[PATCH 3/3 -mm] kexec jump -v8 : access memory image of kexec_image
This patch adds a file in proc file system to access the loaded
kexec_image, which may contains the memory image of kexeced
system. This can be used to:
- Communicate between original kernel and kexeced kernel through write
to some pages in original kernel.
- Communicate between original kernel and kexeced kernel through read
memory image of kexeced kernel, amend the image, and reload the
amended image.
- Accelerate boot of kexeced kernel. If you have a memory image of
kexeced kernel, you need not a normal boot process to jump to the
kexeced kernel, just load the memory image, jump to the point where
you leave last time in kexeced kernel.
Signed-off-by: Huang Ying <[EMAIL PROTECTED]>
---
fs/proc/Makefile |1
fs/proc/kimgcore.c| 277 ++
fs/proc/proc_misc.c |6 +
include/linux/kexec.h |7 +
kernel/kexec.c|5
5 files changed, 291 insertions(+), 5 deletions(-)
--- /dev/null
+++ b/fs/proc/kimgcore.c
@@ -0,0 +1,277 @@
+/*
+ * fs/proc/kimgcore.c - Interface for accessing the loaded
+ * kexec_image, which may contains the memory image of kexeced system.
+ * Heavily borrowed from fs/proc/kcore.c
+ *
+ * Copyright (C) 2007, Intel Corp.
+ * Huang Ying <[EMAIL PROTECTED]>
+ *
+ * This file is released under the GPLv2
+ */
+
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+
+struct proc_dir_entry *proc_root_kimgcore;
+
+static u32 kimgcore_size;
+
+static char *elfcorebuf;
+static size_t elfcorebuf_sz;
+
+static void *buf_page;
+
+static ssize_t kimage_copy_to_user(struct kimage *image, char __user *buf,
+ unsigned long offset, size_t count)
+{
+ kimage_entry_t *ptr, entry;
+ unsigned long off = 0, offinp, trunk;
+ struct page *page;
+ void *vaddr;
+
+ for_each_kimage_entry(image, ptr, entry) {
+ if (!(entry & IND_SOURCE))
+ continue;
+ if (off + PAGE_SIZE > offset) {
+ offinp = offset - off;
+ if (count > PAGE_SIZE - offinp)
+ trunk = PAGE_SIZE - offinp;
+ else
+ trunk = count;
+ page = pfn_to_page(entry >> PAGE_SHIFT);
+ if (PageHighMem(page)) {
+ vaddr = kmap(page);
+ memcpy(buf_page, vaddr+offinp, trunk);
+ kunmap(page);
+ vaddr = buf_page;
+ } else
+ vaddr = __va(entry & PAGE_MASK) + offinp;
+ if (copy_to_user(buf, vaddr, trunk))
+ return -EFAULT;
+ buf += trunk;
+ offset += trunk;
+ count -= trunk;
+ if (!count)
+ break;
+ }
+ off += PAGE_SIZE;
+ }
+ return count;
+}
+
+static ssize_t kimage_copy_from_user(struct kimage *image,
+const char __user *buf,
+unsigned long offset,
+size_t count)
+{
+ kimage_entry_t *ptr, entry;
+ unsigned long off = 0, offinp, trunk;
+ struct page *page;
+ void *vaddr;
+
+ for_each_kimage_entry(image, ptr, entry) {
+ if (!(entry & IND_SOURCE))
+ continue;
+ if (off + PAGE_SIZE > offset) {
+ offinp = offset - off;
+ if (count > PAGE_SIZE - offinp)
+ trunk = PAGE_SIZE - offinp;
+ else
+ trunk = count;
+ page = pfn_to_page(entry >> PAGE_SHIFT);
+ if (PageHighMem(page))
+ vaddr = buf_page;
+ else
+ vaddr = __va(entry & PAGE_MASK) + offinp;
+ if (copy_from_user(vaddr, buf, trunk))
+ return -EFAULT;
+ if (PageHighMem(page)) {
+ vaddr = kmap(page);
+ memcpy(vaddr+offinp, buf_page, trunk);
+ kunmap(page);
+ }
+ buf += trunk;
+ offset += trunk;
+ count -= trunk;
+ if (!count)
+ break;
+ }
+ off += PAGE_SIZE;
+ }
+ return count;
+}
+
+static ssize_t read_kimgcore(struct file *file, char __user *buffer,
+size_t buflen, loff_t *fpos)
+{
+ size_t acc = 0;
+ size_t tsz;
[PATCH 3/3 -mm] kexec jump -v8 : access memory image of kexec_image
This patch adds a file in proc file system to access the loaded
kexec_image, which may contains the memory image of kexeced
system. This can be used to:
- Communicate between original kernel and kexeced kernel through write
to some pages in original kernel.
