"--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 | 27 ++++++++++++++++++++++++++- 1 file changed, 26 insertions(+), 1 deletion(-) diff --git a/kexec/kexec.8 b/kexec/kexec.8 index e0131b4..675a285 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 secondary kernel, you can jump back to the primary kernel with enabling +.B CONFIG_KEXEC_JUMP +option (x86 and sh only). .SH USAGE Using .B kexec @@ -94,7 +97,7 @@ then you would use the following command to load the kernel: .RB \-l\ /boot/vmlinux .RB "\-\-append=" "root=/dev/hda1" "\ \-\-initrd=" /boot/initrd .RE -.PP + After this kernel is loaded, it can be booted to at any time using the command: @@ -102,6 +105,25 @@ command: .BR kexec \ \-e .RE +For jumping back to the primary kernel, you need to prepare the jump with following command: + +.RS +.B kexec +.RB \-\-load\-jump\-back\-helper \ \-\-entry=<address> +.RE + +The +.BR <address> +value is specified by +.BR kexec_jump_back_entry=<address> +kernel parameter in /proc/cmdline. Then the primary kernel can be booted +using the command: + +.RS +.BR kexec \ \-e +.RE +.PP + .SH OPTIONS .TP .B \-d\ (\-\-debug) @@ -173,6 +195,9 @@ 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
