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

Hoeun Ryu
2017-02-19T10:04:09Z

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