162306a36Sopenharmony_ci/* SPDX-License-Identifier: GPL-2.0 */ 262306a36Sopenharmony_ci 362306a36Sopenharmony_ci#ifndef __ASM_ARM_KFENCE_H 462306a36Sopenharmony_ci#define __ASM_ARM_KFENCE_H 562306a36Sopenharmony_ci 662306a36Sopenharmony_ci#include <linux/kfence.h> 762306a36Sopenharmony_ci 862306a36Sopenharmony_ci#include <asm/pgalloc.h> 962306a36Sopenharmony_ci#include <asm/set_memory.h> 1062306a36Sopenharmony_ci 1162306a36Sopenharmony_cistatic inline int split_pmd_page(pmd_t *pmd, unsigned long addr) 1262306a36Sopenharmony_ci{ 1362306a36Sopenharmony_ci int i; 1462306a36Sopenharmony_ci unsigned long pfn = PFN_DOWN(__pa(addr)); 1562306a36Sopenharmony_ci pte_t *pte = pte_alloc_one_kernel(&init_mm); 1662306a36Sopenharmony_ci 1762306a36Sopenharmony_ci if (!pte) 1862306a36Sopenharmony_ci return -ENOMEM; 1962306a36Sopenharmony_ci 2062306a36Sopenharmony_ci for (i = 0; i < PTRS_PER_PTE; i++) 2162306a36Sopenharmony_ci set_pte_ext(pte + i, pfn_pte(pfn + i, PAGE_KERNEL), 0); 2262306a36Sopenharmony_ci pmd_populate_kernel(&init_mm, pmd, pte); 2362306a36Sopenharmony_ci 2462306a36Sopenharmony_ci flush_tlb_kernel_range(addr, addr + PMD_SIZE); 2562306a36Sopenharmony_ci return 0; 2662306a36Sopenharmony_ci} 2762306a36Sopenharmony_ci 2862306a36Sopenharmony_cistatic inline bool arch_kfence_init_pool(void) 2962306a36Sopenharmony_ci{ 3062306a36Sopenharmony_ci unsigned long addr; 3162306a36Sopenharmony_ci pmd_t *pmd; 3262306a36Sopenharmony_ci 3362306a36Sopenharmony_ci for (addr = (unsigned long)__kfence_pool; is_kfence_address((void *)addr); 3462306a36Sopenharmony_ci addr += PAGE_SIZE) { 3562306a36Sopenharmony_ci pmd = pmd_off_k(addr); 3662306a36Sopenharmony_ci 3762306a36Sopenharmony_ci if (pmd_leaf(*pmd)) { 3862306a36Sopenharmony_ci if (split_pmd_page(pmd, addr & PMD_MASK)) 3962306a36Sopenharmony_ci return false; 4062306a36Sopenharmony_ci } 4162306a36Sopenharmony_ci } 4262306a36Sopenharmony_ci 4362306a36Sopenharmony_ci return true; 4462306a36Sopenharmony_ci} 4562306a36Sopenharmony_ci 4662306a36Sopenharmony_cistatic inline bool kfence_protect_page(unsigned long addr, bool protect) 4762306a36Sopenharmony_ci{ 4862306a36Sopenharmony_ci set_memory_valid(addr, 1, !protect); 4962306a36Sopenharmony_ci 5062306a36Sopenharmony_ci return true; 5162306a36Sopenharmony_ci} 5262306a36Sopenharmony_ci 5362306a36Sopenharmony_ci#endif /* __ASM_ARM_KFENCE_H */ 54