[PATCH 2/4] powerpc/32: Make clear_fixmap actually work

[Anton Vorontsov]

The clear_fixmap() routine issues map_page() with flags set to 0.
Currently this causes a BUG_ON() inside the map_page(), as it assumes
that a PTE should be clear before mapping.

This patch makes the map_page() to trigger the BUG_ON() only if the
flags were set.

Signed-off-by: Anton Vorontsov <avorontsov at ru.mvista.com>
---
 arch/powerpc/mm/pgtable_32.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c
index 3414724..23553a7 100644
--- a/arch/powerpc/mm/pgtable_32.c
+++ b/arch/powerpc/mm/pgtable_32.c
@@ -259,7 +259,8 @@ int map_page(unsigned long va, phys_addr_t pa, int flags)
 		/* The PTE should never be already set nor present in the
 		 * hash table
 		 */
-		BUG_ON(pte_val(*pg) & (_PAGE_PRESENT | _PAGE_HASHPTE));
+		BUG_ON((pte_val(*pg) & (_PAGE_PRESENT | _PAGE_HASHPTE)) &&
+		       flags);
 		set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT,
 						     __pgprot(flags)));
 	}
-- 
1.5.6.5