Commit e38457c3 authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Will Deacon
Browse files

arm64: efi: prefer AllocatePages() over efi_low_alloc() for vmlinux

When allocating memory for the kernel image, try the AllocatePages()
boot service to obtain memory at the preferred offset of
'dram_base + TEXT_OFFSET', and only revert to efi_low_alloc() if that
fails. This is the only way to allocate at the base of DRAM if DRAM
starts at 0x0, since efi_low_alloc() refuses to allocate at 0x0.
Tested-by: default avatarHaojian Zhuang <>
Reviewed-by: default avatarMark Rutland <>
Signed-off-by: default avatarArd Biesheuvel <>
Signed-off-by: default avatarWill Deacon <>
parent e094d445
......@@ -13,7 +13,7 @@
#include <asm/efi.h>
#include <asm/sections.h>
efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table,
efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table_arg,
unsigned long *image_addr,
unsigned long *image_size,
unsigned long *reserve_addr,
......@@ -23,21 +23,44 @@ efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table,
efi_status_t status;
unsigned long kernel_size, kernel_memsize = 0;
unsigned long nr_pages;
void *old_image_addr = (void *)*image_addr;
/* Relocate the image, if required. */
kernel_size = _edata - _text;
if (*image_addr != (dram_base + TEXT_OFFSET)) {
kernel_memsize = kernel_size + (_end - _edata);
status = efi_low_alloc(sys_table, kernel_memsize + TEXT_OFFSET,
SZ_2M, reserve_addr);
* First, try a straight allocation at the preferred offset.
* This will work around the issue where, if dram_base == 0x0,
* efi_low_alloc() refuses to allocate at 0x0 (to prevent the
* address of the allocation to be mistaken for a FAIL return
* value or a NULL pointer). It will also ensure that, on
* platforms where the [dram_base, dram_base + TEXT_OFFSET)
* interval is partially occupied by the firmware (like on APM
* Mustang), we can still place the kernel at the address
* 'dram_base + TEXT_OFFSET'.
*image_addr = *reserve_addr = dram_base + TEXT_OFFSET;
nr_pages = round_up(kernel_memsize, EFI_ALLOC_ALIGN) /
status = efi_call_early(allocate_pages, EFI_ALLOCATE_ADDRESS,
EFI_LOADER_DATA, nr_pages,
(efi_physical_addr_t *)reserve_addr);
if (status != EFI_SUCCESS) {
pr_efi_err(sys_table, "Failed to relocate kernel\n");
return status;
kernel_memsize += TEXT_OFFSET;
status = efi_low_alloc(sys_table_arg, kernel_memsize,
SZ_2M, reserve_addr);
if (status != EFI_SUCCESS) {
pr_efi_err(sys_table_arg, "Failed to relocate kernel\n");
return status;
*image_addr = *reserve_addr + TEXT_OFFSET;
memcpy((void *)*reserve_addr + TEXT_OFFSET, (void *)*image_addr,
*image_addr = *reserve_addr + TEXT_OFFSET;
*reserve_size = kernel_memsize + TEXT_OFFSET;
memcpy((void *)*image_addr, old_image_addr, kernel_size);
*reserve_size = kernel_memsize;
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