[IA64] fail mmaps that span areas with incompatible attributes (6d40fc51) · Commits · 戴 / test

arch/ia64/kernel/efi.c

+43 −3

Original line number	Diff line number	Diff line
		@@ -660,6 +660,29 @@ efi_memory_descriptor (unsigned long phys_addr)
		return NULL;
		}

		static int
		efi_memmap_intersects (unsigned long phys_addr, unsigned long size)
		{
		void efi_map_start, efi_map_end, *p;
		efi_memory_desc_t *md;
		u64 efi_desc_size;
		unsigned long end;

		efi_map_start = __va(ia64_boot_param->efi_memmap);
		efi_map_end = efi_map_start + ia64_boot_param->efi_memmap_size;
		efi_desc_size = ia64_boot_param->efi_memdesc_size;

		end = phys_addr + size;

		for (p = efi_map_start; p < efi_map_end; p += efi_desc_size) {
		md = p;

		if (md->phys_addr < end && efi_md_end(md) > phys_addr)
		return 1;
		}
		return 0;
		}

		u32
		efi_mem_type (unsigned long phys_addr)
		{
		@@ -766,11 +789,28 @@ valid_phys_addr_range (unsigned long phys_addr, unsigned long size)
		int
		valid_mmap_phys_addr_range (unsigned long pfn, unsigned long size)
		{
		unsigned long phys_addr = pfn << PAGE_SHIFT;
		u64 attr;

		attr = efi_mem_attribute(phys_addr, size);

		/*
		* MMIO regions are often missing from the EFI memory map.
		* We must allow mmap of them for programs like X, so we
		* currently can't do any useful validation.
		* /dev/mem mmap uses normal user pages, so we don't need the entire
		* granule, but the entire region we're mapping must support the same
		* attribute.
		*/
		if (attr & EFI_MEMORY_WB \|\| attr & EFI_MEMORY_UC)
		return 1;

		/*
		* Intel firmware doesn't tell us about all the MMIO regions, so
		* in general we have to allow mmap requests. But if EFI does
		* tell us about anything inside this region, we should deny it.
		* The user can always map a smaller region to avoid the overlap.
		*/
		if (efi_memmap_intersects(phys_addr, size))
		return 0;

		return 1;
		}

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