arch/arm/include/asm/kfence.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2
   3 #ifndef __ASM_ARM_KFENCE_H
   4 #define __ASM_ARM_KFENCE_H
   5
   6 #include <linux/kfence.h>
   7
   8 #include <asm/pgalloc.h>
   9 #include <asm/set_memory.h>
  10
  11 static inline int split_pmd_page(pmd_t *pmd, unsigned long addr)
  12 {
  13         int i;
  14         unsigned long pfn = PFN_DOWN(__pa(addr));
  15         pte_t *pte = pte_alloc_one_kernel(&init_mm);
  16
  17         if (!pte)
  18                 return -ENOMEM;
  19
  20         for (i = 0; i < PTRS_PER_PTE; i++)
  21                 set_pte_ext(pte + i, pfn_pte(pfn + i, PAGE_KERNEL), 0);
  22         pmd_populate_kernel(&init_mm, pmd, pte);
  23
  24         flush_tlb_kernel_range(addr, addr + PMD_SIZE);
  25         return 0;
  26 }
  27
  28 static inline bool arch_kfence_init_pool(void)
  29 {
  30         unsigned long addr;
  31         pmd_t *pmd;
  32
  33         for (addr = (unsigned long)__kfence_pool; is_kfence_address((void *)addr);
  34              addr += PAGE_SIZE) {
  35                 pmd = pmd_off_k(addr);
  36
  37                 if (pmd_leaf(*pmd)) {
  38                         if (split_pmd_page(pmd, addr & PMD_MASK))
  39                                 return false;
  40                 }
  41         }
  42
  43         return true;
  44 }
  45
  46 static inline bool kfence_protect_page(unsigned long addr, bool protect)
  47 {
  48         set_memory_valid(addr, 1, !protect);
  49
  50         return true;
  51 }
  52
  53 #endif /* __ASM_ARM_KFENCE_H */