Re: patch for kern/efi/mm.c (big memmap)

[Johan Rydberg <jrydberg@night.trouble.net>]

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tgingold@free.fr writes:

> some systems have a really big memmap.  This patch remove the memmap
> size limit.

Overall the patch looks good, I have one comment through; (the patch
is for kern/efi/mm.c if someone wonders.)

+  memory_map = grub_efi_allocate_pages
+    (0, 2 * BYTES_TO_PAGES (memory_map_size + 0x1000));

I suppose you add 0x1000 to round it up.  Maybe we should change the
BYTES_TO_PAGES macro to do roundup.

I'll attach a unified diff, since those is easier to review.

Even through this patch is quite trivial and small, I believe we need
you to sign over the copyright for it to FSF.  Okuji, Marco, what are
your opinions?  

~j


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Index: kern/efi/mm.c
===================================================================
RCS file: /sources/grub/grub2/kern/efi/mm.c,v
retrieving revision 1.3
diff -u -r1.3 mm.c
--- kern/efi/mm.c	28 May 2006 23:01:43 -0000	1.3
+++ kern/efi/mm.c	28 Sep 2006 13:29:16 -0000
@@ -30,10 +30,6 @@
 #define BYTES_TO_PAGES(bytes)	((bytes) >> 12)
 #define PAGES_TO_BYTES(pages)	((pages) << 12)
 
-/* The size of a memory map obtained from the firmware. This must be
-   a multiplier of 4KB.  */
-#define MEMORY_MAP_SIZE	0x1000
-
 /* Maintain the list of allocated pages.  */
 struct allocated_page
 {
@@ -346,6 +342,8 @@
   grub_efi_uintn_t desc_size;
   grub_efi_uint64_t total_pages;
   grub_efi_uint64_t required_pages;
+  grub_efi_uintn_t memory_map_size;
+  int res;
 
   /* First of all, allocate pages to maintain allocations.  */
   allocated_pages
@@ -356,15 +354,20 @@
   grub_memset (allocated_pages, 0, ALLOCATED_PAGES_SIZE);
   
   /* Prepare a memory region to store two memory maps.  */
-  memory_map = grub_efi_allocate_pages (0,
-					2 * BYTES_TO_PAGES (MEMORY_MAP_SIZE));
+  memory_map_size = 0;
+  res = grub_efi_get_memory_map (&memory_map_size, NULL, 0, &desc_size, 0);
+  if (res != 0)
+    grub_fatal ("cannot get memory map size");
+
+  memory_map = grub_efi_allocate_pages
+    (0, 2 * BYTES_TO_PAGES (memory_map_size + 0x1000));
   if (! memory_map)
     grub_fatal ("cannot allocate memory");
 
-  filtered_memory_map = NEXT_MEMORY_DESCRIPTOR (memory_map, MEMORY_MAP_SIZE);
+  filtered_memory_map = NEXT_MEMORY_DESCRIPTOR (memory_map, memory_map_size);
 
   /* Obtain descriptors for available memory.  */
-  map_size = MEMORY_MAP_SIZE;
+  map_size = memory_map_size;
 
   if (grub_efi_get_memory_map (&map_size, memory_map, 0, &desc_size, 0) < 0)
     grub_fatal ("cannot get memory map");
@@ -373,7 +376,7 @@
   
   filtered_memory_map_end = filter_memory_map (memory_map, filtered_memory_map,
 					       desc_size, memory_map_end);
-  
+
   /* By default, request a quarter of the available memory.  */
   total_pages = get_total_pages (filtered_memory_map, desc_size,
 				 filtered_memory_map_end);
@@ -393,7 +396,7 @@
 
 #if 0
   /* For debug.  */
-  map_size = MEMORY_MAP_SIZE;
+  map_size = memory_map_size;
 
   if (grub_efi_get_memory_map (&map_size, memory_map, 0, &desc_size, 0) < 0)
     grub_fatal ("cannot get memory map");
@@ -406,7 +409,7 @@
   
   /* Release the memory maps.  */
   grub_efi_free_pages ((grub_addr_t) memory_map,
-		       2 * BYTES_TO_PAGES (MEMORY_MAP_SIZE));
+		       2 * BYTES_TO_PAGES (memory_map_size + 0x1000));
 }
 
 void

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