diff options
authorArd Biesheuvel <>2015-11-16 11:18:14 +0100
committerCatalin Marinas <>2015-11-17 12:05:18 +0000
commit4fee9f364b9b99f76732f2a6fd6df679a237fa74 (patch)
parentbd1c6ff74ce0bbd8cda6eb7763fa0e2625dfcc8b (diff)
arm64: mm: use correct mapping granularity under DEBUG_RODATA
When booting a 64k pages kernel that is built with CONFIG_DEBUG_RODATA and resides at an offset that is not a multiple of 512 MB, the rounding that occurs in __map_memblock() and fixup_executable() results in incorrect regions being mapped. The following snippet from /sys/kernel/debug/kernel_page_tables shows how, when the kernel is loaded 2 MB above the base of DRAM at 0x40000000, the first 2 MB of memory (which may be inaccessible from non-secure EL1 or just reserved by the firmware) is inadvertently mapped into the end of the module region. ---[ Modules start ]--- 0xfffffdffffe00000-0xfffffe0000000000 2M RW NX ... UXN MEM/NORMAL ---[ Modules end ]--- ---[ Kernel Mapping ]--- 0xfffffe0000000000-0xfffffe0000090000 576K RW NX ... UXN MEM/NORMAL 0xfffffe0000090000-0xfffffe0000200000 1472K ro x ... UXN MEM/NORMAL 0xfffffe0000200000-0xfffffe0000800000 6M ro x ... UXN MEM/NORMAL 0xfffffe0000800000-0xfffffe0000810000 64K ro x ... UXN MEM/NORMAL 0xfffffe0000810000-0xfffffe0000a00000 1984K RW NX ... UXN MEM/NORMAL 0xfffffe0000a00000-0xfffffe00ffe00000 4084M RW NX ... UXN MEM/NORMAL The same issue is likely to occur on 16k pages kernels whose load address is not a multiple of 32 MB (i.e., SECTION_SIZE). So round to SWAPPER_BLOCK_SIZE instead of SECTION_SIZE. Fixes: da141706aea5 ("arm64: add better page protections to arm64") Signed-off-by: Ard Biesheuvel <> Acked-by: Mark Rutland <> Acked-by: Laura Abbott <> Cc: <> # 4.0+ Signed-off-by: Catalin Marinas <>
1 files changed, 6 insertions, 6 deletions
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index e3f563c81c48..32ddd893da9a 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -362,8 +362,8 @@ static void __init __map_memblock(phys_addr_t start, phys_addr_t end)
* for now. This will get more fine grained later once all memory
* is mapped
- unsigned long kernel_x_start = round_down(__pa(_stext), SECTION_SIZE);
- unsigned long kernel_x_end = round_up(__pa(__init_end), SECTION_SIZE);
+ unsigned long kernel_x_start = round_down(__pa(_stext), SWAPPER_BLOCK_SIZE);
+ unsigned long kernel_x_end = round_up(__pa(__init_end), SWAPPER_BLOCK_SIZE);
if (end < kernel_x_start) {
create_mapping(start, __phys_to_virt(start),
@@ -451,18 +451,18 @@ static void __init fixup_executable(void)
/* now that we are actually fully mapped, make the start/end more fine grained */
- if (!IS_ALIGNED((unsigned long)_stext, SECTION_SIZE)) {
+ if (!IS_ALIGNED((unsigned long)_stext, SWAPPER_BLOCK_SIZE)) {
unsigned long aligned_start = round_down(__pa(_stext),
create_mapping(aligned_start, __phys_to_virt(aligned_start),
__pa(_stext) - aligned_start,
- if (!IS_ALIGNED((unsigned long)__init_end, SECTION_SIZE)) {
+ if (!IS_ALIGNED((unsigned long)__init_end, SWAPPER_BLOCK_SIZE)) {
unsigned long aligned_end = round_up(__pa(__init_end),
create_mapping(__pa(__init_end), (unsigned long)__init_end,
aligned_end - __pa(__init_end),