arm64: Fix R/O permissions in mark_rodata_ro

The permissions in mark_rodata_ro trigger a build error
with STRICT_MM_TYPECHECKS. Fix this by introducing
PAGE_KERNEL_ROX for the same reasons as PAGE_KERNEL_RO.
From Ard:

"PAGE_KERNEL_EXEC has PTE_WRITE set as well, making the range
writeable under the ARMv8.1 DBM feature, that manages the
dirty bit in hardware (writing to a page with the PTE_RDONLY
and PTE_WRITE bits both set will clear the PTE_RDONLY bit in that case)"

Signed-off-by: Laura Abbott <labbott@fedoraproject.org>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 9819a94..7e074f9 100644 (file)
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -81,6 +81,7 @@ extern void __pgd_error(const char *file, int line, unsigned long val);
 
 #define PAGE_KERNEL            __pgprot(_PAGE_DEFAULT | PTE_PXN | PTE_UXN | PTE_DIRTY | PTE_WRITE)
 #define PAGE_KERNEL_RO         __pgprot(_PAGE_DEFAULT | PTE_PXN | PTE_UXN | PTE_DIRTY | PTE_RDONLY)
+#define PAGE_KERNEL_ROX        __pgprot(_PAGE_DEFAULT | PTE_UXN | PTE_DIRTY | PTE_RDONLY)
 #define PAGE_KERNEL_EXEC       __pgprot(_PAGE_DEFAULT | PTE_UXN | PTE_DIRTY | PTE_WRITE)
 #define PAGE_KERNEL_EXEC_CONT  __pgprot(_PAGE_DEFAULT | PTE_UXN | PTE_DIRTY | PTE_WRITE | PTE_CONT)
 

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 32ddd89..abb66f8 100644 (file)
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -475,7 +475,7 @@ void mark_rodata_ro(void)
 {
        create_mapping_late(__pa(_stext), (unsigned long)_stext,
                                (unsigned long)_etext - (unsigned long)_stext,
-                               PAGE_KERNEL_EXEC | PTE_RDONLY);
+                               PAGE_KERNEL_ROX);
 
 }
 #endif