[PATCHv1, RFC 8/8] x86/mm: Allow to boot without la57 if CONFIG_X86_5LEVEL=y

From	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Newsgroups	linux.kernel
Subject	[PATCHv1, RFC 8/8] x86/mm: Allow to boot without la57 if CONFIG_X86_5LEVEL=y
Date	2017-05-25 22:40 +0200
Message-ID	<tL7I5-4wz-15@gated-at.bofh.it> (permalink)
References	<tL7I5-4wz-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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All pieces of the puzzle are in place and we can now allow to boot with
CONFIG_X86_5LEVEL=y on a machine without la57 support.

Kernel will detect that la57 is missing and fold p4d at runtime.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 arch/x86/include/asm/required-features.h | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/arch/x86/include/asm/required-features.h b/arch/x86/include/asm/required-features.h
index d91ba04dd007..fac9a5c0abe9 100644
--- a/arch/x86/include/asm/required-features.h
+++ b/arch/x86/include/asm/required-features.h
@@ -53,12 +53,6 @@
 # define NEED_MOVBE	0
 #endif
 
-#ifdef CONFIG_X86_5LEVEL
-# define NEED_LA57	(1<<(X86_FEATURE_LA57 & 31))
-#else
-# define NEED_LA57	0
-#endif
-
 #ifdef CONFIG_X86_64
 #ifdef CONFIG_PARAVIRT
 /* Paravirtualized systems may not have PSE or PGE available */
@@ -104,7 +98,7 @@
 #define REQUIRED_MASK13	0
 #define REQUIRED_MASK14	0
 #define REQUIRED_MASK15	0
-#define REQUIRED_MASK16	(NEED_LA57)
+#define REQUIRED_MASK16	0
 #define REQUIRED_MASK17	0
 #define REQUIRED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 18)
 
-- 
2.11.0

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[PATCHv1, RFC 8/8] x86/mm: Allow to boot without la57 if CONFIG_X86_5LEVEL=y "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-05-25 22:40 +0200

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