git » linux-kernel » commit d3758f8

[IA64] kexec fails on systems with blocks of uncached memory

[IA64] kexec fails on systems with blocks of uncached memory

Currently a memory segment in memory map with attribute of EFI_MEMORY_UC
is denoted as "System RAM" in /proc/iomem, while memory of attribute
(EFI_MEMORY_WB|EFI_MEMORY_UC) is also labeled the same.

The kexec utility then includes uncached memory as part of vmcore. The
kdump kernel MCA'ed when it tries to save the vmcore to a disk. A normal
"cached" access may cause MCAs.

This patch would label memory with attribute of EFI_MEMORY_UC only as
"Uncached RAM" so that kexec would know not to include it in the vmcore.
I will submit a separate kexec-tools patch to the kexec list.

Signed-off-by: Jay Lan <jlan@sgi.com>
Acked-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Tony Luck <tony.luck@intel.com>

diff --git a/arch/ia64/kernel/efi.c b/arch/ia64/kernel/efi.c
index d45f215bc8f..51b75cea701 100644
--- a/arch/ia64/kernel/efi.c
+++ b/arch/ia64/kernel/efi.c
@@ -1232,9 +1232,10 @@ efi_initialize_iomem_resources(struct resource *code_resource,
 				if (md->attribute & EFI_MEMORY_WP) {
 					name = "System ROM";
 					flags |= IORESOURCE_READONLY;
-				} else {
+				} else if (md->attribute == EFI_MEMORY_UC)
+					name = "Uncached RAM";
+				else
 					name = "System RAM";
-				}
 				break;
 
 			case EFI_ACPI_MEMORY_NVS: