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efi/libstub: Move efi_relocate_kernel() into separate source file 

Move efi_relocate_kernel() into a separate source file, so that it
only gets pulled into builds for architectures that use it. Since
efi_relocate_kernel() is the only user of efi_low_alloc(), let's
move that over as well.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
This commit is contained in:
Ard Biesheuvel 2020-04-13 14:23:57 +02:00
parent e71356fe29
commit 685d8164b5
4 changed files with 175 additions and 184 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/firmware/efi/libstub/Makefile
View File

@ -43,7 +43,7 @@ KCOV_INSTRUMENT := n
lib-y := efi-stub-helper.o gop.o secureboot.o tpm.o \
file.o mem.o random.o randomalloc.o pci.o \
skip_spaces.o lib-cmdline.o lib-ctype.o \
alignedmem.o
alignedmem.o relocate.o
# include the stub's generic dependencies from lib/ when building for ARM/arm64
efi-deps-y := fdt_rw.c fdt_ro.c fdt_wip.c fdt.c fdt_empty_tree.c fdt_sw.c

15
drivers/firmware/efi/libstub/efistub.h
View File

@ -639,21 +639,6 @@ char *efi_convert_cmdline(efi_loaded_image_t *image, int *cmd_line_len,
efi_status_t efi_get_memory_map(struct efi_boot_memmap *map);
efi_status_t efi_low_alloc_above(unsigned long size, unsigned long align,
unsigned long *addr, unsigned long min);
static inline
efi_status_t efi_low_alloc(unsigned long size, unsigned long align,
unsigned long *addr)
{
/*
* Don't allocate at 0x0. It will confuse code that
* checks pointers against NULL. Skip the first 8
* bytes so we start at a nice even number.
*/
return efi_low_alloc_above(size, align, addr, 0x8);
}
efi_status_t efi_allocate_pages(unsigned long size, unsigned long *addr,
unsigned long max);

