cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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maccess.c (704B)

      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