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Message-Id: <20060826174253.14790.47973.stgit@memento.home.lan>
Date: Sat, 26 Aug 2006 19:42:53 +0200
From: Paolo 'Blaisorblade' Giarrusso <blaisorblade@...oo.it>
To: Andrew Morton <akpm@...l.org>
Cc: linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: [PATCH RFP-V4 13/13] RFP prot support: uml, i386, x64 bits
From: Paolo 'Blaisorblade' Giarrusso <blaisorblade@...oo.it>, Ingo Molnar <mingo@...e.hu>
Various boilerplate stuff.
Update pte encoding macros for UML, i386 and x86-64.
*) remap_file_pages protection support: improvement for UML bits
Recover one bit by additionally using _PAGE_NEWPROT. Since I wasn't sure this
would work, I've split this out, but it has worked well. We rely on the fact
that pte_newprot always checks first if the PTE is marked present. This is
joined because it worked well during the unit testing I performed, beyond
making sense.
========
RFP: Avoid using _PAGE_PROTNONE
For i386, x86_64, uml:
To encode a pte_file PROTNONE pte, since _PAGE_PROTNONE makes pte_present be
set, and since such a pte actually still references a page, we need to use
another bit for our purposes. Implement this.
* Add _PAGE_FILE_PROTNONE, the bit describe above.
* Add to each arch pgprot_access_bits() to extract the value of protection bits
(i.e._PAGE_RW and _PAGE_PROTNONE) and encode them (translate _PAGE_PROTNONE to
_PAGE_FILE_PROTNONE), and use it in pgoff_prot_to_pte().
* Modify pte_to_pgprot() to do the inverse translation.
* Modify pte_to_pgoff() and pgoff_prot_to_pte() to leave alone the newly used
bit (for 32-bit PTEs).
* Join for UML and x86 pte_to_pgprot() for 2level and 3level page tables, since
they were identical.
* Decrease by 1 PTE_FILE_MAX_BITS where appropriate.
* Also replace in bit operations + with | where appropriate.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@...oo.it>
---
include/asm-i386/pgtable-2level.h | 11 ++++++-----
include/asm-i386/pgtable-3level.h | 7 +++++--
include/asm-i386/pgtable.h | 24 ++++++++++++++++++++++++
include/asm-um/pgtable-2level.h | 16 ++++++++++++----
include/asm-um/pgtable-3level.h | 21 ++++++++++++++-------
include/asm-um/pgtable.h | 21 +++++++++++++++++++++
include/asm-x86_64/pgtable.h | 29 +++++++++++++++++++++++++++--
7 files changed, 109 insertions(+), 20 deletions(-)
diff --git a/include/asm-i386/pgtable-2level.h b/include/asm-i386/pgtable-2level.h
index 2756d4b..01b7652 100644
--- a/include/asm-i386/pgtable-2level.h
+++ b/include/asm-i386/pgtable-2level.h
@@ -46,16 +46,17 @@ static inline int pte_exec_kernel(pte_t
}
/*
- * Bits 0, 6 and 7 are taken, split up the 29 bits of offset
+ * Bits 0, 1, 6, 7 and 8 are taken, split up the 27 bits of offset
* into this range:
*/
-#define PTE_FILE_MAX_BITS 29
+#define PTE_FILE_MAX_BITS 27
#define pte_to_pgoff(pte) \
- ((((pte).pte_low >> 1) & 0x1f ) + (((pte).pte_low >> 8) << 5 ))
+ ((((pte).pte_low >> 2) & 0xf ) | (((pte).pte_low >> 9) << 4 ))
-#define pgoff_to_pte(off) \
- ((pte_t) { (((off) & 0x1f) << 1) + (((off) >> 5) << 8) + _PAGE_FILE })
+#define pgoff_prot_to_pte(off, prot) \
+ ((pte_t) { (((off) & 0xf) << 2) | (((off) >> 4) << 9) | \
+ pgprot_access_bits(prot) | _PAGE_FILE })
/* Encode and de-code a swap entry */
#define __swp_type(x) (((x).val >> 1) & 0x1f)
diff --git a/include/asm-i386/pgtable-3level.h b/include/asm-i386/pgtable-3level.h
index dccb1b3..8231017 100644
--- a/include/asm-i386/pgtable-3level.h
+++ b/include/asm-i386/pgtable-3level.h
@@ -156,11 +156,14 @@ static inline pmd_t pfn_pmd(unsigned lon
}
/*
- * Bits 0, 6 and 7 are taken in the low part of the pte,
+ * Bits 0, 1, 6, 7 and 8 are taken in the low part of the pte,
* put the 32 bits of offset into the high part.