168
drivers/firmware/efi/libstub/mem.c
View File

@ -111,96 +111,6 @@ efi_status_t efi_allocate_pages(unsigned long size, unsigned long *addr,
return EFI_SUCCESS;
}
/**
* efi_low_alloc_above() - allocate pages at or above given address
* @size: size of the memory area to allocate
* @align: minimum alignment of the allocated memory area. It should
* a power of two.
* @addr: on exit the address of the allocated memory
* @min: minimum address to used for the memory allocation
*
* Allocate at the lowest possible address that is not below @min as
* EFI_LOADER_DATA. The allocated pages are aligned according to @align but at
* least EFI_ALLOC_ALIGN. The first allocated page will not below the address
* given by @min.
*
* Return: status code
*/
efi_status_t efi_low_alloc_above(unsigned long size, unsigned long align,
unsigned long *addr, unsigned long min)
{
unsigned long map_size, desc_size, buff_size;
efi_memory_desc_t *map;
efi_status_t status;
unsigned long nr_pages;
int i;
struct efi_boot_memmap boot_map;
boot_map.map = &map;
boot_map.map_size = &map_size;
boot_map.desc_size = &desc_size;
boot_map.desc_ver = NULL;
boot_map.key_ptr = NULL;
boot_map.buff_size = &buff_size;
status = efi_get_memory_map(&boot_map);
if (status != EFI_SUCCESS)
goto fail;
/*
* Enforce minimum alignment that EFI or Linux requires when
* requesting a specific address. We are doing page-based (or
* larger) allocations, and both the address and size must meet
* alignment constraints.
*/
if (align < EFI_ALLOC_ALIGN)
align = EFI_ALLOC_ALIGN;
size = round_up(size, EFI_ALLOC_ALIGN);
nr_pages = size / EFI_PAGE_SIZE;
for (i = 0; i < map_size / desc_size; i++) {
efi_memory_desc_t *desc;
unsigned long m = (unsigned long)map;
u64 start, end;
desc = efi_early_memdesc_ptr(m, desc_size, i);
if (desc->type != EFI_CONVENTIONAL_MEMORY)
continue;
if (efi_soft_reserve_enabled() &&
(desc->attribute & EFI_MEMORY_SP))
continue;
if (desc->num_pages < nr_pages)
continue;
start = desc->phys_addr;
end = start + desc->num_pages * EFI_PAGE_SIZE;
if (start < min)
start = min;
start = round_up(start, align);
if ((start + size) > end)
continue;
status = efi_bs_call(allocate_pages, EFI_ALLOCATE_ADDRESS,
EFI_LOADER_DATA, nr_pages, &start);
if (status == EFI_SUCCESS) {
*addr = start;
break;
}
}
if (i == map_size / desc_size)
status = EFI_NOT_FOUND;
efi_bs_call(free_pool, map);
fail:
return status;
}
/**
* efi_free() - free memory pages
* @size: size of the memory area to free in bytes
@ -222,81 +132,3 @@ void efi_free(unsigned long size, unsigned long addr)
nr_pages = round_up(size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
efi_bs_call(free_pages, addr, nr_pages);
}
/**
* efi_relocate_kernel() - copy memory area
* @image_addr: pointer to address of memory area to copy
* @image_size: size of memory area to copy
* @alloc_size: minimum size of memory to allocate, must be greater or
* equal to image_size
* @preferred_addr: preferred target address
* @alignment: minimum alignment of the allocated memory area. It
* should be a power of two.
* @min_addr: minimum target address
*
* Copy a memory area to a newly allocated memory area aligned according
* to @alignment but at least EFI_ALLOC_ALIGN. If the preferred address
* is not available, the allocated address will not be below @min_addr.
* On exit, @image_addr is updated to the target copy address that was used.
*
* This function is used to copy the Linux kernel verbatim. It does not apply
* any relocation changes.
*
* Return: status code
*/
efi_status_t efi_relocate_kernel(unsigned long *image_addr,
unsigned long image_size,
unsigned long alloc_size,
unsigned long preferred_addr,
unsigned long alignment,
unsigned long min_addr)
{
unsigned long cur_image_addr;
unsigned long new_addr = 0;
efi_status_t status;
unsigned long nr_pages;
efi_physical_addr_t efi_addr = preferred_addr;
if (!image_addr || !image_size || !alloc_size)
return EFI_INVALID_PARAMETER;
if (alloc_size < image_size)
return EFI_INVALID_PARAMETER;
cur_image_addr = *image_addr;
/*
* The EFI firmware loader could have placed the kernel image
* anywhere in memory, but the kernel has restrictions on the
* max physical address it can run at. Some architectures
* also have a prefered address, so first try to relocate
* to the preferred address. If that fails, allocate as low
* as possible while respecting the required alignment.
*/
nr_pages = round_up(alloc_size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
status = efi_bs_call(allocate_pages, EFI_ALLOCATE_ADDRESS,
EFI_LOADER_DATA, nr_pages, &efi_addr);
new_addr = efi_addr;
/*
* If preferred address allocation failed allocate as low as
* possible.
*/
if (status != EFI_SUCCESS) {
status = efi_low_alloc_above(alloc_size, alignment, &new_addr,
min_addr);
}
if (status != EFI_SUCCESS) {
pr_efi_err("Failed to allocate usable memory for kernel.\n");
return status;
}
/*
* We know source/dest won't overlap since both memory ranges
* have been allocated by UEFI, so we can safely use memcpy.
*/
memcpy((void *)new_addr, (void *)cur_image_addr, image_size);
/* Return the new address of the relocated image. */
*image_addr = new_addr;
return status;
}

