* Zachary Amsden (zach@xxxxxxxxxx) wrote: > Your patch looks good, although the minimal change to subarch is to > merely have __FIXADDR_TOP defined by the sub-architecture. Is there any > additional benefit to moving the fixmaps into the subarch - i.e. moving > subarch-specific pieces out of mach-default? As you've identified, so subarch can put whatever wonky junk it needs in there. > I guess there is. For example include/asm-i386/mach-visws/mach_fixmap.h > could do this: > > #define SUBARCH_FIXMAPS \ > FIX_CO_CPU, /* Cobalt timer */ \ > FIX_CO_APIC, /* Cobalt APIC Redirection Table */ \ > FIX_LI_PCIA, /* Lithium PCI Bridge A */ \ > FIX_LI_PCIB, /* Lithium PCI Bridge B */ > > Then include/asm-i386/fixmap.h includes <mach_fixmap.h>, for which the > default is an empty define for SUBARCH_FIXMAPS. nice. > Also, it seems reasonable that people may want to poke holes in high > linear space for other hypervisor projects, research, or performance > reasons without having to build a custom sub-architecture just for > that. So I think there is some benefit to making the hole size a > general configurable option (with defaults depending on the sub-arch you > select). It needs to have tangible value for in-tree code. Seems worthwhile to play with it a bit though. thanks, -chris