*/
#define pte_to_pgoff(pte) ((pte).pte_high)
-#define pgoff_to_pte(off) ((pte_t) { _PAGE_FILE, (off) })
+
+#define pgoff_prot_to_pte(off, prot) \
+ ((pte_t) { _PAGE_FILE | pgprot_access_bits(prot), (off) })
+
#define PTE_FILE_MAX_BITS 32
/* Encode and de-code a swap entry */
diff --git a/include/asm-i386/pgtable.h b/include/asm-i386/pgtable.h
index 09697fe..2661088 100644
--- a/include/asm-i386/pgtable.h
+++ b/include/asm-i386/pgtable.h
@@ -14,6 +14,7 @@ #define _I386_PGTABLE_H
#ifndef __ASSEMBLY__
#include <asm/processor.h>
#include <asm/fixmap.h>
+#include <linux/bitops.h>
#include <linux/threads.h>
#ifndef _I386_BITOPS_H
@@ -99,8 +100,10 @@ #define _PAGE_BIT_PWT 3
#define _PAGE_BIT_PCD 4
#define _PAGE_BIT_ACCESSED 5
#define _PAGE_BIT_DIRTY 6
+#define _PAGE_BIT_PROTNONE 6
#define _PAGE_BIT_PSE 7 /* 4 MB (or 2MB) page, Pentium+, if present.. */
#define _PAGE_BIT_GLOBAL 8 /* Global TLB entry PPro+ */
+#define _PAGE_BIT_FILE_PROTNONE 8
#define _PAGE_BIT_UNUSED1 9 /* available for programmer */
#define _PAGE_BIT_UNUSED2 10
#define _PAGE_BIT_UNUSED3 11
@@ -123,6 +126,26 @@ #define _PAGE_UNUSED3 0x800
#define _PAGE_FILE 0x040 /* nonlinear file mapping, saved PTE; unset:swap */
#define _PAGE_PROTNONE 0x080 /* if the user mapped it with PROT_NONE;
pte_present gives true */
+#define _PAGE_FILE_PROTNONE 0x100 /* indicate that the page is remapped
+ with PROT_NONE - this is different
+ from _PAGE_PROTNONE as no page is
+ held here, so pte_present() is false
+ */
+
+/* Extracts _PAGE_RW and _PAGE_PROTNONE and replace the latter with
+ * _PAGE_FILE_PROTNONE. */
+#define pgprot_access_bits(prot) \
+ ((pgprot_val(prot) & _PAGE_RW) | \
+ bitmask_trans(pgprot_val(prot), _PAGE_PROTNONE, _PAGE_FILE_PROTNONE))
+
+#define pte_to_pgprot(pte) \
+ __pgprot(((pte).pte_low & (_PAGE_RW|_PAGE_PROTNONE)))
+
+#define pte_file_to_pgprot(pte) \
+ __pgprot(((pte).pte_low & _PAGE_RW) | _PAGE_ACCESSED | \
+ (((pte).pte_low & _PAGE_FILE_PROTNONE) ? _PAGE_PROTNONE : \
+ (_PAGE_USER | _PAGE_PRESENT)))
+
#ifdef CONFIG_X86_PAE
#define _PAGE_NX (1ULL<<_PAGE_BIT_NX)
#else
@@ -447,6 +470,7 @@ #define __HAVE_ARCH_PTEP_GET_AND_CLEAR
#define __HAVE_ARCH_PTEP_GET_AND_CLEAR_FULL
#define __HAVE_ARCH_PTEP_SET_WRPROTECT
#define __HAVE_ARCH_PTE_SAME
+#define __HAVE_ARCH_PTE_TO_PGPROT
#include <asm-generic/pgtable.h>
#endif /* _I386_PGTABLE_H */
diff --git a/include/asm-um/pgtable-2level.h b/include/asm-um/pgtable-2level.h
index ffe017f..8066430 100644
--- a/include/asm-um/pgtable-2level.h
+++ b/include/asm-um/pgtable-2level.h
@@ -45,12 +45,20 @@ #define pmd_page_kernel(pmd) \
((unsigned long) __va(pmd_val(pmd) & PAGE_MASK))
/*
- * Bits 0 through 3 are taken
+ * Bits 0, 1, 3 to 5 and 8 are taken, split up the 26 bits of offset
+ * into this range:
*/
-#define PTE_FILE_MAX_BITS 28
+#define PTE_FILE_MAX_BITS 26
-#define pte_to_pgoff(pte) (pte_val(pte) >> 4)
+#define pte_to_pgoff(pte) (((pte_val(pte) >> 2) & 0x1) | \
+ (((pte_val(pte) >> 6) & 0x3) << 1) | \
+ ((pte_val(pte) >> 9) << 3))
-#define pgoff_to_pte(off) ((pte_t) { ((off) << 4) + _PAGE_FILE })
+#define pgoff_prot_to_pte(off, prot) \
+ __pte((((off) & 0x1) << 2) | ((((off) & 0x7) >> 1) << 6) | \
+ ((off >> 3) << 9) | pgprot_access_bits(prot) | _PAGE_FILE)
+
+/* For pte_file_to_pgprot definition only */
+#define __pte_low(pte) pte_val(pte)
#endif
diff --git a/include/asm-um/pgtable-3level.h b/include/asm-um/pgtable-3level.h
index 786c257..8b2fdb3 100644
--- a/include/asm-um/pgtable-3level.h
+++ b/include/asm-um/pgtable-3level.h
@@ -101,25 +101,32 @@ static inline pmd_t pfn_pmd(pfn_t page_n
}
/*
- * Bits 0 through 3 are taken in the low part of the pte,
+ * Bits 0 through 5 are taken in the low part of the pte,
* put the 32 bits of offset into the high part.