174
drivers/firmware/efi/libstub/relocate.c Normal file
View File

@ -0,0 +1,174 @@
// SPDX-License-Identifier: GPL-2.0
#include <linux/efi.h>
#include <asm/efi.h>
#include "efistub.h"
/**
* efi_low_alloc_above() - allocate pages at or above given address
* @size: size of the memory area to allocate
* @align: minimum alignment of the allocated memory area. It should
* a power of two.
* @addr: on exit the address of the allocated memory
* @min: minimum address to used for the memory allocation
*
* Allocate at the lowest possible address that is not below @min as
* EFI_LOADER_DATA. The allocated pages are aligned according to @align but at
* least EFI_ALLOC_ALIGN. The first allocated page will not below the address
* given by @min.
*
* Return: status code
*/
static efi_status_t efi_low_alloc_above(unsigned long size, unsigned long align,
unsigned long *addr, unsigned long min)
{
unsigned long map_size, desc_size, buff_size;
efi_memory_desc_t *map;
efi_status_t status;
unsigned long nr_pages;
int i;
struct efi_boot_memmap boot_map;
boot_map.map = &map;
boot_map.map_size = &map_size;
boot_map.desc_size = &desc_size;
boot_map.desc_ver = NULL;
boot_map.key_ptr = NULL;
boot_map.buff_size = &buff_size;
status = efi_get_memory_map(&boot_map);
if (status != EFI_SUCCESS)
goto fail;
/*
* Enforce minimum alignment that EFI or Linux requires when
* requesting a specific address. We are doing page-based (or
* larger) allocations, and both the address and size must meet
* alignment constraints.
*/
if (align < EFI_ALLOC_ALIGN)
align = EFI_ALLOC_ALIGN;
size = round_up(size, EFI_ALLOC_ALIGN);
nr_pages = size / EFI_PAGE_SIZE;
for (i = 0; i < map_size / desc_size; i++) {
efi_memory_desc_t *desc;
unsigned long m = (unsigned long)map;
u64 start, end;
desc = efi_early_memdesc_ptr(m, desc_size, i);
if (desc->type != EFI_CONVENTIONAL_MEMORY)
continue;
if (efi_soft_reserve_enabled() &&
(desc->attribute & EFI_MEMORY_SP))
continue;
if (desc->num_pages < nr_pages)
continue;
start = desc->phys_addr;
end = start + desc->num_pages * EFI_PAGE_SIZE;
if (start < min)
start = min;
start = round_up(start, align);
if ((start + size) > end)
continue;
status = efi_bs_call(allocate_pages, EFI_ALLOCATE_ADDRESS,
EFI_LOADER_DATA, nr_pages, &start);
if (status == EFI_SUCCESS) {
*addr = start;
break;
}
}
if (i == map_size / desc_size)
status = EFI_NOT_FOUND;
efi_bs_call(free_pool, map);
fail:
return status;
}
/**
* efi_relocate_kernel() - copy memory area
* @image_addr: pointer to address of memory area to copy
* @image_size: size of memory area to copy
* @alloc_size: minimum size of memory to allocate, must be greater or
* equal to image_size
* @preferred_addr: preferred target address
* @alignment: minimum alignment of the allocated memory area. It
* should be a power of two.
* @min_addr: minimum target address
*
* Copy a memory area to a newly allocated memory area aligned according
* to @alignment but at least EFI_ALLOC_ALIGN. If the preferred address
* is not available, the allocated address will not be below @min_addr.
* On exit, @image_addr is updated to the target copy address that was used.
*
* This function is used to copy the Linux kernel verbatim. It does not apply
* any relocation changes.
*
* Return: status code
*/
efi_status_t efi_relocate_kernel(unsigned long *image_addr,
unsigned long image_size,
unsigned long alloc_size,
unsigned long preferred_addr,
unsigned long alignment,
unsigned long min_addr)
{
unsigned long cur_image_addr;
unsigned long new_addr = 0;
efi_status_t status;
unsigned long nr_pages;
efi_physical_addr_t efi_addr = preferred_addr;
if (!image_addr || !image_size || !alloc_size)
return EFI_INVALID_PARAMETER;
if (alloc_size < image_size)
return EFI_INVALID_PARAMETER;
cur_image_addr = *image_addr;
/*
* The EFI firmware loader could have placed the kernel image
* anywhere in memory, but the kernel has restrictions on the
* max physical address it can run at. Some architectures
* also have a prefered address, so first try to relocate
* to the preferred address. If that fails, allocate as low
* as possible while respecting the required alignment.
*/
nr_pages = round_up(alloc_size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
status = efi_bs_call(allocate_pages, EFI_ALLOCATE_ADDRESS,
EFI_LOADER_DATA, nr_pages, &efi_addr);
new_addr = efi_addr;
/*
* If preferred address allocation failed allocate as low as
* possible.
*/
if (status != EFI_SUCCESS) {
status = efi_low_alloc_above(alloc_size, alignment, &new_addr,
min_addr);
}
if (status != EFI_SUCCESS) {
pr_efi_err("Failed to allocate usable memory for kernel.\n");
return status;
}
/*
* We know source/dest won't overlap since both memory ranges
* have been allocated by UEFI, so we can safely use memcpy.
*/
memcpy((void *)new_addr, (void *)cur_image_addr, image_size);
/* Return the new address of the relocated image. */
*image_addr = new_addr;
return status;
}