/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _ASM_RISCV_KFENCE_H #define _ASM_RISCV_KFENCE_H #include <linux/kfence.h> #include <linux/pfn.h> #include <asm-generic/pgalloc.h> #include <asm/pgtable.h> static inline int split_pmd_page(unsigned long addr) { int i; unsigned long pfn = PFN_DOWN(__pa((addr & PMD_MASK))); pmd_t *pmd = pmd_off_k(addr); pte_t *pte = pte_alloc_one_kernel(&init_mm); if (!pte) return -ENOMEM; for (i = 0; i < PTRS_PER_PTE; i++) set_pte(pte + i, pfn_pte(pfn + i, PAGE_KERNEL)); set_pmd(pmd, pfn_pmd(PFN_DOWN(__pa(pte)), PAGE_TABLE)); flush_tlb_kernel_range(addr, addr + PMD_SIZE); return 0; } static inline bool arch_kfence_init_pool(void) { int ret; unsigned long addr; pmd_t *pmd; for (addr = (unsigned long)__kfence_pool; is_kfence_address((void *)addr); addr += PAGE_SIZE) { pmd = pmd_off_k(addr); if (pmd_leaf(*pmd)) { ret = split_pmd_page(addr); if (ret) return false; } } return true; } static inline bool kfence_protect_page(unsigned long addr, bool protect) { pte_t *pte = virt_to_kpte(addr); if (protect) set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_PRESENT)); else set_pte(pte, __pte(pte_val(*pte) | _PAGE_PRESENT)); flush_tlb_kernel_range(addr, addr + PAGE_SIZE); return true; } #endif /* _ASM_RISCV_KFENCE_H */