*/
#define PTE_FILE_MAX_BITS 32
-#ifdef CONFIG_64BIT
-#define pte_to_pgoff(p) ((p).pte >> 32)
+#ifdef CONFIG_64BIT
-#define pgoff_to_pte(off) ((pte_t) { ((off) << 32) | _PAGE_FILE })
+/* For pte_file_to_pgprot definition only */
+#define __pte_low(pte) pte_val(pte)
+#define __pte_high(pte) (pte_val(pte) >> 32)
+#define __build_pte(low, high) ((pte_t) { (high) << 32 | (low)})
#else
-#define pte_to_pgoff(pte) ((pte).pte_high)
-
-#define pgoff_to_pte(off) ((pte_t) { _PAGE_FILE, (off) })
+/* Don't use pte_val below, useless to join the two halves */
+#define __pte_low(pte) ((pte).pte_low)
+#define __pte_high(pte) ((pte).pte_high)
+#define __build_pte(low, high) ((pte_t) {(low), (high)})
#endif
+#define pte_to_pgoff(pte) __pte_high(pte)
+#define pgoff_prot_to_pte(off, prot) \
+ __build_pte(_PAGE_FILE | pgprot_access_bits(prot), (off))
+
#endif
/*
diff --git a/include/asm-um/pgtable.h b/include/asm-um/pgtable.h
index ac64eb9..2cea58f 100644
--- a/include/asm-um/pgtable.h
+++ b/include/asm-um/pgtable.h
@@ -10,6 +10,7 @@ #define __UM_PGTABLE_H
#include "linux/sched.h"
#include "linux/linkage.h"
+#include "linux/bitops.h"
#include "asm/processor.h"
#include "asm/page.h"
#include "asm/fixmap.h"
@@ -25,6 +26,17 @@ #define _PAGE_DIRTY 0x100
#define _PAGE_FILE 0x008 /* nonlinear file mapping, saved PTE; unset:swap */
#define _PAGE_PROTNONE 0x010 /* if the user mapped it with PROT_NONE;
pte_present gives true */
+#define _PAGE_FILE_PROTNONE 0x100 /* indicate that the page is remapped
+ with PROT_NONE - this is different
+ from _PAGE_PROTNONE as no page is
+ held here, so pte_present() is false
+ */
+
+/* Extracts _PAGE_RW and _PAGE_PROTNONE and replace the latter with
+ * _PAGE_FILE_PROTNONE. */
+#define pgprot_access_bits(prot) \
+ ((pgprot_val(prot) & _PAGE_RW) | \
+ bitmask_trans(pgprot_val(prot), _PAGE_PROTNONE, _PAGE_FILE_PROTNONE))
#ifdef CONFIG_3_LEVEL_PGTABLES
#include "asm/pgtable-3level.h"
@@ -32,6 +44,14 @@ #else
#include "asm/pgtable-2level.h"
#endif
+#define pte_to_pgprot(pte) \
+ __pgprot((__pte_low(pte) & (_PAGE_RW|_PAGE_PROTNONE)))
+
+#define pte_file_to_pgprot(pte) \
+ __pgprot((__pte_low(pte) & _PAGE_RW) | _PAGE_ACCESSED | \
+ ((__pte_low(pte) & _PAGE_FILE_PROTNONE) ? _PAGE_PROTNONE : \
+ (_PAGE_USER | _PAGE_PRESENT)))
+
extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
extern void *um_virt_to_phys(struct task_struct *task, unsigned long virt,
@@ -410,6 +430,7 @@ #define __swp_entry_to_pte(x) ((pte_t)
#define kern_addr_valid(addr) (1)
+#define __HAVE_ARCH_PTE_TO_PGPROT
#include <asm-generic/pgtable.h>
