arm64/mm: fold check for KFENCE into can_set_direct_map()

KFENCE requires linear map to be mapped at page granularity, so that it
is possible to protect/unprotect single pages, just like with
rodata_full and DEBUG_PAGEALLOC.

Instead of repating

	can_set_direct_map() || IS_ENABLED(CONFIG_KFENCE)

make can_set_direct_map() handle the KFENCE case.

This also prevents potential false positives in kernel_page_present()
that may return true for non-present page if CONFIG_KFENCE is enabled.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lore.kernel.org/r/20220921074841.382615-1-rppt@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 69deed27dec8fa9553c2be635764bc9dd6a402fe..e8a48dfd550fc139f7b2ca0da2b05bd342644a76 100644 (file)
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -535,7 +535,7 @@ static void __init map_mem(pgd_t *pgdp)
         */
        BUILD_BUG_ON(pgd_index(direct_map_end - 1) == pgd_index(direct_map_end));
 
-       if (can_set_direct_map() || IS_ENABLED(CONFIG_KFENCE))
+       if (can_set_direct_map())
                flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
 
        /*
@@ -1542,11 +1542,7 @@ int arch_add_memory(int nid, u64 start, u64 size,
 
        VM_BUG_ON(!mhp_range_allowed(start, size, true));
 
-       /*
-        * KFENCE requires linear map to be mapped at page granularity, so that
-        * it is possible to protect/unprotect single pages in the KFENCE pool.
-        */
-       if (can_set_direct_map() || IS_ENABLED(CONFIG_KFENCE))
+       if (can_set_direct_map())
                flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
 
        __create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start),

diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c
index 64e985eaa52d8df35244427a0479c0b173ee8668..d107c3d434e224552ae34011a4df3319cc977516 100644 (file)
--- a/arch/arm64/mm/pageattr.c
+++ b/arch/arm64/mm/pageattr.c
@@ -21,7 +21,13 @@ bool rodata_full __ro_after_init = IS_ENABLED(CONFIG_RODATA_FULL_DEFAULT_ENABLED
 
 bool can_set_direct_map(void)
 {
-       return rodata_full || debug_pagealloc_enabled();
+       /*
+        * rodata_full, DEBUG_PAGEALLOC and KFENCE require linear map to be
+        * mapped at page granularity, so that it is possible to
+        * protect/unprotect single pages.
+        */
+       return rodata_full || debug_pagealloc_enabled() ||
+               IS_ENABLED(CONFIG_KFENCE);
 }
 
 static int change_page_range(pte_t *ptep, unsigned long addr, void *data)