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