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Thu, 15 Oct 2026 23:17:07 -0700 (PDT) From: Wandun Chen To: robh@kernel.org, baoquan.he@linux.dev, rppt@kernel.org, m.szyprowski@samsung.com Cc: catalin.marinas@arm.com, will@kernel.org, mark.rutland@arm.com, chenhuacai@kernel.org, kernel@xen0n.name, pjw@kernel.org, palmer@dabbelt.com, aou@eecs.berkeley.edu, alex@ghiti.fr, tglx@kernel.org, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, saravanak@kernel.org, akpm@linux-foundation.org, pasha.tatashin@soleen.com, pratyush@kernel.org, ruirui.yang@linux.dev, robin.murphy@arm.com, 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, linux-mm@kvack.org, iommu@lists.linux.dev Subject: [RESEND PATCH v8 5/8] memblock: introduce MEMBLOCK_NODUMP flag Date: Fri, 16 Oct 2026 14:15:46 +0800 Message-ID: <20261016061549.4181390-6-chenwandun1@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20261016061549.4181390-1-chenwandun1@gmail.com> References: <20261016061549.4181390-1-chenwandun1@gmail.com> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Wandun Chen Add MEMBLOCK_NODUMP to mark regions that should be excluded from kdump vmcores. The flag is meant for reserved memory that carries no data useful for crash analysis. Reusable reserved regions such as CMA may hold useful data, so these regions must not be marked MEMBLOCK_NODUMP. Subsequent patches wire this up for /reserved-memory entries. Suggested-by: Rob Herring Signed-off-by: Wandun Chen Tested-by: Meijing Zhao Reviewed-by: Mike Rapoport (Microsoft) --- include/linux/memblock.h | 9 +++++++++ mm/memblock.c | 16 ++++++++++++++++ 2 files changed, 25 insertions(+) diff --git a/include/linux/memblock.h b/include/linux/memblock.h index ea288cf21400..04fbdff2b808 100644 --- a/include/linux/memblock.h +++ b/include/linux/memblock.h @@ -52,6 +52,8 @@ extern unsigned long long max_possible_pfn; * know is good to use. It is the only memory that allocations may happen from * in this phase. * @MEMBLOCK_RSRV_HUGETLB: memory is reserved for hugetlb pages + * @MEMBLOCK_NODUMP: exclude from kdump vmcore. It carries no data useful + * for crash analysis (e.g. firmware carveouts). */ enum memblock_flags { MEMBLOCK_NONE = 0x0, /* No special request */ @@ -63,6 +65,7 @@ enum memblock_flags { MEMBLOCK_RSRV_KERN = 0x20, /* memory reserved for kernel use */ MEMBLOCK_KHO_NOPRSRV = 0x40, /* memory with no KHO preservations */ MEMBLOCK_RSRV_HUGETLB = 0x80, /* memory reserved for hugetlb pages */ + MEMBLOCK_NODUMP = 0x100,/* exclude from kdump vmcore */ }; /** @@ -160,6 +163,7 @@ int memblock_reserved_mark_noinit(phys_addr_t base, phys_addr_t size); int memblock_reserved_mark_kern(phys_addr_t base, phys_addr_t size); int memblock_mark_kho_noprsrv(phys_addr_t base, phys_addr_t size); int memblock_clear_kho_noprsrv(phys_addr_t base, phys_addr_t size); +int memblock_mark_nodump(phys_addr_t base, phys_addr_t size); void memblock_free(void *ptr, size_t size); @@ -305,6 +309,11 @@ static inline bool memblock_is_kho_noprsrv(struct memblock_region *m) return m->flags & MEMBLOCK_KHO_NOPRSRV; } +static inline bool memblock_is_nodump(struct memblock_region *m) +{ + return m->flags & MEMBLOCK_NODUMP; +} + int memblock_search_pfn_nid(unsigned long pfn, unsigned long *start_pfn, unsigned long *end_pfn); void __next_mem_pfn_range(int *idx, int nid, unsigned long *out_start_pfn, diff --git a/mm/memblock.c b/mm/memblock.c index cbb172fbf06a..31c89bd64036 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -1204,6 +1204,21 @@ __init int memblock_clear_kho_noprsrv(phys_addr_t base, phys_addr_t size) MEMBLOCK_KHO_NOPRSRV); } +/** + * memblock_mark_nodump - Mark a memory region with flag MEMBLOCK_NODUMP. + * @base: the base phys addr of the region + * @size: the size of the region + * + * Mark the region as not to be included in crash dumps. + * + * Return: 0 on success, -errno on failure. + */ +int __init_memblock memblock_mark_nodump(phys_addr_t base, phys_addr_t size) +{ + return memblock_setclr_flag(&memblock.memory, base, size, 1, + MEMBLOCK_NODUMP); +} + static bool should_skip_region(struct memblock_type *type, struct memblock_region *m, int nid, int flags) @@ -2880,6 +2895,7 @@ static const char * const flagname[] = { [ilog2(MEMBLOCK_RSRV_KERN)] = "RSV_KERN", [ilog2(MEMBLOCK_KHO_NOPRSRV)] = "KHO_NOPRSRV", [ilog2(MEMBLOCK_RSRV_HUGETLB)] = "RSV_HUGETLB", + [ilog2(MEMBLOCK_NODUMP)] = "NODUMP", }; static int memblock_debug_show(struct seq_file *m, void *private) -- 2.43.0