[PATCH 18/26] mm/memblock: Add MEMBLOCK_INSPECT flag

Eugen Hristev
2025-11-19T15:45:51Z

This memblock flag indicates that a specific block is registered
into an inspection table.
The block can be marked for inspection using memblock_mark_inspect()
and cleared with memblock_clear_inspect()

Signed-off-by: Eugen Hristev <eugen.hristev@linaro.org>
---
include/linux/memblock.h | 7 +++++++
mm/memblock.c | 36 ++++++++++++++++++++++++++++++++++++
2 files changed, 43 insertions(+)

diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index 221118b5a16e..c3e55a4475cf 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -51,6 +51,10 @@ extern unsigned long long max_possible_pfn;
* memory reservations yet, so we get scratch memory from the previous
* kernel that we know is good to use. It is the only memory that
* allocations may happen from in this phase.
+ * @MEMBLOCK_INSPECT: memory region is annotated in kernel memory inspection
+ * table. This means a dedicated entry will be created for this region which
+ * will contain the memory's address and size. This allows kernel inspectors
+ * to retrieve the memory.
*/
enum memblock_flags {
MEMBLOCK_NONE = 0x0, /* No special request */
@@ -61,6 +65,7 @@ enum memblock_flags {
MEMBLOCK_RSRV_NOINIT = 0x10, /* don't initialize struct pages */
MEMBLOCK_RSRV_KERN = 0x20, /* memory reserved for kernel use */
MEMBLOCK_KHO_SCRATCH = 0x40, /* scratch memory for kexec handover */
+ MEMBLOCK_INSPECT = 0x80, /* memory selected for kernel inspection */
};

/**
@@ -149,6 +154,8 @@ unsigned long memblock_addrs_overlap(phys_addr_t base1, phys_addr_t size1,
bool memblock_overlaps_region(struct memblock_type *type,
phys_addr_t base, phys_addr_t size);
bool memblock_validate_numa_coverage(unsigned long threshold_bytes);
+int memblock_mark_inspect(phys_addr_t base, phys_addr_t size);
+int memblock_clear_inspect(phys_addr_t base, phys_addr_t size);
int memblock_mark_hotplug(phys_addr_t base, phys_addr_t size);
int memblock_clear_hotplug(phys_addr_t base, phys_addr_t size);
int memblock_mark_mirror(phys_addr_t base, phys_addr_t size);
diff --git a/mm/memblock.c b/mm/memblock.c
index e23e16618e9b..a5df5ab286e5 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -17,6 +17,7 @@
#include <linux/seq_file.h>
#include <linux/memblock.h>
#include <linux/mutex.h>
+#include <linux/meminspect.h>

#ifdef CONFIG_KEXEC_HANDOVER
#include <linux/libfdt.h>
@@ -1016,6 +1017,40 @@ static int __init_memblock memblock_setclr_flag(struct memblock_type *type,
return 0;
}

+/**
+ * memblock_mark_inspect - Mark inspectable memory with flag MEMBLOCK_INSPECT.
+ * @base: the base phys addr of the region
+ * @size: the size of the region
+ *
+ * Return: 0 on success, -errno on failure.
+ */
+int __init_memblock memblock_mark_inspect(phys_addr_t base, phys_addr_t size)
+{
+ int ret;
+
+ ret = memblock_setclr_flag(&memblock.memory, base, size, 1, MEMBLOCK_INSPECT);
+ if (ret)
+ return ret;
+
+ meminspect_lock_register_pa(base, size);
+
+ return 0;
+}
+
+/**
+ * memblock_clear_inspect - Clear flag MEMBLOCK_INSPECT for a specified region.
+ * @base: the base phys addr of the region
+ * @size: the size of the region
+ *
+ * Return: 0 on success, -errno on failure.
+ */
+int __init_memblock memblock_clear_inspect(phys_addr_t base, phys_addr_t size)
+{
+ meminspect_lock_unregister_pa(base, size);
+
+ return memblock_setclr_flag(&memblock.memory, base, size, 0, MEMBLOCK_INSPECT);
+}
+
/**
* memblock_mark_hotplug - Mark hotpluggable memory with flag MEMBLOCK_HOTPLUG.
* @base: the base phys addr of the region
@@ -2704,6 +2739,7 @@ static const char * const flagname[] = {
[ilog2(MEMBLOCK_RSRV_NOINIT)] = "RSV_NIT",
[ilog2(MEMBLOCK_RSRV_KERN)] = "RSV_KERN",
[ilog2(MEMBLOCK_KHO_SCRATCH)] = "KHO_SCRATCH",
+ [ilog2(MEMBLOCK_INSPECT)] = "INSPECT",
};

static int memblock_debug_show(struct seq_file *m, void *private)
--
2.43.0