Re: GRUB2 for UEFI crashes at startup when we got 8 gigabyte of memory

["Vladimir 'φ-coder/phcoder' Serbinenko" <phcoder@gmail.com>]

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On 04/21/2010 09:53 AM, gburanov@gmail.com wrote:
> In Febryary I was testing GRUB for UEFI and noticed that it was simply crashing.
>
> See topic
> http://lists.gnu.org/archive/html/grub-devel/2010-02/msg00000.html
>
> At that time I blamed incorrect UEFI implementation on that computer (cause it worked fine on another one), but now I noticed that when I took off one memory stick, everything is working fine on that special computer!!!!
>
> So, it seems that GRUB2 is crashing on computers with  8 gb of memory (or more?)
>
>   
It has been discovered that some EFI implementations contrary to the
following sentence from the spec "                           any memory
space defined by the UEFI memory map is identity
mapped (virtual address equals physical address).
"
do not map the post-4G memory. Attached is a possible workaround. Can
you test it?
> Is it known bug? Are there workarounds?
>
>
> --
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> http://www.opensubscriber.com/messages/grub-devel@gnu.org/topic.html
>
>
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>
>   


-- 
Regards
Vladimir 'φ-coder/phcoder' Serbinenko


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=== modified file 'grub-core/kern/efi/mm.c'
--- grub-core/kern/efi/mm.c	2010-10-16 15:50:48 +0000
+++ grub-core/kern/efi/mm.c	2011-01-04 12:56:14 +0000
@@ -52,13 +52,13 @@
   grub_efi_status_t status;
   grub_efi_boot_services_t *b;
 
-#if GRUB_TARGET_SIZEOF_VOID_P < 8
+#if 1
   /* Limit the memory access to less than 4GB for 32-bit platforms.  */
   if (address > 0xffffffff)
     return 0;
 #endif
 
-#if GRUB_TARGET_SIZEOF_VOID_P < 8 || defined (MCMODEL_SMALL)
+#if 1
   if (address == 0)
     {
       type = GRUB_EFI_ALLOCATE_MAX_ADDRESS;
@@ -251,7 +251,7 @@
        desc = NEXT_MEMORY_DESCRIPTOR (desc, desc_size))
     {
       if (desc->type == GRUB_EFI_CONVENTIONAL_MEMORY
-#if GRUB_TARGET_SIZEOF_VOID_P < 8 || defined (MCMODEL_SMALL)
+#if 1
 	  && desc->physical_start <= 0xffffffff
 #endif
 	  && desc->physical_start + PAGES_TO_BYTES (desc->num_pages) > 0x100000
@@ -267,7 +267,7 @@
 	      desc->physical_start = 0x100000;
 	    }
 
-#if GRUB_TARGET_SIZEOF_VOID_P < 8 || defined (MCMODEL_SMALL)
+#if 1
 	  if (BYTES_TO_PAGES (filtered_desc->physical_start)
 	      + filtered_desc->num_pages
 	      > BYTES_TO_PAGES (0x100000000LL))


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=== modified file 'grub-core/lib/efi/relocator.c'
--- grub-core/lib/efi/relocator.c	2010-04-20 16:08:26 +0000
+++ grub-core/lib/efi/relocator.c	2011-01-04 11:02:37 +0000
@@ -62,13 +62,25 @@
        (char *) desc < ((char *) descs + mmapsize);
        desc = NEXT_MEMORY_DESCRIPTOR (desc, desc_size))
     {
+      grub_uint64_t start = desc->physical_start;
+      grub_uint64_t end = desc->physical_start + (desc->num_pages << 12);
+
+      /* post-4G addresses are never supported on 32-bit EFI. 
+	 Moreover it has been reported that some 64-bit EFI contrary to the
+	 spec don't map post-4G pages. So if you enable post-4G allocations,
+	 map pages manually or check that they are mapped.
+       */
+      if (end >= 0x100000000ULL)
+	end = 0x100000000ULL;
+      if (end <= start)
+	continue;
       if (desc->type != GRUB_EFI_CONVENTIONAL_MEMORY)
 	continue;
       events[counter].type = REG_FIRMWARE_START;
-      events[counter].pos = desc->physical_start;
+      events[counter].pos = start;
       counter++;
       events[counter].type = REG_FIRMWARE_END;
-      events[counter].pos = desc->physical_start + (desc->num_pages << 12);
+      events[counter].pos = end;
       counter++;      
     }
 
@@ -85,6 +97,9 @@
   if (grub_efi_is_finished)
     return 1;
 
+  grub_dprintf ("relocator", "EFI alloc: %llx, %llx\n",
+		(unsigned long long) start, (unsigned long long) size);
+
   b = grub_efi_system_table->boot_services;
   status = efi_call_4 (b->allocate_pages, GRUB_EFI_ALLOCATE_ADDRESS,
 		       GRUB_EFI_LOADER_DATA, size >> 12, &address);


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