Re: 2.6.39.1 immediately reboots/resets on EFI system

[Matthew Garrett <mjg59@srcf.ucam.org>]

Ok, let's just try this in a somewhat more brute force way. Can you try 
this patch on top of current git, and give me the full dmesg and 
/proc/iomem ?

diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 0d3a4fa..ffbe47c 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -312,11 +312,35 @@ void __init efi_reserve_boot_services(void)
 		efi_memory_desc_t *md = p;
 		unsigned long long start = md->phys_addr;
 		unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
+		unsigned long long end = start + size;
 
-		if (md->type != EFI_BOOT_SERVICES_CODE &&
-		    md->type != EFI_BOOT_SERVICES_DATA)
+		if (md->type != EFI_BOOT_SERVICES_CODE)
 			continue;
 
+		/*
+		 * Trying to map EFI code over the zero page is just asking
+		 * for trouble. The good news is that it's almost certainly
+		 * only there for graphics card bringup at POST time, so
+		 * we should be able to get away with not having it there
+		 */
+
+		if (start == 0) {
+			md->num_pages = 0;
+			continue;
+		}
+
+		/*
+		 * We probably also want to avoid mapping code over the
+		 * kernel...
+		 */
+
+		if ((start <= virt_to_phys(_etext)-1 && end >= virt_to_phys(_text)) ||
+		    (start <= virt_to_phys(_edata)-1 && end >= virt_to_phys(_etext)) ||
+		    (start <= virt_to_phys(&__bss_stop)-1 && end >= virt_to_phys(&__bss_start))) {
+			md->num_pages = 0;
+			continue;
+		}
+
 		memblock_x86_reserve_range(start, start + size, "EFI Boot");
 	}
 }
@@ -330,8 +354,10 @@ static void __init efi_free_boot_services(void)
 		unsigned long long start = md->phys_addr;
 		unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
 
-		if (md->type != EFI_BOOT_SERVICES_CODE &&
-		    md->type != EFI_BOOT_SERVICES_DATA)
+		if (md->type != EFI_BOOT_SERVICES_CODE)
+			continue;
+
+		if (size == 0)
 			continue;
 
 		free_bootmem_late(start, size);
@@ -483,9 +509,6 @@ void __init efi_init(void)
 	x86_platform.set_wallclock = efi_set_rtc_mmss;
 #endif
 
-	/* Setup for EFI runtime service */
-	reboot_type = BOOT_EFI;
-
 #if EFI_DEBUG
 	print_efi_memmap();
 #endif

-- 
Matthew Garrett | mjg59@srcf.ucam.org