[PATCH] PPC32: Fixup pmd_page to work when ARCH_PFN_OFFSET isnon-zero

From: Jason Gunthorpe
Date: Tue Mar 09 2010 - 14:35:12 EST


Instead of referencing mem_map directly, use pfn_to_page. Otherwise
the kernel crashes when trying to start userspace if ARCH_PFN_OFFSET is
non-zero and CONFIG_BOOKE is not defined

Signed-off-by: Jason Gunthorpe <jgunthorpe@xxxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/include/asm/pgtable-ppc32.h | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

For reference, on powerpc 32 with CONFIG_FLATMEM:

#define pfn_to_page __pfn_to_page
#define __pfn_to_page(pfn) (mem_map + ((pfn) - ARCH_PFN_OFFSET))

So the below patch has no effect if ARCH_PFN_OFFEST is 0.

diff --git a/arch/powerpc/include/asm/pgtable-ppc32.h b/arch/powerpc/include/asm/pgtable-ppc32.h
index 55646ad..a7db96f 100644
--- a/arch/powerpc/include/asm/pgtable-ppc32.h
+++ b/arch/powerpc/include/asm/pgtable-ppc32.h
@@ -287,7 +287,7 @@ static inline void __ptep_set_access_flags(pte_t *ptep, pte_t entry)
#define pmd_page_vaddr(pmd) \
((unsigned long) __va(pmd_val(pmd) & PAGE_MASK))
#define pmd_page(pmd) \
- (mem_map + (pmd_val(pmd) >> PAGE_SHIFT))
+ pfn_to_page(pmd_val(pmd) >> PAGE_SHIFT)
#else
#define pmd_page_vaddr(pmd) \
((unsigned long) (pmd_val(pmd) & PAGE_MASK))
--
1.5.4.2

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