efi: Add grub_efi_get_ram_base() function for arm64

Since ARM platforms do not have a common memory map, add a helper
function that finds the lowest address region with the EFI_MEMORY_WB
attribute set in the UEFI memory map.

Required for the arm64 efi linux loader to restrict the initrd
location to where it will be accessible by the kernel at runtime.

Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This commit is contained in:
Leif Lindholm 2018-07-09 18:33:01 +01:00 committed by Daniel Kiper
parent 8ec18d1a4c
commit bad144c60f
2 changed files with 34 additions and 0 deletions

View file

@ -633,3 +633,34 @@ grub_efi_mm_init (void)
grub_efi_free_pages ((grub_addr_t) memory_map,
2 * BYTES_TO_PAGES (MEMORY_MAP_SIZE));
}
#if defined (__aarch64__)
grub_err_t
grub_efi_get_ram_base(grub_addr_t *base_addr)
{
grub_efi_memory_descriptor_t *memory_map, *desc;
grub_efi_uintn_t memory_map_size, desc_size;
int ret;
memory_map_size = grub_efi_find_mmap_size();
memory_map = grub_malloc (memory_map_size);
if (! memory_map)
return GRUB_ERR_OUT_OF_MEMORY;
ret = grub_efi_get_memory_map (&memory_map_size, memory_map, NULL,
&desc_size, NULL);
if (ret < 1)
return GRUB_ERR_BUG;
for (desc = memory_map, *base_addr = GRUB_UINT_MAX;
(grub_addr_t) desc < ((grub_addr_t) memory_map + memory_map_size);
desc = NEXT_MEMORY_DESCRIPTOR (desc, desc_size))
if (desc->attribute & GRUB_EFI_MEMORY_WB)
*base_addr = grub_min (*base_addr, desc->physical_start);
grub_free(memory_map);
return GRUB_ERR_NONE;
}
#endif

View file

@ -93,6 +93,9 @@ extern void (*EXPORT_VAR(grub_efi_net_config)) (grub_efi_handle_t hnd,
#if defined(__arm__) || defined(__aarch64__)
void *EXPORT_FUNC(grub_efi_get_firmware_fdt)(void);
#endif
#if defined(__aarch64__)
grub_err_t EXPORT_FUNC(grub_efi_get_ram_base)(grub_addr_t *);
#endif
grub_addr_t grub_efi_modules_addr (void);