22.01.2016 22:06, Vladimir 'φ-coder/phcoder' Serbinenko пишет: > On 18.08.2015 21:17, Ben Hildred wrote: >> Let's assume for a minute that I have compiled grub as a multiboot image >> and have called it from another bootloader, say iPXE.Now iPXE assumes >> that any false return is an error. What happens when grub returns with >> exit next, does iPXE get a true or false? What about exit fred where >> fred is not defined by any platform? What if I do an exit config which >> is only defined for coreboot? > Neither multiboot nor coreboot have any return semantics. The situation > with current platforms is as follows: > No return/exit semantics at all or machine shutdown: > i386_coreboot, i386_qemu, i386_multiboot, mips_qemu_mips, mips_loongson > no-args exit: > *-ieee1275, i386-pc, mips-arc > Xen semantics (crash vs poweroff): > *-xen > EFI semantics: > *-efi > Unix-like semantics: > arm-uboot, emu > > Emu is of no real interest and I have no idea what Uboot does with > return code but I suppose nothing. > > This leaves us only with xen and EFI semantics. Xen is enough of outlier > to handle it separately. So only EFI is remaining. > > On i386-pc the default behaviour of exit is to try next boot entry. EFI > should probably do the same. What is the current behaviour of grub_exit > and what is the value in returning EFI_SUCCESS ?
Currently it returns EFI_SUCCESS that tells firmware boot manager to return to menu and stop attempting to load further boot options. I.e. this is directly opposite to what i386-pc. OTOH I still find it useful to be able to explicitly return to boot menu from GRUB (or EFI Shell for that matter). > Can we have returncode-aware command to be EFI-specific? > I'm fine with changing default EFI exit code to be not EFI_SUCCESS (but this should be commented in sources) and to have fwmenu (similar to fwsetup) that explicitly returns EFI_SUCCESS.
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