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From: David Laight <David.Laight@ACULAB.COM>
To: 'Grygorii Strashko' <grygorii.strashko@ti.com>,
	Ilias Apalodimas <ilias.apalodimas@linaro.org>,
	Jesper Dangaard Brouer <brouer@redhat.com>,
	Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <willy@infradead.org>,
	kernel test robot <lkp@intel.com>, Linux-MM <linux-mm@kvack.org>,
	"kbuild-all@lists.01.org" <kbuild-all@lists.01.org>,
	"clang-built-linux@googlegroups.com"
	<clang-built-linux@googlegroups.com>,
	open list <linux-kernel@vger.kernel.org>,
	"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	"David S. Miller" <davem@davemloft.net>,
	Matteo Croce <mcroce@linux.microsoft.com>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>
Subject: RE: Bogus struct page layout on 32-bit
Date: Sat, 17 Apr 2021 13:08:30 +0000	[thread overview]
Message-ID: <e8247c8d079d45928990031870db7a9e@AcuMS.aculab.com> (raw)
In-Reply-To: <ab9f1a6c-4099-2b59-457d-fcc45d2396f4@ti.com>

From: Grygorii Strashko
> Sent: 16 April 2021 10:27
...
> Sry, for delayed reply.
> 
> The TI platforms am3/4/5 (cpsw) and Keystone 2 (netcp) can do only 32bit DMA even in case of LPAE
> (dma-ranges are used).
> Originally, as I remember, CONFIG_ARCH_DMA_ADDR_T_64BIT has not been selected for the LPAE case
> on TI platforms and the fact that it became set is the result of multi-paltform/allXXXconfig/DMA
> optimizations and unification.
> (just checked - not set in 4.14)
> 
> Probable commit 4965a68780c5 ("arch: define the ARCH_DMA_ADDR_T_64BIT config symbol in lib/Kconfig").
> 
> The TI drivers have been updated, finally to accept ARCH_DMA_ADDR_T_64BIT=y by using things like
> (__force u32)
> for example.

Hmmm using (__force u32) is probably wrong.
If an address +length >= 2**32 can get passed then the IO request
needs to be errored (or a bounce buffer used).

Otherwise you can get particularly horrid corruptions.

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)

  parent reply	other threads:[~2021-04-17 13:08 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-09 18:50 [PATCH v7 00/28] Memory Folios Matthew Wilcox (Oracle)
2021-04-09 18:50 ` [PATCH v7 01/28] mm: Optimise nth_page for contiguous memmap Matthew Wilcox (Oracle)
2021-04-12  6:08   ` Christoph Hellwig
2021-04-09 18:50 ` [PATCH v7 04/28] mm/vmstat: Add functions to account folio statistics Matthew Wilcox (Oracle)
2021-04-09 18:50 ` [PATCH v7 05/28] mm/debug: Add VM_BUG_ON_FOLIO and VM_WARN_ON_ONCE_FOLIO Matthew Wilcox (Oracle)
2021-04-09 18:50 ` [PATCH v7 07/28] mm: Add put_folio Matthew Wilcox (Oracle)
2021-04-09 18:50 ` [PATCH v7 08/28] mm: Add get_folio Matthew Wilcox (Oracle)
2021-04-09 18:50 ` [PATCH v7 11/28] mm/filemap: Add folio_index, folio_file_page and folio_contains Matthew Wilcox (Oracle)
2021-04-09 18:50 ` [PATCH v7 12/28] mm/filemap: Add folio_next_index Matthew Wilcox (Oracle)
2021-04-09 18:50 ` [PATCH v7 15/28] mm: Add folio_mapcount Matthew Wilcox (Oracle)
2021-04-09 18:50 ` [PATCH v7 16/28] mm/memcg: Add folio wrappers for various functions Matthew Wilcox (Oracle)
2021-04-09 18:51 ` [PATCH v7 25/28] mm/writeback: Add wait_for_stable_folio Matthew Wilcox (Oracle)
2021-04-09 18:51 ` [PATCH v7 27/28] mm/filemap: Convert wake_up_page_bit to wake_up_folio_bit Matthew Wilcox (Oracle)
     [not found] ` <20210409185105.188284-3-willy@infradead.org>
2021-04-09 22:45   ` [PATCH v7 02/28] mm: Introduce struct folio kernel test robot
2021-04-10  2:43     ` Bogus struct page layout on 32-bit Matthew Wilcox
2021-04-10  6:21       ` Jesper Dangaard Brouer
2021-04-10  8:52         ` Ilias Apalodimas
2021-04-10 14:06           ` Matthew Wilcox
2021-04-10 15:54             ` Russell King - ARM Linux admin
2021-04-16  9:26           ` Grygorii Strashko
2021-04-16 14:10             ` Arnd Bergmann
2021-04-17 13:08             ` David Laight [this message]
2021-04-10 14:17       ` David Laight
2021-04-10 19:10       ` Arnd Bergmann
2021-04-11 22:35         ` Matthew Wilcox
2021-04-10  2:51   ` [PATCH v7 02/28] mm: Introduce struct folio kernel test robot
2021-04-16 15:55   ` Matthew Wilcox
2021-04-19  9:06     ` Kirill A. Shutemov
     [not found] ` <20210409185105.188284-10-willy@infradead.org>
2021-04-19 13:25   ` [PATCH v7 09/28] mm: Create FolioFlags Peter Zijlstra
2021-04-19 13:55     ` Matthew Wilcox

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