x86: unify KERNEL_PGD_PTRS

Make KERNEL_PGD_PTRS common, as previously it was only being defined
for 32-bit.

There are a couple of follow-on changes from this:
 - KERNEL_PGD_PTRS was being defined in terms of USER_PGD_PTRS.  The
   definition of USER_PGD_PTRS doesn't really make much sense on x86-64,
   since it can have two different user address-space configurations.
   I renamed USER_PGD_PTRS to KERNEL_PGD_BOUNDARY, which is meaningful
   for all of 32/32, 32/64 and 64/64 process configurations.

 - USER_PTRS_PER_PGD was also defined and was being used for similar
   purposes.  Converting its users to KERNEL_PGD_BOUNDARY left it
   completely unused, and so I removed it.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Zach Amsden <zach@vmware.com>

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/kernel/reboot.c

@@ -8,6 +8,7 @@
 #include <asm/apic.h>
 #include <asm/desc.h>
 #include <asm/hpet.h>
+#include <asm/pgtable.h>
 #include <asm/reboot_fixups.h>
 #include <asm/reboot.h>
 
@@ -15,7 +16,6 @@
 # include <linux/dmi.h>
 # include <linux/ctype.h>
 # include <linux/mc146818rtc.h>
-# include <asm/pgtable.h>
 #else
 # include <asm/iommu.h>
 #endif
@@ -275,7 +275,7 @@ void machine_real_restart(unsigned char *code, int length)
 	/* Remap the kernel at virtual address zero, as well as offset zero
 	   from the kernel segment.  This assumes the kernel segment starts at
 	   virtual address PAGE_OFFSET. */
-	memcpy(swapper_pg_dir, swapper_pg_dir + USER_PGD_PTRS,
+	memcpy(swapper_pg_dir, swapper_pg_dir + KERNEL_PGD_BOUNDARY,
 		sizeof(swapper_pg_dir [0]) * KERNEL_PGD_PTRS);
 
 	/*

arch/x86/kernel/smpboot.c

@@ -1039,8 +1039,8 @@ int __cpuinit native_cpu_up(unsigned int cpu)
 
 #ifdef CONFIG_X86_32
 	/* init low mem mapping */
-	clone_pgd_range(swapper_pg_dir, swapper_pg_dir + USER_PGD_PTRS,
+	clone_pgd_range(swapper_pg_dir, swapper_pg_dir + KERNEL_PGD_BOUNDARY,
-			min_t(unsigned long, KERNEL_PGD_PTRS, USER_PGD_PTRS));
+			min_t(unsigned long, KERNEL_PGD_PTRS, KERNEL_PGD_BOUNDARY));
 	flush_tlb_all();
 #endif
 

arch/x86/kernel/vmi_32.c

@@ -320,7 +320,7 @@ static void check_zeroed_page(u32 pfn, int type, struct page *page)
 	 * pdes need to be zeroed.
 	 */
 	if (type & VMI_PAGE_CLONE)
-		limit = USER_PTRS_PER_PGD;
+		limit = KERNEL_PGD_BOUNDARY;
 	for (i = 0; i < limit; i++)
 		BUG_ON(ptr[i]);
 }

arch/x86/mach-voyager/voyager_smp.c

@@ -560,8 +560,8 @@ static void __init do_boot_cpu(__u8 cpu)
 		hijack_source.idt.Offset, stack_start.sp));
 
 	/* init lowmem identity mapping */
-	clone_pgd_range(swapper_pg_dir, swapper_pg_dir + USER_PGD_PTRS,
+	clone_pgd_range(swapper_pg_dir, swapper_pg_dir + KERNEL_PGD_BOUNDARY,
-			min_t(unsigned long, KERNEL_PGD_PTRS, USER_PGD_PTRS));
+			min_t(unsigned long, KERNEL_PGD_PTRS, KERNEL_PGD_BOUNDARY));
 	flush_tlb_all();
 
 	if (quad_boot) {

arch/x86/mm/init_32.c

@@ -457,7 +457,7 @@ void zap_low_mappings(void)
 	 * Note that "pgd_clear()" doesn't do it for
 	 * us, because pgd_clear() is a no-op on i386.
 	 */
-	for (i = 0; i < USER_PTRS_PER_PGD; i++) {
+	for (i = 0; i < KERNEL_PGD_BOUNDARY; i++) {
 #ifdef CONFIG_X86_PAE
 		set_pgd(swapper_pg_dir+i, __pgd(1 + __pa(empty_zero_page)));
 #else

