Re: [tip:x86/urgent] x86, apic: Map the local apic when parsing theMP table.

From: Yinghai Lu
Date: Fri Aug 06 2010 - 20:53:01 EST

On 08/06/2010 05:15 PM, H. Peter Anvin wrote:
> On 08/06/2010 05:08 PM, Yinghai Lu wrote:
>> this change is not needed, it will break:
>> 1. found mptable, but is using default contruct path.
>> 2. visws path, found found mptable, but get_smp_conf is not called.
>> YH
> I'm not sure the above is decipherable. Please provide an incremental
> patch with a more detailed description.
please check

[PATCH] x86: Fix lapic mapping with construct ISA and visws mptable path

do need to set lapic mapping for them

in arch/x86/kernel/visws_quirks.c:
we only have visws_find_smp_config() to set mp_lapic_addr to APIC_DEFAULT_PHYS_BASE
visws_get_smp_config() is nop call.
default_get_smp_config/check_physptr/smp_read_mpc is not called in the path.
So smp_register_lapic_address() is not called, and lapic is not mapped.

in arch/x86/kernel/mpparse.c
if mpf->feature1 != 0, it will go through contruct_default_ISA_mptable instead
of check_phystr path, so smp_register_lapic_address is not called.

those two path all have smp_found_config set.

So let remove !smp_found_config checking

Actually set fixmap two times does not hurt.

Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>

arch/x86/kernel/apic/apic.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux-2.6/arch/x86/kernel/apic/apic.c
--- linux-2.6.orig/arch/x86/kernel/apic/apic.c
+++ linux-2.6/arch/x86/kernel/apic/apic.c
@@ -1606,7 +1606,7 @@ void __init init_apic_mappings(void)
* acpi lapic path already maps that address in
* acpi_register_lapic_address()
- if (!acpi_lapic && !smp_found_config)
+ if (!acpi_lapic)
set_fixmap_nocache(FIX_APIC_BASE, apic_phys);

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