"--load-preserve-context", "--load-jump-back-helper" and "--entry" options are described separately but there is not any description how to use them. Signed-off-by: Gioh Kim <gi-oh.kim@xxxxxxxxxxxxxxxx> --- kexec/kexec.8 | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/kexec/kexec.8 b/kexec/kexec.8 index e0131b4..b7ac028 100644 --- a/kexec/kexec.8 +++ b/kexec/kexec.8 @@ -30,6 +30,9 @@ when configuring the kernel. The option enables the .B kexec system call. +After booting into another kernel, you can jump back to the first kernel with enabling +.B CONFIG_KEXEC_JUMP +option (x86 only). .SH USAGE Using .B kexec @@ -102,6 +105,30 @@ command: .BR kexec \ \-e .RE +After booting the kernel, you can jump back to the first kernel if you enable +.B CONFIG_KEXEC_JUMP +kernel option and specify \-\-load\-preserve\-context option. +You can see +.BR "kexec_jump_back_entry=<address>" +kernel parameter in /proc/cmdline file, for example: + +.RS +.BR "kexec_jump_back_entry=0x00000000000810d2" +.RE + +Frist you need to prepare jump with \-\-load\-jump\-back\-helper and \-\-entry options. + +.RS +.B kexec +.RB \-\-load\-jump\-back\-helper \-\-entry=0x810d2 +.RE + +Then the first kernel can be rebooted using the command: + +.RS +.BR kexec \ \-e +.RE + .SH OPTIONS .TP .B \-d\ (\-\-debug) @@ -173,6 +200,9 @@ Specify the jump back address. (0 means it's not jump back or preserve context) .TP .BI \-\-load\-preserve\-context Load the new kernel and preserve context of current kernel during kexec. +(kexec returns error if +.B CONFIG_KEXEC_JUMP +is not enabled) .TP .BI \-\-load\-jump\-back\-helper Load a helper image to jump back to original kernel. -- 2.14.1 _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
