diff options
Diffstat (limited to 'arch/arm64/mm')
| -rw-r--r-- | arch/arm64/mm/Makefile | 2 | ||||
| -rw-r--r-- | arch/arm64/mm/init.c | 1 | ||||
| -rw-r--r-- | arch/arm64/mm/mmu.c | 66 |
3 files changed, 68 insertions, 1 deletions
diff --git a/arch/arm64/mm/Makefile b/arch/arm64/mm/Makefile index 773d37a14039..9d84feb41a16 100644 --- a/arch/arm64/mm/Makefile +++ b/arch/arm64/mm/Makefile @@ -4,3 +4,5 @@ obj-y := dma-mapping.o extable.o fault.o init.o \ context.o proc.o pageattr.o obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o obj-$(CONFIG_ARM64_PTDUMP) += dump.o + +CFLAGS_mmu.o := -I$(srctree)/scripts/dtc/libfdt/ diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 89a05f467ffb..597831bdddf3 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -170,7 +170,6 @@ void __init arm64_memblock_init(void) memblock_reserve(__virt_to_phys(initrd_start), initrd_end - initrd_start); #endif - early_init_fdt_reserve_self(); early_init_fdt_scan_reserved_mem(); /* 4GB maximum for 32-bit only capable devices */ diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 5b8b664422d3..82d3435bf14f 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -21,6 +21,7 @@ #include <linux/kernel.h> #include <linux/errno.h> #include <linux/init.h> +#include <linux/libfdt.h> #include <linux/mman.h> #include <linux/nodemask.h> #include <linux/memblock.h> @@ -643,3 +644,68 @@ void __set_fixmap(enum fixed_addresses idx, flush_tlb_kernel_range(addr, addr+PAGE_SIZE); } } + +void *__init fixmap_remap_fdt(phys_addr_t dt_phys) +{ + const u64 dt_virt_base = __fix_to_virt(FIX_FDT); + pgprot_t prot = PAGE_KERNEL | PTE_RDONLY; + int granularity, size, offset; + void *dt_virt; + + /* + * Check whether the physical FDT address is set and meets the minimum + * alignment requirement. Since we are relying on MIN_FDT_ALIGN to be + * at least 8 bytes so that we can always access the size field of the + * FDT header after mapping the first chunk, double check here if that + * is indeed the case. + */ + BUILD_BUG_ON(MIN_FDT_ALIGN < 8); + if (!dt_phys || dt_phys % MIN_FDT_ALIGN) + return NULL; + + /* + * Make sure that the FDT region can be mapped without the need to + * allocate additional translation table pages, so that it is safe + * to call create_mapping() this early. + * + * On 64k pages, the FDT will be mapped using PTEs, so we need to + * be in the same PMD as the rest of the fixmap. + * On 4k pages, we'll use section mappings for the FDT so we only + * have to be in the same PUD. + */ + BUILD_BUG_ON(dt_virt_base % SZ_2M); + + if (IS_ENABLED(CONFIG_ARM64_64K_PAGES)) { + BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> PMD_SHIFT != + __fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT); + + granularity = PAGE_SIZE; + } else { + BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> PUD_SHIFT != + __fix_to_virt(FIX_BTMAP_BEGIN) >> PUD_SHIFT); + + granularity = PMD_SIZE; + } + + offset = dt_phys % granularity; + dt_virt = (void *)dt_virt_base + offset; + + /* map the first chunk so we can read the size from the header */ + create_mapping(round_down(dt_phys, granularity), dt_virt_base, + granularity, prot); + + if (fdt_check_header(dt_virt) != 0) + return NULL; + + size = fdt_totalsize(dt_virt); + if (size > MAX_FDT_SIZE) + return NULL; + + if (offset + size > granularity) + create_mapping(round_down(dt_phys, granularity), dt_virt_base, + round_up(offset + size, granularity), prot); + + memblock_reserve(dt_phys, size); + + return dt_virt; +} |