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Filename Latest commit message Latest commit date
Will Deacon 7b9c3bfbad arm64: mm: Don't invalidate FROM_DEVICE buffers at start of DMA transfer
commit c50f11c6196f45c92ca48b16a5071615d4ae0572 upstream.

Invalidating the buffer memory in arch_sync_dma_for_device() for
FROM_DEVICE transfers

When using the streaming DMA API to map a buffer prior to inbound
non-coherent DMA (i.e. DMA_FROM_DEVICE), we invalidate any dirty CPU
cachelines so that they will not be written back during the transfer and
corrupt the buffer contents written by the DMA. This, however, poses two
potential problems:

  (1) If the DMA transfer does not write to every byte in the buffer,
      then the unwritten bytes will contain stale data once the transfer
      has completed.

  (2) If the buffer has a virtual alias in userspace, then stale data
      may be visible via this alias during the period between performing
      the cache invalidation and the DMA writes landing in memory.

Address both of these issues by cleaning (aka writing-back) the dirty
lines in arch_sync_dma_for_device(DMA_FROM_DEVICE) instead of discarding
them using invalidation.

Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220606152150.GA31568@willie-the-truck
Signed-off-by: Will Deacon <will@kernel.org>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20220610151228.4562-2-will@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-06-25 12:44:36 +02:00
arch arm64: mm: Don't invalidate FROM_DEVICE buffers at start of DMA transfer 2022-06-25 12:44:36 +02:00
block
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:11:22 +02:00
crypto crypto: drbg - make reseeding from get_random_bytes() synchronous 2022-06-22 14:11:18 +02:00
Documentation random: fix sysctl documentation nits 2022-06-22 14:11:14 +02:00
drivers usb: gadget: u_ether: fix regression in setting fixed MAC address 2022-06-25 12:44:35 +02:00
fs ext4: add reserved GDT blocks check 2022-06-22 14:11:23 +02:00
include dm: remove special-casing of bio-based immutable singleton target on NVMe 2022-06-25 12:44:35 +02:00
init random: handle latent entropy and command line from random_init() 2022-06-22 14:11:17 +02:00
ipc
kernel dma-debug: make things less spammy under memory pressure 2022-06-22 14:11:19 +02:00
lib random: remove ratelimiting for in-kernel unseeded randomness 2022-06-22 14:11:17 +02:00
LICENSES
mm random: move randomize_page() into mm where it belongs 2022-06-22 14:11:17 +02:00
net tcp: drop the hash_32() part from the index calculation 2022-06-25 12:44:36 +02:00
samples
scripts faddr2line: Fix overlapping text section failures, the sequel 2022-06-22 14:11:22 +02:00
security
sound ALSA: hda/realtek: fix right sounds and mute/micmute LEDs for HP machine 2022-06-22 14:11:24 +02:00
tools
usr
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
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COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile Linux 5.4.200 2022-06-22 14:11:24 +02:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.