arch/x86/mm/pgtable.c

@@ -104,7 +104,7 @@ void pgd_free(struct mm_struct *mm, pgd_t *pgd)
  * -- wli
  */
 #define UNSHARED_PTRS_PER_PGD				\
-	(SHARED_KERNEL_PMD ? USER_PTRS_PER_PGD : PTRS_PER_PGD)
+	(SHARED_KERNEL_PMD ? KERNEL_PGD_BOUNDARY : PTRS_PER_PGD)
 
 static void pgd_ctor(void *p)
 {
@@ -112,7 +112,7 @@ static void pgd_ctor(void *p)
 	unsigned long flags;
 
 	/* Clear usermode parts of PGD */
-	memset(pgd, 0, USER_PTRS_PER_PGD*sizeof(pgd_t));
+	memset(pgd, 0, KERNEL_PGD_BOUNDARY*sizeof(pgd_t));
 
 	spin_lock_irqsave(&pgd_lock, flags);
 
@@ -121,12 +121,12 @@ static void pgd_ctor(void *p)
 	   references from swapper_pg_dir. */
 	if (PAGETABLE_LEVELS == 2 ||
 	    (PAGETABLE_LEVELS == 3 && SHARED_KERNEL_PMD)) {
-		clone_pgd_range(pgd + USER_PTRS_PER_PGD,
+		clone_pgd_range(pgd + KERNEL_PGD_BOUNDARY,
-				swapper_pg_dir + USER_PTRS_PER_PGD,
+				swapper_pg_dir + KERNEL_PGD_BOUNDARY,
 				KERNEL_PGD_PTRS);
 		paravirt_alloc_pmd_clone(__pa(pgd) >> PAGE_SHIFT,
 					 __pa(swapper_pg_dir) >> PAGE_SHIFT,
-					 USER_PTRS_PER_PGD,
+					 KERNEL_PGD_BOUNDARY,
 					 KERNEL_PGD_PTRS);
 	}
 
@@ -201,7 +201,7 @@ static int pgd_prepopulate_pmd(struct mm_struct *mm, pgd_t *pgd)
 			return 0;
 		}
 
-		if (i >= USER_PTRS_PER_PGD)
+		if (i >= KERNEL_PGD_BOUNDARY)
 			memcpy(pmd, (pmd_t *)pgd_page_vaddr(swapper_pg_dir[i]),
 			       sizeof(pmd_t) * PTRS_PER_PMD);
 

include/asm-x86/pgtable.h

@@ -1,7 +1,6 @@
 #ifndef _ASM_X86_PGTABLE_H
 #define _ASM_X86_PGTABLE_H
 
-#define USER_PTRS_PER_PGD	((TASK_SIZE-1)/PGDIR_SIZE+1)
 #define FIRST_USER_ADDRESS	0
 
 #define _PAGE_BIT_PRESENT	0	/* is present */
@@ -330,6 +329,9 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 # include "pgtable_64.h"
 #endif
 
+#define KERNEL_PGD_BOUNDARY	pgd_index(PAGE_OFFSET)
+#define KERNEL_PGD_PTRS		(PTRS_PER_PGD - KERNEL_PGD_BOUNDARY)
+
 #ifndef __ASSEMBLY__
 
 enum {

include/asm-x86/pgtable_32.h

@@ -48,9 +48,6 @@ void paging_init(void);
 #define PGDIR_SIZE	(1UL << PGDIR_SHIFT)
 #define PGDIR_MASK	(~(PGDIR_SIZE - 1))
 
-#define USER_PGD_PTRS (PAGE_OFFSET >> PGDIR_SHIFT)
-#define KERNEL_PGD_PTRS (PTRS_PER_PGD-USER_PGD_PTRS)
-
 /* Just any arbitrary offset to the start of the vmalloc VM area: the
  * current 8MB value just means that there will be a 8MB "hole" after the
  * physical memory until the kernel virtual memory starts.  That means that