[PATCH v6 08/10] of: reserved_mem: mark /reserved-memory entries with MEMBLOCK_NODUMP

[Wandun Chen <chenwandun1@gmail.com>]

From: Wandun Chen <chenwandun@lixiang.com>

Mark non-dumpable reserved-memory regions with MEMBLOCK_NODUMP so
kdump can omit them from the vmcore.

The marking is guarded by CONFIG_CRASH_DUMP so non-kdump kernels do not
pay the cost of splitting memblock.memory entries at NODUMP boundaries.

Signed-off-by: Wandun Chen <chenwandun@lixiang.com>
Tested-by: Meijing Zhao <zhaomeijing@lixiang.com>
---
 drivers/of/fdt.c             |  1 +
 drivers/of/of_private.h      |  1 +
 drivers/of/of_reserved_mem.c | 15 +++++++++++++++
 3 files changed, 17 insertions(+)

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index a64afc3ded3d..286fd4db6312 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -1285,6 +1285,7 @@ void __init unflatten_device_tree(void)
 
 	/* Save the statically-placed regions in the reserved_mem array */
 	fdt_scan_reserved_mem_late();
+	fdt_mark_reserve_mem_nodump();
 
 	/* Populate an empty root node when bootloader doesn't provide one */
 	if (!fdt) {
diff --git a/drivers/of/of_private.h b/drivers/of/of_private.h
index 0ae16da066e2..505735732c13 100644
--- a/drivers/of/of_private.h
+++ b/drivers/of/of_private.h
@@ -187,6 +187,7 @@ static inline struct device_node *__of_get_dma_parent(const struct device_node *
 
 int fdt_scan_reserved_mem(void);
 void __init fdt_scan_reserved_mem_late(void);
+void __init fdt_mark_reserve_mem_nodump(void);
 
 bool of_fdt_device_is_available(const void *blob, unsigned long node);
 
diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
index 8c9d6395d6a3..f29a07e8fb23 100644
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c
@@ -677,6 +677,21 @@ static void __init fdt_init_reserved_mem_node(unsigned long node, const char *un
 	reserved_mem_count++;
 }
 
+void __init fdt_mark_reserve_mem_nodump(void)
+{
+	struct reserved_mem *rmem;
+	int i;
+
+	if (!IS_ENABLED(CONFIG_CRASH_DUMP))
+		return;
+
+	for (i = 0; i < reserved_mem_count; i++) {
+		rmem = &reserved_mem[i];
+		if (rmem->size && !rmem->dumpable)
+			memblock_mark_nodump(rmem->base, rmem->size);
+	}
+}
+
 struct rmem_assigned_device {
 	struct device *dev;
 	struct reserved_mem *rmem;
-- 
2.43.0