linux-kernel - Re: [PATCH v2 2/2] x86_32: Remove user bit from identity map PDE

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Message-ID: <20140312183925.GA19927@redhat.com>
Date:	Wed, 12 Mar 2014 14:39:25 -0400
From:	Dave Jones <davej@...hat.com>
To:	Andy Lutomirski <luto@...capital.net>
Cc:	"H. Peter Anvin" <hpa@...ux.intel.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>, x86@...nel.org,
	Stefani Seibold <stefani@...bold.net>,
	Andreas Brief <Andreas.Brief@...de-schwarz.com>,
	Martin Runge <Martin.Runge@...de-schwarz.com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Andi Kleen <andi@...stfloor.org>
Subject: Re: [PATCH v2 2/2] x86_32: Remove user bit from identity map PDE

On Wed, Mar 12, 2014 at 11:29:45AM -0700, Andy Lutomirski wrote:
 > 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.
 > 
 > -/*
 > - * 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+USER+DIRTY+ACCESSED */
 >  #define PGD_IDENT_ATTR	 0x001		/* PRESENT (no other attributes) */
 
update the comment too ?

	Dave

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