// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2014, The Linux Foundation. All rights reserved.
 */
#include <linux/mm.h>
#include <linux/module.h>

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

struct page_change_data {
        pgprot_t set_mask;
        pgprot_t clear_mask;
};

static int change_page_range(pte_t *ptep, unsigned long addr, void *data)
{
        struct page_change_data *cdata = data;
        pte_t pte = *ptep;

        pte = clear_pte_bit(pte, cdata->clear_mask);
        pte = set_pte_bit(pte, cdata->set_mask);

        set_pte_ext(ptep, pte, 0);
        return 0;
}

static bool range_in_range(unsigned long start, unsigned long size,
        unsigned long range_start, unsigned long range_end)
{
        return start >= range_start && start < range_end &&
                size <= range_end - start;
}

/*
 * This function assumes that the range is mapped with PAGE_SIZE pages.
 */
static int __change_memory_common(unsigned long start, unsigned long size,
                                pgprot_t set_mask, pgprot_t clear_mask)
{
        struct page_change_data data;
        int ret;

        data.set_mask = set_mask;
        data.clear_mask = clear_mask;

        ret = apply_to_page_range(&init_mm, start, size, change_page_range,
                                  &data);

        flush_tlb_kernel_range(start, start + size);
        return ret;
}

static int change_memory_common(unsigned long addr, int numpages,
                                pgprot_t set_mask, pgprot_t clear_mask)
{
        unsigned long start = addr & PAGE_MASK;
        unsigned long end = PAGE_ALIGN(addr) + numpages * PAGE_SIZE;
        unsigned long size = end - start;

        WARN_ON_ONCE(start != addr);

        if (!size)
                return 0;

        if (!range_in_range(start, size, MODULES_VADDR, MODULES_END) &&
            !range_in_range(start, size, VMALLOC_START, VMALLOC_END))
                return -EINVAL;

        return __change_memory_common(start, size, set_mask, clear_mask);
}

int set_memory_ro(unsigned long addr, int numpages)
{
        return change_memory_common(addr, numpages,
                                        __pgprot(L_PTE_RDONLY),
                                        __pgprot(0));
}

int set_memory_rw(unsigned long addr, int numpages)
{
        return change_memory_common(addr, numpages,
                                        __pgprot(0),
                                        __pgprot(L_PTE_RDONLY));
}

int set_memory_nx(unsigned long addr, int numpages)
{
        return change_memory_common(addr, numpages,
                                        __pgprot(L_PTE_XN),
                                        __pgprot(0));
}

int set_memory_x(unsigned long addr, int numpages)
{
        return change_memory_common(addr, numpages,
                                        __pgprot(0),
                                        __pgprot(L_PTE_XN));
}

int set_memory_valid(unsigned long addr, int numpages, int enable)
{
        if (enable)
                return __change_memory_common(addr, PAGE_SIZE * numpages,
                                              __pgprot(L_PTE_VALID),
                                              __pgprot(0));
        else
                return __change_memory_common(addr, PAGE_SIZE * numpages,
                                              __pgprot(0),
                                              __pgprot(L_PTE_VALID));
}