linux-kernel - [tip:x86/asm] x86-64: Also clear _PAGE_GLOBAL from __supported_pte_mask if !cpu_has

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Message-ID: <tip-0cdb81bef20b1d9e12111fa6cd81f748ebd87778@git.kernel.org>
Date:	Wed, 18 Feb 2015 17:21:30 -0800
From:	tip-bot for Jan Beulich <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, jbeulich@...e.com,
	torvalds@...ux-foundation.org, tglx@...utronix.de,
	mingo@...nel.org, JBeulich@...e.com, hpa@...or.com,
	luto@...capital.net
Subject: [tip:x86/asm] x86-64:
  Also clear _PAGE_GLOBAL from __supported_pte_mask if !cpu_has_pge

Commit-ID:  0cdb81bef20b1d9e12111fa6cd81f748ebd87778
Gitweb:     http://git.kernel.org/tip/0cdb81bef20b1d9e12111fa6cd81f748ebd87778
Author:     Jan Beulich <JBeulich@...e.com>
AuthorDate: Fri, 23 Jan 2015 08:35:13 +0000
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Thu, 19 Feb 2015 02:18:26 +0100

x86-64: Also clear _PAGE_GLOBAL from __supported_pte_mask if !cpu_has_pge

Not just setting it when the feature is available is for
consistency, and may allow Xen to drop its custom clearing of
the flag (unless it needs it cleared earlier than this code
executes). Note that the change is benign to ix86, as the flag
starts out clear there.

Signed-off-by: Jan Beulich <jbeulich@...e.com>
Cc: Andy Lutomirski <luto@...capital.net>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Link: http://lkml.kernel.org/r/54C215D10200007800058912@mail.emea.novell.com
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/mm/init.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 079c3b6..090499a 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -179,7 +179,8 @@ static void __init probe_page_size_mask(void)
 	if (cpu_has_pge) {
 		set_in_cr4(X86_CR4_PGE);
 		__supported_pte_mask |= _PAGE_GLOBAL;
-	}
+	} else
+		__supported_pte_mask &= ~_PAGE_GLOBAL;
 }
 
 #ifdef CONFIG_X86_32
--
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