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-rw-r--r--arch/x86_64/kernel/smp.c25
1 files changed, 25 insertions, 0 deletions
diff --git a/arch/x86_64/kernel/smp.c b/arch/x86_64/kernel/smp.c
index e3cdbf9a88b..1e379ed17b1 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 */
+}