[PATCH v3 5/6] efi: mm: Pass up errors from `add_memory_regions ()`

[Patrick Steinhardt <ps@pks.im>]

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The function `add_memory_regions ()` is currently only called on system
initialization to allocate a fixed amount of pages. As such, it didn't
need to return any errors: in case it failed, we cannot proceed anyway.
This will change with the upcoming support for requesting more memory
from the firmware at runtime, where it doesn't make sense anymore to
fail hard.

Refactor the function to return an error to prepare for this. Note that
this does not change the behaviour when initializing the memory system
because `grub_efi_mm_init ()` knows to call `grub_fatal ()` in case
`grub_efi_mm_add_regions ()` returns an error.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
---
 grub-core/kern/efi/mm.c | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/grub-core/kern/efi/mm.c b/grub-core/kern/efi/mm.c
index cfc6a67fc..ced3ee5e7 100644
--- a/grub-core/kern/efi/mm.c
+++ b/grub-core/kern/efi/mm.c
@@ -478,7 +478,7 @@ filter_memory_map (grub_efi_memory_descriptor_t *memory_map,
 }
 
 /* Add memory regions.  */
-static void
+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,
@@ -506,9 +506,9 @@ add_memory_regions (grub_efi_memory_descriptor_t *memory_map,
 					   GRUB_EFI_ALLOCATE_ADDRESS,
 					   GRUB_EFI_LOADER_CODE);
       if (! addr)
-	grub_fatal ("cannot allocate conventional memory %p with %u pages",
-		    (void *) ((grub_addr_t) start),
-		    (unsigned) pages);
+	return grub_error (GRUB_ERR_OUT_OF_MEMORY,
+			    "cannot allocate conventional memory %p with %u pages",
+			    (void *) ((grub_addr_t) start), (unsigned) pages);
 
       grub_mm_init_region (addr, PAGES_TO_BYTES (pages));
 
@@ -518,7 +518,9 @@ add_memory_regions (grub_efi_memory_descriptor_t *memory_map,
     }
 
   if (required_pages > 0)
-    grub_fatal ("too little memory");
+    return grub_error (GRUB_ERR_OUT_OF_MEMORY, "too little memory");
+
+  return GRUB_ERR_NONE;
 }
 
 void
@@ -565,6 +567,7 @@ grub_efi_mm_add_regions (grub_efi_uint64_t required_bytes)
   grub_efi_memory_descriptor_t *filtered_memory_map_end;
   grub_efi_uintn_t map_size;
   grub_efi_uintn_t desc_size;
+  grub_err_t err;
   int mm_status;
 
   /* Prepare a memory region to store two memory maps.  */
@@ -609,8 +612,11 @@ grub_efi_mm_add_regions (grub_efi_uint64_t required_bytes)
   sort_memory_map (filtered_memory_map, desc_size, filtered_memory_map_end);
 
   /* Allocate memory regions for GRUB's memory management.  */
-  add_memory_regions (filtered_memory_map, desc_size,
-		      filtered_memory_map_end, BYTES_TO_PAGES (required_bytes));
+  err = add_memory_regions (filtered_memory_map, desc_size,
+			    filtered_memory_map_end,
+			    BYTES_TO_PAGES (required_bytes));
+  if (err != GRUB_ERR_NONE)
+    return err;
 
 #if 0
   /* For debug.  */
-- 
2.32.0


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