From: Wandun Chen <[email protected]> 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 <[email protected]> Tested-by: Meijing Zhao <[email protected]> --- drivers/of/fdt.c | 2 ++ drivers/of/of_private.h | 1 + drivers/of/of_reserved_mem.c | 32 ++++++++++++++++++++++++++++++++ 3 files changed, 35 insertions(+) diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c index a64afc3ded3d..2aa888997e9b 100644 --- a/drivers/of/fdt.c +++ b/drivers/of/fdt.c @@ -1286,6 +1286,8 @@ void __init unflatten_device_tree(void) /* Save the statically-placed regions in the reserved_mem array */ fdt_scan_reserved_mem_late(); + fdt_mark_memreserve_nodump(); + /* Populate an empty root node when bootloader doesn't provide one */ if (!fdt) { fdt = (void *) __dtb_empty_root_begin; diff --git a/drivers/of/of_private.h b/drivers/of/of_private.h index 0ae16da066e2..667ce9e46aab 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_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 f38d11df6f15..f0683b5d77b3 100644 --- a/drivers/of/of_reserved_mem.c +++ b/drivers/of/of_reserved_mem.c @@ -251,6 +251,38 @@ 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 < rmem->base + rmem->size && + 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
