x86, lib: Add wbinvd smp helpers

Add wbinvd_on_cpu and wbinvd_on_all_cpus stubs for executing wbinvd on a
particular CPU.

[ hpa: renamed lib/smp.c to lib/cache-smp.c ]
[ hpa: wbinvd_on_all_cpus() returns int, but wbinvd() returns
  void.  Thus, the former cannot be a macro for the latter,
  replace with an inline function. ]

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
LKML-Reference: <1264172467-25155-2-git-send-email-bp@amd64.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

arch/x86/include/asm/smp.h

@@ -135,6 +135,8 @@ int native_cpu_disable(void);
 void native_cpu_die(unsigned int cpu);
 void native_play_dead(void);
 void play_dead_common(void);
+void wbinvd_on_cpu(int cpu);
+int wbinvd_on_all_cpus(void);
 
 void native_send_call_func_ipi(const struct cpumask *mask);
 void native_send_call_func_single_ipi(int cpu);
@@ -147,6 +149,13 @@ static inline int num_booting_cpus(void)
 {
 	return cpumask_weight(cpu_callout_mask);
 }
+#else /* !CONFIG_SMP */
+#define wbinvd_on_cpu(cpu)     wbinvd()
+static inline int wbinvd_on_all_cpus(void)
+{
+	wbinvd();
+	return 0;
+}
 #endif /* CONFIG_SMP */
 
 extern unsigned disabled_cpus __cpuinitdata;

arch/x86/lib/Makefile

@@ -14,7 +14,7 @@ $(obj)/inat.o: $(obj)/inat-tables.c
 
 clean-files := inat-tables.c
 
-obj-$(CONFIG_SMP) += msr-smp.o
+obj-$(CONFIG_SMP) += msr-smp.o cache-smp.o
 
 lib-y := delay.o
 lib-y += thunk_$(BITS).o

arch/x86/lib/cache-smp.c

@@ -0,0 +1,19 @@
+#include <linux/smp.h>
+#include <linux/module.h>
+
+static void __wbinvd(void *dummy)
+{
+	wbinvd();
+}
+
+void wbinvd_on_cpu(int cpu)
+{
+	smp_call_function_single(cpu, __wbinvd, NULL, 1);
+}
+EXPORT_SYMBOL(wbinvd_on_cpu);
+
+int wbinvd_on_all_cpus(void)
+{
+	return on_each_cpu(__wbinvd, NULL, 1);
+}
+EXPORT_SYMBOL(wbinvd_on_all_cpus);