From 4401da6111ac58f94234417427d06a72c4048c74 Mon Sep 17 00:00:00 2001 From: Yinghai Lu Date: Sat, 2 May 2009 10:40:57 -0700 Subject: [PATCH] x86: read apic ID in the !acpi_lapic case Ed found that on 32-bit, boot_cpu_physical_apicid is not read right, when the mptable is broken. Interestingly, actually three paths use/set it: 1. acpi: at that time that is already read from reg 2. mptable: only read from mptable 3. no madt, and no mptable, that use default apic id 0 for 64-bit, -1 for 32-bit so we could read the apic id for the 2/3 path. We trust the hardware register more than we trust a BIOS data structure (the mptable). We can also avoid the double set_fixmap() when acpi_lapic is used, and also need to move cpu_has_apic earlier and call apic_disable(). Also when need to update the apic id, we'd better read and set the apic version as well - so that quirks are applied precisely. v2: make path 3 with 64bit, use -1 as apic id, so could read it later. v3: fix whitespace problem pointed out by Ed Swierk [ Impact: get correct apic id for bsp other than acpi path ] Reported-by: Ed Swierk Signed-off-by: Yinghai Lu Acked-by: Cyrill Gorcunov LKML-Reference: <49FC85A9.2070702@kernel.org> [ v4: sanity-check in the ACPI case too ] Signed-off-by: Ingo Molnar --- arch/x86/kernel/apic/apic.c | 31 +++++++++++++++++++++---------- 1 file changed, 21 insertions(+), 10 deletions(-) diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index e258bed..1ee966f 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -1456,7 +1456,6 @@ static int __init detect_init_APIC(void) } mp_lapic_addr = APIC_DEFAULT_PHYS_BASE; - boot_cpu_physical_apicid = 0; return 0; } #else @@ -1570,6 +1569,8 @@ void __init early_init_lapic_mapping(void) */ void __init init_apic_mappings(void) { + unsigned int new_apicid; + if (x2apic_mode) { boot_cpu_physical_apicid = read_apic_id(); return; @@ -1586,21 +1587,31 @@ void __init init_apic_mappings(void) } else apic_phys = mp_lapic_addr; - set_fixmap_nocache(FIX_APIC_BASE, apic_phys); + /* lets check if we may NOP'ify apic operations */ + if (!cpu_has_apic) { + pr_info("APIC: disable apic facility\n"); + apic_disable(); + return; + } + + /* + * acpi lapic path already maps that address in + * acpi_register_lapic_address() + */ + if (!acpi_lapic) + set_fixmap_nocache(FIX_APIC_BASE, apic_phys); + apic_printk(APIC_VERBOSE, "mapped APIC to %08lx (%08lx)\n", APIC_BASE, apic_phys); - /* * Fetch the APIC ID of the BSP in case we have a * default configuration (or the MP table is broken). */ - if (boot_cpu_physical_apicid == -1U) - boot_cpu_physical_apicid = read_apic_id(); - - /* lets check if we may to NOP'ify apic operations */ - if (!cpu_has_apic) { - pr_info("APIC: disable apic facility\n"); - apic_disable(); + new_apicid = read_apic_id(); + if (boot_cpu_physical_apicid != new_apicid) { + boot_cpu_physical_apicid = new_apicid; + apic_version[new_apicid] = + GET_APIC_VERSION(apic_read(APIC_LVR)); } } -- 2.7.4