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Mon, 1 Jun 2026 17:41:42 +0800 (CST) Received: from dggpemf500011.china.huawei.com (unknown [7.185.36.131]) by mail.maildlp.com (Postfix) with ESMTPS id E11DF4056C; Mon, 1 Jun 2026 17:49:32 +0800 (CST) Received: from huawei.com (10.90.53.73) by dggpemf500011.china.huawei.com (7.185.36.131) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Mon, 1 Jun 2026 17:49:28 +0800 From: Jinjie Ruan To: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , CC: Subject: [PATCH v15 15/23] crash: Add crash_prepare_headers() to exclude crash kernel memory Date: Mon, 1 Jun 2026 17:47:57 +0800 Message-ID: <20260601094805.2928614-16-ruanjinjie@huawei.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260601094805.2928614-1-ruanjinjie@huawei.com> References: <20260601094805.2928614-1-ruanjinjie@huawei.com> X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-Originating-IP: [10.90.53.73] X-ClientProxiedBy: kwepems100002.china.huawei.com (7.221.188.206) To dggpemf500011.china.huawei.com (7.185.36.131) The crash memory alloc, and the exclude of crashk_res, crashk_low_res and crashk_cma memory are almost identical across different architectures, handling them in the crash core would eliminate a lot of duplication, so add crash_prepare_headers() helper to handle them in the common code. To achieve the above goal, three architecture-specific functions are introduced: - arch_get_system_nr_ranges(). Pre-counts the max number of memory ranges. - arch_crash_populate_cmem(). Collects the memory ranges and fills them into cmem. - arch_crash_exclude_ranges(). Architecture's additional crash memory ranges exclusion, defaulting to empty. Reviewed-by: Sourabh Jain Acked-by: Baoquan He Acked-by: Mike Rapoport (Microsoft) Signed-off-by: Jinjie Ruan --- include/linux/crash_core.h | 5 +++ kernel/crash_core.c | 82 ++++++++++++++++++++++++++++++++++++-- 2 files changed, 84 insertions(+), 3 deletions(-) diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h index d4762e000098..43baf9c87355 100644 --- a/include/linux/crash_core.h +++ b/include/linux/crash_core.h @@ -65,6 +65,8 @@ extern int crash_exclude_mem_range(struct crash_mem *mem, unsigned long long mend); extern int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map, void **addr, unsigned long *sz); +extern int crash_prepare_headers(int need_kernel_map, void **addr, + unsigned long *sz, unsigned long *nr_mem_ranges); struct kimage; struct kexec_segment; @@ -82,6 +84,9 @@ int kexec_should_crash(struct task_struct *p); int kexec_crash_loaded(void); void crash_save_cpu(struct pt_regs *regs, int cpu); extern int kimage_crash_copy_vmcoreinfo(struct kimage *image); +extern unsigned int arch_get_system_nr_ranges(void); +extern int arch_crash_populate_cmem(struct crash_mem *cmem); +extern int arch_crash_exclude_ranges(struct crash_mem *cmem); #else /* !CONFIG_CRASH_DUMP*/ struct pt_regs; diff --git a/kernel/crash_core.c b/kernel/crash_core.c index 4f21fc3b108b..481babc29131 100644 --- a/kernel/crash_core.c +++ b/kernel/crash_core.c @@ -168,9 +168,6 @@ static inline resource_size_t crash_resource_size(const struct resource *res) return !res->end ? 0 : resource_size(res); } - - - int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map, void **addr, unsigned long *sz) { @@ -272,6 +269,85 @@ int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map, return 0; } +static struct crash_mem *alloc_cmem(unsigned int nr_ranges) +{ + struct crash_mem *cmem; + + cmem = kvzalloc_flex(*cmem, ranges, nr_ranges); + if (!cmem) + return NULL; + + cmem->max_nr_ranges = nr_ranges; + return cmem; +} + +unsigned int __weak arch_get_system_nr_ranges(void) { return 0; } +int __weak arch_crash_populate_cmem(struct crash_mem *cmem) { return -1; } +int __weak arch_crash_exclude_ranges(struct crash_mem *cmem) { return 0; } + +static int crash_exclude_core_ranges(struct crash_mem *cmem) +{ + int ret, i; + + /* Exclude crashkernel region */ + ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end); + if (ret) + return ret; + + if (crashk_low_res.end) { + ret = crash_exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end); + if (ret) + return ret; + } + + for (i = 0; i < crashk_cma_cnt; ++i) { + ret = crash_exclude_mem_range(cmem, crashk_cma_ranges[i].start, + crashk_cma_ranges[i].end); + if (ret) + return ret; + } + + return 0; +} + +int crash_prepare_headers(int need_kernel_map, void **addr, unsigned long *sz, + unsigned long *nr_mem_ranges) +{ + unsigned int max_nr_ranges; + struct crash_mem *cmem; + int ret; + + max_nr_ranges = arch_get_system_nr_ranges(); + if (!max_nr_ranges) + return -ENOMEM; + + cmem = alloc_cmem(max_nr_ranges); + if (!cmem) + return -ENOMEM; + + ret = arch_crash_populate_cmem(cmem); + if (ret) + goto out; + + ret = crash_exclude_core_ranges(cmem); + if (ret) + goto out; + + ret = arch_crash_exclude_ranges(cmem); + if (ret) + goto out; + + /* Return the computed number of memory ranges, for hotplug usage */ + if (nr_mem_ranges) + *nr_mem_ranges = cmem->nr_ranges; + + ret = crash_prepare_elf64_headers(cmem, need_kernel_map, addr, sz); + +out: + kvfree(cmem); + return ret; +} + /** * crash_exclude_mem_range - exclude a mem range for existing ranges * @mem: mem->range contains an array of ranges sorted in ascending order -- 2.34.1