2018-10-04 16:14   ` Andy Lutomirski
2018-10-12 20:25     ` Sebastian Andrzej Siewior
2018-10-04 16:45 ` [PATCH 00/11 v3] x86: load FPU registers on return to userland Rik van Riel
2018-10-04 16:50   ` Andy Lutomirski
2018-10-05 11:55   ` Sebastian Andrzej Siewior

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