Re: [PATCH] [8/8] RFC: Fix some EFI problems

From: Thomas Gleixner
Date: Tue Feb 12 2008 - 15:04:36 EST

On Mon, 11 Feb 2008, Andi Kleen wrote:

> >From code review the EFI memory map handling has a couple of problems:
> - The test for _WB memory was reversed so it would set cache able memory
> to uncached
> - It would always set a wrong uninitialized zero address to uncached
> (so I suspect it always set the first few pages in phys memory to uncached,
> that is why it may have gone unnoticed)
> - It would call set_memory_x() on a fixmap address that it doesn't
> handle correct.
> - Some other problems I commented in the code (but was unable to solve
> for now)
> I changed the ioremaps to set the correct caching attributes
> and also corrected the ordering so it looks roughly correct now.

The only effective change is:

- if (md->attribute & EFI_MEMORY_WB)
+ if (!(md->attribute & EFI_MEMORY_WB))

I appreciate that you noticed the reverse logic, which I messed up
when I fixed up rejects.

I pulled this out as it is a real fix. The rest of this patch is just
turning code in circles for nothing, simply because it is functionally
completely irrelevant whether does simply:

if ((end >> PAGE_SHIFT) <= max_pfn_mapped)
va = __va(md->phys_addr);
va = efi_ioremap(md->phys_addr, size);

if (!(md->attribute & EFI_MEMORY_WB))
set_memory_uc(md->virt_addr, size);

if ((end >> PAGE_SHIFT) <= max_pfn_mapped) {
va = __va(md->phys_addr);

if (!(md->attribute & EFI_MEMORY_WB))
set_memory_uc(md->virt_addr, size);
} else
va = efi_ioremap(md->phys_addr, size,
!!(md->attribute & EFI_MEMORY_WB));

And you just copied the real bug in that logic as well:

set_memory_uc(md->virt_addr, size);

which is initialized a couple of lines down.

md->virt_addr = (u64) (unsigned long) va;

The reordering/optimizing needs to be a separate patch.

Please keep bugfixes and other changes separate.

> + /* RED-PEN does not handle overlapped areas */

Can you please use CHECKME/FIXME which is used everywhere else. No need to
invent an extra marker.


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