(2013/11/12 9:40), HATAYAMA Daisuke wrote: > (2013/11/12 1:52), Vivek Goyal wrote: >> On Mon, Nov 11, 2013 at 11:52:30AM +0900, HATAYAMA Daisuke wrote: >> >> [..] >>> Looking at my past investigation, kernel/mpparse.c, mm/amdtopology.c and >>> platform/visws/visws_quirks.c assumes that boot_cpu_physical_apicid >>> has initial apicid of the BSP, not the current actual booting-up cpu. >>> >>> These three are called in get_smp_config() below. If either of them is >>> called actually, boot_cpu_physical_apicid has the apicid different from >>> the current actual booting-up cpu temporarily. But init_apic_mappings() >>> soon modifies back the value to the one obtained by read_apic_id(). >>> >>> /* >>> * Read APIC and some other early information from ACPI tables. >>> */ >>> acpi_boot_init(); >>> sfi_init(); >>> x86_dtb_init(); >>> >>> /* >>> * get boot-time SMP configuration: >>> */ >>> if (smp_found_config) >>> get_smp_config(); >>> >>> prefill_possible_map(); >>> >>> init_cpu_to_node(); >>> >>> init_apic_mappings(); >>> >>> So, thanks to init_apic_mappings(), the patch set would work without the >>> first patch... This is a careless point in this patch set. >>> >> >> If init_apic_mappings(), is making sure that boot_cpu_physical_apicid is >> apic id of booting processor, and you don't need first patch of your >> series, then I think atleast re-post your patch series without first >> patch. >> > > Yes, I'll repost soon. > >> And then there can be another series which looks into whether we need >> two different variables or not and if we do, then a separate variable >> bsp_physical_apicid will track the bsp id as reported by BIOS and >> boot_cpu_physical_apicid will track apic id of booting cpu. This might >> a very big and slow cleanup. So I think blocking the first patch series >> behind it might not make much sense. >> > > Yes, the current handling of boot_cpu_physical_apicid looks strange and > should be cleaned up, but the cleaning up needs reviewing together with > the maintainers for the corresponding part; in particular, it can be > lengthy for the reviewing on amdtopology.c. I leave this as another > work for the time being. > Sorry for my confusion. It's necessary to introduce a new variable to keep the initial APIC ID for the processor with BSP flag on IA32_APIC_BASE MSR, which is needed in case of AP is specified by disable_cpu_apicid and using MP table. I've posted new v5 patch set a little ago. Could you please review it? -- Thanks. HATAYAMA, Daisuke
