[PATCH 0 of 8] x86: use PTE_MASK consistently

[PATCH 0 of 8] x86: use PTE_MASK consistently

[Jeremy Fitzhardinge]

Hi all,

Here's a series to rationalize the use of PTE_MASK and remove some
amount of ad-hocery.

This gist of the series is:
 1. Fix the definition of PTE_MASK so that its equally applicable in
    all pagetable modes
 2. Use it consistently

I haven't tried to address the *_bad() stuff, other than to convert
pmd_bad_* to use PTE_MASK.

I've compile tested it a bit and run it on 32-bit PAE (native and
Xen), but I haven't tested it with >4G memory, non-PAE or 64-bit.  In
other words, it needs some time in Ingo's torture machine.

      J

[PATCH 1 of 8] x86: define PTE_MASK in a universally useful way

[Jeremy Fitzhardinge]

Define PTE_MASK so that it contains a meaningful value for all x86
pagetable configurations.  Previously it was defined as a "long" which
means that it was too short to cover a 32-bit PAE pte entry.

It is now defined as a pteval_t, which is an integer type long enough
to contain a full pte (or pmd, pud, pgd).

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
---
 include/asm-x86/page.h |   13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/include/asm-x86/page.h b/include/asm-x86/page.h
--- a/include/asm-x86/page.h
+++ b/include/asm-x86/page.h
@@ -10,8 +10,13 @@
 
 #ifdef __KERNEL__
 
-#define PHYSICAL_PAGE_MASK	(PAGE_MASK & __PHYSICAL_MASK)
-#define PTE_MASK		(_AT(long, PHYSICAL_PAGE_MASK))
+/* Cast PAGE_MASK to a signed type so that it is sign-extended if
+   virtual addresses are 32-bits but physical addresses are larger
+   (ie, 32-bit PAE). */
+#define PHYSICAL_PAGE_MASK	(((signed long)PAGE_MASK) & __PHYSICAL_MASK)
+
+/* PTE_MASK extracts the PFN from a (pte|pmd|pud|pgd)val_t */
+#define PTE_MASK		((pteval_t)PHYSICAL_PAGE_MASK)
 
 #define PMD_PAGE_SIZE		(_AC(1, UL) << PMD_SHIFT)
 #define PMD_PAGE_MASK		(~(PMD_PAGE_SIZE-1))
@@ -24,8 +29,8 @@
 /* to align the pointer to the (next) page boundary */
 #define PAGE_ALIGN(addr)	(((addr)+PAGE_SIZE-1)&PAGE_MASK)
 
-#define __PHYSICAL_MASK		_AT(phys_addr_t, (_AC(1,ULL) << __PHYSICAL_MASK_SHIFT) - 1)
-#define __VIRTUAL_MASK		((_AC(1,UL) << __VIRTUAL_MASK_SHIFT) - 1)
+#define __PHYSICAL_MASK		((((phys_addr_t)1) << __PHYSICAL_MASK_SHIFT) - 1)
+#define __VIRTUAL_MASK		((1UL << __VIRTUAL_MASK_SHIFT) - 1)
 
 #ifndef __ASSEMBLY__
 #include <linux/types.h>

[PATCH 2 of 8] x86: fix warning on 32-bit non-PAE

[Jeremy Fitzhardinge]

Fix the warning:

include2/asm/pgtable.h: In function `pte_modify':
include2/asm/pgtable.h:290: warning: left shift count >= width of type

On 32-bit PAE the virtual and physical addresses are both 32-bits,
so it ends up evaluating 1<<32.  Do the shift as a 64-bit shift then
cast to the appropriate size.  This should all be done at compile time,
and so have no effect on generated code.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
---
 include/asm-x86/page.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/asm-x86/page.h b/include/asm-x86/page.h
--- a/include/asm-x86/page.h
+++ b/include/asm-x86/page.h
@@ -29,7 +29,7 @@
 /* to align the pointer to the (next) page boundary */
 #define PAGE_ALIGN(addr)	(((addr)+PAGE_SIZE-1)&PAGE_MASK)
 
-#define __PHYSICAL_MASK		((((phys_addr_t)1) << __PHYSICAL_MASK_SHIFT) - 1)
+#define __PHYSICAL_MASK		((phys_addr_t)(1ULL << __PHYSICAL_MASK_SHIFT) - 1)
 #define __VIRTUAL_MASK		((1UL << __VIRTUAL_MASK_SHIFT) - 1)
 
