Commit ac91cb8d authored by Arnd Bergmann's avatar Arnd Bergmann Committed by Paul Mackerras
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[POWERPC] spufs: use correct pg_prot for mapping SPU local store



This hopefully fixes a long-standing bug in the spu file system.
An spu context comes with local memory that can be either saved
in kernel pages or point directly to a physical SPE.

When mapping the physical SPE, that mapping needs to be cache-inhibited.
For simplicity, we used to map the kernel backing memory that way
too, but unfortunately that was not only inefficient, but also incorrect
because the same page could then be accessed simultaneously through
a cacheable and a cache-inhibited mapping, which is not allowed
by the powerpc specification and in our case caused data inconsistency
for which we did a really ugly workaround in user space.

Signed-off-by: default avatarArnd Bergmann <arnd.bergmann@de.ibm.com>
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
parent 6263203e
......@@ -102,12 +102,16 @@ spufs_mem_mmap_nopage(struct vm_area_struct *vma,
spu_acquire(ctx);
if (ctx->state == SPU_STATE_SAVED)
if (ctx->state == SPU_STATE_SAVED) {
vma->vm_page_prot = __pgprot(pgprot_val(vma->vm_page_prot)
& ~(_PAGE_NO_CACHE | _PAGE_GUARDED));
page = vmalloc_to_page(ctx->csa.lscsa->ls + offset);
else
} else {
vma->vm_page_prot = __pgprot(pgprot_val(vma->vm_page_prot)
| _PAGE_NO_CACHE | _PAGE_GUARDED);
page = pfn_to_page((ctx->spu->local_store_phys + offset)
>> PAGE_SHIFT);
}
spu_release(ctx);
if (type)
......
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