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Diffstat (limited to '')
| -rw-r--r-- | arch/loongarch/mm/mmap.c | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/arch/loongarch/mm/mmap.c b/arch/loongarch/mm/mmap.c index 381a569635a9..fbe1a4856fc4 100644 --- a/arch/loongarch/mm/mmap.c +++ b/arch/loongarch/mm/mmap.c @@ -3,6 +3,8 @@ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited */ #include <linux/export.h> +#include <linux/io.h> +#include <linux/memblock.h> #include <linux/mm.h> #include <linux/mman.h> @@ -116,3 +118,30 @@ int __virt_addr_valid(volatile void *kaddr) return pfn_valid(PFN_DOWN(PHYSADDR(kaddr))); } EXPORT_SYMBOL_GPL(__virt_addr_valid); + +/* + * You really shouldn't be using read() or write() on /dev/mem. This might go + * away in the future. + */ +int valid_phys_addr_range(phys_addr_t addr, size_t size) +{ + /* + * Check whether addr is covered by a memory region without the + * MEMBLOCK_NOMAP attribute, and whether that region covers the + * entire range. In theory, this could lead to false negatives + * if the range is covered by distinct but adjacent memory regions + * that only differ in other attributes. However, few of such + * attributes have been defined, and it is debatable whether it + * follows that /dev/mem read() calls should be able traverse + * such boundaries. + */ + return memblock_is_region_memory(addr, size) && memblock_is_map_memory(addr); +} + +/* + * Do not allow /dev/mem mappings beyond the supported physical range. + */ +int valid_mmap_phys_addr_range(unsigned long pfn, size_t size) +{ + return !(((pfn << PAGE_SHIFT) + size) & ~(GENMASK_ULL(cpu_pabits, 0))); +} |