- Communicate between original kernel and kexeced kernel through read
memory image of kexeced kernel, amend the image, and reload the
amended image.
- Accelerate boot of kexeced kernel. If you have a memory image of
kexeced kernel, you need not a normal boot process to jump to the
kexeced kernel, just load the memory image, jump to the point where
you leave last time in kexeced kernel.
Signed-off-by: Huang Ying [EMAIL PROTECTED]
---
fs/proc/Makefile |1
fs/proc/kimgcore.c| 277 ++
fs/proc/proc_misc.c |6 +
include/linux/kexec.h |7 +
kernel/kexec.c|5
5 files changed, 291 insertions(+), 5 deletions(-)
--- /dev/null
+++ b/fs/proc/kimgcore.c
@@ -0,0 +1,277 @@
+/*
+ * fs/proc/kimgcore.c - Interface for accessing the loaded
+ * kexec_image, which may contains the memory image of kexeced system.
+ * Heavily borrowed from fs/proc/kcore.c
+ *
+ * Copyright (C) 2007, Intel Corp.
+ * Huang Ying [EMAIL PROTECTED]
+ *
+ * This file is released under the GPLv2
+ */
+
+#include linux/mm.h
+#include linux/proc_fs.h
+#include linux/user.h
+#include linux/elf.h
+#include linux/init.h
+#include linux/kexec.h
+#include linux/io.h
+#include linux/highmem.h
+#include linux/page-flags.h
+#include asm/uaccess.h
+
+struct proc_dir_entry *proc_root_kimgcore;
+
+static u32 kimgcore_size;
+
+static char *elfcorebuf;
+static size_t elfcorebuf_sz;
+
+static void *buf_page;
+
+static ssize_t kimage_copy_to_user(struct kimage *image, char __user *buf,
+ unsigned long offset, size_t count)
+{
+ kimage_entry_t *ptr, entry;
+ unsigned long off = 0, offinp, trunk;
+ struct page *page;
+ void *vaddr;
+
+ for_each_kimage_entry(image, ptr, entry) {
+ if (!(entry IND_SOURCE))
+ continue;
+ if (off + PAGE_SIZE offset) {
+ offinp = offset - off;
+ if (count PAGE_SIZE - offinp)
+ trunk = PAGE_SIZE - offinp;
+ else
+ trunk = count;
+ page = pfn_to_page(entry PAGE_SHIFT);
+ if (PageHighMem(page)) {
+ vaddr = kmap(page);
+ memcpy(buf_page, vaddr+offinp, trunk);
+ kunmap(page);
+ vaddr = buf_page;
+ } else
+ vaddr = __va(entry PAGE_MASK) + offinp;
+ if (copy_to_user(buf, vaddr, trunk))
+ return -EFAULT;
+ buf += trunk;
+ offset += trunk;
+ count -= trunk;
+ if (!count)
+ break;
+ }
+ off += PAGE_SIZE;
+ }
+ return count;
+}
+
+static ssize_t kimage_copy_from_user(struct kimage *image,
+const char __user *buf,
+unsigned long offset,
+size_t count)
+{
+ kimage_entry_t *ptr, entry;
+ unsigned long off = 0, offinp, trunk;
+ struct page *page;
+ void *vaddr;
+
+ for_each_kimage_entry(image, ptr, entry) {
+ if (!(entry IND_SOURCE))
+ continue;
+ if (off + PAGE_SIZE offset) {
+ offinp = offset - off;
+ if (count PAGE_SIZE - offinp)
+ trunk = PAGE_SIZE - offinp;
+ else
+ trunk = count;
+ page = pfn_to_page(entry PAGE_SHIFT);
+ if (PageHighMem(page))
+ vaddr = buf_page;
+ else
+ vaddr = __va(entry PAGE_MASK) + offinp;
+ if (copy_from_user(vaddr, buf, trunk))
+ return -EFAULT;
+ if (PageHighMem(page)) {
+ vaddr = kmap(page);
+ memcpy(vaddr+offinp, buf_page, trunk);
+ kunmap(page);
+ }
+ buf += trunk;
+ offset += trunk;
+ count -= trunk;
+ if (!count)
+ break;
+ }
+ off += PAGE_SIZE;
+ }
+ return count;
+}
+
+static ssize_t read_kimgcore(struct file *file, char __user
