Commit e19f97ed authored by Mike Rapoport's avatar Mike Rapoport Committed by Linus Torvalds
Browse files

um: add support for folded p4d page tables 

The UML port uses 4 and 5 level fixups to support higher level page
table directories in the generic VM code.

Implement primitives necessary for the 4th level folding, add walks of
p4d level where appropriate and drop usage of __ARCH_USE_5LEVEL_HACK.

Link: http://lkml.kernel.org/r/1572938135-31886-13-git-send-email-rppt@kernel.org


Signed-off-by: default avatarMike Rapoport <rppt@linux.ibm.com>
Cc: Anatoly Pugachev <matorola@gmail.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: Russell King <rmk+kernel@armlinux.org.uk>
Cc: Sam Creasey <sammy@sammy.net>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Vineet Gupta <Vineet.Gupta1@synopsys.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 4e65e76f

arch/um/include/asm/pgtable-2level.h

+0 −1
Original line number Diff line number Diff line
@@ -8,7 +8,6 @@ 
#ifndef __UM_PGTABLE_2LEVEL_H

#define __UM_PGTABLE_2LEVEL_H



#define __ARCH_USE_5LEVEL_HACK

#include <asm-generic/pgtable-nopmd.h>



/* PGDIR_SHIFT determines what a third-level page table entry can map */

arch/um/include/asm/pgtable-3level.h

+0 −1
Original line number Diff line number Diff line
@@ -7,7 +7,6 @@ 
#ifndef __UM_PGTABLE_3LEVEL_H

#define __UM_PGTABLE_3LEVEL_H



#define __ARCH_USE_5LEVEL_HACK

#include <asm-generic/pgtable-nopud.h>



/* PGDIR_SHIFT determines what a third-level page table entry can map */

arch/um/include/asm/pgtable.h

+3 −0
Original line number Diff line number Diff line
@@ -106,6 +106,9 @@ extern unsigned long end_iomem; 
#define pud_newpage(x)  (pud_val(x) & _PAGE_NEWPAGE)

#define pud_mkuptodate(x) (pud_val(x) &= ~_PAGE_NEWPAGE)



#define p4d_newpage(x)  (p4d_val(x) & _PAGE_NEWPAGE)

#define p4d_mkuptodate(x) (p4d_val(x) &= ~_PAGE_NEWPAGE)



#define pmd_page(pmd) phys_to_page(pmd_val(pmd) & PAGE_MASK)



#define pte_page(x) pfn_to_page(pte_pfn(x))

arch/um/kernel/mem.c

+6 −2
Original line number Diff line number Diff line
@@ -96,6 +96,7 @@ static void __init fixrange_init(unsigned long start, unsigned long end, 
				 pgd_t *pgd_base)

{

	pgd_t *pgd;

	p4d_t *p4d;

	pud_t *pud;

	pmd_t *pmd;

	int i, j;
@@ -107,7 +108,8 @@ static void __init fixrange_init(unsigned long start, unsigned long end, 
	pgd = pgd_base + i;



	for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) {

		pud = pud_offset(pgd, vaddr);

		p4d = p4d_offset(pgd, vaddr);

		pud = pud_offset(p4d, vaddr);

		if (pud_none(*pud))

			one_md_table_init(pud);

		pmd = pmd_offset(pud, vaddr);
@@ -124,6 +126,7 @@ static void __init fixaddr_user_init( void) 
#ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA

	long size = FIXADDR_USER_END - FIXADDR_USER_START;

	pgd_t *pgd;

	p4d_t *p4d;

	pud_t *pud;

	pmd_t *pmd;

	pte_t *pte;
@@ -144,7 +147,8 @@ static void __init fixaddr_user_init( void) 
	for ( ; size > 0; size -= PAGE_SIZE, vaddr += PAGE_SIZE,

		      p += PAGE_SIZE) {

		pgd = swapper_pg_dir + pgd_index(vaddr);

		pud = pud_offset(pgd, vaddr);

		p4d = p4d_offset(pgd, vaddr);

		pud = pud_offset(p4d, vaddr);

		pmd = pmd_offset(pud, vaddr);

		pte = pte_offset_kernel(pmd, vaddr);

		pte_set_val(*pte, p, PAGE_READONLY);

arch/um/kernel/skas/mmu.c

+10 −2
Original line number Diff line number Diff line
@@ -19,15 +19,21 @@ static int init_stub_pte(struct mm_struct *mm, unsigned long proc, 
			 unsigned long kernel)

{

	pgd_t *pgd;

	p4d_t *p4d;

	pud_t *pud;

	pmd_t *pmd;

	pte_t *pte;



	pgd = pgd_offset(mm, proc);

	pud = pud_alloc(mm, pgd, proc);

	if (!pud)



	p4d = p4d_alloc(mm, pgd, proc);

	if (!p4d)

		goto out;



	pud = pud_alloc(mm, p4d, proc);

	if (!pud)

		goto out_pud;



	pmd = pmd_alloc(mm, pud, proc);

	if (!pmd)

		goto out_pmd;
@@ -44,6 +50,8 @@ static int init_stub_pte(struct mm_struct *mm, unsigned long proc, 
	pmd_free(mm, pmd);

 out_pmd:

	pud_free(mm, pud);

 out_pud:

	p4d_free(mm, p4d);

 out:

	return -ENOMEM;

}

CRA Git | Maintained and supported by SUSTech CRA and CCSE