From: Wandun Chen <chenwandun1@gmail•com>
To: linux-arm-kernel@lists•infradead.org,
linux-kernel@vger•kernel.org, loongarch@lists•linux.dev,
linux-riscv@lists•infradead.org, devicetree@vger•kernel.org,
kexec@lists•infradead.org, iommu@lists•linux.dev,
zhaomeijing@lixiang•com
Cc: catalin.marinas@arm•com, will@kernel•org, chenhuacai@kernel•org,
kernel@xen0n•name, pjw@kernel•org, palmer@dabbelt•com,
aou@eecs•berkeley.edu, alex@ghiti•fr, robh@kernel•org,
saravanak@kernel•org, akpm@linux-foundation•org, bhe@redhat•com,
rppt@kernel•org, pasha.tatashin@soleen•com, pratyush@kernel•org,
ruirui.yang@linux•dev, m.szyprowski@samsung•com,
robin.murphy@arm•com, quic_obabatun@quicinc•com
Subject: [PATCH v3 07/11] of: reserved_mem: save /memreserve/ entries into the reserved_mem array
Date: Wed, 27 May 2026 11:29:13 +0800 [thread overview]
Message-ID: <20260527032917.3385849-8-chenwandun1@gmail.com> (raw)
In-Reply-To: <20260527032917.3385849-1-chenwandun1@gmail.com>
From: Wandun Chen <chenwandun@lixiang•com>
/memreserve/ is used by firmware or bootloaders, such regions hold no
useful data for crash analysis, they should be excluded from the
kdump vmcore, so save /memreserve/ entries into the reserved_mem array
for later exclusion.
If a /memreserve/ entry overlaps any dumpable reserved region, mark
the whole memreserve entry dumpable as well. This may keep slightly
more memory in vmcore than strictly necessary, but avoids splitting
entries and never drops data that may be useful for crash analysis.
Signed-off-by: Wandun Chen <chenwandun@lixiang•com>
Tested-by: Meijing Zhao <zhaomeijing@lixiang•com>
---
drivers/of/fdt.c | 4 +++
drivers/of/of_private.h | 2 ++
drivers/of/of_reserved_mem.c | 55 ++++++++++++++++++++++++++++++++++++
3 files changed, 61 insertions(+)
diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 83a2a474831e..745e53b1c564 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -499,6 +499,7 @@ void __init early_init_fdt_scan_reserved_mem(void)
int n;
int res;
u64 base, size;
+ int nr_memreserve = 0;
if (!initial_boot_params)
return;
@@ -516,7 +517,9 @@ void __init early_init_fdt_scan_reserved_mem(void)
if (!size)
break;
memblock_reserve(base, size);
+ nr_memreserve++;
}
+ fdt_reserved_mem_account_memreserve(nr_memreserve);
}
/**
@@ -1288,6 +1291,7 @@ void __init unflatten_device_tree(void)
if (fdt && alloc_reserved_mem_array()) {
/* Save the statically-placed regions in the reserved_mem array */
fdt_scan_reserved_mem_late();
+ fdt_reserved_mem_save_memreserve_entries();
}
/* Populate an empty root node when bootloader doesn't provide one */
diff --git a/drivers/of/of_private.h b/drivers/of/of_private.h
index 50e5a533e059..30954e859689 100644
--- a/drivers/of/of_private.h
+++ b/drivers/of/of_private.h
@@ -188,6 +188,8 @@ 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);
bool __init alloc_reserved_mem_array(void);
+void __init fdt_reserved_mem_account_memreserve(int n);
+void __init fdt_reserved_mem_save_memreserve_entries(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 888dcb6bdce5..5e27f9403786 100644
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c
@@ -248,6 +248,43 @@ static void __init __rmem_check_for_overlap(void)
}
}
+static void __init fdt_reserved_mem_add_memreserve(phys_addr_t base,
+ phys_addr_t size)
+{
+ struct reserved_mem *rmem;
+ bool dumpable = false;
+ int i;
+
+ if (reserved_mem_count == total_reserved_mem_cnt) {
+ pr_err("not enough space for memreserve regions.\n");
+ return;
+ }
+
+ for (i = 0; i < reserved_mem_count; i++) {
+ rmem = &reserved_mem[i];
+
+ if (!rmem->dumpable)
+ continue;
+
+ if (base < rmem->base + rmem->size && rmem->base < base + size) {
+ dumpable = true;
+ break;
+ }
+ }
+
+ rmem = &reserved_mem[reserved_mem_count];
+ rmem->base = base;
+ rmem->size = size;
+ rmem->dumpable = dumpable;
+
+ reserved_mem_count++;
+}
+
+void __init fdt_reserved_mem_account_memreserve(int n)
+{
+ total_reserved_mem_cnt += n;
+}
+
/**
* fdt_scan_reserved_mem_late() - Scan FDT and initialize remaining reserved
* memory regions.
