// SPDX-License-Identifier: GPL-2.0
/*
 * Common EFI memory map functions.
 */

#define pr_fmt(fmt) "efi: " fmt

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/efi.h>
#include <linux/io.h>
#include <asm/early_ioremap.h>
#include <asm/efi.h>
#include <linux/memblock.h>
#include <linux/slab.h>

static phys_addr_t __init __efi_memmap_alloc_early(unsigned long size)
{
        return memblock_phys_alloc(size, SMP_CACHE_BYTES);
}

static phys_addr_t __init __efi_memmap_alloc_late(unsigned long size)
{
        unsigned int order = get_order(size);
        struct page *p = alloc_pages(GFP_KERNEL, order);

        if (!p)
                return 0;

        return PFN_PHYS(page_to_pfn(p));
}

static
void __init __efi_memmap_free(u64 phys, unsigned long size, unsigned long flags)
{
        if (flags & EFI_MEMMAP_MEMBLOCK) {
                if (slab_is_available())
                        memblock_free_late(phys, size);
                else
                        memblock_phys_free(phys, size);
        } else if (flags & EFI_MEMMAP_SLAB) {
                struct page *p = pfn_to_page(PHYS_PFN(phys));
                unsigned int order = get_order(size);

                __free_pages(p, order);
        }
}

/**
 * efi_memmap_alloc - Allocate memory for the EFI memory map
 * @num_entries: Number of entries in the allocated map.
 * @data: efi memmap installation parameters
 *
 * Depending on whether mm_init() has already been invoked or not,
 * either memblock or "normal" page allocation is used.
 *
 * Returns zero on success, a negative error code on failure.
 */
int __init efi_memmap_alloc(unsigned int num_entries,
                struct efi_memory_map_data *data)
{
        /* Expect allocation parameters are zero initialized */
        WARN_ON(data->phys_map || data->size);

        data->size = num_entries * efi.memmap.desc_size;
        data->desc_version = efi.memmap.desc_version;
        data->desc_size = efi.memmap.desc_size;
        data->flags &= ~(EFI_MEMMAP_SLAB | EFI_MEMMAP_MEMBLOCK);
        data->flags |= efi.memmap.flags & EFI_MEMMAP_LATE;

        if (slab_is_available()) {
                data->flags |= EFI_MEMMAP_SLAB;
                data->phys_map = __efi_memmap_alloc_late(data->size);
        } else {
                data->flags |= EFI_MEMMAP_MEMBLOCK;
                data->phys_map = __efi_memmap_alloc_early(data->size);
        }

        if (!data->phys_map)
                return -ENOMEM;
        return 0;
}

/**
 * efi_memmap_install - Install a new EFI memory map in efi.memmap
 * @data: efi memmap installation parameters
 *
 * Unlike efi_memmap_init_*(), this function does not allow the caller
 * to switch from early to late mappings. It simply uses the existing
 * mapping function and installs the new memmap.
 *
 * Returns zero on success, a negative error code on failure.
 */
int __init efi_memmap_install(struct efi_memory_map_data *data)
{
        unsigned long size = efi.memmap.desc_size * efi.memmap.nr_map;
        unsigned long flags = efi.memmap.flags;
        u64 phys = efi.memmap.phys_map;
        int ret;

        efi_memmap_unmap();

        if (efi_enabled(EFI_PARAVIRT))
                return 0;

        ret = __efi_memmap_init(data);
        if (ret)
                return ret;

        __efi_memmap_free(phys, size, flags);
        return 0;
}

/**
 * efi_memmap_split_count - Count number of additional EFI memmap entries
 * @md: EFI memory descriptor to split
 * @range: Address range (start, end) to split around
 *
 * Returns the number of additional EFI memmap entries required to
 * accommodate @range.
 */
int __init efi_memmap_split_count(efi_memory_desc_t *md, struct range *range)
{
        u64 m_start, m_end;
        u64 start, end;
        int count = 0;

        start = md->phys_addr;
        end = start + (md->num_pages << EFI_PAGE_SHIFT) - 1;

