powerpc/mm: Rework usage of _PAGE_COHERENT/NO_CACHE/GUARDED

Currently, we never set _PAGE_COHERENT in the PTEs, we just OR it in
in the hash code based on some CPU feature bit.  We also manipulate
_PAGE_NO_CACHE and _PAGE_GUARDED by hand in all sorts of places.

This changes the logic so that instead, the PTE now contains
_PAGE_COHERENT for all normal RAM pages thay have I = 0 on platforms
that need it.  The hash code clears it if the feature bit is not set.

It also adds some clean accessors to setup various valid combinations
of access flags and change various bits of code to use them instead.

This should help having the PTE actually containing the bit
combinations that we really want.

I also removed _PAGE_GUARDED from _PAGE_BASE on 44x and instead
set it explicitely from the TLB miss.  I will ultimately remove it
completely as it appears that it might not be needed after all
but in the meantime, having it in the TLB miss makes things a
lot easier.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This commit is contained in:
Benjamin Herrenschmidt
2008-12-18 19:13:51 +00:00
committed by Paul Mackerras
parent 7752035180
commit 64b3d0e812
9 changed files with 69 additions and 78 deletions

View File

@ -323,8 +323,8 @@ _GLOBAL(create_hpte)
ori r8,r8,0xe14 /* clear out reserved bits and M */
andc r8,r5,r8 /* PP = user? (rw&dirty? 2: 3): 0 */
BEGIN_FTR_SECTION
ori r8,r8,_PAGE_COHERENT /* set M (coherence required) */
END_FTR_SECTION_IFSET(CPU_FTR_NEED_COHERENT)
rlwinm r8,r8,0,~_PAGE_COHERENT /* clear M (coherence not required) */
END_FTR_SECTION_IFCLR(CPU_FTR_NEED_COHERENT)
#ifdef CONFIG_PTE_64BIT
/* Put the XPN bits into the PTE */
rlwimi r8,r10,8,20,22

View File

@ -102,8 +102,8 @@ pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
return ppc_md.phys_mem_access_prot(file, pfn, size, vma_prot);
if (!page_is_ram(pfn))
vma_prot = __pgprot(pgprot_val(vma_prot)
| _PAGE_GUARDED | _PAGE_NO_CACHE);
vma_prot = pgprot_noncached(vma_prot);
return vma_prot;
}
EXPORT_SYMBOL(phys_mem_access_prot);