powerpc: Add VDSO version of getcpu

[karo-tx-linux.git] / arch / powerpc / kernel / vdso.c

diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index 9eb5b9b536a71b704b62a6cc6b38660f80d426b4..b67db22e102dd93dc11ec131ac7e942cf6de3d5c 100644 (file)
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -706,6 +706,34 @@ static void __init vdso_setup_syscall_map(void)
        }
 }
 
+#ifdef CONFIG_PPC64
+int __cpuinit vdso_getcpu_init(void)
+{
+       unsigned long cpu, node, val;
+
+       /*
+        * SPRG3 contains the CPU in the bottom 16 bits and the NUMA node in
+        * the next 16 bits. The VDSO uses this to implement getcpu().
+        */
+       cpu = get_cpu();
+       WARN_ON_ONCE(cpu > 0xffff);
+
+       node = cpu_to_node(cpu);
+       WARN_ON_ONCE(node > 0xffff);
+
+       val = (cpu & 0xfff) | ((node & 0xffff) << 16);
+       mtspr(SPRN_SPRG3, val);
+#ifdef CONFIG_KVM_BOOK3S_HANDLER
+       get_paca()->kvm_hstate.sprg3 = val;
+#endif
+
+       put_cpu();
+
+       return 0;
+}
+/* We need to call this before SMP init */
+early_initcall(vdso_getcpu_init);
+#endif
 
 static int __init vdso_init(void)
 {