[PATCH 3/3] arm64: memory: Give hotplug memory a different resource name

[James Morse <james.morse@arm.com>]

If kexec chooses to place the kernel in a memory region that was
added after boot, we fail to boot as the kernel is running from a
location that is not described as memory by the UEFI memory map or
the original DT.

To prevent unaware user-space kexec from doing this accidentally,
give these regions a different name.

Signed-off-by: James Morse <james.morse@arm.com>
---
This is a change in behaviour as seen by user-space, because memory hot-add
has already been merged.

 arch/arm64/include/asm/memory.h | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index 2be67b232499..ef1686518469 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -166,6 +166,17 @@
 #define IOREMAP_MAX_ORDER	(PMD_SHIFT)
 #endif
 
+/*
+ * Memory hotplug allows new regions of 'System RAM' to be added to the system.
+ * These aren't described as memory by the UEFI memory map, or DT memory node.
+ * If we kexec from one of these regions, the new kernel boots from a location
+ * that isn't described as RAM.
+ *
+ * Give these resources a different name, so unaware kexec doesn't do this by
+ * accident.
+ */
+#define MEMORY_HOTPLUG_RES_NAME "System RAM (hotplug)"
+
 #ifndef __ASSEMBLY__
 extern u64			vabits_actual;
 #define PAGE_END		(_PAGE_END(vabits_actual))
-- 
2.25.1