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
11static 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
28static 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
46static 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 */