 #ifndef __ASSEMBLY__

[PATCH 3 of 8] x86: rearrange __(VIRTUAL|PHYSICAL)_MASK

[Jeremy Fitzhardinge]

Put the definitions of __(VIRTUAL|PHYSICAL)_MASK before their uses.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
---
 include/asm-x86/page.h |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/asm-x86/page.h b/include/asm-x86/page.h
--- a/include/asm-x86/page.h
+++ b/include/asm-x86/page.h
@@ -9,6 +9,9 @@
 #define PAGE_MASK	(~(PAGE_SIZE-1))
 
 #ifdef __KERNEL__
+
+#define __PHYSICAL_MASK		((phys_addr_t)(1ULL << __PHYSICAL_MASK_SHIFT) - 1)
+#define __VIRTUAL_MASK		((1UL << __VIRTUAL_MASK_SHIFT) - 1)
 
 /* Cast PAGE_MASK to a signed type so that it is sign-extended if
    virtual addresses are 32-bits but physical addresses are larger
@@ -28,9 +31,6 @@
 
 /* to align the pointer to the (next) page boundary */
 #define PAGE_ALIGN(addr)	(((addr)+PAGE_SIZE-1)&PAGE_MASK)
-
-#define __PHYSICAL_MASK		((phys_addr_t)(1ULL << __PHYSICAL_MASK_SHIFT) - 1)
-#define __VIRTUAL_MASK		((1UL << __VIRTUAL_MASK_SHIFT) - 1)
 
 #ifndef __ASSEMBLY__
 #include <linux/types.h>

[PATCH 4 of 8] x86: use PTE_MASK in 32-bit PAE

[Jeremy Fitzhardinge]

Use PTE_MASK in 3-level pagetables (ie, 32-bit PAE).

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
---
 include/asm-x86/pgtable-3level.h |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/asm-x86/pgtable-3level.h b/include/asm-x86/pgtable-3level.h
--- a/include/asm-x86/pgtable-3level.h
+++ b/include/asm-x86/pgtable-3level.h
@@ -120,9 +120,9 @@
 		write_cr3(pgd);
 }
 
-#define pud_page(pud) ((struct page *) __va(pud_val(pud) & PAGE_MASK))
+#define pud_page(pud) ((struct page *) __va(pud_val(pud) & PTE_MASK))
 
-#define pud_page_vaddr(pud) ((unsigned long) __va(pud_val(pud) & PAGE_MASK))
+#define pud_page_vaddr(pud) ((unsigned long) __va(pud_val(pud) & PTE_MASK))
 
 
 /* Find an entry in the second-level page table.. */
@@ -160,7 +160,7 @@
 
 static inline unsigned long pte_pfn(pte_t pte)
 {
-	return (pte_val(pte) & ~_PAGE_NX) >> PAGE_SHIFT;
+	return (pte_val(pte) & PTE_MASK) >> PAGE_SHIFT;
 }
 
 /*

[PATCH 5 of 8] x86: use PTE_MASK in pgtable_32.h

[Jeremy Fitzhardinge]

---
 include/asm-x86/pgtable_32.h |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/asm-x86/pgtable_32.h b/include/asm-x86/pgtable_32.h
--- a/include/asm-x86/pgtable_32.h
+++ b/include/asm-x86/pgtable_32.h
@@ -98,9 +98,9 @@
 extern int pmd_bad(pmd_t pmd);
 
 #define pmd_bad_v1(x)							\
-	(_KERNPG_TABLE != (pmd_val((x)) & ~(PAGE_MASK | _PAGE_USER)))
+	(_KERNPG_TABLE != (pmd_val((x)) & ~(PTE_MASK | _PAGE_USER)))
 #define	pmd_bad_v2(x)							\
-	(_KERNPG_TABLE != (pmd_val((x)) & ~(PAGE_MASK | _PAGE_USER |	\
+	(_KERNPG_TABLE != (pmd_val((x)) & ~(PTE_MASK | _PAGE_USER |	\
 					    _PAGE_PSE | _PAGE_NX)))
 
 #define pages_to_mb(x) ((x) >> (20-PAGE_SHIFT))
@@ -172,7 +172,7 @@
 #define pmd_page(pmd) (pfn_to_page(pmd_val((pmd)) >> PAGE_SHIFT))
 
