Commit 4797f6b0 authored by Yinghai Lu's avatar Yinghai Lu Committed by Ingo Molnar
Browse files

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
v5: fix boot crash

[ 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 6cda3eb6

arch/x86/include/asm/smp.h

+1 −1
Original line number Diff line number Diff line
@@ -180,7 +180,7 @@ extern int safe_smp_processor_id(void); 
static inline int logical_smp_processor_id(void)

{

	/* we don't want to mark this access volatile - bad code generation */

	return GET_APIC_LOGICAL_ID(*(u32 *)(APIC_BASE + APIC_LDR));

	return GET_APIC_LOGICAL_ID(apic_read(APIC_LDR));

}



#endif

arch/x86/kernel/apic/apic.c

+22 −24
Original line number Diff line number Diff line
@@ -242,17 +242,24 @@ static int modern_apic(void) 
 * bare function to substitute write operation

 * and it's _that_ fast :)

 */

void native_apic_write_dummy(u32 reg, u32 v)

static void native_apic_write_dummy(u32 reg, u32 v)

{

	WARN_ON_ONCE((cpu_has_apic || !disable_apic));

}



static u32 native_apic_read_dummy(u32 reg)

{

	WARN_ON_ONCE((cpu_has_apic || !disable_apic));

	return 0;

}



/*

 * right after this call apic->write doesn't do anything

 * right after this call apic->write/read doesn't do anything

 * note that there is no restore operation it works one way

 */

void apic_disable(void)

{

	apic->read = native_apic_read_dummy;

	apic->write = native_apic_write_dummy;

}
@@ -1576,15 +1583,12 @@ void __init init_apic_mappings(void) 
		return;

	}



	/*

	 * If no local APIC can be found then set up a fake all

	 * zeroes page to simulate the local APIC and another

	 * one for the IO-APIC.

	 */

	/* If no local APIC can be found return early */

	if (!smp_found_config && detect_init_APIC()) {

		apic_phys = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);

		apic_phys = __pa(apic_phys);

	} else

		/* lets NOP'ify apic operations */

		pr_info("APIC: disable apic facility\n");

		apic_disable();

	} else {

		apic_phys = mp_lapic_addr;



		/*
@@ -1596,12 +1600,6 @@ void __init init_apic_mappings(void) 


		apic_printk(APIC_VERBOSE, "mapped APIC to %08lx (%08lx)\n",

					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;

	}



	/*

arch/x86/kernel/apic/io_apic.c

+5 −0
Original line number Diff line number Diff line
@@ -1878,6 +1878,11 @@ __apicdebuginit(void) print_PIC(void) 
__apicdebuginit(int) print_all_ICs(void)

{

	print_PIC();



	/* don't print out if apic is not there */

	if (!cpu_has_apic || disable_apic)

		return 0;



	print_all_local_APICs();

	print_IO_APIC();

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