[PATCH] 8/8 Create MMU 2/3 level accessors in the sub-arch layer(i386)

From: Zachary Amsden
Date: Sat Aug 06 2005 - 02:32:27 EST


i386 Transparent paravirtualization sub-arch patch #8.

Transparent paravirtualization support for MMU operations.

All operations which update live page table entries have been moved to the
sub-architecture layer. Unfortunately, this required yet another parallel set
of pgtable-Nlevel-ops.h files, but this avoids the ugliness of having to use
#ifdef's all of the code.

This is pure code motion. Anything else would be a bug.

Signed-off-by: Zachary Amsden <zach@xxxxxxxxxx>
Index: linux-2.6.13/include/asm-i386/pgtable-2level.h
===================================================================
--- linux-2.6.13.orig/include/asm-i386/pgtable-2level.h 2005-08-04 13:42:31.000000000 -0700
+++ linux-2.6.13/include/asm-i386/pgtable-2level.h 2005-08-04 14:02:16.000000000 -0700
@@ -8,17 +8,6 @@
#define pgd_ERROR(e) \
printk("%s:%d: bad pgd %08lx.\n", __FILE__, __LINE__, pgd_val(e))

-/*
- * Certain architectures need to do special things when PTEs
- * within a page table are directly modified. Thus, the following
- * hook is made available.
- */
-#define set_pte(pteptr, pteval) (*(pteptr) = pteval)
-#define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)
-#define set_pte_atomic(pteptr, pteval) set_pte(pteptr,pteval)
-#define set_pmd(pmdptr, pmdval) (*(pmdptr) = (pmdval))
-
-#define ptep_get_and_clear(mm,addr,xp) __pte(xchg(&(xp)->pte_low, 0))
#define pte_same(a, b) ((a).pte_low == (b).pte_low)
#define pte_page(x) pfn_to_page(pte_pfn(x))
#define pte_none(x) (!(x).pte_low)
Index: linux-2.6.13/include/asm-i386/pgtable-3level.h
===================================================================
--- linux-2.6.13.orig/include/asm-i386/pgtable-3level.h 2005-08-04 13:42:31.000000000 -0700
+++ linux-2.6.13/include/asm-i386/pgtable-3level.h 2005-08-04 14:02:16.000000000 -0700
@@ -44,28 +44,6 @@
return pte_x(pte);
}

-/* Rules for using set_pte: the pte being assigned *must* be
- * either not present or in a state where the hardware will
- * not attempt to update the pte. In places where this is
- * not possible, use pte_get_and_clear to obtain the old pte
- * value and then use set_pte to update it. -ben
- */
-static inline void set_pte(pte_t *ptep, pte_t pte)
-{
- ptep->pte_high = pte.pte_high;
- smp_wmb();
- ptep->pte_low = pte.pte_low;
-}
-#define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)
-
-#define __HAVE_ARCH_SET_PTE_ATOMIC
-#define set_pte_atomic(pteptr,pteval) \
- set_64bit((unsigned long long *)(pteptr),pte_val(pteval))
-#define set_pmd(pmdptr,pmdval) \
- set_64bit((unsigned long long *)(pmdptr),pmd_val(pmdval))
-#define set_pud(pudptr,pudval) \
- (*(pudptr) = (pudval))
-
/*
* Pentium-II erratum A13: in PAE mode we explicitly have to flush
* the TLB via cr3 if the top-level pgd is changed...
@@ -90,18 +68,6 @@
#define pmd_offset(pud, address) ((pmd_t *) pud_page(*(pud)) + \
pmd_index(address))

-static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
-{
- pte_t res;
-
- /* xchg acts as a barrier before the setting of the high bits */
- res.pte_low = xchg(&ptep->pte_low, 0);
- res.pte_high = ptep->pte_high;
- ptep->pte_high = 0;
-
- return res;
-}
-
static inline int pte_same(pte_t a, pte_t b)
{
return a.pte_low == b.pte_low && a.pte_high == b.pte_high;
Index: linux-2.6.13/include/asm-i386/pgtable.h
===================================================================
--- linux-2.6.13.orig/include/asm-i386/pgtable.h 2005-08-04 13:47:07.000000000 -0700
+++ linux-2.6.13/include/asm-i386/pgtable.h 2005-08-04 14:02:29.000000000 -0700
@@ -201,11 +201,9 @@
extern unsigned long pg0[];

