On 11/21/2013 11:21 AM, Vivek Goyal wrote: >> >> What do you mean by the "real mode entry"? Do we need to care about >> that because we aren't falling back to real mode when executing this, >> are we? Or does that just happen for 32bit kernels? > > Original kexec offers real mode entry choice too. So we fall back > to real mode and jump to kernel and kernel makes bunch of BIOS calls. I > don't think this is a commonly used option. > I know some users of it (who I shall not name.) In general it is a bad option, because after running the first kernel the state of the hardware is not guaranteed to be such that executing the BIOS is safe. In general, I do think they do it just because they tried at some point and it happened to work; discouraging its use is probably for the better. -hpa
