[linux-2.6-block.git] / arch / x86 / mm / maccess.c

// SPDX-License-Identifier: GPL-2.0-only

#include <linux/uaccess.h>
#include <linux/kernel.h>

#ifdef CONFIG_X86_64
bool copy_from_kernel_nofault_allowed(const void *unsafe_src, size_t size)
{
	unsigned long vaddr = (unsigned long)unsafe_src;

	/*
	 * Do not allow userspace addresses.  This disallows
	 * normal userspace and the userspace guard page:
	 */
	if (vaddr < TASK_SIZE_MAX + PAGE_SIZE)
		return false;

	/*
	 * Allow everything during early boot before 'x86_virt_bits'
	 * is initialized.  Needed for instruction decoding in early
	 * exception handlers.
	 */
	if (!boot_cpu_data.x86_virt_bits)
		return true;

	return __is_canonical_address(vaddr, boot_cpu_data.x86_virt_bits);
}
#else
bool copy_from_kernel_nofault_allowed(const void *unsafe_src, size_t size)
{
	return (unsigned long)unsafe_src >= TASK_SIZE_MAX;
}
#endif
Commit	Line	Data
75a1a607 DB	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
fe557319	7	bool copy_from_kernel_nofault_allowed(const void *unsafe_src, size_t size)
75a1a607	8	{
eab0c608 CH	9	unsigned long vaddr = (unsigned long)unsafe_src;
eab0c608 CH	10
75a1a607	11	/*
f7993654 AD	12	* Do not allow userspace addresses. This disallows
f7993654 AD	13	* normal userspace and the userspace guard page:
75a1a607	14	*/
f7993654 AD	15	if (vaddr < TASK_SIZE_MAX + PAGE_SIZE)
	16	return false;
	17
	18	/*
	19	* Allow everything during early boot before 'x86_virt_bits'
	20	* is initialized. Needed for instruction decoding in early
	21	* exception handlers.
	22	*/
	23	if (!boot_cpu_data.x86_virt_bits)
	24	return true;
	25
	26	return __is_canonical_address(vaddr, boot_cpu_data.x86_virt_bits);
75a1a607 DB	27	}
75a1a607 DB	28	#else
fe557319	29	bool copy_from_kernel_nofault_allowed(const void *unsafe_src, size_t size)
75a1a607	30	{
eab0c608	31	return (unsigned long)unsafe_src >= TASK_SIZE_MAX;
75a1a607 DB	32	}
75a1a607 DB	33	#endif