linux-kernel - [tip:x86/urgent] x86/mm: Fix types used in pgprot cacheability flags translations

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Message-ID: <tip-3625c2c234ef66acf21a72d47a5ffa94f6c5ebf2@git.kernel.org>
Date:	Tue, 26 Jan 2016 12:12:39 -0800
From:	tip-bot for Jan Beulich <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	mingo@...nel.org, JBeulich@...e.com, jbeulich@...e.com,
	hpa@...or.com, linux-kernel@...r.kernel.org, JGross@...e.com,
	tglx@...utronix.de
Subject: [tip:x86/urgent] x86/mm:
  Fix types used in pgprot cacheability flags translations

Commit-ID:  3625c2c234ef66acf21a72d47a5ffa94f6c5ebf2
Gitweb:     http://git.kernel.org/tip/3625c2c234ef66acf21a72d47a5ffa94f6c5ebf2
Author:     Jan Beulich <JBeulich@...e.com>
AuthorDate: Tue, 26 Jan 2016 04:15:18 -0700
Committer:  Thomas Gleixner <tglx@...utronix.de>
CommitDate: Tue, 26 Jan 2016 21:05:36 +0100

x86/mm: Fix types used in pgprot cacheability flags translations

For PAE kernels "unsigned long" is not suitable to hold page protection
flags, since _PAGE_NX doesn't fit there. This is the reason for quite a
few W+X pages getting reported as insecure during boot (observed namely
for the entire initrd range).

Fixes: 281d4078be ("x86: Make page cache mode a real type")
Signed-off-by: Jan Beulich <jbeulich@...e.com>
Reviewed-by: Juergen Gross <JGross@...e.com>
Cc: stable@...r.kernel.org
Link: http://lkml.kernel.org/r/56A7635602000078000CAFF1@prv-mh.provo.novell.com
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
 arch/x86/include/asm/pgtable_types.h | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index a471cad..79c9185 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -363,20 +363,18 @@ static inline enum page_cache_mode pgprot2cachemode(pgprot_t pgprot)
 }
 static inline pgprot_t pgprot_4k_2_large(pgprot_t pgprot)
 {
+	pgprotval_t val = pgprot_val(pgprot);
 	pgprot_t new;
-	unsigned long val;
 
-	val = pgprot_val(pgprot);
 	pgprot_val(new) = (val & ~(_PAGE_PAT | _PAGE_PAT_LARGE)) |
 		((val & _PAGE_PAT) << (_PAGE_BIT_PAT_LARGE - _PAGE_BIT_PAT));
 	return new;
 }
 static inline pgprot_t pgprot_large_2_4k(pgprot_t pgprot)
 {
+	pgprotval_t val = pgprot_val(pgprot);
 	pgprot_t new;
-	unsigned long val;
 
-	val = pgprot_val(pgprot);
 	pgprot_val(new) = (val & ~(_PAGE_PAT | _PAGE_PAT_LARGE)) |
 			  ((val & _PAGE_PAT_LARGE) >>
 			   (_PAGE_BIT_PAT_LARGE - _PAGE_BIT_PAT));