1 // SPDX-License-Identifier: GPL-2.0-only 2 3 #include <linux/uaccess.h> 4 #include <linux/kernel.h> 5 6 #ifdef CONFIG_X86_64 7 bool copy_from_kernel_nofault_allowed(const void *unsafe_src, size_t size) 8 { 9 unsigned long vaddr = (unsigned long)unsafe_src; 10 11 /* 12 * Range covering the highest possible canonical userspace address 13 * as well as non-canonical address range. For the canonical range 14 * we also need to include the userspace guard page. 15 */ 16 return vaddr >= TASK_SIZE_MAX + PAGE_SIZE && 17 __is_canonical_address(vaddr, boot_cpu_data.x86_virt_bits); 18 } 19 #else 20 bool copy_from_kernel_nofault_allowed(const void *unsafe_src, size_t size) 21 { 22 return (unsigned long)unsafe_src >= TASK_SIZE_MAX; 23 } 24 #endif 25