kern/efi/mm: Implement runtime addition of pages

Adjust the interface of grub_efi_mm_add_regions() to take a set of
GRUB_MM_ADD_REGION_* flags, which most notably is currently only the
GRUB_MM_ADD_REGION_CONSECUTIVE flag. This allows us to set the function
up as callback for the memory subsystem and have it call out to us in
case there's not enough pages available in the current heap.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Tested-by: Patrick Steinhardt <ps@pks.im>

diff --git a/grub-core/kern/efi/mm.c b/grub-core/kern/efi/mm.c
index 0e7eb1cc16dd341396feb4a2fa6d47d05cd84869..d290c9a76270420da3edea79f279750f2a76219d 100644 (file)
--- a/grub-core/kern/efi/mm.c
+++ b/grub-core/kern/efi/mm.c
@@ -482,7 +482,8 @@ static grub_err_t
 add_memory_regions (grub_efi_memory_descriptor_t *memory_map,
                    grub_efi_uintn_t desc_size,
                    grub_efi_memory_descriptor_t *memory_map_end,
-                   grub_efi_uint64_t required_pages)
+                   grub_efi_uint64_t required_pages,
+                   unsigned int flags)
 {
   grub_efi_memory_descriptor_t *desc;
 
@@ -496,6 +497,10 @@ add_memory_regions (grub_efi_memory_descriptor_t *memory_map,
 
       start = desc->physical_start;
       pages = desc->num_pages;
+
+      if (pages < required_pages && (flags & GRUB_MM_ADD_REGION_CONSECUTIVE))
+       continue;
+
       if (pages > required_pages)
        {
          start += PAGES_TO_BYTES (pages - required_pages);
@@ -561,7 +566,7 @@ print_memory_map (grub_efi_memory_descriptor_t *memory_map,
 #endif
 
 static grub_err_t
-grub_efi_mm_add_regions (grub_size_t required_bytes)
+grub_efi_mm_add_regions (grub_size_t required_bytes, unsigned int flags)
 {
   grub_efi_memory_descriptor_t *memory_map;
   grub_efi_memory_descriptor_t *memory_map_end;
@@ -616,7 +621,8 @@ grub_efi_mm_add_regions (grub_size_t required_bytes)
   /* Allocate memory regions for GRUB's memory management.  */
   err = add_memory_regions (filtered_memory_map, desc_size,
                            filtered_memory_map_end,
-                           BYTES_TO_PAGES (required_bytes));
+                           BYTES_TO_PAGES (required_bytes),
+                           flags);
   if (err != GRUB_ERR_NONE)
     return err;
 
@@ -643,8 +649,9 @@ grub_efi_mm_add_regions (grub_size_t required_bytes)
 void
 grub_efi_mm_init (void)
 {
-  if (grub_efi_mm_add_regions (DEFAULT_HEAP_SIZE) != GRUB_ERR_NONE)
+  if (grub_efi_mm_add_regions (DEFAULT_HEAP_SIZE, GRUB_MM_ADD_REGION_NONE) != GRUB_ERR_NONE)
     grub_fatal ("%s", grub_errmsg);
+  grub_mm_add_region_fn = grub_efi_mm_add_regions;
 }
 
 #if defined (__aarch64__) || defined (__arm__) || defined (__riscv)