// SPDX-License-Identifier: GPL-2.0-only #include <linux/uaccess.h> #include <linux/kernel.h> #ifdef CONFIG_X86_64 static __always_inline u64 canonical_address(u64 vaddr, u8 vaddr_bits) { return ((s64)vaddr << (64 - vaddr_bits)) >> (64 - vaddr_bits); } bool copy_from_kernel_nofault_allowed(const void *unsafe_src, size_t size) { unsigned long vaddr = (unsigned long)unsafe_src; /* * Range covering the highest possible canonical userspace address * as well as non-canonical address range. For the canonical range * we also need to include the userspace guard page. */ return vaddr >= TASK_SIZE_MAX + PAGE_SIZE && canonical_address(vaddr, boot_cpu_data.x86_virt_bits) == vaddr; } #else bool copy_from_kernel_nofault_allowed(const void *unsafe_src, size_t size) { return (unsigned long)unsafe_src >= TASK_SIZE_MAX; } #endif