kernel/arch/x86/platform/efi/memmap.c

// 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((unsigned long) page_address(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;
		}
	}
}