ARM: mm: use pteval_t to represent page protection values

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: Ben Hutchings <ben@decadent.org.uk>

diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index dc8c550e6cbde82ae786488dadc33d92550c1d0c..9e28fdb1c739371687a7b51a143516cd255c105a 100644 (file)
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -475,7 +475,7 @@ static void __init build_mem_type_table(void)
        }
 
        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);
        }