#include <asm-generic/pgtable-nopud.h>
diff --git a/include/asm-x86_64/pgtable.h b/include/asm-x86_64/pgtable.h
index a31ab4e..566bef7 100644
--- a/include/asm-x86_64/pgtable.h
+++ b/include/asm-x86_64/pgtable.h
@@ -7,7 +7,7 @@ #define _X86_64_PGTABLE_H
*/
#include <asm/processor.h>
#include <asm/fixmap.h>
-#include <asm/bitops.h>
+#include <linux/bitops.h>
#include <linux/threads.h>
#include <asm/pda.h>
@@ -151,6 +151,7 @@ #define _PAGE_BIT_ACCESSED 5
#define _PAGE_BIT_DIRTY 6
#define _PAGE_BIT_PSE 7 /* 4 MB (or 2MB) page */
#define _PAGE_BIT_GLOBAL 8 /* Global TLB entry PPro+ */
+#define _PAGE_BIT_FILE_PROTNONE 8
#define _PAGE_BIT_NX 63 /* No execute: only valid after cpuid check */
#define _PAGE_PRESENT 0x001
@@ -165,6 +166,12 @@ #define _PAGE_FILE 0x040 /* nonlinear fi
#define _PAGE_GLOBAL 0x100 /* Global TLB entry */
#define _PAGE_PROTNONE 0x080 /* If not present */
+#define _PAGE_FILE_PROTNONE 0x100 /* indicate that the page is remapped
+ with PROT_NONE - this is different
+ from _PAGE_PROTNONE as no page is
+ held here, so pte_present() is false
+ */
+
#define _PAGE_NX (1UL<<_PAGE_BIT_NX)
#define _PAGE_TABLE (_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | _PAGE_ACCESSED | _PAGE_DIRTY)
@@ -354,9 +361,26 @@ #define pfn_pmd(nr,prot) (__pmd(((nr) <<
#define pmd_pfn(x) ((pmd_val(x) & __PHYSICAL_MASK) >> PAGE_SHIFT)
#define pte_to_pgoff(pte) ((pte_val(pte) & PHYSICAL_PAGE_MASK) >> PAGE_SHIFT)
-#define pgoff_to_pte(off) ((pte_t) { ((off) << PAGE_SHIFT) | _PAGE_FILE })
#define PTE_FILE_MAX_BITS __PHYSICAL_MASK_SHIFT
+#define pte_to_pgprot(pte) \
+ __pgprot((pte_val(pte) & (_PAGE_RW|_PAGE_PROTNONE)))
+
+#define pte_file_to_pgprot(pte) \
+ __pgprot((pte_val(pte) & _PAGE_RW) | _PAGE_ACCESSED | \
+ ((pte_val(pte) & _PAGE_FILE_PROTNONE) ? _PAGE_PROTNONE : \
+ (_PAGE_USER | _PAGE_PRESENT)))
+
+/* Extracts _PAGE_RW and _PAGE_PROTNONE and replace the latter with
+ * _PAGE_FILE_PROTNONE. */
+#define pgprot_access_bits(prot) \
+ ((pgprot_val(prot) & _PAGE_RW) | \
+ bitmask_trans(pgprot_val(prot), _PAGE_PROTNONE, _PAGE_FILE_PROTNONE))
+
+#define pgoff_prot_to_pte(off, prot) \
+ ((pte_t) { _PAGE_FILE | pgprot_access_bits(prot) | ((off) << PAGE_SHIFT) })
+
+
/* PTE - Level 1 access. */
/* page, protection -> pte */
@@ -448,6 +472,7 @@ #define __HAVE_ARCH_PTEP_GET_AND_CLEAR
#define __HAVE_ARCH_PTEP_GET_AND_CLEAR_FULL
#define __HAVE_ARCH_PTEP_SET_WRPROTECT
#define __HAVE_ARCH_PTE_SAME
+#define __HAVE_ARCH_PTE_TO_PGPROT
#include <asm-generic/pgtable.h>
#endif /* _X86_64_PGTABLE_H */
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