[PATCH 2/3] mm/memory_hotplug: Allow arch override of non boot memory resource names

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

Memory added to the system by hotplug has a 'System RAM' resource created
for it. This is exposed to user-space via /proc/iomem.

This poses problems for kexec on arm64. If kexec decides to place the
kernel in one of these newly onlined regions, the new kernel will find
itself booting from a region not described as memory in the firmware
tables.

Arm64 doesn't have a structure like the e820 memory map that can be
re-written when memory is brought online. Instead arm64 uses the UEFI
memory map, or the memory node from the DT, sometimes both. We never
rewrite these.

Allow an architecture to specify a different name for these hotplug
regions.

Signed-off-by: James Morse <james.morse@arm.com>
---
 mm/memory_hotplug.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 0a54ffac8c68..69b03dd7fc74 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -42,6 +42,10 @@
 #include "internal.h"
 #include "shuffle.h"
 
+#ifndef MEMORY_HOTPLUG_RES_NAME
+#define MEMORY_HOTPLUG_RES_NAME "System RAM"
+#endif
+
 /*
  * online_page_callback contains pointer to current page onlining function.
  * Initially it is generic_online_page(). If it is required it could be
@@ -103,7 +107,7 @@ static struct resource *register_memory_resource(u64 start, u64 size)
 {
 	struct resource *res;
 	unsigned long flags =  IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
-	char *resource_name = "System RAM";
+	char *resource_name = MEMORY_HOTPLUG_RES_NAME;
 
 	if (start + size > max_mem_size)
 		return ERR_PTR(-E2BIG);
-- 
2.25.1


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