alpha: use pgtable-nopud instead of 4level-fixup

Patch series "mm: remove __ARCH_HAS_4LEVEL_HACK", v13.

These patches convert several architectures to use page table folding
and remove __ARCH_HAS_4LEVEL_HACK along with
include/asm-generic/4level-fixup.h.

For the nommu configurations the folding is already implemented by the
generic code so the only change was to use the appropriate header file.

As for the rest, the changes are mostly about mechanical replacement of
pgd accessors with pud/pmd ones and the addition of higher levels to
page table traversals.

With Vineet's patches from "elide extraneous generated code for folded
p4d/pud/pmd" series [1] there is a small shrink of the kernel size of
about -0.01% for the defconfig builds.

This patch (of 13):

It is not likely alpha will have 5-level page tables.

Replace usage of include/asm-generic/4level-fixup.h and implied
__ARCH_HAS_4LEVEL_HACK with include/asm-generic/pgtable-nopud.h and
adjust page table manipulation macros and functions accordingly.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Mike Rapoport <[email protected]>
Cc: Anton Ivanov <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Geert Uytterhoeven <[email protected]>
Cc: Greentime Hu <[email protected]>
Cc: Greg Ungerer <[email protected]>
Cc: Helge Deller <[email protected]>
Cc: "James E.J. Bottomley" <[email protected]>
Cc: Jeff Dike <[email protected]>
Cc: "Kirill A. Shutemov" <[email protected]>
Cc: Mark Salter <[email protected]>
Cc: Matt Turner <[email protected]>
Cc: Michal Simek <[email protected]>
Cc: Peter Rosin <[email protected]>
Cc: Richard Weinberger <[email protected]>
Cc: Rolf Eike Beer <[email protected]>
Cc: Russell King <[email protected]>
Cc: Sam Creasey <[email protected]>
Cc: Vincent Chen <[email protected]>
Cc: Vineet Gupta <[email protected]>
Cc: Anatoly Pugachev <[email protected]>
Cc: Russell King <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Author: rppt

arch/alpha/include/asm/mmzone.h

@@ -73,7 +73,6 @@ PLAT_NODE_DATA_LOCALNR(unsigned long p, int n)
 #define virt_to_page(kaddr)	pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)
 
 #define pmd_page(pmd)		(pfn_to_page(pmd_val(pmd) >> 32))
-#define pgd_page(pgd)		(pfn_to_page(pgd_val(pgd) >> 32))
 #define pte_pfn(pte)		(pte_val(pte) >> 32)
 
 #define mk_pte(page, pgprot)						     \

arch/alpha/include/asm/pgalloc.h

@@ -27,9 +27,9 @@ pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, pte_t *pte)
 }
 
 static inline void
-pgd_populate(struct mm_struct *mm, pgd_t *pgd, pmd_t *pmd)
+pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd)
 {
-	pgd_set(pgd, pmd);
+	pud_set(pud, pmd);
 }
 
 extern pgd_t *pgd_alloc(struct mm_struct *mm);

arch/alpha/include/asm/pgtable.h

@@ -2,7 +2,7 @@
 #ifndef _ALPHA_PGTABLE_H
 #define _ALPHA_PGTABLE_H
 
-#include <asm-generic/4level-fixup.h>
+#include <asm-generic/pgtable-nopud.h>
 
 /*
  * This file contains the functions and defines necessary to modify and use
@@ -226,8 +226,8 @@ extern inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 extern inline void pmd_set(pmd_t * pmdp, pte_t * ptep)
 { pmd_val(*pmdp) = _PAGE_TABLE | ((((unsigned long) ptep) - PAGE_OFFSET) << (32-PAGE_SHIFT)); }
 
-extern inline void pgd_set(pgd_t * pgdp, pmd_t * pmdp)
-{ pgd_val(*pgdp) = _PAGE_TABLE | ((((unsigned long) pmdp) - PAGE_OFFSET) << (32-PAGE_SHIFT)); }
+extern inline void pud_set(pud_t * pudp, pmd_t * pmdp)
+{ pud_val(*pudp) = _PAGE_TABLE | ((((unsigned long) pmdp) - PAGE_OFFSET) << (32-PAGE_SHIFT)); }
 
 
 extern inline unsigned long
@@ -238,11 +238,11 @@ pmd_page_vaddr(pmd_t pmd)
 
 #ifndef CONFIG_DISCONTIGMEM
 #define pmd_page(pmd)	(mem_map + ((pmd_val(pmd) & _PFN_MASK) >> 32))
-#define pgd_page(pgd)	(mem_map + ((pgd_val(pgd) & _PFN_MASK) >> 32))
+#define pud_page(pud)	(mem_map + ((pud_val(pud) & _PFN_MASK) >> 32))
 #endif
 
