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

[Kumar Gala]

On Dec 29, 2008, at 10:40 AM, Anton Vorontsov wrote:

> 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)));
> 	}

Acked-by: Kumar Gala <galak at kernel.crashing.org>

- k