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
 
 
 
 
 
 7bool 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
20bool 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

 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
 7static __always_inline u64 canonical_address(u64 vaddr, u8 vaddr_bits)
 8{
 9	return ((s64)vaddr << (64 - vaddr_bits)) >> (64 - vaddr_bits);
10}
11
12bool copy_from_kernel_nofault_allowed(const void *unsafe_src, size_t size)
13{
14	unsigned long vaddr = (unsigned long)unsafe_src;
15
16	/*
17	 * Range covering the highest possible canonical userspace address
18	 * as well as non-canonical address range. For the canonical range
19	 * we also need to include the userspace guard page.
20	 */
21	return vaddr >= TASK_SIZE_MAX + PAGE_SIZE &&
22	       canonical_address(vaddr, boot_cpu_data.x86_virt_bits) == vaddr;
23}
24#else
25bool copy_from_kernel_nofault_allowed(const void *unsafe_src, size_t size)
26{
27	return (unsigned long)unsafe_src >= TASK_SIZE_MAX;
28}
29#endif