linux-kernel - [tip:x86/vdso] x86_32, mm: Remove user bit from identity map PDE

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Message-ID: <tip-7dda038756704b3562187b29c81f86de935148c6@git.kernel.org>
Date:	Thu, 13 Mar 2014 16:33:39 -0700
From:	tip-bot for Andy Lutomirski <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, luto@...capital.net, hpa@...or.com,
	mingo@...nel.org, tglx@...utronix.de, hpa@...ux.intel.com
Subject: [tip:x86/vdso] x86_32, mm: Remove user bit from identity map PDE

Commit-ID:  7dda038756704b3562187b29c81f86de935148c6
Gitweb:     http://git.kernel.org/tip/7dda038756704b3562187b29c81f86de935148c6
Author:     Andy Lutomirski <luto@...capital.net>
AuthorDate: Thu, 13 Mar 2014 16:01:27 -0700
Committer:  H. Peter Anvin <hpa@...ux.intel.com>
CommitDate: Thu, 13 Mar 2014 16:20:17 -0700

x86_32, mm: Remove user bit from identity map PDE

The only reason that the user bit was set was to support userspace
access to the compat vDSO in the fixmap.  The compat vDSO is gone,
so the user bit can be removed.

Signed-off-by: Andy Lutomirski <luto@...capital.net>
Link: http://lkml.kernel.org/r/e240a977f3c7cbd525a091fd6521499ec4b8e94f.1394751608.git.luto@amacapital.net
Signed-off-by: H. Peter Anvin <hpa@...ux.intel.com>
---
 arch/x86/include/asm/pgtable_types.h | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index 1aa9ccd..757f9c4 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -214,13 +214,8 @@
 #ifdef CONFIG_X86_64
 #define __PAGE_KERNEL_IDENT_LARGE_EXEC	__PAGE_KERNEL_LARGE_EXEC
 #else
-/*
- * For PDE_IDENT_ATTR include USER bit. As the PDE and PTE protection
- * bits are combined, this will alow user to access the high address mapped
- * VDSO in the presence of CONFIG_COMPAT_VDSO
- */
 #define PTE_IDENT_ATTR	 0x003		/* PRESENT+RW */
-#define PDE_IDENT_ATTR	 0x067		/* PRESENT+RW+USER+DIRTY+ACCESSED */
+#define PDE_IDENT_ATTR	 0x063		/* PRESENT+RW+DIRTY+ACCESSED */
 #define PGD_IDENT_ATTR	 0x001		/* PRESENT (no other attributes) */
 #endif
 
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