That's a much better idea, thanks. Though it wasn't *quite* the same
in the 32-bit 2-level case, because that mode didn't need any mask at
all, the right shift was sufficient.
I expected gcc to optimize away that difference, and often it does,
but not always (I'm using 4.2.1 and CC_OPTIMIZE_FOR_SIZE here):
pte_page() involved
228: c1 e8 0c shr $0xc,%eax
22b: c1 e0 05 shl $0x5,%eax
before the unification, but afterwards
228: 25 00 f0 ff ff and $0xfffff000,%eax
22d: c1 e8 07 shr $0x7,%eax
So it's bloated that kernel by 0.001% (around 40 bytes). Oh well,
I think we may suppose that with a different version of gcc or
different optimizations, it could just as well have gone the
other way - I vote to go with your unification.
[PATCH tip] x86: unsigned long pte_pfn
pte_pfn() has always been of type unsigned long, even on 32-bit PAE;
but in the current tip/next/mm tree it works out to be unsigned long
long on 64-bit, which gives an irritating warning if you try to printk
a pfn with the usual %lx.
Now use the same pte_pfn() function, moved from pgtable-3level.h
to pgtable.h, for all models: as suggested by Jeremy Fitzhardinge.
And pte_page() can well move along with it (remaining a macro to
avoid dependence on mm_types.h).
Signed-off-by: Hugh Dickins <hugh@veritas.com>
---
include/asm-x86/pgtable-2level.h | 2 --
include/asm-x86/pgtable-3level.h | 7 -------
include/asm-x86/pgtable.h | 7 +++++++
include/asm-x86/pgtable_64.h | 2 --
4 files changed, 7 insertions(+), 11 deletions(-)
--- 2.6.27-rc5-mm1/include/asm-x86/pgtable-2level.h 2008-09-05 10:05:51.000000000 +0100
+++ linux/include/asm-x86/pgtable-2level.h 2008-09-09 13:53:34.000000000 +0100
@@ -53,9 +53,7 @@ static inline pte_t native_ptep_get_and_
#define native_ptep_get_and_clear(xp) native_local_ptep_get_and_clear(xp)
#endif
-#define pte_page(x) pfn_to_page(pte_pfn(x))
#define pte_none(x) (!(x).pte_low)
-#define pte_pfn(x) (pte_val(x) >> PAGE_SHIFT)
/*
* Bits 0, 6 and 7 are taken, split up the 29 bits of offset
--- 2.6.27-rc5-mm1/include/asm-x86/pgtable-3level.h 2008-09-05 10:05:51.000000000 +0100
+++ linux/include/asm-x86/pgtable-3level.h 2008-09-09 13:53:34.000000000 +0100
@@ -151,18 +151,11 @@ static inline int pte_same(pte_t a, pte_
return a.pte_low == b.pte_low && a.pte_high == b.pte_high;
}
-#define pte_page(x) pfn_to_page(pte_pfn(x))
-
static inline int pte_none(pte_t pte)
{
return !pte.pte_low && !pte.pte_high;
}
-static inline unsigned long pte_pfn(pte_t pte)
-{
- return (pte_val(pte) & PTE_PFN_MASK) >> PAGE_SHIFT;
-}
-
/*
* Bits 0, 6 and 7 are taken in the low part of the pte,
* put the 32 bits of offset into the high part.
--- 2.6.27-rc5-mm1/include/asm-x86/pgtable.h 2008-09-05 10:05:51.000000000 +0100
+++ linux/include/asm-x86/pgtable.h 2008-09-09 13:53:34.000000000 +0100
@@ -186,6 +186,13 @@ static inline int pte_special(pte_t pte)
return pte_val(pte) & _PAGE_SPECIAL;
}
+static inline unsigned long pte_pfn(pte_t pte)
+{
+ return (pte_val(pte) & PTE_PFN_MASK) >> PAGE_SHIFT;
+}
+
+#define pte_page(pte) pfn_to_page(pte_pfn(pte))
+
static inline int pmd_large(pmd_t pte)
{
return (pmd_val(pte) & (_PAGE_PSE | _PAGE_PRESENT)) ==
--- 2.6.27-rc5-mm1/include/asm-x86/pgtable_64.h 2008-09-05 10:05:51.000000000 +0100
+++ linux/include/asm-x86/pgtable_64.h 2008-09-09 13:53:34.000000000 +0100
@@ -181,8 +181,6 @@ static inline int pmd_bad(pmd_t pmd)
#endif
#define pages_to_mb(x) ((x) >> (20 - PAGE_SHIFT)) /* FIXME: is this right? */
-#define pte_page(x) pfn_to_page(pte_pfn((x)))
-#define pte_pfn(x) ((pte_val((x)) & __PHYSICAL_MASK) >> PAGE_SHIFT)
/*
* Macro to mark a page protection value as "uncacheable".
--
