From 0f6be7b77ceaea01a35b37fab26f4ea3b01efe14 Mon Sep 17 00:00:00 2001 From: David Gibson <david@gibson.dropbear.id.au> Date: Mon, 6 Mar 2006 12:51:29 +1100 Subject: [PATCH] [PATCH] powerpc: Better pmd_bad() and pud_bad() checks At present, the powerpc pmd_bad() and pud_bad() macros return false unless the given 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 <dwg@au1.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org> --- include/asm-powerpc/pgtable.h | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/include/asm-powerpc/pgtable.h b/include/asm-powerpc/pgtable.h index e38931379a72..8dc3eb54276f 100644 --- a/include/asm-powerpc/pgtable.h +++ b/include/asm-powerpc/pgtable.h @@ -188,9 +188,13 @@ static inline pte_t pfn_pte(unsigned long pfn, pgprot_t pgprot) #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 long pfn, pgprot_t pgprot) #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)