 #define pmd_page_vaddr(pmd)					\
-	((unsigned long)__va(pmd_val((pmd)) & PAGE_MASK))
+	((unsigned long)__va(pmd_val((pmd)) & PTE_MASK))
 
 #if defined(CONFIG_HIGHPTE)
 #define pte_offset_map(dir, address)					\

Re: [PATCH 5 of 8] x86: use PTE_MASK in pgtable_32.h

[Thomas Gleixner]

On Fri, 9 May 2008, Jeremy Fitzhardinge wrote:

> ---
>  include/asm-x86/pgtable_32.h |    6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/include/asm-x86/pgtable_32.h b/include/asm-x86/pgtable_32.h
> --- a/include/asm-x86/pgtable_32.h
> +++ b/include/asm-x86/pgtable_32.h
> @@ -98,9 +98,9 @@
>  extern int pmd_bad(pmd_t pmd);
>  
>  #define pmd_bad_v1(x)							\
> -	(_KERNPG_TABLE != (pmd_val((x)) & ~(PAGE_MASK | _PAGE_USER)))
> +	(_KERNPG_TABLE != (pmd_val((x)) & ~(PTE_MASK | _PAGE_USER)))
>  #define	pmd_bad_v2(x)							\
> -	(_KERNPG_TABLE != (pmd_val((x)) & ~(PAGE_MASK | _PAGE_USER |	\
> +	(_KERNPG_TABLE != (pmd_val((x)) & ~(PTE_MASK | _PAGE_USER |	\

that's gone from mainline already. Hugh's patch restored the old pmd_bad check.

Thanks,
	tglx

Re: [PATCH 5 of 8] x86: use PTE_MASK in pgtable_32.h

[Jeremy Fitzhardinge]

Thomas Gleixner wrote:
> that's gone from mainline already. Hugh's patch restored the old pmd_bad check.
>   

Here's the rebased patch.

---
 include/asm-x86/pgtable_32.h |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

===================================================================
--- a/include/asm-x86/pgtable_32.h
+++ b/include/asm-x86/pgtable_32.h
@@ -94,7 +94,7 @@
 /* To avoid harmful races, pmd_none(x) should check only the lower when PAE */
 #define pmd_none(x)	(!(unsigned long)pmd_val((x)))
 #define pmd_present(x)	(pmd_val((x)) & _PAGE_PRESENT)
-#define pmd_bad(x) ((pmd_val(x) & (~PAGE_MASK & ~_PAGE_USER)) != _KERNPG_TABLE)
+#define pmd_bad(x) ((pmd_val(x) & (~PTE_MASK & ~_PAGE_USER)) != _KERNPG_TABLE)
 
 #define pages_to_mb(x) ((x) >> (20-PAGE_SHIFT))
 
@@ -165,7 +165,7 @@
 #define pmd_page(pmd) (pfn_to_page(pmd_val((pmd)) >> PAGE_SHIFT))
 
 #define pmd_page_vaddr(pmd)					\
-	((unsigned long)__va(pmd_val((pmd)) & PAGE_MASK))
+	((unsigned long)__va(pmd_val((pmd)) & PTE_MASK))
 
 #if defined(CONFIG_HIGHPTE)
 #define pte_offset_map(dir, address)					\

[PATCH 6 of 8] x86: clarify use of _PAGE_CHG_MASK

[Jeremy Fitzhardinge]

_PAGE_CHG_MASK is defined as the set of bits not updated by
pte_modify(); specifically, the pfn itself, and the Accessed and Dirty
bits (which are updated by hardware).

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
---
 include/asm-x86/pgtable.h |    8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/include/asm-x86/pgtable.h b/include/asm-x86/pgtable.h
--- a/include/asm-x86/pgtable.h
+++ b/include/asm-x86/pgtable.h
@@ -58,6 +58,7 @@
 #define _KERNPG_TABLE	(_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED |	\
 			 _PAGE_DIRTY)
 
+/* Set of bits not changed in pte_modify */
 #define _PAGE_CHG_MASK	(PTE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY)
 
 #define _PAGE_CACHE_MASK	(_PAGE_PCD | _PAGE_PWT)
@@ -285,11 +286,8 @@
 {
 	pteval_t val = pte_val(pte);
 
