[PATCH 4/4] kexec: Add crash_save_vmcsinfo to update VMCSINFO

[zhangyanfei <zhangyanfei-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>]

crash_save_vmcsinfo updates the VMCSINFO when kernel crashes.
If no VMCSINFO has been saved before, this function will do nothing.

Signed-off-by: zhangyanfei <zhangyanfei-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
---
 include/linux/kexec.h |    1 +
 kernel/kexec.c        |   14 ++++++++++++++
 2 files changed, 15 insertions(+), 0 deletions(-)

diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 0d7d6a1..6e8ff13 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -145,6 +145,7 @@ void arch_crash_save_vmcoreinfo(void);
 __printf(1, 2)
 void vmcoreinfo_append_str(const char *fmt, ...);
 unsigned long paddr_vmcoreinfo_note(void);
+void crash_save_vmcsinfo(void);
 
 #define VMCOREINFO_OSRELEASE(value) \
 	vmcoreinfo_append_str("OSRELEASE=%s\n", value)
diff --git a/kernel/kexec.c b/kernel/kexec.c
index 4e2e472..19843ef 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -38,6 +38,7 @@
 #include <asm/uaccess.h>
 #include <asm/io.h>
 #include <asm/sections.h>
+#include <asm/vmcsinfo.h>
 
 /* Per cpu memory for storing cpu states in case of system crash. */
 note_buf_t __percpu *crash_notes;
@@ -1094,6 +1095,7 @@ void crash_kexec(struct pt_regs *regs)
 
 			crash_setup_regs(&fixed_regs, regs);
 			crash_save_vmcoreinfo();
+			crash_save_vmcsinfo();
 			machine_crash_shutdown(&fixed_regs);
 			machine_kexec(kexec_crash_image);
 		}
@@ -1458,6 +1460,18 @@ unsigned long __attribute__ ((weak)) paddr_vmcoreinfo_note(void)
 	return __pa((unsigned long)(char *)&vmcoreinfo_note);
 }
 
+#ifdef CONFIG_X86
+void crash_save_vmcsinfo(void)
+{
+	if (!vmcsinfo_size)
+		return;
+	vmcsinfo_append_str("CRASHTIME=%ld", get_seconds());
+	update_vmcsinfo_note();
+}
+#else
+void crash_save_vmcsinfo(void) {}
+#endif /* CONFIG_X86 */
+
 static int __init crash_save_vmcoreinfo_init(void)
 {
 	VMCOREINFO_OSRELEASE(init_uts_ns.name.release);
-- 
1.7.1