x86: use static _cpu_pda array

_cpu_pda array first uses statically allocated storage in data.init
and then switches to allocated bootmem to conserve space.  However,
after folding pda area into percpu area, _cpu_pda array will be
removed completely.  Drop the reallocation part to simplify the code
for soon-to-follow changes.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/include/asm/pda.h

@@ -5,6 +5,7 @@
 #include <linux/stddef.h>
 #include <linux/types.h>
 #include <linux/cache.h>
+#include <linux/threads.h>
 #include <asm/page.h>
 
 /* Per processor datastructure. %gs points to it while the kernel runs */
@@ -39,7 +40,7 @@ struct x8664_pda {
 	unsigned irq_spurious_count;
 } ____cacheline_aligned_in_smp;
 
-extern struct x8664_pda **_cpu_pda;
+extern struct x8664_pda *_cpu_pda[NR_CPUS];
 extern void pda_init(int);
 
 #define cpu_pda(i) (_cpu_pda[i])

arch/x86/kernel/cpu/common.c

@@ -879,7 +879,7 @@ static __init int setup_disablecpuid(char *arg)
 __setup("clearcpuid=", setup_disablecpuid);
 
 #ifdef CONFIG_X86_64
-struct x8664_pda **_cpu_pda __read_mostly;
+struct x8664_pda *_cpu_pda[NR_CPUS] __read_mostly;
 EXPORT_SYMBOL(_cpu_pda);
 
 struct desc_ptr idt_descr = { 256 * 16 - 1, (unsigned long) idt_table };

arch/x86/kernel/head64.c

@@ -29,20 +29,8 @@
 /* boot cpu pda, referenced by head_64.S to initialize %gs for boot CPU */
 struct x8664_pda _boot_cpu_pda;
 
-#ifdef CONFIG_SMP
-/*
- * We install an empty cpu_pda pointer table to indicate to early users
- * (numa_set_node) that the cpu_pda pointer table for cpus other than
- * the boot cpu is not yet setup.
- */
-static struct x8664_pda *__cpu_pda[NR_CPUS] __initdata;
-#else
-static struct x8664_pda *__cpu_pda[NR_CPUS] __read_mostly;
-#endif
-
 void __init x86_64_init_pda(void)
 {
-	_cpu_pda = __cpu_pda;
 	cpu_pda(0) = &_boot_cpu_pda;
 	cpu_pda(0)->data_offset =
 		(unsigned long)(__per_cpu_load - __per_cpu_start);

arch/x86/kernel/setup_percpu.c

@@ -114,7 +114,6 @@ static inline void setup_cpu_pda_map(void) { }
 static void __init setup_cpu_pda_map(void)
 {
 	char *pda;
-	struct x8664_pda **new_cpu_pda;
 	unsigned long size;
 	int cpu;
 
@@ -122,28 +121,21 @@ static void __init setup_cpu_pda_map(void)
 
 	/* allocate cpu_pda array and pointer table */
 	{
-		unsigned long tsize = nr_cpu_ids * sizeof(void *);
 		unsigned long asize = size * (nr_cpu_ids - 1);
 
-		tsize = roundup(tsize, cache_line_size());
-		new_cpu_pda = alloc_bootmem(tsize + asize);
-		pda = (char *)new_cpu_pda + tsize;
+		pda = alloc_bootmem(asize);
 	}
 
 	/* initialize pointer table to static pda's */
 	for_each_possible_cpu(cpu) {
 		if (cpu == 0) {
 			/* leave boot cpu pda in place */
-			new_cpu_pda[0] = cpu_pda(0);
 			continue;
 		}
-		new_cpu_pda[cpu] = (struct x8664_pda *)pda;
-		new_cpu_pda[cpu]->in_bootmem = 1;
+		cpu_pda(cpu) = (struct x8664_pda *)pda;
+		cpu_pda(cpu)->in_bootmem = 1;
 		pda += size;
 	}
-
-	/* point to new pointer table */
-	_cpu_pda = new_cpu_pda;
 }
 
 #endif /* CONFIG_SMP && CONFIG_X86_64 */