From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1UHmLK-0006BA-7G for kexec@lists.infradead.org; Tue, 19 Mar 2013 02:32:03 +0000 Received: from m4.gw.fujitsu.co.jp (unknown [10.0.50.74]) by fgwmail5.fujitsu.co.jp (Postfix) with ESMTP id 71CD13EE0BC for ; Tue, 19 Mar 2013 11:31:57 +0900 (JST) Received: from smail (m4 [127.0.0.1]) by outgoing.m4.gw.fujitsu.co.jp (Postfix) with ESMTP id 5567645DE55 for ; Tue, 19 Mar 2013 11:31:57 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (s4.gw.fujitsu.co.jp [10.0.50.94]) by m4.gw.fujitsu.co.jp (Postfix) with ESMTP id 2683E45DE4F for ; Tue, 19 Mar 2013 11:31:57 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id 0A5A6E38006 for ; Tue, 19 Mar 2013 11:31:57 +0900 (JST) Received: from ml14.s.css.fujitsu.com (ml14.s.css.fujitsu.com [10.240.81.134]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id B5A061DB803E for ; Tue, 19 Mar 2013 11:31:56 +0900 (JST) From: HATAYAMA Daisuke Subject: [PATCH v3 21/21] vmcore: introduce mmap_vmcore() Date: Sat, 16 Mar 2013 13:02:45 +0900 Message-ID: <20130316040245.15064.91206.stgit@localhost6.localdomain6> In-Reply-To: <20130316040003.15064.62308.stgit@localhost6.localdomain6> References: <20130316040003.15064.62308.stgit@localhost6.localdomain6> MIME-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: vgoyal@redhat.com, ebiederm@xmission.com, cpw@sgi.com, kumagai-atsushi@mxc.nes.nec.co.jp, lisa.mitchell@hp.com, heiko.carstens@de.ibm.com, akpm@linux-foundation.org Cc: zhangyanfei@cn.fujitsu.com, kexec@lists.infradead.org, linux-kernel@vger.kernel.org This patch introduces mmap_vmcore(). If flag MEM_TYPE_CURRENT_KERNEL is set, remapped is the buffer on the 2nd kernel. If not set, remapped is some area in old memory. Neither writable nor executable mapping is permitted even with mprotect(). Non-writable mapping is also requirement of remap_pfn_range() when mapping linear pages on non-consequtive physical pages; see is_cow_mapping(). On x86-32 PAE kernels, mmap() supports at most 16TB memory only. This limitation comes from the fact that the third argument of remap_pfn_range(), pfn, is of 32-bit length on x86-32: unsigned long. Signed-off-by: HATAYAMA Daisuke --- fs/proc/vmcore.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 72 insertions(+), 0 deletions(-) diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c index dd1d601..bc4848c 100644 --- a/fs/proc/vmcore.c +++ b/fs/proc/vmcore.c @@ -185,9 +185,81 @@ static ssize_t read_vmcore(struct file *file, char __user *buffer, return acc; } +static int mmap_vmcore(struct file *file, struct vm_area_struct *vma) +{ + size_t size = vma->vm_end - vma->vm_start; + u64 start, end, len, tsz; + struct vmcore *m; + + if (!support_mmap_vmcore) + return -ENODEV; + + start = (u64)vma->vm_pgoff << PAGE_SHIFT; + end = start + size; + + if (size > vmcore_size || end > vmcore_size) + return -EINVAL; + + if (vma->vm_flags & (VM_WRITE | VM_EXEC)) + return -EPERM; + + vma->vm_flags &= ~(VM_MAYWRITE | VM_MAYEXEC); + + len = 0; + + if (start < elfcorebuf_sz) { + u64 pfn; + + tsz = elfcorebuf_sz - start; + if (size < tsz) + tsz = size; + pfn = __pa(elfcorebuf + start) >> PAGE_SHIFT; + if (remap_pfn_range(vma, vma->vm_start, pfn, tsz, + vma->vm_page_prot)) + return -EAGAIN; + size -= tsz; + start += tsz; + len += tsz; + + if (size == 0) + return 0; + } + + list_for_each_entry(m, &vmcore_list, list) { + if (start < m->offset + m->size) { + u64 pfn = 0; + + tsz = m->offset + m->size - start; + if (size < tsz) + tsz = size; + if (m->flag & MEM_TYPE_CURRENT_KERNEL) { + pfn = __pa(m->buf + start - m->offset) + >> PAGE_SHIFT; + } else { + pfn = (m->paddr + (start - m->offset)) + >> PAGE_SHIFT; + } + if (remap_pfn_range(vma, vma->vm_start + len, pfn, tsz, + vma->vm_page_prot)) { + do_munmap(vma->vm_mm, vma->vm_start, len); + return -EAGAIN; + } + size -= tsz; + start += tsz; + len += tsz; + + if (size == 0) + return 0; + } + } + + return 0; +} + static const struct file_operations proc_vmcore_operations = { .read = read_vmcore, .llseek = default_llseek, + .mmap = mmap_vmcore, }; static struct vmcore* __init get_new_element(void) _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec