x86/apic/32: Sanitize logical APIC ID handling

apic::x86_32_early_logical_apicid() is yet another historical joke.

It is used to preset the x86_cpu_to_logical_apicid per CPU variable during
APIC enumeration with:

  - 1 shifted left by the CPU number
  - the physical APIC ID in case of bigsmp

The latter is hillarious because bigsmp uses physical destination mode
which never can use the logical APIC ID.

It gets even worse. As bigsmp can be enforced late in the boot process the
probe function overwrites the per CPU variable which is never used for this
APIC type once again.

Remove that gunk and store 1 << cpunr unconditionally if and only if the
CPU number is less than 8, because the default logical destination mode
only allows up to 8 CPUs.

This is just an intermediate step before removing the per CPU insanity
completely. Stay tuned.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

1 files changed, 0 insertions, 13 deletions

diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index 098d193f93fb..daef6812141f 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -315,19 +315,6 @@ struct apic {
 	/* wakeup secondary CPU using 64-bit wakeup point */
 	int	(*wakeup_secondary_cpu_64)(int apicid, unsigned long start_eip);
 
-#ifdef CONFIG_X86_32
-	/*
-	 * Called very early during boot from get_smp_config().  It should
-	 * return the logical apicid.  x86_[bios]_cpu_to_apicid is
-	 * initialized before this function is called.
-	 *
-	 * If logical apicid can't be determined that early, the function
-	 * may return BAD_APICID.  Logical apicid will be configured after
-	 * init_apic_ldr() while bringing up CPUs.  Note that NUMA affinity
-	 * won't be applied properly during early boot in this case.
-	 */
-	int (*x86_32_early_logical_apicid)(int cpu);
-#endif
 	char	*name;
 };