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Tue, 28 Apr 2026 23:59:52 -0700 (PDT) From: Chen Wandun X-Google-Original-From: Chen Wandun To: kexec@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, loongarch@lists.linux.dev, linux-riscv@lists.infradead.org, devicetree@vger.kernel.org Cc: akpm@linux-foundation.org, bhe@redhat.com, rppt@kernel.org, pasha.tatashin@soleen.com, pratyush@kernel.org, ruirui.yang@linux.dev, corbet@lwn.net, skhan@linuxfoundation.org, catalin.marinas@arm.com, will@kernel.org, chenhuacai@kernel.org, kernel@xen0n.name, pjw@kernel.org, palmer@dabbelt.com, aou@eecs.berkeley.edu, robh@kernel.org, saravanak@kernel.org, chenwandun@lixiang.com, zhaomeijing@lixiang.com, everyzhao@126.com Subject: [PATCH 07/11] of: reserved_mem: add no-dump crash_mem exclusion helpers Date: Wed, 29 Apr 2026 14:58:27 +0800 Message-ID: <20260429065831.1510858-8-chenwandun@lixiang.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260429065831.1510858-1-chenwandun@lixiang.com> References: <20260429065831.1510858-1-chenwandun@lixiang.com> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Provide two kdump-oriented helpers so that arch kexec_file code does not have to open-code the no-dump filtering loop: - of_reserved_mem_no_dump_nr_ranges() returns the number of reserved regions flagged with linux,no-dump. Each exclusion may split one existing crash_mem range into two, so callers use this count to pre-size their crash_mem allocation. - of_reserved_mem_exclude_no_dump() walks the reserved_mem[] array and calls crash_exclude_mem_range() for each no-dump region. Both helpers are guarded by CONFIG_KEXEC_FILE; empty inline stubs are provided for the !KEXEC_FILE case so architecture code can call them unconditionally. The consumers are added in the following arm64, riscv and loongarch patches in this series. Signed-off-by: Chen Wandun Tested-by: Zhao Meijing --- drivers/of/of_reserved_mem.c | 54 +++++++++++++++++++++++++++++++++ include/linux/of_reserved_mem.h | 15 +++++++++ 2 files changed, 69 insertions(+) diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c index 4b80420da2d2..038056a6408a 100644 --- a/drivers/of/of_reserved_mem.c +++ b/drivers/of/of_reserved_mem.c @@ -27,6 +27,10 @@ #include "of_private.h" +#ifdef CONFIG_KEXEC_FILE +#include +#endif + static struct reserved_mem reserved_mem_array[MAX_RESERVED_REGIONS] __initdata; static struct reserved_mem *reserved_mem __refdata = reserved_mem_array; static int total_reserved_mem_cnt = MAX_RESERVED_REGIONS; @@ -916,6 +920,56 @@ struct reserved_mem *of_reserved_mem_lookup(struct device_node *np) } EXPORT_SYMBOL_GPL(of_reserved_mem_lookup); +#ifdef CONFIG_KEXEC_FILE +/** + * of_reserved_mem_no_dump_nr_ranges() - count reserved regions flagged + * with the linux,no-dump property. + * + * Each such region may split an existing crash_mem range into two when + * it is excluded, so callers can use this count to pre-size their + * crash_mem allocation. + */ +unsigned int of_reserved_mem_no_dump_nr_ranges(void) +{ + unsigned int i, n = 0; + + for (i = 0; i < reserved_mem_count; i++) + if (reserved_mem[i].no_dump) + n++; + return n; +} + +/** + * of_reserved_mem_exclude_no_dump() - exclude no-dump reserved regions + * from a crash_mem list. + * @cmem: crash memory list to modify + * + * Walks the reserved_mem[] array and calls crash_exclude_mem_range() for + * every region with no_dump set. Intended to be called from arch kdump + * code when constructing the elfcorehdr. + * + * Returns 0 on success, or a negative error returned by + * crash_exclude_mem_range() on the first failure. + */ +int of_reserved_mem_exclude_no_dump(struct crash_mem *cmem) +{ + unsigned int i; + int ret; + + for (i = 0; i < reserved_mem_count; i++) { + struct reserved_mem *r = &reserved_mem[i]; + + if (!r->no_dump || !r->size) + continue; + ret = crash_exclude_mem_range(cmem, r->base, + r->base + r->size - 1); + if (ret) + return ret; + } + return 0; +} +#endif /* CONFIG_KEXEC_FILE */ + /** * of_reserved_mem_region_to_resource() - Get a reserved memory region as a resource * @np: node containing 'memory-region' property diff --git a/include/linux/of_reserved_mem.h b/include/linux/of_reserved_mem.h index 29674f572673..cd0f88f29579 100644 --- a/include/linux/of_reserved_mem.h +++ b/include/linux/of_reserved_mem.h @@ -8,6 +8,7 @@ struct of_phandle_args; struct reserved_mem_ops; struct resource; +struct crash_mem; struct reserved_mem { const char *name; @@ -94,6 +95,20 @@ static inline int of_reserved_mem_region_count(const struct device_node *np) } #endif +#if defined(CONFIG_OF_RESERVED_MEM) && defined(CONFIG_KEXEC_FILE) +unsigned int of_reserved_mem_no_dump_nr_ranges(void); +int of_reserved_mem_exclude_no_dump(struct crash_mem *cmem); +#else +static inline unsigned int of_reserved_mem_no_dump_nr_ranges(void) +{ + return 0; +} +static inline int of_reserved_mem_exclude_no_dump(struct crash_mem *cmem) +{ + return 0; +} +#endif + /** * of_reserved_mem_device_init() - assign reserved memory region to given device * @dev: Pointer to the device to configure -- 2.43.0