/* 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 */