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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>
This commit is contained in:
Mike Rapoport 2022-09-21 10:48:41 +03:00 committed by Catalin Marinas
parent 2305b809be
commit b9dd04a20f
2 changed files with 9 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
arch/arm64/mm/mmu.c
View File

@ -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),

8
arch/arm64/mm/pageattr.c
View File

@ -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)