linux-kernel - [PATCH 18/26] mm/memblock: Add MEMBLOCK

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Message-ID: <20251119154427.1033475-19-eugen.hristev@linaro.org>
Date: Wed, 19 Nov 2025 17:44:19 +0200
From: Eugen Hristev <eugen.hristev@...aro.org>
To: linux-arm-msm@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-mm@...ck.org,
	tglx@...utronix.de,
	andersson@...nel.org,
	pmladek@...e.com,
	rdunlap@...radead.org,
	corbet@....net,
	david@...hat.com,
	mhocko@...e.com
Cc: tudor.ambarus@...aro.org,
	mukesh.ojha@....qualcomm.com,
	linux-arm-kernel@...ts.infradead.org,
	linux-hardening@...r.kernel.org,
	jonechou@...gle.com,
	rostedt@...dmis.org,
	linux-doc@...r.kernel.org,
	devicetree@...r.kernel.org,
	linux-remoteproc@...r.kernel.org,
	linux-arch@...r.kernel.org,
	tony.luck@...el.com,
	kees@...nel.org,
	Eugen Hristev <eugen.hristev@...aro.org>
Subject: [PATCH 18/26] mm/memblock: Add MEMBLOCK_INSPECT flag

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@...aro.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