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From: Andy Lutomirski <luto@kernel.org>
To: x86@kernel.org
Cc: Borislav Petkov <bp@alien8.de>,
	linux-kernel@vger.kernel.org,
	Rusty Russell <rusty@rustcorp.com.au>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Rik van Riel <riel@redhat.com>, kvm list <kvm@vger.kernel.org>,
	Andy Lutomirski <luto@kernel.org>
Subject: [PATCH 1/8] fpu/init: Get rid of two redundant clts() calls
Date: Mon, 31 Oct 2016 15:18:42 -0700	[thread overview]
Message-ID: <476d2d5066eda24838853426ea74c94140b50c85.1477951965.git.luto@kernel.org> (raw)
In-Reply-To: <cover.1477951965.git.luto@kernel.org>
In-Reply-To: <cover.1477951965.git.luto@kernel.org>

CR0.TS is cleared by a direct CR0 write in fpu__init_cpu_generic().
We don't need to call clts() two more times right after that.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
 arch/x86/kernel/fpu/init.c | 18 ------------------
 1 file changed, 18 deletions(-)

diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c
index 1a09d133c801..60dece392b3a 100644
--- a/arch/x86/kernel/fpu/init.c
+++ b/arch/x86/kernel/fpu/init.c
@@ -10,15 +10,6 @@
 #include <linux/init.h>
 
 /*
- * Initialize the TS bit in CR0 according to the style of context-switches
- * we are using:
- */
-static void fpu__init_cpu_ctx_switch(void)
-{
-	clts();
-}
-
-/*
  * Initialize the registers found in all CPUs, CR0 and CR4:
  */
 static void fpu__init_cpu_generic(void)
@@ -55,7 +46,6 @@ void fpu__init_cpu(void)
 {
 	fpu__init_cpu_generic();
 	fpu__init_cpu_xstate();
-	fpu__init_cpu_ctx_switch();
 }
 
 /*
@@ -290,14 +280,6 @@ void __init fpu__init_system(struct cpuinfo_x86 *c)
 	 */
 	fpu__init_cpu();
 
-	/*
-	 * But don't leave CR0::TS set yet, as some of the FPU setup
-	 * methods depend on being able to execute FPU instructions
-	 * that will fault on a set TS, such as the FXSAVE in
-	 * fpu__init_system_mxcsr().
-	 */
-	clts();
-
 	fpu__init_system_generic();
 	fpu__init_system_xstate_size_legacy();
 	fpu__init_system_xstate();
-- 
2.7.4

  reply	other threads:[~2016-10-31 22:19 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-31 22:18 [PATCH 0/8] x86/fpu: Remove CR0.TS support Andy Lutomirski
2016-10-31 22:18 ` Andy Lutomirski [this message]
2016-11-01  7:13   ` [tip:x86/fpu] x86/fpu: Get rid of two redundant clts() calls tip-bot for Andy Lutomirski
2016-10-31 22:18 ` [PATCH 2/8] fpu/bugs: Stop saving and restoring CR0.TS in fpu__init_check_bugs() Andy Lutomirski
2016-11-01  7:14   ` [tip:x86/fpu] x86/fpu: " tip-bot for Andy Lutomirski
2016-10-31 22:18 ` [PATCH 3/8] x86/fpu: Remove irq_ts_save() and irq_ts_restore() Andy Lutomirski
2016-11-01  7:14   ` [tip:x86/fpu] " tip-bot for Andy Lutomirski
2016-10-31 22:18 ` [PATCH 4/8] x86/kvm: Remove host CR0.TS manipulation Andy Lutomirski
2016-11-01  7:15   ` [tip:x86/fpu] x86/fpu, kvm: " tip-bot for Andy Lutomirski
2016-10-31 22:18 ` [PATCH 5/8] lguest: Remove CR0.TS support Andy Lutomirski
2016-11-01  7:15   ` [tip:x86/fpu] x86/fpu, " tip-bot for Andy Lutomirski
2016-10-31 22:18 ` [PATCH 6/8] x86/fpu: #NM without FPU emulation is an error Andy Lutomirski
2016-11-01  7:16   ` [tip:x86/fpu] x86/fpu: Handle #NM without FPU emulation as " tip-bot for Andy Lutomirski
2016-10-31 22:18 ` [PATCH 7/8] x86/fpu: Remove stts() Andy Lutomirski
2016-11-01  7:16   ` [tip:x86/fpu] " tip-bot for Andy Lutomirski
2016-10-31 22:18 ` [PATCH 8/8] x86/fpu: Remove clts() Andy Lutomirski
2016-11-01  7:17   ` [tip:x86/fpu] " tip-bot for Andy Lutomirski
2016-10-31 22:41 ` [PATCH 0/8] x86/fpu: Remove CR0.TS support Paul Bolle
2016-10-31 23:04   ` Borislav Petkov
2016-10-31 23:10     ` Paul Bolle
2016-10-31 23:48       ` Borislav Petkov
2016-11-01  7:51         ` Paul Bolle
2016-11-01  8:50           ` Borislav Petkov

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