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Filename Latest commit message Latest commit date
Jacob Pan 26cd726c32 iommu/vt-d: Handle volatile descriptor status read
[ Upstream commit b5e86a95541cea737394a1da967df4cd4d8f7182 ]

Queued invalidation wait descriptor status is volatile in that IOMMU
hardware writes the data upon completion.

Use READ_ONCE() to prevent compiler optimizations which ensures memory
reads every time. As a side effect, READ_ONCE() also enforces strict
types and may add an extra instruction. But it should not have negative
performance impact since we use cpu_relax anyway and the extra time(by
adding an instruction) may allow IOMMU HW request cacheline ownership
easier.

e.g. gcc 12.3
BEFORE:
	81 38 ad de 00 00       cmpl   $0x2,(%rax)

AFTER (with READ_ONCE())
    772f:       8b 00                   mov    (%rax),%eax
    7731:       3d ad de 00 00          cmp    $0x2,%eax
                                        //status data is 32 bit

Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Yi Liu <yi.l.liu@intel.com>
Link: https://lore.kernel.org/r/20240607173817.3914600-1-jacob.jun.pan@linux.intel.com
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/20240702130839.108139-2-baolu.lu@linux.intel.com
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-09-12 11:03:53 +02:00
arch openrisc: Call setup_memory() earlier in the init sequence 2024-09-04 13:14:57 +02:00
block block: initialize integrity buffer to zero before writing it to media 2024-09-12 11:03:50 +02:00
certs
crypto crypto: ecrdsa - Fix module auto-load on add_key 2024-06-16 13:28:51 +02:00
Documentation overflow: Implement size_t saturating arithmetic helpers 2024-09-04 13:14:51 +02:00
drivers iommu/vt-d: Handle volatile descriptor status read 2024-09-12 11:03:53 +02:00
fs udf: Avoid excessive partition lengths 2024-09-12 11:03:52 +02:00
include i2c: Use IS_REACHABLE() for substituting empty ACPI functions 2024-09-12 11:03:50 +02:00
init init: open /initrd.image with O_LARGEFILE 2024-04-13 12:51:36 +02:00
ipc ipc: replace costly bailout check in sysvipc_find_ipc() 2024-09-04 13:15:02 +02:00
kernel cgroup/cpuset: Prevent UAF in proc_cpuset_show() 2024-09-04 13:15:03 +02:00
lib overflow: Implement size_t saturating arithmetic helpers 2024-09-04 13:14:51 +02:00
LICENSES
mm memcg_write_event_control(): fix a user-triggerable oops 2024-09-04 13:14:50 +02:00
net net: bridge: br_fdb_external_learn_add(): always set EXT_LEARN 2024-09-12 11:03:53 +02:00
samples media: rename VFL_TYPE_GRABBER to _VIDEO 2024-03-26 18:22:22 -04:00
scripts kbuild: Fix '-S -c' in x86 stack protector scripts 2024-08-19 05:33:53 +02:00
security smack: unix sockets: fix accept()ed socket label 2024-09-12 11:03:52 +02:00
sound ASoC: topology: Properly initialize soc_enum values 2024-09-12 11:03:53 +02:00
tools tools: move alignment-related macros to new <linux/align.h> 2024-09-04 13:15:02 +02:00
usr
virt KVM: async_pf: Cleanup kvm_setup_async_pf() 2024-05-02 16:18:32 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS iio: stx104: Move to addac subdirectory 2023-08-30 16:27:12 +02:00
Makefile Linux 5.4.283 2024-09-04 13:15:05 +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.