        /* modifying range */
        m_start = range->start;
        m_end = range->end;

        if (m_start <= start) {
                /* split into 2 parts */
                if (start < m_end && m_end < end)
                        count++;
        }

        if (start < m_start && m_start < end) {
                /* split into 3 parts */
                if (m_end < end)
                        count += 2;
                /* split into 2 parts */
                if (end <= m_end)
                        count++;
        }

        return count;
}

/**
 * efi_memmap_insert - Insert a memory region in an EFI memmap
 * @old_memmap: The existing EFI memory map structure
 * @buf: Address of buffer to store new map
 * @mem: Memory map entry to insert
 *
 * It is suggested that you call efi_memmap_split_count() first
 * to see how large @buf needs to be.
 */
void __init efi_memmap_insert(struct efi_memory_map *old_memmap, void *buf,
                              struct efi_mem_range *mem)
{
        u64 m_start, m_end, m_attr;
        efi_memory_desc_t *md;
        u64 start, end;
        void *old, *new;

        /* modifying range */
        m_start = mem->range.start;
        m_end = mem->range.end;
        m_attr = mem->attribute;

        /*
         * The EFI memory map deals with regions in EFI_PAGE_SIZE
         * units. Ensure that the region described by 'mem' is aligned
         * correctly.
         */
        if (!IS_ALIGNED(m_start, EFI_PAGE_SIZE) ||
            !IS_ALIGNED(m_end + 1, EFI_PAGE_SIZE)) {
                WARN_ON(1);
                return;
        }

        for (old = old_memmap->map, new = buf;
             old < old_memmap->map_end;
             old += old_memmap->desc_size, new += old_memmap->desc_size) {

                /* copy original EFI memory descriptor */
                memcpy(new, old, old_memmap->desc_size);
                md = new;
                start = md->phys_addr;
                end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT) - 1;

                if (m_start <= start && end <= m_end)
                        md->attribute |= m_attr;

                if (m_start <= start &&
                    (start < m_end && m_end < end)) {
                        /* first part */
                        md->attribute |= m_attr;
                        md->num_pages = (m_end - md->phys_addr + 1) >>
                                EFI_PAGE_SHIFT;
                        /* latter part */
                        new += old_memmap->desc_size;
                        memcpy(new, old, old_memmap->desc_size);
                        md = new;
                        md->phys_addr = m_end + 1;
                        md->num_pages = (end - md->phys_addr + 1) >>
                                EFI_PAGE_SHIFT;
                }

                if ((start < m_start && m_start < end) && m_end < end) {
                        /* first part */
                        md->num_pages = (m_start - md->phys_addr) >>
                                EFI_PAGE_SHIFT;
                        /* middle part */
                        new += old_memmap->desc_size;
                        memcpy(new, old, old_memmap->desc_size);
                        md = new;
                        md->attribute |= m_attr;
                        md->phys_addr = m_start;
                        md->num_pages = (m_end - m_start + 1) >>
                                EFI_PAGE_SHIFT;
                        /* last part */
                        new += old_memmap->desc_size;
                        memcpy(new, old, old_memmap->desc_size);
                        md = new;
                        md->phys_addr = m_end + 1;
                        md->num_pages = (end - m_end) >>
                                EFI_PAGE_SHIFT;
                }

                if ((start < m_start && m_start < end) &&
                    (end <= m_end)) {
                        /* first part */
                        md->num_pages = (m_start - md->phys_addr) >>
                                EFI_PAGE_SHIFT;
                        /* latter part */
                        new += old_memmap->desc_size;
                        memcpy(new, old, old_memmap->desc_size);
                        md = new;
                        md->phys_addr = m_start;
                        md->num_pages = (end - md->phys_addr + 1) >>
                                EFI_PAGE_SHIFT;
                        md->attribute |= m_attr;
                }
        }
}