Follow @Openwall on Twitter for new release announcements and other news
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Thu, 14 Feb 2019 08:47:47 +0100
From: Christoph Hellwig <hch@....de>
To: Khalid Aziz <khalid.aziz@...cle.com>
Cc: juergh@...il.com, tycho@...ho.ws, jsteckli@...zon.de,
	ak@...ux.intel.com, torvalds@...ux-foundation.org,
	liran.alon@...cle.com, keescook@...gle.com,
	akpm@...ux-foundation.org, mhocko@...e.com, catalin.marinas@....com,
	will.deacon@....com, jmorris@...ei.org, konrad.wilk@...cle.com,
	Juerg Haefliger <juerg.haefliger@...onical.com>,
	deepa.srinivasan@...cle.com, chris.hyser@...cle.com,
	tyhicks@...onical.com, dwmw@...zon.co.uk, andrew.cooper3@...rix.com,
	jcm@...hat.com, boris.ostrovsky@...cle.com,
	kanth.ghatraju@...cle.com, oao.m.martins@...cle.com,
	jmattson@...gle.com, pradeep.vincent@...cle.com,
	john.haxby@...cle.com, tglx@...utronix.de,
	kirill.shutemov@...ux.intel.com, hch@....de,
	steven.sistare@...cle.com, labbott@...hat.com, luto@...nel.org,
	dave.hansen@...el.com, peterz@...radead.org,
	kernel-hardening@...ts.openwall.com, linux-mm@...ck.org,
	x86@...nel.org, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org, Tycho Andersen <tycho@...ker.com>
Subject: Re: [RFC PATCH v8 04/14] swiotlb: Map the buffer if it was
 unmapped by XPFO

On Wed, Feb 13, 2019 at 05:01:27PM -0700, Khalid Aziz wrote:
> +++ b/kernel/dma/swiotlb.c
> @@ -396,8 +396,9 @@ static void swiotlb_bounce(phys_addr_t orig_addr, phys_addr_t tlb_addr,
>  {
>  	unsigned long pfn = PFN_DOWN(orig_addr);
>  	unsigned char *vaddr = phys_to_virt(tlb_addr);
> +	struct page *page = pfn_to_page(pfn);
>  
> -	if (PageHighMem(pfn_to_page(pfn))) {
> +	if (PageHighMem(page) || xpfo_page_is_unmapped(page)) {

I think this just wants a page_unmapped or similar helper instead of
needing the xpfo_page_is_unmapped check.  We actually have quite
a few similar construct in the arch dma mapping code for architectures
that require cache flushing.

> +bool xpfo_page_is_unmapped(struct page *page)
> +{
> +	struct xpfo *xpfo;
> +
> +	if (!static_branch_unlikely(&xpfo_inited))
> +		return false;
> +
> +	xpfo = lookup_xpfo(page);
> +	if (unlikely(!xpfo) && !xpfo->inited)
> +		return false;
> +
> +	return test_bit(XPFO_PAGE_UNMAPPED, &xpfo->flags);
> +}
> +EXPORT_SYMBOL(xpfo_page_is_unmapped);

And at least for swiotlb there is no need to export this helper,
as it is always built in.

Powered by blists - more mailing lists

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.