@@ -305,6 +342,24 @@ void __init fdt_scan_reserved_mem_late(void)
__rmem_check_for_overlap();
}
+void __init fdt_reserved_mem_save_memreserve_entries(void)
+{
+ const void *fdt = initial_boot_params;
+ u64 base, size;
+ int n;
+
+ if (!fdt)
+ return;
+
+ for (n = 0; ; n++) {
+ if (fdt_get_mem_rsv(fdt, n, &base, &size))
+ break;
+ if (!size)
+ break;
+ fdt_reserved_mem_add_memreserve(base, size);
+ }
+}
+
static int __init __reserved_mem_alloc_size(unsigned long node, const char *uname);
/*
--
2.43.0
next prev parent reply other threads:[~2026-05-27 3:31 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-27 3:29 [PATCH v3 00/11] kdump: reduce vmcore size and capture time Wandun Chen
2026-05-27 3:29 ` [PATCH v3 01/11] of: reserved_mem: handle NULL name in of_reserved_mem_lookup() Wandun Chen
2026-05-27 3:29 ` [PATCH v3 02/11] kexec/crash: provide crash_exclude_mem_range() stub when CONFIG_CRASH_DUMP=n Wandun Chen
2026-05-27 3:29 ` [PATCH v3 03/11] of: reserved_mem: avoid post-init UAF when alloc_reserved_mem_array() fails Wandun Chen
2026-06-02 16:24 ` Rob Herring
2026-06-03 6:44 ` Wandun
2026-06-03 17:44 ` Rob Herring
2026-06-04 1:48 ` Wandun
2026-05-27 3:29 ` [PATCH v3 04/11] of: reserved_mem: zero total_reserved_mem_cnt if no valid /reserved-memory entry Wandun Chen
2026-05-27 3:29 ` [PATCH v3 05/11] of: reserved_mem: split alloc_reserved_mem_array() from fdt_scan_reserved_mem_late() Wandun Chen
2026-05-27 3:29 ` [PATCH v3 06/11] of: reserved_mem: add dumpable flag to opt-in vmcore Wandun Chen
2026-05-27 3:29 ` Wandun Chen [this message]
2026-05-27 3:29 ` [PATCH v3 08/11] of: reserved_mem: add kdump helpers to exclude non-dumpable regions Wandun Chen
2026-05-27 3:29 ` [PATCH v3 09/11] arm64: kdump: exclude non-dumpable reserved memory regions from vmcore Wandun Chen
2026-05-29 15:08 ` Will Deacon
2026-05-30 16:25 ` Mike Rapoport
2026-06-01 5:00 ` Baoquan He
2026-06-02 9:34 ` Mike Rapoport
2026-05-27 3:29 ` [PATCH v3 10/11] riscv: " Wandun Chen
2026-05-27 3:29 ` [PATCH v3 11/11] loongarch: " Wandun Chen
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