[PATCH v7 8/9] of: reserved_mem: mark /memreserve/ entries as MEMBLOCK_NODUMP
From: Wandun Chen <hidden>
Date: 2026-09-22 08:45:11
Also in:
kexec, linux-devicetree, linux-iommu, linux-mm, linux-riscv, lkml, loongarch
Subsystem:
open firmware and flattened device tree, the rest · Maintainers:
Rob Herring, Saravana Kannan, Linus Torvalds
From: Wandun Chen <redacted> The /memreserve/ entries are memory reservations made by the bootloader or firmware, their contents are not needed for kernel crash analysis, so mark them MEMBLOCK_NODUMP to have kdump omit them from the vmcore. Entries that overlap a dumpable region (such as CMA) are left unmarked, because the pages of a dumpable region may carry crash-relevant data. Signed-off-by: Wandun Chen <redacted> Tested-by: Meijing Zhao <redacted> Acked-by: Marek Szyprowski <m.szyprowski@samsung.com> --- drivers/of/fdt.c | 1 + drivers/of/of_private.h | 1 + drivers/of/of_reserved_mem.c | 33 +++++++++++++++++++++++++++++++++ 3 files changed, 35 insertions(+)
diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 286fd4db6312..9a727941b5af 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c@@ -1286,6 +1286,7 @@ 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(); + fdt_mark_memreserve_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 505735732c13..6497404ec751 100644
--- a/drivers/of/of_private.h
+++ b/drivers/of/of_private.h@@ -188,6 +188,7 @@ 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); +void __init fdt_mark_memreserve_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 f29a07e8fb23..a42cf6eac55b 100644
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c@@ -251,6 +251,39 @@ static void __init __rmem_check_for_overlap(void) } } +void __init fdt_mark_memreserve_nodump(void) +{ + u64 base, size; + int n; + const void *fdt = initial_boot_params; + + if (!IS_ENABLED(CONFIG_CRASH_DUMP)) + return; + + if (!fdt) + return; + + for (n = 0; ; n++) { + int i; + + if (fdt_get_mem_rsv(fdt, n, &base, &size)) + break; + if (!size) + break; + + for (i = 0; i < reserved_mem_count; i++) { + struct reserved_mem *rmem = &reserved_mem[i]; + + if (rmem->dumpable && + base < (u64)rmem->base + (u64)rmem->size && + (u64)rmem->base < base + size) + break; + } + if (i == reserved_mem_count) + memblock_mark_nodump(base, size); + } +} + /** * fdt_scan_reserved_mem_late() - Scan FDT and initialize remaining reserved * memory regions.
--
2.43.0