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authorSteve Capper <steve.capper@linaro.org>2014-02-25 11:38:53 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-03-23 21:44:20 -0700
commit52e7d049fa89983fe97d39a67b788360cce36dea (patch)
treef10d30d02fb99e4805527d3ad35b478d1337db02
parentc6f538a871a86edca8e555aee2db07880b980eea (diff)
arm64: mm: Add double logical invert to pte accessors
commit 84fe6826c28f69d8708bd575faed7f75e6b6f57f upstream. Page table entries on ARM64 are 64 bits, and some pte functions such as pte_dirty return a bitwise-and of a flag with the pte value. If the flag to be tested resides in the upper 32 bits of the pte, then we run into the danger of the result being dropped if downcast. For example: gather_stats(page, md, pte_dirty(*pte), 1); where pte_dirty(*pte) is downcast to an int. This patch adds a double logical invert to all the pte_ accessors to ensure predictable downcasting. Signed-off-by: Steve Capper <steve.capper@linaro.org> [steve.capper@linaro.org: rebased patch to leave pte_write alone to allow for merge with 3.13 stable] Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/arm64/include/asm/pgtable.h8
1 files changed, 4 insertions, 4 deletions
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 7f2b60affbb4..2c121f77cae7 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -136,10 +136,10 @@ extern struct page *empty_zero_page;
/*
* The following only work if pte_present(). Undefined behaviour otherwise.
*/
-#define pte_present(pte) (pte_val(pte) & (PTE_VALID | PTE_PROT_NONE))
-#define pte_dirty(pte) (pte_val(pte) & PTE_DIRTY)
-#define pte_young(pte) (pte_val(pte) & PTE_AF)
-#define pte_special(pte) (pte_val(pte) & PTE_SPECIAL)
+#define pte_present(pte) (!!(pte_val(pte) & (PTE_VALID | PTE_PROT_NONE)))
+#define pte_dirty(pte) (!!(pte_val(pte) & PTE_DIRTY))
+#define pte_young(pte) (!!(pte_val(pte) & PTE_AF))
+#define pte_special(pte) (!!(pte_val(pte) & PTE_SPECIAL))
#define pte_write(pte) (!(pte_val(pte) & PTE_RDONLY))
#define pte_exec(pte) (!(pte_val(pte) & PTE_UXN))