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Commit 4401da61 authored by Yinghai Lu's avatar Yinghai Lu Committed by Ingo Molnar
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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: default avatarEd Swierk <eswierk@aristanetworks.com>
Signed-off-by: default avatarYinghai Lu <yinghai@kernel.org>
Acked-by: default avatarCyrill Gorcunov <gorcunov@openvz.org>
LKML-Reference: <49FC85A9.2070702@kernel.org>
[ v4: sanity-check in the ACPI case too ]
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 61fe91e1

arch/x86/kernel/apic/apic.c

+21 −10
Original line number Diff line number Diff line
@@ -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;



	/* 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));

	}

}