Implement _PAGE_SPECIAL and pte_special() for 32-bit powerpc. This bit will
be used by the fast get_user_pages() to differenciate PTEs that correspond
to a valid struct page from special mappings that don't such as IO mappings
obtained via io_remap_pfn_ranges().
We currently only implement this on sub-arch that support SMP or will so
in the future (6xx, 44x, FSL-BookE) and not (8xx, 40x).
Signed-off-by: Kumar Gala <[email protected]>
---
Nick, do you forsee using _PAGE_SPECIAL for other applications that would
be of interested to non-SMP hw?
We can look at adding it into 8xx and 40x, but was being lazy as I assume
there is no point.
- k
include/asm-powerpc/pgtable-ppc32.h | 15 +++++++++++++--
1 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/include/asm-powerpc/pgtable-ppc32.h b/include/asm-powerpc/pgtable-ppc32.h
index 6fe39e3..58afaee 100644
--- a/include/asm-powerpc/pgtable-ppc32.h
+++ b/include/asm-powerpc/pgtable-ppc32.h
@@ -261,6 +261,7 @@ extern int icache_44x_need_flush;
#define _PAGE_HWEXEC 0x00000004 /* H: Execute permission */
#define _PAGE_ACCESSED 0x00000008 /* S: Page referenced */
#define _PAGE_DIRTY 0x00000010 /* S: Page dirty */
+#define _PAGE_SPECIAL 0x00000020 /* S: Special page */
#define _PAGE_USER 0x00000040 /* S: User page */
#define _PAGE_ENDIAN 0x00000080 /* H: E bit */
#define _PAGE_GUARDED 0x00000100 /* H: G bit */
@@ -276,6 +277,7 @@ extern int icache_44x_need_flush;
/* ERPN in a PTE never gets cleared, ignore it */
#define _PTE_NONE_MASK 0xffffffff00000000ULL
+#define __HAVE_ARCH_PTE_SPECIAL
#elif defined(CONFIG_FSL_BOOKE)
/*
@@ -305,6 +307,7 @@ extern int icache_44x_need_flush;
#define _PAGE_COHERENT 0x00100 /* H: M bit */
#define _PAGE_NO_CACHE 0x00200 /* H: I bit */
#define _PAGE_WRITETHRU 0x00400 /* H: W bit */
+#define _PAGE_SPECIAL 0x00800 /* S: Special page */
#ifdef CONFIG_PTE_64BIT
/* ERPN in a PTE never gets cleared, ignore it */
@@ -315,6 +318,8 @@ extern int icache_44x_need_flush;
#define _PMD_PRESENT_MASK (PAGE_MASK)
#define _PMD_BAD (~PAGE_MASK)
+#define __HAVE_ARCH_PTE_SPECIAL
+
#elif defined(CONFIG_8xx)
/* Definitions for 8xx embedded chips. */
#define _PAGE_PRESENT 0x0001 /* Page is valid */
@@ -362,6 +367,7 @@ extern int icache_44x_need_flush;
#define _PAGE_ACCESSED 0x100 /* R: page referenced */
#define _PAGE_EXEC 0x200 /* software: i-cache coherency required */
#define _PAGE_RW 0x400 /* software: user write access allowed */
+#define _PAGE_SPECIAL 0x800 /* software: Special page */
#define _PTE_NONE_MASK _PAGE_HASHPTE
@@ -372,6 +378,8 @@ extern int icache_44x_need_flush;
/* Hash table based platforms need atomic updates of the linux PTE */
#define PTE_ATOMIC_UPDATES 1
+#define __HAVE_ARCH_PTE_SPECIAL
+
#endif
/*
@@ -404,6 +412,9 @@ extern int icache_44x_need_flush;
#ifndef _PAGE_WRITETHRU
#define _PAGE_WRITETHRU 0
#endif
+#ifndef _PAGE_SPECIAL
+#define _PAGE_SPECIAL 0
+#endif
#ifndef _PMD_PRESENT_MASK
#define _PMD_PRESENT_MASK _PMD_PRESENT
#endif
@@ -533,7 +544,7 @@ static inline int pte_write(pte_t pte) { return pte_val(pte) & _PAGE_RW; }
static inline int pte_dirty(pte_t pte) { return pte_val(pte) & _PAGE_DIRTY; }
static inline int pte_young(pte_t pte) { return pte_val(pte) & _PAGE_ACCESSED; }
static inline int pte_file(pte_t pte) { return pte_val(pte) & _PAGE_FILE; }
-static inline int pte_special(pte_t pte) { return 0; }
+static inline int pte_special(pte_t pte) { return pte_val(pte) & _PAGE_SPECIAL; }
static inline void pte_uncache(pte_t pte) { pte_val(pte) |= _PAGE_NO_CACHE; }
static inline void pte_cache(pte_t pte) { pte_val(pte) &= ~_PAGE_NO_CACHE; }
@@ -552,7 +563,7 @@ static inline pte_t pte_mkdirty(pte_t pte) {
static inline pte_t pte_mkyoung(pte_t pte) {
pte_val(pte) |= _PAGE_ACCESSED; return pte; }
static inline pte_t pte_mkspecial(pte_t pte) {
- return pte; }
+ pte_val(pte) |= _PAGE_SPECIAL; return pte; }
static inline unsigned long pte_pgprot(pte_t pte)
{
return __pgprot(pte_val(pte)) & PAGE_PROT_BITS;
--
1.5.5.1
On Jul 31, 2008, at 1:48 PM, Kumar Gala wrote:
> Implement _PAGE_SPECIAL and pte_special() for 32-bit powerpc. This
> bit will
> be used by the fast get_user_pages() to differenciate PTEs that
> correspond
> to a valid struct page from special mappings that don't such as IO
> mappings
> obtained via io_remap_pfn_ranges().
>
> We currently only implement this on sub-arch that support SMP or
> will so
> in the future (6xx, 44x, FSL-BookE) and not (8xx, 40x).
>
> Signed-off-by: Kumar Gala <[email protected]>
> ---
> Nick, do you forsee using _PAGE_SPECIAL for other applications that
> would
> be of interested to non-SMP hw?
>
> We can look at adding it into 8xx and 40x, but was being lazy as I
> assume
> there is no point.
>
> - k
Josh,
Can you test this on 44x for me.
thanks
- k
On Thu, Jul 31, 2008 at 01:48:31PM -0500, Kumar Gala wrote:
> Implement _PAGE_SPECIAL and pte_special() for 32-bit powerpc. This bit will
> be used by the fast get_user_pages() to differenciate PTEs that correspond
> to a valid struct page from special mappings that don't such as IO mappings
> obtained via io_remap_pfn_ranges().
>
> We currently only implement this on sub-arch that support SMP or will so
> in the future (6xx, 44x, FSL-BookE) and not (8xx, 40x).
>
> Signed-off-by: Kumar Gala <[email protected]>
Cool
> ---
> Nick, do you forsee using _PAGE_SPECIAL for other applications that would
> be of interested to non-SMP hw?
>
> We can look at adding it into 8xx and 40x, but was being lazy as I assume
> there is no point.
I don't forsee it being used for anything else, but it is possible I guess.
We currently will also use it in the VM (vm_normal_page), turning
that function into a much more compact and simple version. It doesn't
do a great deal for performance, but you _may_ want to consider using it
just so the entire powerpc architecture takes this same path.
Not a big deal though.