[PATCH] x86_64: Switch SMP bootup over to new CPU hotplug state machine

This will allow hotplug CPU in the future and in general cleans up a lot of
crufty code.  It also should plug some races that the old hackish way
introduces.  Remove one old race workaround in NMI watchdog setup that is not
needed anymore.

I removed the old total sum of bogomips reporting code.  The brag value of
BogoMips has been greatly devalued in the last years on the open market.

Real CPU hotplug will need some more work, but the infrastructure for it is
there now.

One drawback: the new TSC sync algorithm is less accurate than before.  The
old way of zeroing TSCs is too intrusive to do later.  Instead the TSC of the
BP is duplicated now, which is less accurate.

akpm:

- sync_tsc_bp_init seems to have the sense of `init' inverted.

- SPIN_LOCK_UNLOCKED is deprecated - use DEFINE_SPINLOCK.

Cc: <rusty@rustcorp.com.au>
Cc: <mingo@elte.hu>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 25 insertions, 0 deletions

diff --git a/arch/x86_64/kernel/smp.c b/arch/x86_64/kernel/smp.c
index e3cdbf9a88bd..1e379ed17b1d 100644
--- a/arch/x86_64/kernel/smp.c
+++ b/arch/x86_64/kernel/smp.c
@@ -27,6 +27,7 @@
 #include <asm/mach_apic.h>
 #include <asm/mmu_context.h>
 #include <asm/proto.h>
+#include <asm/apicdef.h>
 
 /*
  *	Smarter SMP flushing macros. 
@@ -413,3 +414,27 @@ asmlinkage void smp_call_function_interrupt(void)
 		atomic_inc(&call_data->finished);
 	}
 }
+
+int safe_smp_processor_id(void)
+{
+	int apicid, i;
+
+	if (disable_apic)
+		return 0;
+
+	apicid = hard_smp_processor_id();
+	if (x86_cpu_to_apicid[apicid] == apicid)
+		return apicid;
+
+	for (i = 0; i < NR_CPUS; ++i) {
+		if (x86_cpu_to_apicid[i] == apicid)
+			return i;
+	}
+
+	/* No entries in x86_cpu_to_apicid?  Either no MPS|ACPI,
+	 * or called too early.  Either way, we must be CPU 0. */
+      	if (x86_cpu_to_apicid[0] == BAD_APICID)
+		return 0;
+
+	return 0; /* Should not happen */
+}