[PATCH v2 3/8] of: reserved_mem: add dumpable flag to opt-in vmcore

[Wandun Chen]

From: Wandun Chen <chenwandun1 at gmail.com>

From: Wandun Chen <chenwandun at lixiang.com>

Add a 'dumpable' flag to struct reserved_mem so the kernel can decide
whether a reserved area should be included in the kdump vmcore. Most
reserved regions are owned by devices and do not contain data useful
for kernel crash analysis, so excluding them by default is the right
behaviour.

Reusable CMA regions are different: pages in a CMA region are handed
back to the buddy allocator and may contain key data for crash
analysis, so set dumpable to true in rmem_cma_setup().

Suggested-by: Rob Herring <robh at kernel.org>
Signed-off-by: Wandun Chen <chenwandun at lixiang.com>
Tested-by: Meijing Zhao <zhaomeijing at lixiang.com>
Link: https://lore.kernel.org/all/20260506144542.GA2072596-robh@kernel.org/
---
 include/linux/of_reserved_mem.h | 1 +
 kernel/dma/contiguous.c         | 1 +
 2 files changed, 2 insertions(+)

diff --git a/include/linux/of_reserved_mem.h b/include/linux/of_reserved_mem.h
index e8b20b29fa68..55a67cee41ea 100644
--- a/include/linux/of_reserved_mem.h
+++ b/include/linux/of_reserved_mem.h
@@ -15,6 +15,7 @@ struct reserved_mem {
 	phys_addr_t			base;
 	phys_addr_t			size;
 	void				*priv;
+	bool				dumpable;
 };
 
 struct reserved_mem_ops {
diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c
index 03f52bd17120..eddec89eb414 100644
--- a/kernel/dma/contiguous.c
+++ b/kernel/dma/contiguous.c
@@ -579,6 +579,7 @@ static int __init rmem_cma_setup(unsigned long node, struct reserved_mem *rmem)
 		dma_contiguous_default_area = cma;
 
 	rmem->priv = cma;
+	rmem->dumpable = true;
 
 	pr_info("Reserved memory: created CMA memory pool at %pa, size %ld MiB\n",
 		&rmem->base, (unsigned long)rmem->size / SZ_1M);
-- 
2.43.0