#define pte_present(x) ((x).pte_low & (_PAGE_PRESENT | _PAGE_PROTNONE))
-#define pte_clear(mm,addr,xp) do { set_pte_at(mm, addr, xp, __pte(0)); } while (0)

#define pmd_none(x) (!pmd_val(x))
#define pmd_present(x) (pmd_val(x) & _PAGE_PRESENT)
-#define pmd_clear(xp) do { set_pmd(xp, __pmd(0)); } while (0)
#define pmd_bad(x) ((pmd_val(x) & (~PAGE_MASK & ~_PAGE_USER)) != _KERNPG_TABLE)


@@ -243,20 +241,12 @@
#else
# include <asm/pgtable-2level.h>
#endif
+#include <pgtable-ops.h>
+
+#define set_pte_at(mm,addr,pteptr,pteval) set_pte(pteptr,pteval)

-static inline int ptep_test_and_clear_dirty(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep)
-{
- if (!pte_dirty(*ptep))
- return 0;
- return test_and_clear_bit(_PAGE_BIT_DIRTY, &ptep->pte_low);
-}
-
-static inline int ptep_test_and_clear_young(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep)
-{
- if (!pte_young(*ptep))
- return 0;
- return test_and_clear_bit(_PAGE_BIT_ACCESSED, &ptep->pte_low);
-}
+#define pte_clear(mm,addr,xp) do { set_pte_at(mm, addr, xp, __pte(0)); } while (0)
+#define pmd_clear(xp) do { set_pmd(xp, __pmd(0)); } while (0)

static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm, unsigned long addr, pte_t *ptep, int full)
{
@@ -270,26 +260,6 @@
return pte;
}

-static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
-{
- clear_bit(_PAGE_BIT_RW, &ptep->pte_low);
-}
-
-/*
- * clone_pgd_range(pgd_t *dst, pgd_t *src, int count);
- *
- * dst - pointer to pgd range anwhere on a pgd page
- * src - ""
- * count - the number of pgds to copy.
- *
- * dst and src can be on the same page, but the range must not overlap,
- * and must not cross a page boundary.
- */
-static inline void clone_pgd_range(pgd_t *dst, pgd_t *src, int count)
-{
- memcpy(dst, src, count * sizeof(pgd_t));
-}
-
/*
* Macro to mark a page protection value as "uncacheable". On processors which do not support
* it, this is a no-op.
@@ -414,14 +384,6 @@
* bit at the same time.
*/
#define update_mmu_cache(vma,address,pte) do { } while (0)
-#define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
-#define ptep_set_access_flags(__vma, __address, __ptep, __entry, __dirty) \
- do { \
- if (__dirty) { \
- (__ptep)->pte_low = (__entry).pte_low; \
- flush_tlb_page(__vma, __address); \
- } \
- } while (0)

