Subject: + vmcore-support-mmap-on-proc-vmcore.patch added to -mm tree
To: d.hatayama@xxxxxxxxxxxxxx,kosaki.motohiro@xxxxxxxxxxxxxx,kumagai-atsushi@xxxxxxxxxxxxxxxxx,lisa.mitchell@xxxxxx,vgoyal@xxxxxxxxxx,zhangyanfei@xxxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Thu, 23 May 2013 17:20:41 -0700
The patch titled
Subject: vmcore: support mmap() on /proc/vmcore
has been added to the -mm tree. Its filename is
vmcore-support-mmap-on-proc-vmcore.patch
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------------------------------------------------------
From: HATAYAMA Daisuke <d.hatayama@xxxxxxxxxxxxxx>
Subject: vmcore: support mmap() on /proc/vmcore
This patch introduces mmap_vmcore().
Don't permit writable nor executable mapping even with mprotect() because
this mmap() is aimed at reading crash dump memory. Non-writable mapping
is also requirement of remap_pfn_range() when mapping linear pages on
non-consecutive physical pages; see is_cow_mapping().
Set VM_MIXEDMAP flag to remap memory by remap_pfn_range and by
remap_vmalloc_range_pertial at the same time for a single vma.
do_munmap() can correctly clean partially remapped vma with two functions
in abnormal case. See zap_pte_range(), vm_normal_page() and their
comments for details.
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@xxxxxxxxxxxxxx>
Acked-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Cc: Atsushi Kumagai <kumagai-atsushi@xxxxxxxxxxxxxxxxx>
Cc: Lisa Mitchell <lisa.mitchell@xxxxxx>
Cc: Zhang Yanfei <zhangyanfei@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/vmcore.c | 86 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 86 insertions(+)
diff -puN fs/proc/vmcore.c~vmcore-support-mmap-on-proc-vmcore fs/proc/vmcore.c
--- a/fs/proc/vmcore.c~vmcore-support-mmap-on-proc-vmcore
+++ a/fs/proc/vmcore.c
@@ -20,6 +20,7 @@
#include <linux/init.h>
#include <linux/crash_dump.h>
#include <linux/list.h>
+#include <linux/vmalloc.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include "internal.h"
@@ -194,9 +195,94 @@ static ssize_t read_vmcore(struct file *
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;
+
+ 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);
+ vma->vm_flags |= VM_MIXEDMAP;
+
+ 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;
+ }
+
+ if (start < elfcorebuf_sz + elfnotes_sz) {
+ void *kaddr;
+
+ tsz = elfcorebuf_sz + elfnotes_sz - start;
+ if (size < tsz)
+ tsz = size;
+ kaddr = elfnotes_buf + start - elfcorebuf_sz;
+ if (remap_vmalloc_range_partial(vma, vma->vm_start + len,
+ kaddr, tsz)) {
+ do_munmap(vma->vm_mm, vma->vm_start, len);
+ 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 paddr = 0;
+
+ tsz = m->offset + m->size - start;
+ if (size < tsz)
+ tsz = size;
+ paddr = m->paddr + start - m->offset;
+ if (remap_pfn_range(vma, vma->vm_start + len,
+ paddr >> PAGE_SHIFT, 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)
_
Patches currently in -mm which might be from d.hatayama@xxxxxxxxxxxxxx are
include-linux-mmh-add-page_aligned-helper.patch
vmcore-clean-up-read_vmcore.patch
vmcore-allocate-buffer-for-elf-headers-on-page-size-alignment.patch
vmcore-allocate-buffer-for-elf-headers-on-page-size-alignment-fix.patch
vmcore-treat-memory-chunks-referenced-by-pt_load-program-header-entries-in-page-size-boundary-in-vmcore_list.patch
vmalloc-make-find_vm_area-check-in-range.patch
vmalloc-introduce-remap_vmalloc_range_partial.patch
vmalloc-introduce-remap_vmalloc_range_partial-fix.patch
vmcore-allocate-elf-note-segment-in-the-2nd-kernel-vmalloc-memory.patch
vmcore-allocate-elf-note-segment-in-the-2nd-kernel-vmalloc-memory-fix.patch
vmcore-allow-user-process-to-remap-elf-note-segment-buffer.patch
vmcore-allow-user-process-to-remap-elf-note-segment-buffer-fix.patch
vmcore-calculate-vmcore-file-size-from-buffer-size-and-total-size-of-vmcore-objects.patch
vmcore-support-mmap-on-proc-vmcore.patch
vmcore-support-mmap-on-proc-vmcore-fix.patch
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