Messages in this thread | | | Subject | Re: [PATCH v5 03/10] swiotlb: Map the buffer if it was unmapped by XPFO | From | Dave Hansen <> | Date | Wed, 20 Sep 2017 16:25:48 -0700 |
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On 09/20/2017 03:47 PM, Tycho Andersen wrote: > >>> static inline void *skcipher_map(struct scatter_walk *walk) >>> { >>> struct page *page = scatterwalk_page(walk); >>> >>> return (PageHighMem(page) ? kmap_atomic(page) : page_address(page)) + >>> offset_in_page(walk->offset); >>> } >> Is there any better way to catch these? Like, can we add some debugging >> to check for XPFO pages in __va()? > Yes, and perhaps also a debugging check in PageHighMem?
I'm not sure what PageHighMem() would check. It's OK to use as long as you don't depend on the contents of the page.
> Would __va have caught either of the two cases you've pointed out? Yes. __va() is what is eventually called by lowmem_page_address(), which is only OK to call on things that are actually mapped into the kernel.
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