-	/*
-	 * Chop off the NX bit (if present), and add the NX portion of
-	 * the newprot (if present):
-	 */
-	val &= _PAGE_CHG_MASK & ~_PAGE_NX;
+	/* Extract unchanged bits from pte */
+	val &= _PAGE_CHG_MASK;
 	val |= pgprot_val(newprot) & __supported_pte_mask;
 
 	return __pte(val);

[PATCH 7 of 8] x86: use PTE_MASK rather than ad-hoc mask

[Jeremy Fitzhardinge]

Use ~PTE_MASK to extract the non-pfn parts of the pte (ie, the pte
flags), rather than constructing an ad-hoc mask.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
---
 include/asm-x86/pgtable.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/asm-x86/pgtable.h b/include/asm-x86/pgtable.h
--- a/include/asm-x86/pgtable.h
+++ b/include/asm-x86/pgtable.h
@@ -293,7 +293,7 @@
 	return __pte(val);
 }
 
-#define pte_pgprot(x) __pgprot(pte_val(x) & (0xfff | _PAGE_NX))
+#define pte_pgprot(x) __pgprot(pte_val(x) & ~PTE_MASK)
 
 #define canon_pgprot(p) __pgprot(pgprot_val(p) & __supported_pte_mask)
 

[PATCH 8 of 8] xen: use PTE_MASK in pte_mfn()

[Jeremy Fitzhardinge]

Use PTE_MASK to extract mfn from pte.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
---
 include/asm-x86/xen/page.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/asm-x86/xen/page.h b/include/asm-x86/xen/page.h
--- a/include/asm-x86/xen/page.h
+++ b/include/asm-x86/xen/page.h
@@ -127,7 +127,7 @@
 
 static inline unsigned long pte_mfn(pte_t pte)
 {
-	return (pte.pte & ~_PAGE_NX) >> PAGE_SHIFT;
+	return (pte.pte & PTE_MASK) >> PAGE_SHIFT;
 }
 
 static inline pte_t mfn_pte(unsigned long page_nr, pgprot_t pgprot)

Re: [PATCH 0 of 8] x86: use PTE_MASK consistently

[Ingo Molnar]

* Jeremy Fitzhardinge <jeremy@goop.org> wrote:

> Here's a series to rationalize the use of PTE_MASK and remove some 
> amount of ad-hocery.
> 
> This gist of the series is:
>  1. Fix the definition of PTE_MASK so that its equally applicable in
>     all pagetable modes
>  2. Use it consistently
> 
> I haven't tried to address the *_bad() stuff, other than to convert 
> pmd_bad_* to use PTE_MASK.
> 
> I've compile tested it a bit and run it on 32-bit PAE (native and 
> Xen), but I haven't tested it with >4G memory, non-PAE or 64-bit.  In 
> other words, it needs some time in Ingo's torture machine.

applied, thanks. This patchset has held up fine so far in overnight 
testing, nice work.

	Ingo

[PATCH 0 of 8] x86: use PTE_MASK consistently

[Jeremy Fitzhardinge]

[ Repost due to screwed up mail headers. ]

Hi all,

Here's a series to rationalize the use of PTE_MASK and remove some
amount of ad-hocery.

This gist of the series is:
 1. Fix the definition of PTE_MASK so that its equally applicable in
    all pagetable modes
 2. Use it consistently

I haven't tried to address the *_bad() stuff, other than to convert
pmd_bad_* to use PTE_MASK.

This series has had some testing in the x86.git tree, and hasn't shown
any problems.  Each patch is more or less absolutely trivial and the
series is very bisectable, to help track down any problems which might
arise (this area has always been a source of subtle problems).

      J

[PATCH 7 of 8] x86: use PTE_MASK rather than ad-hoc mask

[Jeremy Fitzhardinge]

Use ~PTE_MASK to extract the non-pfn parts of the pte (ie, the pte
flags), rather than constructing an ad-hoc mask.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
---
 include/asm-x86/pgtable.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/asm-x86/pgtable.h b/include/asm-x86/pgtable.h
--- a/include/asm-x86/pgtable.h
+++ b/include/asm-x86/pgtable.h
@@ -305,7 +305,7 @@
 	return __pgprot(preservebits | addbits);
 }
 
-#define pte_pgprot(x) __pgprot(pte_val(x) & (0xfff | _PAGE_NX))
+#define pte_pgprot(x) __pgprot(pte_val(x) & ~PTE_MASK)
 
 #define canon_pgprot(p) __pgprot(pgprot_val(p) & __supported_pte_mask)