#endif /* !__ASSEMBLY__ */

Index: linux-2.6.13/include/asm-i386/mach-default/pgtable-2level-ops.h
===================================================================
--- linux-2.6.13.orig/include/asm-i386/mach-default/pgtable-2level-ops.h 2005-08-04 14:02:04.000000000 -0700
+++ linux-2.6.13/include/asm-i386/mach-default/pgtable-2level-ops.h 2005-08-04 14:02:16.000000000 -0700
@@ -0,0 +1,15 @@
+#ifndef _MACH_PGTABLE_LEVEL_OPS_H
+#define _MACH_PGTABLE_LEVEL_OPS_H
+
+/*
+ * Certain architectures need to do special things when PTEs
+ * within a page table are directly modified. Thus, the following
+ * hook is made available.
+ */
+#define set_pte(pteptr, pteval) (*(pteptr) = pteval)
+#define set_pte_atomic(pteptr, pteval) set_pte(pteptr,pteval)
+#define set_pmd(pmdptr, pmdval) (*(pmdptr) = (pmdval))
+
+#define ptep_get_and_clear(mm,addr,xp) __pte(xchg(&(xp)->pte_low, 0))
+
+#endif /* _PGTABLE_OPS_H */
Index: linux-2.6.13/include/asm-i386/mach-default/pgtable-3level-ops.h
===================================================================
--- linux-2.6.13.orig/include/asm-i386/mach-default/pgtable-3level-ops.h 2005-08-04 14:02:04.000000000 -0700
+++ linux-2.6.13/include/asm-i386/mach-default/pgtable-3level-ops.h 2005-08-04 14:02:16.000000000 -0700
@@ -0,0 +1,37 @@
+#ifndef _MACH_PGTABLE_LEVEL_OPS_H
+#define _MACH_PGTABLE_LEVEL_OPS_H
+
+/* Rules for using set_pte: the pte being assigned *must* be
+ * either not present or in a state where the hardware will
+ * not attempt to update the pte. In places where this is
+ * not possible, use pte_get_and_clear to obtain the old pte
+ * value and then use set_pte to update it. -ben
+ */
+static inline void set_pte(pte_t *ptep, pte_t pte)
+{
+ ptep->pte_high = pte.pte_high;
+ smp_wmb();
+ ptep->pte_low = pte.pte_low;
+}
+
+#define __HAVE_ARCH_SET_PTE_ATOMIC
+#define set_pte_atomic(pteptr,pteval) \
+ set_64bit((unsigned long long *)(pteptr),pte_val(pteval))
+#define set_pmd(pmdptr,pmdval) \
+ set_64bit((unsigned long long *)(pmdptr),pmd_val(pmdval))
+#define set_pud(pudptr,pudval) \
+ (*(pudptr) = (pudval))
+
+static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
+{
+ pte_t res;
+
+ /* xchg acts as a barrier before the setting of the high bits */
+ res.pte_low = xchg(&ptep->pte_low, 0);
+ res.pte_high = ptep->pte_high;
+ ptep->pte_high = 0;
+
+ return res;
+}
+
+#endif
Index: linux-2.6.13/include/asm-i386/mach-default/pgtable-ops.h
===================================================================
--- linux-2.6.13.orig/include/asm-i386/mach-default/pgtable-ops.h 2005-08-04 14:02:04.000000000 -0700
+++ linux-2.6.13/include/asm-i386/mach-default/pgtable-ops.h 2005-08-04 14:02:44.000000000 -0700
@@ -0,0 +1,77 @@
+/*
+ * Copyright (C) 2005, VMware, Inc.
+ *
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ * NON INFRINGEMENT. See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * Send feedback to zach@xxxxxxxxxx
+ *
+ */
+
+#ifndef _PGTABLE_OPS_H
+#define _PGTABLE_OPS_H
+
+#ifdef CONFIG_X86_PAE
+# include <pgtable-3level-ops.h>
+#else
+# include <pgtable-2level-ops.h>
+#endif
+
+static inline int ptep_test_and_clear_dirty(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep)
+{
+ if (!pte_dirty(*ptep))
+ return 0;
+ return test_and_clear_bit(_PAGE_BIT_DIRTY, &ptep->pte_low);
+}
+
+static inline int ptep_test_and_clear_young(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep)
+{
+ if (!pte_young(*ptep))
+ return 0;
+ return test_and_clear_bit(_PAGE_BIT_ACCESSED, &ptep->pte_low);
+}
+
+static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
+{
+ clear_bit(_PAGE_BIT_RW, &ptep->pte_low);
+}
+
+/*
+ * clone_pgd_range(pgd_t *dst, pgd_t *src, int count);
+ *
+ * dst - pointer to pgd range anwhere on a pgd page
+ * src - ""
+ * count - the number of pgds to copy.
+ *
+ * dst and src can be on the same page, but the range must not overlap,
+ * and must not cross a page boundary.
+ */
+static inline void clone_pgd_range(pgd_t *dst, pgd_t *src, int count)
+{
+ memcpy(dst, src, count * sizeof(pgd_t));
+}
+
+#define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
+#define ptep_set_access_flags(__vma, __address, __ptep, __entry, __dirty) \
+ do { \
+ if (__dirty) { \
+ (__ptep)->pte_low = (__entry).pte_low; \
+ flush_tlb_page(__vma, __address); \
+ } \
+ } while (0)
+
+#endif /* _PGTABLE_OPS_H */