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Message-Id: <1188177296.3247.38.camel@caritas-dev.intel.com>
Date: Mon, 27 Aug 2007 09:14:56 +0800
From: "Huang, Ying" <ying.huang@...el.com>
To: "Eric W. Biederman" <ebiederm@...ssion.com>,
Pavel Machek <pavel@....cz>, nigel@...el.suspend2.net,
Andrew Morton <akpm@...ux-foundation.org>,
Jeremy Maitin-Shepard <jbms@....edu>
Cc: linux-kernel@...r.kernel.org, linux-pm@...ts.linux-foundation.org,
Kexec Mailing List <kexec@...ts.infradead.org>
Subject: [RFC][PATCH 2/2 -mm] kexec based hibernation: kexec restore
This patch adds writing support for /dev/oldmem. This is used to
restore the memory contents of hibernated system.
Signed-off-by: Huang Ying <ying.huang@...el.com>
---
arch/i386/kernel/crash_dump.c | 27 +++++++++++++++++++++++++++
drivers/char/mem.c | 32 ++++++++++++++++++++++++++++++++
include/linux/crash_dump.h | 2 ++
3 files changed, 61 insertions(+)
Index: linux-2.6.23-rc3/arch/i386/kernel/crash_dump.c
===================================================================
--- linux-2.6.23-rc3.orig/arch/i386/kernel/crash_dump.c 2007-08-25 21:56:52.000000000 +0800
+++ linux-2.6.23-rc3/arch/i386/kernel/crash_dump.c 2007-08-25 21:57:11.000000000 +0800
@@ -58,6 +58,33 @@
return csize;
}
+ssize_t write_oldmem_page(unsigned long pfn, const char *buf,
+ size_t csize, unsigned long offset, int userbuf)
+{
+ void *vaddr;
+
+ if (!csize)
+ return 0;
+
+ if (!userbuf) {
+ vaddr = kmap_atomic_pfn(pfn, KM_PTE0);
+ memcpy(vaddr + offset, buf, csize);
+ } else {
+ if (!kdump_buf_page) {
+ printk(KERN_WARNING "Kdump: Kdump buffer page not"
+ " allocated\n");
+ return -EFAULT;
+ }
+ if (copy_from_user(kdump_buf_page, buf, csize))
+ return -EFAULT;
+ vaddr = kmap_atomic_pfn(pfn, KM_PTE0);
+ memcpy(vaddr + offset, kdump_buf_page, csize);
+ }
+ kunmap_atomic(vaddr, KM_PTE0);
+
+ return csize;
+}
+
static int __init kdump_buf_page_init(void)
{
int ret = 0;
Index: linux-2.6.23-rc3/include/linux/crash_dump.h
===================================================================
--- linux-2.6.23-rc3.orig/include/linux/crash_dump.h 2007-08-25 21:56:52.000000000 +0800
+++ linux-2.6.23-rc3/include/linux/crash_dump.h 2007-08-25 21:57:11.000000000 +0800
@@ -11,6 +11,8 @@
extern unsigned long long elfcorehdr_addr;
extern ssize_t copy_oldmem_page(unsigned long, char *, size_t,
unsigned long, int);
+extern ssize_t write_oldmem_page(unsigned long, const char *, size_t,
+ unsigned long, int);
extern const struct file_operations proc_vmcore_operations;
extern struct proc_dir_entry *proc_vmcore;
Index: linux-2.6.23-rc3/drivers/char/mem.c
===================================================================
--- linux-2.6.23-rc3.orig/drivers/char/mem.c 2007-08-25 21:56:52.000000000 +0800
+++ linux-2.6.23-rc3/drivers/char/mem.c 2007-08-25 21:57:11.000000000 +0800
@@ -348,6 +348,37 @@
}
return read;
}
+
+/*
+ * Write memory corresponding to the old kernel.
+ */
+static ssize_t write_oldmem(struct file *file, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ unsigned long pfn, offset;
+ size_t write = 0, csize;
+ int rc = 0;
+
+ while (count) {
+ pfn = *ppos / PAGE_SIZE;
+ if (pfn > saved_max_pfn)
+ return write;
+
+ offset = (unsigned long)(*ppos % PAGE_SIZE);
+ if (count > PAGE_SIZE - offset)
+ csize = PAGE_SIZE - offset;
+ else
+ csize = count;
+ rc = write_oldmem_page(pfn, buf, csize, offset, 1);
+ if (rc < 0)
+ return rc;
+ buf += csize;
+ *ppos += csize;
+ write += csize;
+ count -= csize;
+ }
+ return write;
+}
#endif
extern long vread(char *buf, char *addr, unsigned long count);
@@ -783,6 +814,7 @@
#ifdef CONFIG_CRASH_DUMP
static const struct file_operations oldmem_fops = {
.read = read_oldmem,
+ .write = write_oldmem,
.open = open_oldmem,
};
#endif
-
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