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: Ed Swierk <eswierk@aristanetworks.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
LKML-Reference: <49FC85A9.2070702@kernel.org>
[ v4: sanity-check in the ACPI case too ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 1 insertions, 1 deletions

diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index 19e0d88..6a84ed1 100644
--- a/arch/x86/include/asm/smp.h
+++ b/arch/x86/include/asm/smp.h
@@ -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