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 */
54
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