include/asm/kfence.h

0001 /* SPDX-License-Identifier: GPL-2.0 */
0002
0003 #ifndef __ASM_ARM_KFENCE_H
0004 #define __ASM_ARM_KFENCE_H
0005
0006 #include <linux/kfence.h>
0007
0008 #include <asm/pgalloc.h>
0009 #include <asm/set_memory.h>
0010
0011 static inline int split_pmd_page(pmd_t *pmd, unsigned long addr)
0012 {
0013     int i;
0014     unsigned long pfn = PFN_DOWN(__pa(addr));
0015     pte_t *pte = pte_alloc_one_kernel(&init_mm);
0016
0017     if (!pte)
0018         return -ENOMEM;
0019
0020     for (i = 0; i < PTRS_PER_PTE; i++)
0021         set_pte_ext(pte + i, pfn_pte(pfn + i, PAGE_KERNEL), 0);
0022     pmd_populate_kernel(&init_mm, pmd, pte);
0023
0024     flush_tlb_kernel_range(addr, addr + PMD_SIZE);
0025     return 0;
0026 }
0027
0028 static inline bool arch_kfence_init_pool(void)
0029 {
0030     unsigned long addr;
0031     pmd_t *pmd;
0032
0033     for (addr = (unsigned long)__kfence_pool; is_kfence_address((void *)addr);
0034          addr += PAGE_SIZE) {
0035         pmd = pmd_off_k(addr);
0036
0037         if (pmd_leaf(*pmd)) {
0038             if (split_pmd_page(pmd, addr & PMD_MASK))
0039                 return false;
0040         }
0041     }
0042
0043     return true;
0044 }
0045
0046 static inline bool kfence_protect_page(unsigned long addr, bool protect)
0047 {
0048     set_memory_valid(addr, 1, !protect);
0049
0050     return true;
0051 }
0052
0053 #endif /* __ASM_ARM_KFENCE_H */