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/1572938135-31886-2-git-send-email-rppt@kernel.org
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Mark Salter <msalter@redhat.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Peter Rosin <peda@axentia.se>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rolf Eike Beer <eike-kernel@sf-tec.de>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sam Creasey <sammy@sammy.net>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Vineet Gupta <Vineet.Gupta1@synopsys.com>
Cc: Anatoly Pugachev <matorola@gmail.com>
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 8 insertions, 4 deletions

diff --git a/arch/alpha/mm/init.c b/arch/alpha/mm/init.c
index e2cbec3789e8..12e218d3792a 100644
--- a/arch/alpha/mm/init.c
+++ b/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;
 				}