On Thu, Feb 15, 2018 at 7:54 PM, Bhupesh SHARMA <bhupesh.linux@xxxxxxxxx> wrote: > Hi, > > Some nitpicks inline.. I thank you again for your review. I'll send the second version patch soon. > > On Thu, Feb 15, 2018 at 5:14 PM, Gioh Kim <gi-oh.kim@xxxxxxxxxxxxxxxx> wrote: >> "--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 > > I would suggest using the already prevalent naming conventions - primary kernel > and secondary kernel for the two kernels. > >> +.B CONFIG_KEXEC_JUMP >> +option (x86 only). > > I think this is also supported on sh architecture, so may be you can > reword this to something like: > (currently only x86 and sh architectures are supported). > >> .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. > > Do we need to repeat the details of CONFIG_KEXEC_JUMP here and below, > as we have already the captured the same above. > >> +You can see > > ^^^ specify (instead of see) > >> +.BR "kexec_jump_back_entry=<address>" >> +kernel parameter in /proc/cmdline file, for example: >> + >> +.RS >> +.BR "kexec_jump_back_entry=0x00000000000810d2" > > Better to specify literal addr instead of specifying a value here. > >> +.RE >> + >> +Frist you need to prepare jump with \-\-load\-jump\-back\-helper and \-\-entry options. > > ^^^ First (rather than Frist) > >> + >> +.RS >> +.B kexec >> +.RB \-\-load\-jump\-back\-helper \-\-entry=0x810d2 > > Better to use literal addr instead of specifying a particular value > here, to keep the man page generic. > > Regards, > Bhupesh > >> +.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 >> -- GIOH KIM Linux Kernel Entwickler ProfitBricks GmbH Greifswalder Str. 207 D - 10405 Berlin Tel: +49 176 2697 8962 Fax: +49 30 577 008 299 Email: gi-oh.kim@xxxxxxxxxxxxxxxx URL: https://www.profitbricks.de Sitz der Gesellschaft: Berlin Registergericht: Amtsgericht Charlottenburg, HRB 125506 B Geschäftsführer: Achim Weiss, Matthias Steinberg _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
