x86: create smpcommon.c

This patch creates smpcommon.c with functions that are
equal between architectures. The i386-only init_gdt
is ifdef'd.

Note that smpcommon.o figures twice in the Makefile:
this is because sub-architectures like voyager that does
not use the normal smp_$(BITS) files also have to access them

Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 83 insertions, 0 deletions

diff --git a/arch/x86/kernel/smpcommon.c b/arch/x86/kernel/smpcommon.c
new file mode 100644
index 000000000000..3449064d141a
--- /dev/null
+++ b/arch/x86/kernel/smpcommon.c
@@ -0,0 +1,83 @@
+/*
+ * SMP stuff which is common to all sub-architectures.
+ */
+#include <linux/module.h>
+#include <asm/smp.h>
+
+#ifdef CONFIG_X86_32
+DEFINE_PER_CPU(unsigned long, this_cpu_off);
+EXPORT_PER_CPU_SYMBOL(this_cpu_off);
+
+/* Initialize the CPU's GDT.  This is either the boot CPU doing itself
+   (still using the master per-cpu area), or a CPU doing it for a
+   secondary which will soon come up. */
+__cpuinit void init_gdt(int cpu)
+{
+        struct desc_struct *gdt = get_cpu_gdt_table(cpu);
+
+        pack_descriptor(&gdt[GDT_ENTRY_PERCPU],
+                        __per_cpu_offset[cpu], 0xFFFFF,
+                        0x2 | DESCTYPE_S, 0x8);
+
+        gdt[GDT_ENTRY_PERCPU].s = 1;
+
+        per_cpu(this_cpu_off, cpu) = __per_cpu_offset[cpu];
+        per_cpu(cpu_number, cpu) = cpu;
+}
+#endif
+
+/**
+ * smp_call_function(): Run a function on all other CPUs.
+ * @func: The function to run. This must be fast and non-blocking.
+ * @info: An arbitrary pointer to pass to the function.
+ * @nonatomic: Unused.
+ * @wait: If true, wait (atomically) until function has completed on other CPUs.
+ *
+ * Returns 0 on success, else a negative status code.
+ *
+ * If @wait is true, then returns once @func has returned; otherwise
+ * it returns just before the target cpu calls @func.
+ *
+ * You must not call this function with disabled interrupts or from a
+ * hardware interrupt handler or from a bottom half handler.
+ */
+int smp_call_function(void (*func) (void *info), void *info, int nonatomic,
+                      int wait)
+{
+        return smp_call_function_mask(cpu_online_map, func, info, wait);
+}
+EXPORT_SYMBOL(smp_call_function);
+
+/**
+ * smp_call_function_single - Run a function on a specific CPU
+ * @cpu: The target CPU.  Cannot be the calling CPU.
+ * @func: The function to run. This must be fast and non-blocking.
+ * @info: An arbitrary pointer to pass to the function.
+ * @nonatomic: Unused.
+ * @wait: If true, wait until function has completed on other CPUs.
+ *
+ * Returns 0 on success, else a negative status code.
+ *
+ * If @wait is true, then returns once @func has returned; otherwise
+ * it returns just before the target cpu calls @func.
+ */
+int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
+                             int nonatomic, int wait)
+{
+        /* prevent preemption and reschedule on another processor */
+        int ret;
+        int me = get_cpu();
+        if (cpu == me) {
+                local_irq_disable();
+                func(info);
+                local_irq_enable();
+                put_cpu();
+                return 0;
+        }
+
+        ret = smp_call_function_mask(cpumask_of_cpu(cpu), func, info, wait);
+
+        put_cpu();
+        return ret;
+}
+EXPORT_SYMBOL(smp_call_function_single);