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// 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 <linux/memblock.h>
#include <linux/slab.h>
#include <asm/early_ioremap.h>
#include <asm/efi.h>
/**
* __efi_memmap_init - Common code for mapping the EFI memory map
* @data: EFI memory map data
*
* This function takes care of figuring out which function to use to
* map the EFI memory map in efi.memmap based on how far into the boot
* we are.
*
* During bootup EFI_MEMMAP_LATE in data->flags should be clear since we
* only have access to the early_memremap*() functions as the vmalloc
* space isn't setup. Once the kernel is fully booted we can fallback
* to the more robust memremap*() API.
*
* Returns: zero on success, a negative error code on failure.
*/
int __init __efi_memmap_init(struct efi_memory_map_data *data)
{
struct efi_memory_map map;
phys_addr_t phys_map;
phys_map = data->phys_map;
if (data->flags & EFI_MEMMAP_LATE)
map.map = memremap(phys_map, data->size, MEMREMAP_WB);
else
map.map = early_memremap(phys_map, data->size);
if (!map.map) {
pr_err("Could not map the memory map!\n");
return -ENOMEM;
}
map.phys_map = data->phys_map;
map.nr_map = data->size / data->desc_size;
map.map_end = map.map + data->size;
map.desc_version = data->desc_version;
map.desc_size = data->desc_size;
map.flags = data->flags;
set_bit(EFI_MEMMAP, &efi.flags);
efi.memmap = map;
return 0;
}
/**
* efi_memmap_init_early - Map the EFI memory map data structure
* @data: EFI memory map data
*
* Use early_memremap() to map the passed in EFI memory map and assign
* it to efi.memmap.
*
* Returns: zero on success, a negative error code on failure.
*/
int __init efi_memmap_init_early(struct efi_memory_map_data *data)
{
/* Cannot go backwards */
WARN_ON(efi.memmap.flags & EFI_MEMMAP_LATE);
data->flags = 0;
return __efi_memmap_init(data);
}
void __init efi_memmap_unmap(void)
{
if (!efi_enabled(EFI_MEMMAP))
return;
if (!(efi.memmap.flags & EFI_MEMMAP_LATE)) {
unsigned long size;
size = efi.memmap.desc_size * efi.memmap.nr_map;
early_memunmap(efi.memmap.map, size);
} else {
memunmap(efi.memmap.map);
}
efi.memmap.map = NULL;
clear_bit(EFI_MEMMAP, &efi.flags);
}
/**
* efi_memmap_init_late - Map efi.memmap with memremap()
* @addr: Physical address of the new EFI memory map
* @size: Size in bytes of the new EFI memory map
*
* Setup a mapping of the EFI memory map using ioremap_cache(). This
* function should only be called once the vmalloc space has been
* setup and is therefore not suitable for calling during early EFI
* initialise, e.g. in efi_init(). Additionally, it expects
* efi_memmap_init_early() to have already been called.
*
* The reason there are two EFI memmap initialisation
* (efi_memmap_init_early() and this late version) is because the
* early EFI memmap should be explicitly unmapped once EFI
* initialisation is complete as the fixmap space used to map the EFI
* memmap (via early_memremap()) is a scarce resource.
*
* This late mapping is intended to persist for the duration of
* runtime so that things like efi_mem_desc_lookup() and
* efi_mem_attributes() always work.
*
* Returns: zero on success, a negative error code on failure.
*/
int __init efi_memmap_init_late(phys_addr_t addr, unsigned long size)
{
struct efi_memory_map_data data = {
.phys_map = addr,
.size = size,
.flags = EFI_MEMMAP_LATE,
};
/* Did we forget to unmap the early EFI memmap? */
WARN_ON(efi.memmap.map);
/* Were we already called? */
WARN_ON(efi.memmap.flags & EFI_MEMMAP_LATE);
/*
* It makes no sense to allow callers to register different
* values for the following fields. Copy them out of the
* existing early EFI memmap.
*/
data.desc_version = efi.memmap.desc_version;
data.desc_size = efi.memmap.desc_size;
return __efi_memmap_init(&data);
}
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