[PATCH v4 08/10] arm64: kdump: exclude non-dumpable reserved memory regions from vmcore

From: Wandun Chen <[email protected]>

Reserved memory regions are excluded from vmcore by default unless
marked dumpable. Honor the dumpable flag to filter out device firmware
regions (e.g., GPU, DSP, modem) reserved via device tree, since they
typically contain data not useful for kernel crash analysis and can
significantly increase vmcore size.

Use of_reserved_mem_kdump_exclude() to perform the exclusion, and
pre-size the crash_mem array via of_reserved_mem_kdump_nr_ranges().

Signed-off-by: Wandun Chen <[email protected]>
Tested-by: Meijing Zhao <[email protected]>
Acked-by: Will Deacon <[email protected]>
---
 arch/arm64/kernel/machine_kexec_file.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c
index e31fabed378a..1d65320c6ba4 100644
--- a/arch/arm64/kernel/machine_kexec_file.c
+++ b/arch/arm64/kernel/machine_kexec_file.c
@@ -17,6 +17,7 @@
 #include <linux/memblock.h>
 #include <linux/of.h>
 #include <linux/of_fdt.h>
+#include <linux/of_reserved_mem.h>
 #include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/types.h>
@@ -51,6 +52,7 @@ static int prepare_elf_headers(void **addr, unsigned long *sz)
 	nr_ranges = 2; /* for exclusion of crashkernel region */
 	for_each_mem_range(i, &start, &end)
 		nr_ranges++;
+	nr_ranges += of_reserved_mem_kdump_nr_ranges();
 
 	cmem = kmalloc_flex(*cmem, ranges, nr_ranges);
 	if (!cmem)
@@ -75,6 +77,10 @@ static int prepare_elf_headers(void **addr, unsigned long *sz)
 			goto out;
 	}
 
+	ret = of_reserved_mem_kdump_exclude(cmem);
+	if (ret)
+		goto out;
+
 	ret = crash_prepare_elf64_headers(cmem, true, addr, sz);
 
 out:
-- 
2.43.0