/* SPDX-License-Identifier: GPL-2.0 */

#ifndef __ASM_ARM_KFENCE_H
#define __ASM_ARM_KFENCE_H

#include <linux/kfence.h>

#include <asm/pgalloc.h>
#include <asm/set_memory.h>

static inline int split_pmd_page(pmd_t *pmd, unsigned long addr)
{
        int i;
        unsigned long pfn = PFN_DOWN(__pa(addr));
        pte_t *pte = pte_alloc_one_kernel(&init_mm);

        if (!pte)
                return -ENOMEM;

        for (i = 0; i < PTRS_PER_PTE; i++)
                set_pte_ext(pte + i, pfn_pte(pfn + i, PAGE_KERNEL), 0);
        pmd_populate_kernel(&init_mm, pmd, pte);

        flush_tlb_kernel_range(addr, addr + PMD_SIZE);
        return 0;
}

static inline bool arch_kfence_init_pool(void)
{
        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)) {
                        if (split_pmd_page(pmd, addr & PMD_MASK))
                                return false;
                }
        }

        return true;
}

static inline bool kfence_protect_page(unsigned long addr, bool protect)
{
        set_memory_valid(addr, 1, !protect);

        return true;
}

#endif /* __ASM_ARM_KFENCE_H */