linux-stable/arch/x86/mm/maccess.c
Adrian Hunter 1fb85d06ad x86: Share definition of __is_canonical_address()
Reduce code duplication by moving canonical address code to a common header
file.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220131072453.2839535-3-adrian.hunter@intel.com
2022-02-02 13:11:42 +01:00

24 lines
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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;
/*
* 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 &&
__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