On Mon, Oct 04, 2010 at 12:27:02AM +0200, Patrick Georgi wrote: > Am 03.10.2010 23:59, schrieb Uwe Hermann: > > + /* > > + * Important: The code below makes a run-time decision depending on > > + * whether this is a K8 or Fam10h system. Depending on which it is, > > + * the CONFIG_CPU_ADDR_BITS_MASK value might be be different. > > + */ > > movl $MTRRphysMask_MSR(1), %ecx > > - movl $0xff, %edx /* (1 << (CONFIG_CPU_ADDR_BITS - 32)) - 1 for K8 > > (CONFIG_CPU_ADDR_BITS = 40) */ > > + movl $CONFIG_CPU_ADDR_BITS_MASK, %edx /* K8 */ > > jmp_if_k8(wbcache_post_fam10_setup) > > - movl $0xffff, %edx /* (1 << (CONFIG_CPU_ADDR_BITS - 32)) - 1 for > > FAM10 (CONFIG_CPU_ADDR_BITS = 48) */ > > + movl $CONFIG_CPU_ADDR_BITS_MASK, %edx /* Fam10h */ > > wbcache_post_fam10_setup: > > movl $(~(CONFIG_XIP_ROM_SIZE - 1) | 0x800), %eax > > wrmsr > > + > > #endif /* CONFIG_XIP_ROM_SIZE && CONFIG_XIP_ROM_BASE */ > How is this supposed to work? > "Set to the build specific value, and if it is fam10 (ie. jmp_if_k8 not > taken), set to the build specific value again"?
Hm, seems I misunderstood how this works. I was under the impression such a two-image solution (K8 + Fam10h code in one coreboot.rom) would also set two different CONFIG_CPU_ADDR_BITS_MASK values, one for K8, and one for Fam10h. And if the K8 image is running it will use CONFIG_CPU_ADDR_BITS_MASK (=40) at runtime, but if the Fam10h image runs it would use CONFIG_CPU_ADDR_BITS_MASK (=48) instead. That's probably not how it would work though, it seems? Anyway, I'll just leave this snippet alone for now. Updated patch will follow, need to fix another kconfig-related issue brought up by Peter. But note that the current form is also a bit dangerous. It hardcodes 40bits for K8 and 48bits for Fam10h here unconditionally. I don't know if this assumption is always correct for all CPUs. Using the correct per-CPU CONFIG_CPU_ADDR_BITS_MASK would definately be safer (if this mechanism can work here at all). Are we sure there are no K8 systems that support CPUs with bits != 40? Are we sure there are no Fam10h CPUs with bits != 48 (and that there never will be in the future)? Uwe. -- http://hermann-uwe.de | http://sigrok.org http://randomprojects.org | http://unmaintained-free-software.org -- coreboot mailing list: [email protected] http://www.coreboot.org/mailman/listinfo/coreboot
