Paulus, please apply.
At present, the powerpc pmd_bad() and pud_bad() macros return false
unless the fiven pmd or pud is zero. This patch makes these tests
more thorough, checking if the given pmd or pud looks like a plausible
pte page or pmd page pointer respectively. This can result in helpful
error messages when messing with the pagetable code.
Signed-off-by: David Gibson <[email protected]>
Index: working-2.6/include/asm-powerpc/pgtable.h
===================================================================
--- working-2.6.orig/include/asm-powerpc/pgtable.h 2006-03-06 11:38:45.000000000 +1100
+++ working-2.6/include/asm-powerpc/pgtable.h 2006-03-06 12:51:14.000000000 +1100
@@ -188,9 +188,13 @@ static inline pte_t pfn_pte(unsigned lon
#define pte_pfn(x) ((unsigned long)((pte_val(x)>>PTE_RPN_SHIFT)))
#define pte_page(x) pfn_to_page(pte_pfn(x))
+#define PMD_BAD_BITS (PTE_TABLE_SIZE-1)
+#define PUD_BAD_BITS (PMD_TABLE_SIZE-1)
+
#define pmd_set(pmdp, pmdval) (pmd_val(*(pmdp)) = (pmdval))
#define pmd_none(pmd) (!pmd_val(pmd))
-#define pmd_bad(pmd) (pmd_val(pmd) == 0)
+#define pmd_bad(pmd) (!is_kernel_addr(pmd_val(pmd)) \
+ || (pmd_val(pmd) & PMD_BAD_BITS))
#define pmd_present(pmd) (pmd_val(pmd) != 0)
#define pmd_clear(pmdp) (pmd_val(*(pmdp)) = 0)
#define pmd_page_kernel(pmd) (pmd_val(pmd) & ~PMD_MASKED_BITS)
@@ -198,7 +202,8 @@ static inline pte_t pfn_pte(unsigned lon
#define pud_set(pudp, pudval) (pud_val(*(pudp)) = (pudval))
#define pud_none(pud) (!pud_val(pud))
-#define pud_bad(pud) ((pud_val(pud)) == 0)
+#define pud_bad(pud) (!is_kernel_addr(pud_val(pud)) \
+ || (pud_val(pud) & PUD_BAD_BITS))
#define pud_present(pud) (pud_val(pud) != 0)
#define pud_clear(pudp) (pud_val(*(pudp)) = 0)
#define pud_page(pud) (pud_val(pud) & ~PUD_MASKED_BITS)
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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