arm64: add support for kernel ASLR

[cascardo/linux.git] / arch / arm64 / mm / mmu.c

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 32c4a37..00d1664 100644 (file)
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -678,7 +678,8 @@ void __init early_fixmap_init(void)
        unsigned long addr = FIXADDR_START;
 
        pgd = pgd_offset_k(addr);
-       if (CONFIG_PGTABLE_LEVELS > 3 && !pgd_none(*pgd)) {
+       if (CONFIG_PGTABLE_LEVELS > 3 &&
+           !(pgd_none(*pgd) || pgd_page_paddr(*pgd) == __pa(bm_pud))) {
                /*
                 * We only end up here if the kernel mapping and the fixmap
                 * share the top level pgd entry, which should only happen on
@@ -735,11 +736,10 @@ void __set_fixmap(enum fixed_addresses idx,
        }
 }
 
-void *__init fixmap_remap_fdt(phys_addr_t dt_phys)
+void *__init __fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot)
 {
        const u64 dt_virt_base = __fix_to_virt(FIX_FDT);
-       pgprot_t prot = PAGE_KERNEL_RO;
-       int size, offset;
+       int offset;
        void *dt_virt;
 
        /*
@@ -778,16 +778,27 @@ void *__init fixmap_remap_fdt(phys_addr_t dt_phys)
        if (fdt_check_header(dt_virt) != 0)
                return NULL;
 
-       size = fdt_totalsize(dt_virt);
-       if (size > MAX_FDT_SIZE)
+       *size = fdt_totalsize(dt_virt);
+       if (*size > MAX_FDT_SIZE)
                return NULL;
 
-       if (offset + size > SWAPPER_BLOCK_SIZE)
+       if (offset + *size > SWAPPER_BLOCK_SIZE)
                create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base,
-                              round_up(offset + size, SWAPPER_BLOCK_SIZE), prot);
+                              round_up(offset + *size, SWAPPER_BLOCK_SIZE), prot);
 
-       memblock_reserve(dt_phys, size);
+       return dt_virt;
+}
 
+void *__init fixmap_remap_fdt(phys_addr_t dt_phys)
+{
+       void *dt_virt;
+       int size;
+
+       dt_virt = __fixmap_remap_fdt(dt_phys, &size, PAGE_KERNEL_RO);
+       if (!dt_virt)
+               return NULL;
+
+       memblock_reserve(dt_phys, size);
        return dt_virt;
 }