x86/apic/32: Remove x86_cpu_to_logical_apicid

This per CPU variable is just yet another form of voodoo programming. The
boot ordering is:

  per_cpu(x86_cpu_to_logical_apicid, cpu) = 1U << cpu;

  .....

  setup_apic()
     apic->init_apic_ldr()
       default_init_apic_ldr()
         apic_write(SET_APIC_LOGICAL_ID(1UL << smp_processor_id(), APIC_LDR);

     id = GET_APIC_LOGICAL_ID(apic_read(APIC_LDR);
     WARN_ON(id != per_cpu(x86_cpu_to_logical_apicid, cpu));
     per_cpu(x86_cpu_to_logical_apicid, cpu) = id;

So first write the default into LDR and then validate it against the same default
which was set up during early boot APIC enumeration.

Brilliant, isn't it?

The comment above the per CPU variable declaration describes it well:
'Let's keep it ugly for now.'

Remove the useless gunk and use '1U << cpu' consistently all over the place.

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, 9 insertions, 27 deletions

diff --git a/arch/x86/kernel/apic/ipi.c b/arch/x86/kernel/apic/ipi.c
index 29273e0151fc..aa51e16cb7d8 100644
--- a/arch/x86/kernel/apic/ipi.c
+++ b/arch/x86/kernel/apic/ipi.c
@@ -243,50 +243,32 @@ void default_send_IPI_self(int vector)
 }
 
 #ifdef CONFIG_X86_32
-
-void default_send_IPI_mask_sequence_logical(const struct cpumask *mask,
-						 int vector)
+void default_send_IPI_mask_sequence_logical(const struct cpumask *mask, int vector)
 {
 	unsigned long flags;
-	unsigned int query_cpu;
-
-	/*
-	 * Hack. The clustered APIC addressing mode doesn't allow us to send
-	 * to an arbitrary mask, so I do a unicasts to each CPU instead. This
-	 * should be modified to do 1 message per cluster ID - mbligh
-	 */
+	unsigned int cpu;
 
 	local_irq_save(flags);
-	for_each_cpu(query_cpu, mask)
-		__default_send_IPI_dest_field(
-			early_per_cpu(x86_cpu_to_logical_apicid, query_cpu),
-			vector, APIC_DEST_LOGICAL);
+	for_each_cpu(cpu, mask)
+		__default_send_IPI_dest_field(1U << cpu, vector, APIC_DEST_LOGICAL);
 	local_irq_restore(flags);
 }
 
 void default_send_IPI_mask_allbutself_logical(const struct cpumask *mask,
 						 int vector)
 {
+	unsigned int cpu, this_cpu = smp_processor_id();
 	unsigned long flags;
-	unsigned int query_cpu;
-	unsigned int this_cpu = smp_processor_id();
-
-	/* See Hack comment above */
 
 	local_irq_save(flags);
-	for_each_cpu(query_cpu, mask) {
-		if (query_cpu == this_cpu)
+	for_each_cpu(cpu, mask) {
+		if (cpu == this_cpu)
 			continue;
-		__default_send_IPI_dest_field(
-			early_per_cpu(x86_cpu_to_logical_apicid, query_cpu),
-			vector, APIC_DEST_LOGICAL);
-		}
+		__default_send_IPI_dest_field(1U << cpu, vector, APIC_DEST_LOGICAL);
+	}
 	local_irq_restore(flags);
 }
 
-/*
- * This is only used on smaller machines.
- */
 void default_send_IPI_mask_logical(const struct cpumask *cpumask, int vector)
 {
 	unsigned long mask = cpumask_bits(cpumask)[0];