x86: use specialized routine for setup per-cpu area

We use the same routing as x86_64, moved now to setup.c.
Just with a few ifdefs inside.
Note that this routing uses prefill_possible_map().
It has the very nice side effect of allowing hotplugging of
cpus that are marked as present but disabled by acpi bios.

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

1 files changed, 103 insertions, 0 deletions

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
new file mode 100644
index 000000000000..1179aa06cdbf
--- /dev/null
+++ b/arch/x86/kernel/setup.c
@@ -0,0 +1,103 @@
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/bootmem.h>
+#include <linux/percpu.h>
+#include <asm/smp.h>
+#include <asm/percpu.h>
+#include <asm/sections.h>
+#include <asm/processor.h>
+#include <asm/setup.h>
+#include <asm/topology.h>
+
+#ifdef CONFIG_HAVE_SETUP_PER_CPU_AREA
+/*
+ * Copy data used in early init routines from the initial arrays to the
+ * per cpu data areas.  These arrays then become expendable and the
+ * *_early_ptr's are zeroed indicating that the static arrays are gone.
+ */
+static void __init setup_per_cpu_maps(void)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu) {
+#ifdef CONFIG_SMP
+		if (per_cpu_offset(cpu)) {
+#endif
+			per_cpu(x86_cpu_to_apicid, cpu) =
+						x86_cpu_to_apicid_init[cpu];
+			per_cpu(x86_bios_cpu_apicid, cpu) =
+						x86_bios_cpu_apicid_init[cpu];
+#ifdef CONFIG_NUMA
+			per_cpu(x86_cpu_to_node_map, cpu) =
+						x86_cpu_to_node_map_init[cpu];
+#endif
+#ifdef CONFIG_SMP
+		} else
+			printk(KERN_NOTICE "per_cpu_offset zero for cpu %d\n",
+									cpu);
+#endif
+	}
+
+	/* indicate the early static arrays will soon be gone */
+	x86_cpu_to_apicid_early_ptr = NULL;
+	x86_bios_cpu_apicid_early_ptr = NULL;
+#ifdef CONFIG_NUMA
+	x86_cpu_to_node_map_early_ptr = NULL;
+#endif
+}
+
+#ifdef CONFIG_X86_32
+/*
+ * Great future not-so-futuristic plan: make i386 and x86_64 do it
+ * the same way
+ */
+unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
+EXPORT_SYMBOL(__per_cpu_offset);
+#endif
+
+/*
+ * Great future plan:
+ * Declare PDA itself and support (irqstack,tss,pgd) as per cpu data.
+ * Always point %gs to its beginning
+ */
+void __init setup_per_cpu_areas(void)
+{
+	int i;
+	unsigned long size;
+
+#ifdef CONFIG_HOTPLUG_CPU
+	prefill_possible_map();
+#endif
+
+	/* Copy section for each CPU (we discard the original) */
+	size = PERCPU_ENOUGH_ROOM;
+
+	printk(KERN_INFO "PERCPU: Allocating %lu bytes of per cpu data\n",
+			  size);
+	for_each_cpu_mask(i, cpu_possible_map) {
+		char *ptr;
+#ifndef CONFIG_NEED_MULTIPLE_NODES
+		ptr = alloc_bootmem_pages(size);
+#else
+		int node = early_cpu_to_node(i);
+		if (!node_online(node) || !NODE_DATA(node))
+			ptr = alloc_bootmem_pages(size);
+		else
+			ptr = alloc_bootmem_pages_node(NODE_DATA(node), size);
+#endif
+		if (!ptr)
+			panic("Cannot allocate cpu data for CPU %d\n", i);
+#ifdef CONFIG_X86_64
+		cpu_pda(i)->data_offset = ptr - __per_cpu_start;
+#else
+		__per_cpu_offset[i] = ptr - __per_cpu_start;
+#endif
+		memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start);
+	}
+
+	/* setup percpu data maps early */
+	setup_per_cpu_maps();
+}
+
+#endif