-extern inline unsigned long pgd_page_vaddr(pgd_t pgd)
-{ return PAGE_OFFSET + ((pgd_val(pgd) & _PFN_MASK) >> (32-PAGE_SHIFT)); }
+extern inline unsigned long pud_page_vaddr(pud_t pgd)
+{ return PAGE_OFFSET + ((pud_val(pgd) & _PFN_MASK) >> (32-PAGE_SHIFT)); }
 
 extern inline int pte_none(pte_t pte)		{ return !pte_val(pte); }
 extern inline int pte_present(pte_t pte)	{ return pte_val(pte) & _PAGE_VALID; }
@@ -256,10 +256,10 @@ extern inline int pmd_bad(pmd_t pmd)		{ return (pmd_val(pmd) & ~_PFN_MASK) != _P
 extern inline int pmd_present(pmd_t pmd)	{ return pmd_val(pmd) & _PAGE_VALID; }
 extern inline void pmd_clear(pmd_t * pmdp)	{ pmd_val(*pmdp) = 0; }
 
-extern inline int pgd_none(pgd_t pgd)		{ return !pgd_val(pgd); }
-extern inline int pgd_bad(pgd_t pgd)		{ return (pgd_val(pgd) & ~_PFN_MASK) != _PAGE_TABLE; }
-extern inline int pgd_present(pgd_t pgd)	{ return pgd_val(pgd) & _PAGE_VALID; }
-extern inline void pgd_clear(pgd_t * pgdp)	{ pgd_val(*pgdp) = 0; }
+extern inline int pud_none(pud_t pud)		{ return !pud_val(pud); }
+extern inline int pud_bad(pud_t pud)		{ return (pud_val(pud) & ~_PFN_MASK) != _PAGE_TABLE; }
+extern inline int pud_present(pud_t pud)	{ return pud_val(pud) & _PAGE_VALID; }
+extern inline void pud_clear(pud_t * pudp)	{ pud_val(*pudp) = 0; }
 
 /*
  * The following only work if pte_present() is true.
@@ -301,9 +301,9 @@ extern inline pte_t pte_mkspecial(pte_t pte)	{ return pte; }
  */
 
 /* Find an entry in the second-level page table.. */
-extern inline pmd_t * pmd_offset(pgd_t * dir, unsigned long address)
+extern inline pmd_t * pmd_offset(pud_t * dir, unsigned long address)
 {
-	pmd_t *ret = (pmd_t *) pgd_page_vaddr(*dir) + ((address >> PMD_SHIFT) & (PTRS_PER_PAGE - 1));
+	pmd_t *ret = (pmd_t *) pud_page_vaddr(*dir) + ((address >> PMD_SHIFT) & (PTRS_PER_PAGE - 1));
 	smp_read_barrier_depends(); /* see above */
 	return ret;
 }

arch/alpha/mm/init.c

@@ -146,6 +146,8 @@ callback_init(void * kernel_end)
 {
 	struct crb_struct * crb;
 	pgd_t *pgd;
+	p4d_t *p4d;
+	pud_t *pud;
 	pmd_t *pmd;
 	void *two_pages;
 
@@ -184,8 +186,10 @@ callback_init(void * kernel_end)
 	memset(two_pages, 0, 2*PAGE_SIZE);
 
 	pgd = pgd_offset_k(VMALLOC_START);
-	pgd_set(pgd, (pmd_t *)two_pages);
-	pmd = pmd_offset(pgd, VMALLOC_START);
+	p4d = p4d_offset(pgd, VMALLOC_START);
+	pud = pud_offset(p4d, VMALLOC_START);
+	pud_set(pud, (pmd_t *)two_pages);
+	pmd = pmd_offset(pud, VMALLOC_START);
 	pmd_set(pmd, (pte_t *)(two_pages + PAGE_SIZE));
 
 	if (alpha_using_srm) {
@@ -214,9 +218,9 @@ callback_init(void * kernel_end)
 				/* Newer consoles (especially on larger
 				   systems) may require more pages of
 				   PTEs. Grab additional pages as needed. */
-				if (pmd != pmd_offset(pgd, vaddr)) {
+				if (pmd != pmd_offset(pud, vaddr)) {
 					memset(kernel_end, 0, PAGE_SIZE);
-					pmd = pmd_offset(pgd, vaddr);
+					pmd = pmd_offset(pud, vaddr);
 					pmd_set(pmd, (pte_t *)kernel_end);
 					kernel_end += PAGE_SIZE;
 				}