1 /* SPDX-License-Identifier: GPL-2.0 */
2
3 #ifndef _ASM_RISCV_KFENCE_H
4 #define _ASM_RISCV_KFENCE_H
5
6 #include <linux/kfence.h>
7 #include <linux/pfn.h>
8 #include <asm-generic/pgalloc.h>
9 #include <asm/pgtable.h>
10
split_pmd_page(unsigned long addr)11 static inline int split_pmd_page(unsigned long addr)
12 {
13 int i;
14 unsigned long pfn = PFN_DOWN(__pa((addr & PMD_MASK)));
15 pmd_t *pmd = pmd_off_k(addr);
16 pte_t *pte = pte_alloc_one_kernel(&init_mm);
17
18 if (!pte)
19 return -ENOMEM;
20
21 for (i = 0; i < PTRS_PER_PTE; i++)
22 set_pte(pte + i, pfn_pte(pfn + i, PAGE_KERNEL));
23 set_pmd(pmd, pfn_pmd(PFN_DOWN(__pa(pte)), PAGE_TABLE));
24
25 flush_tlb_kernel_range(addr, addr + PMD_SIZE);
26 return 0;
27 }
28
arch_kfence_init_pool(void)29 static inline bool arch_kfence_init_pool(void)
30 {
31 int ret;
32 unsigned long addr;
33 pmd_t *pmd;
34
35 for (addr = (unsigned long)__kfence_pool; is_kfence_address((void *)addr);
36 addr += PAGE_SIZE) {
37 pmd = pmd_off_k(addr);
38
39 if (pmd_leaf(*pmd)) {
40 ret = split_pmd_page(addr);
41 if (ret)
42 return false;
43 }
44 }
45
46 return true;
47 }
48
kfence_protect_page(unsigned long addr,bool protect)49 static inline bool kfence_protect_page(unsigned long addr, bool protect)
50 {
51 pte_t *pte = virt_to_kpte(addr);
52
53 if (protect)
54 set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_PRESENT));
55 else
56 set_pte(pte, __pte(pte_val(*pte) | _PAGE_PRESENT));
57
58 flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
59
60 return true;
61 }
62
63 #endif /* _ASM_RISCV_KFENCE_H */
64