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From: tip-bot for Borislav Petkov <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: mingo@kernel.org, tedheadster@gmail.com, oleg@redhat.com,
	tglx@linutronix.de, peterz@infradead.org,
	gnomes@lxorguk.ukuu.org.uk, linux-kernel@vger.kernel.org,
	riel@redhat.com, torvalds@linux-foundation.org, hpa@zytor.com,
	fenghua.yu@intel.com, brgerst@gmail.com, bp@suse.de,
	yu-cheng.yu@intel.com, dave.hansen@linux.intel.com, bp@alien8.de,
	luto@kernel.org
Subject: [tip:x86/fpu] x86/cpu: Add X86_FEATURE_CPUID
Date: Wed, 25 Jan 2017 03:40:15 -0800
Message-ID: <tip-78d1b296843a719935277b0d24d1358416ed0204@git.kernel.org> (raw)
In-Reply-To: <dcb355adae3ab812c79397056a61c212f1a0c7cc.1484705016.git.luto@kernel.org>

Commit-ID:  78d1b296843a719935277b0d24d1358416ed0204
Gitweb:     http://git.kernel.org/tip/78d1b296843a719935277b0d24d1358416ed0204
Author:     Borislav Petkov <bp@suse.de>
AuthorDate: Wed, 18 Jan 2017 11:15:37 -0800
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 25 Jan 2017 10:12:39 +0100

x86/cpu: Add X86_FEATURE_CPUID

Add a synthetic CPUID flag denoting whether the CPU sports the CPUID
instruction or not. This will come useful later when accomodating
CPUID-less CPUs.

Signed-off-by: Borislav Petkov <bp@suse.de>
[ Slightly prettified. ]
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Whitehead <tedheadster@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/dcb355adae3ab812c79397056a61c212f1a0c7cc.1484705016.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/include/asm/cpufeatures.h | 2 +-
 arch/x86/kernel/cpu/common.c       | 7 ++++---
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index eafee31..a0f4ff2 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -100,7 +100,7 @@
 #define X86_FEATURE_XTOPOLOGY	( 3*32+22) /* cpu topology enum extensions */
 #define X86_FEATURE_TSC_RELIABLE ( 3*32+23) /* TSC is known to be reliable */
 #define X86_FEATURE_NONSTOP_TSC	( 3*32+24) /* TSC does not stop in C states */
-/* free, was #define X86_FEATURE_CLFLUSH_MONITOR ( 3*32+25) * "" clflush reqd with monitor */
+#define X86_FEATURE_CPUID	( 3*32+25) /* CPU has CPUID instruction itself */
 #define X86_FEATURE_EXTD_APICID	( 3*32+26) /* has extended APICID (8 bits) */
 #define X86_FEATURE_AMD_DCM     ( 3*32+27) /* multi-node processor */
 #define X86_FEATURE_APERFMPERF	( 3*32+28) /* APERFMPERF */
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 9bab7a8..c3328d0 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -801,14 +801,12 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c)
 	memset(&c->x86_capability, 0, sizeof c->x86_capability);
 	c->extended_cpuid_level = 0;
 
-	if (!have_cpuid_p())
-		identify_cpu_without_cpuid(c);
-
 	/* cyrix could have cpuid enabled via c_identify()*/
 	if (have_cpuid_p()) {
 		cpu_detect(c);
 		get_cpu_vendor(c);
 		get_cpu_cap(c);
+		setup_force_cpu_cap(X86_FEATURE_CPUID);
 
 		if (this_cpu->c_early_init)
 			this_cpu->c_early_init(c);
@@ -818,6 +816,9 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c)
 
 		if (this_cpu->c_bsp_init)
 			this_cpu->c_bsp_init(c);
+	} else {
+		identify_cpu_without_cpuid(c);
+		setup_clear_cpu_cap(X86_FEATURE_CPUID);
 	}
 
 	setup_force_cpu_cap(X86_FEATURE_ALWAYS);

  reply index

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-18 19:15 [PATCH v2 0/6] CPUID and FPU fixes Andy Lutomirski
2017-01-18 19:15 ` [PATCH v2 1/6] x86/cpu: Add X86_FEATURE_CPUID Andy Lutomirski
2017-01-25 11:40   ` tip-bot for Borislav Petkov [this message]
2017-01-18 19:15 ` [PATCH v2 2/6] x86/cpu: Factor out application of forced cpu caps Andy Lutomirski
2017-01-25 11:40   ` [tip:x86/fpu] x86/cpu: Factor out application of forced CPU caps tip-bot for Andy Lutomirski
2017-01-18 19:15 ` [PATCH v2 3/6] x86/cpu: Re-apply forced caps every time cpu caps are re-read Andy Lutomirski
2017-01-19 11:23   ` Borislav Petkov
2017-01-25 11:41   ` [tip:x86/fpu] x86/cpu: Re-apply forced caps every time CPU " tip-bot for Andy Lutomirski
2017-01-18 19:15 ` [PATCH v2 4/6] x86/fpu: Fix "x86/fpu: Legacy x87 FPU detected" message Andy Lutomirski
2017-01-25 11:42   ` [tip:x86/fpu] " tip-bot for Andy Lutomirski
2017-01-18 19:15 ` [PATCH v2 5/6] x86/fpu: Fix CPUID-less FPU detection Andy Lutomirski
2017-01-19 11:23   ` Borislav Petkov
2017-01-25 11:42   ` [tip:x86/fpu] " tip-bot for Andy Lutomirski
2017-01-18 19:15 ` [PATCH v2 6/6] x86/fpu: Fix the "Giving up, no FPU found" test Andy Lutomirski
2017-01-25 11:43   ` [tip:x86/fpu] " tip-bot for Andy Lutomirski

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