Patchwork [017/222] ARM: mm: use pteval_t to represent page protection values

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Submitter Herton Ronaldo Krzesinski
Date Jan. 16, 2013, 3:53 p.m.
Message ID <1358351822-7675-18-git-send-email-herton.krzesinski@canonical.com>
Download mbox | patch
Permalink /patch/212594/
State New
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Comments

Herton Ronaldo Krzesinski - Jan. 16, 2013, 3:53 p.m.
3.5.7.3 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Will Deacon <will.deacon@arm.com>

commit 864aa04cd02979c2c755cb28b5f4fe56039171c0 upstream.

When updating the page protection map after calculating the user_pgprot
value, the base protection map is temporarily stored in an unsigned long
type, causing truncation of the protection bits when LPAE is enabled.
This effectively means that calls to mprotect() will corrupt the upper
page attributes, clearing the XN bit unconditionally.

This patch uses pteval_t to store the intermediate protection values,
preserving the upper bits for 64-bit descriptors.

Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
---
 arch/arm/mm/mmu.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Patch

diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 15c6abe..f117e1f 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -504,7 +504,7 @@  static void __init build_mem_type_table(void)
 #endif
 
 	for (i = 0; i < 16; i++) {
-		unsigned long v = pgprot_val(protection_map[i]);
+		pteval_t v = pgprot_val(protection_map[i]);
 		protection_map[i] = __pgprot(v | user_pgprot);
 	}