From: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
To: ebiederm@xmission.com, vgoyal@redhat.com, cpw@sgi.com,
kumagai-atsushi@mxc.nes.nec.co.jp, lisa.mitchell@hp.com
Cc: kexec@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH 13/13] vmcore: introduce mmap_vmcore()
Date: Thu, 14 Feb 2013 19:12:54 +0900 [thread overview]
Message-ID: <20130214101254.22466.874.stgit@localhost6.localdomain6> (raw)
In-Reply-To: <20130214100945.22466.4172.stgit@localhost6.localdomain6>
This patch introduces mmap_vmcore().
If vmcore object has VMCORE_OLD_MEMORY type, remaped is a page on old
memory. If vmcore object has VMCORE_2ND_KERNEL type, remaped is buffer
on 2nd kernel.
Neither writable nor executable mapping is permitted even with
mprotect(). Non-writable mapping is also requirement of
remap_pfn_range() when mapping linear pags on non-consequtive physical
pages; see is_cow_mapping().
On ELF32 mmap() is not suppoted, returning -ENODEV, since then dump
file size must be less than 4GB; exiting read() interface is enough.
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 <d.hatayama@jp.fujitsu.com>
---
fs/proc/vmcore.c | 76 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 76 insertions(+), 0 deletions(-)
diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index 99f5673..f521480 100644
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c
@@ -186,9 +186,85 @@ 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)
+{
+ unsigned char *e_ident = (unsigned char *)elfcorebuf;
+ size_t size = vma->vm_end - vma->vm_start;
+ u64 start, end, len, tsz;
+ struct vmcore *m;
+
+ if (e_ident[EI_CLASS] == ELFCLASS32)
+ 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;
+ switch (m->type) {
+ case VMCORE_OLD_MEMORY:
+ pfn = (m->paddr + (start - m->offset))
+ >> PAGE_SHIFT;
+ break;
+ case VMCORE_2ND_KERNEL:
+ pfn = __pa(m->buf + start - m->offset)
+ >> PAGE_SHIFT;
+ break;
+ }
+ 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)
next prev parent reply other threads:[~2013-02-14 10:13 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-14 10:11 [PATCH 00/13] kdump, vmcore: support mmap() on /proc/vmcore HATAYAMA Daisuke
2013-02-14 10:11 ` [PATCH 01/13] vmcore: allocate buffer for ELF headers on page-size alignment HATAYAMA Daisuke
2013-02-15 15:01 ` Vivek Goyal
2013-02-14 10:11 ` [PATCH 02/13] vmcore: round up buffer size of ELF headers by PAGE_SIZE HATAYAMA Daisuke
2013-02-15 15:18 ` Vivek Goyal
2013-02-18 15:58 ` HATAYAMA Daisuke
2013-02-14 10:11 ` [PATCH 03/13] vmcore: fill unused part of buffer for ELF headers with 0 HATAYAMA Daisuke
2013-02-14 10:12 ` [PATCH 04/13] vmcore: introduce types for objects copied in 2nd kernel HATAYAMA Daisuke
2013-02-15 15:28 ` Vivek Goyal
2013-02-18 16:06 ` HATAYAMA Daisuke
2013-02-19 23:07 ` Vivek Goyal
2013-02-14 10:12 ` [PATCH 05/13] vmcore: modify ELF32 code according to new type HATAYAMA Daisuke
2013-02-15 15:30 ` Vivek Goyal
2013-02-18 16:11 ` HATAYAMA Daisuke
2013-02-14 10:12 ` [PATCH 06/13] vmcore: modify vmcore clean-up function to free buffer on 2nd kernel HATAYAMA Daisuke
2013-02-15 15:32 ` Vivek Goyal
2013-02-14 10:12 ` [PATCH 07/13] vmcore: modify read_vmcore() to read " HATAYAMA Daisuke
2013-02-15 15:51 ` Vivek Goyal
2013-02-14 10:12 ` [PATCH 08/13] vmcore: remove unused helper function HATAYAMA Daisuke
2013-02-15 15:52 ` Vivek Goyal
2013-02-14 10:12 ` [PATCH 09/13] vmcore: copy ELF note segments in buffer on 2nd kernel HATAYAMA Daisuke
2013-02-15 16:53 ` Vivek Goyal
2013-02-18 17:02 ` HATAYAMA Daisuke
2013-02-19 23:05 ` Vivek Goyal
2013-02-14 10:12 ` [PATCH 10/13] vmcore: round-up offset of vmcore object in page-size boundary HATAYAMA Daisuke
2013-02-14 10:12 ` [PATCH 11/13] vmcore: count holes generated by round-up operation for vmcore size HATAYAMA Daisuke
2013-02-14 10:12 ` [PATCH 12/13] vmcore: copy non page-size aligned head and tail pages in 2nd kernel HATAYAMA Daisuke
2013-02-14 10:12 ` HATAYAMA Daisuke [this message]
2013-02-15 3:57 ` [PATCH 00/13] kdump, vmcore: support mmap() on /proc/vmcore Atsushi Kumagai
2013-02-18 0:16 ` Hatayama, Daisuke
2013-03-27 5:51 ` makedumpfile mmap() benchmark Jingbai Ma
2013-03-27 6:23 ` HATAYAMA Daisuke
2013-03-27 6:35 ` Jingbai Ma
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