The patch titled
Subject: arm64: memory: give hotplug memory a different resource name
has been added to the -mm tree. Its filename is
arm64-memory-give-hotplug-memory-a-different-resource-name.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/arm64-memory-give-hotplug-memory-a-different-resource-name.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/arm64-memory-give-hotplug-memory-a-different-resource-name.patch
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------------------------------------------------------
From: James Morse <james.morse@xxxxxxx>
Subject: arm64: memory: give hotplug memory a different resource name
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.
Link: http://lkml.kernel.org/r/20200326180730.4754-4-james.morse@xxxxxxx
Signed-off-by: James Morse <james.morse@xxxxxxx>
Cc: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Cc: Bhupesh Sharma <bhsharma@xxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Eric Biederman <ebiederm@xxxxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/arm64/include/asm/memory.h | 11 +++++++++++
1 file changed, 11 insertions(+)
--- a/arch/arm64/include/asm/memory.h~arm64-memory-give-hotplug-memory-a-different-resource-name
+++ a/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))
_
Patches currently in -mm which might be from james.morse@xxxxxxx are
kexec-prevent-removal-of-memory-in-use-by-a-loaded-kexec-image.patch
mm-memory_hotplug-allow-arch-override-of-non-boot-memory-resource-names.patch
arm64-memory-give-hotplug-memory-a-different-resource-name.patch
