linux-kernel - [PATCH] x86/fpu: Revert earlier patch of Disable AVX when eagerfpu is off

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Date:	Fri, 22 Jan 2016 17:10:38 -0800
From:	Yu-cheng Yu <yu-cheng.yu@...el.com>
To:	<linux-kernel@...r.kernel.org>
Cc:	Yu-cheng Yu <yu-cheng.yu@...el.com>, x86@...nel.org,
	"H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...e.de>,
	Sai Praneeth Prakhya <sai.praneeth.prakhya@...el.com>,
	"Ravi V. Shankar" <ravi.v.shankar@...el.com>,
	Leonid Shatz <leonid.shatz@...ellosystems.com>,
	Fenghua Yu <fenghua.yu@...el.com>
Subject: [PATCH] x86/fpu: Revert earlier patch of Disable AVX when eagerfpu is off

AVX was mistakenly believed to be dependent on eagerfpu switch.
This turns out to be false. The earlier patch should be reverted.

Original patch:
    http://git.kernel.org/tip/394db20ca240741a08d472173db13d6f6a6e5a28

Signed-off-by: Yu-cheng Yu <yu-cheng.yu@...el.com>
Reported_by: Leonid Shatz <leonid.shatz@...ellosystems.com>
Cc: x86@...nel.org
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Dave Hansen <dave.hansen@...ux.intel.com>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Borislav Petkov <bp@...e.de>
Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya@...el.com>
Cc: Ravi V. Shankar <ravi.v.shankar@...el.com>
Cc: Leonid Shatz <leonid.shatz@...ellosystems.com>
Cc: Fenghua Yu <fenghua.yu@...el.com>
---
 arch/x86/include/asm/fpu/xstate.h | 9 ++++-----
 arch/x86/kernel/fpu/init.c        | 6 ------
 2 files changed, 4 insertions(+), 11 deletions(-)

diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h
index af30fde..f23cd8c 100644
--- a/arch/x86/include/asm/fpu/xstate.h
+++ b/arch/x86/include/asm/fpu/xstate.h
@@ -20,16 +20,15 @@
 
 /* Supported features which support lazy state saving */
 #define XFEATURE_MASK_LAZY	(XFEATURE_MASK_FP | \
-				 XFEATURE_MASK_SSE)
-
-/* Supported features which require eager state saving */
-#define XFEATURE_MASK_EAGER	(XFEATURE_MASK_BNDREGS | \
-				 XFEATURE_MASK_BNDCSR | \
+				 XFEATURE_MASK_SSE | \
 				 XFEATURE_MASK_YMM | \
 				 XFEATURE_MASK_OPMASK | \
 				 XFEATURE_MASK_ZMM_Hi256 | \
 				 XFEATURE_MASK_Hi16_ZMM)
 
+/* Supported features which require eager state saving */
+#define XFEATURE_MASK_EAGER	(XFEATURE_MASK_BNDREGS | XFEATURE_MASK_BNDCSR)
+
 /* All currently supported features */
 #define XCNTXT_MASK	(XFEATURE_MASK_LAZY | XFEATURE_MASK_EAGER)
 
diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c
index 6d9f0a7..f0ab368 100644
--- a/arch/x86/kernel/fpu/init.c
+++ b/arch/x86/kernel/fpu/init.c
@@ -300,12 +300,6 @@ u64 __init fpu__get_supported_xfeatures_mask(void)
 static void __init fpu__clear_eager_fpu_features(void)
 {
 	setup_clear_cpu_cap(X86_FEATURE_MPX);
-	setup_clear_cpu_cap(X86_FEATURE_AVX);
-	setup_clear_cpu_cap(X86_FEATURE_AVX2);
-	setup_clear_cpu_cap(X86_FEATURE_AVX512F);
-	setup_clear_cpu_cap(X86_FEATURE_AVX512PF);
-	setup_clear_cpu_cap(X86_FEATURE_AVX512ER);
-	setup_clear_cpu_cap(X86_FEATURE_AVX512CD);
 }
 
 /*
-- 
1.9.1