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>
Origin: upstream, https://git.savannah.gnu.org/cgit/grub.git/commit/?id=bad144c60f664a83f5a7d3a014927bffaa2abbf1
Bug-Debian: https://bugs.debian.org/907596
Bug-Debian: https://bugs.debian.org/909420
Last-Update: 2018-12-06

Patch-Name: efi-add-grub_efi_get_ram_base-for-arm64.patch

Gbp-Pq: Name efi-add-grub_efi_get_ram_base-for-arm64.patch

diff --git a/grub-core/kern/efi/mm.c b/grub-core/kern/efi/mm.c
index 680ea9d6a1a74d136f21187dff4a5962024dfcdd..3033d5f578b6d8c5bee42e40c87e510c2363cac3 100644 (file)
--- a/grub-core/kern/efi/mm.c
+++ b/grub-core/kern/efi/mm.c
@@ -583,3 +583,34 @@ 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

diff --git a/include/grub/efi/efi.h b/include/grub/efi/efi.h
index 1adc00f9ee4359ba8affb3694b8e8ae39239fe4b..c42a090c96c877acfdc9ccd83642ada330b7a336 100644 (file)
--- a/include/grub/efi/efi.h
+++ b/include/grub/efi/efi.h
@@ -96,6 +96,9 @@ 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);