[kernel-hardening] [RFC 6/7] arm64: add __map_kernel_segment to accept additional vm flags

[Hoeun Ryu <hoeun.ryu@gmail.com>]

 Memory attribute for `__ro_mostly_after_init` section should be changed
via set_memory_rw/ro that doesn't work against vm areas which don't have
VM_ALLOC. Add this function to map `__ro_mostly_after_init` section with
VM_ALLOC flag set in map_kernel.

Signed-off-by: Hoeun Ryu <hoeun.ryu@gmail.com>
---
 arch/arm64/mm/mmu.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index b805c01..91271b1 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -444,8 +444,10 @@ void mark_rodata_ro(void)
 	debug_checkwx();
 }
 
-static void __init map_kernel_segment(pgd_t *pgd, void *va_start, void *va_end,
-				      pgprot_t prot, struct vm_struct *vma)
+static void __init __map_kernel_segment(pgd_t *pgd,
+					void *va_start, void *va_end,
+					pgprot_t prot, struct vm_struct *vma,
+					unsigned long flags)
 {
 	phys_addr_t pa_start = __pa_symbol(va_start);
 	unsigned long size = va_end - va_start;
@@ -459,12 +461,18 @@ static void __init map_kernel_segment(pgd_t *pgd, void *va_start, void *va_end,
 	vma->addr	= va_start;
 	vma->phys_addr	= pa_start;
 	vma->size	= size;
-	vma->flags	= VM_MAP;
+	vma->flags	= flags;
 	vma->caller	= __builtin_return_address(0);
 
 	vm_area_add_early(vma);
 }
 
+static void __init map_kernel_segment(pgd_t *pgd, void *va_start, void *va_end,
+				      pgprot_t prot, struct vm_struct *vma)
+{
+	return __map_kernel_segment(pgd, va_start, va_end, prot, vma, VM_MAP);
+}
+
 /*
  * Create fine-grained mappings for the kernel.
  */
-- 
2.7.4