commit ddbd89deb7 upstream.
The problem I'm addressing was discovered by the LTP test covering
cve-2018-1000204.
A short description of what happens follows:
1) The test case issues a command code 00 (TEST UNIT READY) via the SG_IO
interface with: dxfer_len == 524288, dxdfer_dir == SG_DXFER_FROM_DEV
and a corresponding dxferp. The peculiar thing about this is that TUR
is not reading from the device.
2) In sg_start_req() the invocation of blk_rq_map_user() effectively
bounces the user-space buffer. As if the device was to transfer into
it. Since commit a45b599ad8 ("scsi: sg: allocate with __GFP_ZERO in
sg_build_indirect()") we make sure this first bounce buffer is
allocated with GFP_ZERO.
3) For the rest of the story we keep ignoring that we have a TUR, so the
device won't touch the buffer we prepare as if the we had a
DMA_FROM_DEVICE type of situation. My setup uses a virtio-scsi device
and the buffer allocated by SG is mapped by the function
virtqueue_add_split() which uses DMA_FROM_DEVICE for the "in" sgs (here
scatter-gather and not scsi generics). This mapping involves bouncing
via the swiotlb (we need swiotlb to do virtio in protected guest like
s390 Secure Execution, or AMD SEV).
4) When the SCSI TUR is done, we first copy back the content of the second
(that is swiotlb) bounce buffer (which most likely contains some
previous IO data), to the first bounce buffer, which contains all
zeros. Then we copy back the content of the first bounce buffer to
the user-space buffer.
5) The test case detects that the buffer, which it zero-initialized,
ain't all zeros and fails.
One can argue that this is an swiotlb problem, because without swiotlb
we leak all zeros, and the swiotlb should be transparent in a sense that
it does not affect the outcome (if all other participants are well
behaved).
Copying the content of the original buffer into the swiotlb buffer is
the only way I can think of to make swiotlb transparent in such
scenarios. So let's do just that if in doubt, but allow the driver
to tell us that the whole mapped buffer is going to be overwritten,
in which case we can preserve the old behavior and avoid the performance
impact of the extra bounce.
Signed-off-by: Halil Pasic <pasic@linux.ibm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Document the new dma_alloc_pages and dma_free_pages APIs, and fix
up the documentation for dma_alloc_noncoherent and dma_free_noncoherent.
Reported-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Pull documentation updates from Mauro Carvalho Chehab:
"A series of patches addressing warnings produced by make htmldocs.
This includes:
- kernel-doc markup fixes
- ReST fixes
- Updates at the build system in order to support newer versions of
the docs build toolchain (Sphinx)
After this series, the number of html build warnings should reduce
significantly, and building with Sphinx 3.1 or later should now be
supported (although it is still recommended to use Sphinx 2.4.4).
As agreed with Jon, I should be sending you a late pull request by the
end of the merge window addressing remaining issues with docs build,
as there are a number of warning fixes that depends on pull requests
that should be happening along the merge window.
The end goal is to have a clean htmldocs build on Kernel 5.10.
PS. It should be noticed that Sphinx 3.0 is not currently supported,
as it lacks support for C domain namespaces. Such feature, needed in
order to document uAPI system calls with Sphinx 3.x, was added only on
Sphinx 3.1"
* tag 'docs/v5.10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (75 commits)
PM / devfreq: remove a duplicated kernel-doc markup
mm/doc: fix a literal block markup
workqueue: fix a kernel-doc warning
docs: virt: user_mode_linux_howto_v2.rst: fix a literal block markup
Input: sparse-keymap: add a description for @sw
rcu/tree: docs: document bkvcache new members at struct kfree_rcu_cpu
nl80211: docs: add a description for s1g_cap parameter
usb: docs: document altmode register/unregister functions
kunit: test.h: fix a bad kernel-doc markup
drivers: core: fix kernel-doc markup for dev_err_probe()
docs: bio: fix a kerneldoc markup
kunit: test.h: solve kernel-doc warnings
block: bio: fix a warning at the kernel-doc markups
docs: powerpc: syscall64-abi.rst: fix a malformed table
drivers: net: hamradio: fix document location
net: appletalk: Kconfig: Fix docs location
dt-bindings: fix references to files converted to yaml
memblock: get rid of a :c:type leftover
math64.h: kernel-docs: Convert some markups into normal comments
media: uAPI: buffer.rst: remove a left-over documentation
...
Pull dma-mapping updates from Christoph Hellwig:
- rework the non-coherent DMA allocator
- move private definitions out of <linux/dma-mapping.h>
- lower CMA_ALIGNMENT (Paul Cercueil)
- remove the omap1 dma address translation in favor of the common code
- make dma-direct aware of multiple dma offset ranges (Jim Quinlan)
- support per-node DMA CMA areas (Barry Song)
- increase the default seg boundary limit (Nicolin Chen)
- misc fixes (Robin Murphy, Thomas Tai, Xu Wang)
- various cleanups
* tag 'dma-mapping-5.10' of git://git.infradead.org/users/hch/dma-mapping: (63 commits)
ARM/ixp4xx: add a missing include of dma-map-ops.h
dma-direct: simplify the DMA_ATTR_NO_KERNEL_MAPPING handling
dma-direct: factor out a dma_direct_alloc_from_pool helper
dma-direct check for highmem pages in dma_direct_alloc_pages
dma-mapping: merge <linux/dma-noncoherent.h> into <linux/dma-map-ops.h>
dma-mapping: move large parts of <linux/dma-direct.h> to kernel/dma
dma-mapping: move dma-debug.h to kernel/dma/
dma-mapping: remove <asm/dma-contiguous.h>
dma-mapping: merge <linux/dma-contiguous.h> into <linux/dma-map-ops.h>
dma-contiguous: remove dma_contiguous_set_default
dma-contiguous: remove dev_set_cma_area
dma-contiguous: remove dma_declare_contiguous
dma-mapping: split <linux/dma-mapping.h>
cma: decrease CMA_ALIGNMENT lower limit to 2
firewire-ohci: use dma_alloc_pages
dma-iommu: implement ->alloc_noncoherent
dma-mapping: add new {alloc,free}_noncoherent dma_map_ops methods
dma-mapping: add a new dma_alloc_pages API
dma-mapping: remove dma_cache_sync
53c700: convert to dma_alloc_noncoherent
...
As there's already a rst file with workqueue markups, containing
part of them, move the other definitions, in order to avoid
warnings with Sphinx.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
This is already included at genericirq.rst. Adding it twice
causes C namespace duplication:
.../Documentation/core-api/kernel-api:237: ../kernel/irq/manage.c💯 WARNING: Duplicate C declaration, also defined in 'genericirq'.
Declaration is 'synchronize_hardirq'.
.../Documentation/core-api/kernel-api:237: ../kernel/irq/manage.c:128: WARNING: Duplicate C declaration, also defined in 'genericirq'.
Declaration is 'synchronize_irq'.
.../Documentation/core-api/kernel-api:237: ../kernel/irq/manage.c:443: WARNING: Duplicate C declaration, also defined in 'genericirq'.
Declaration is 'irq_set_affinity_notifier'.
...
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Currently, kernel/irq/chip.c is included twice, one for
export functions, and then for internal ones. However, as
the :export: and :internal: tags are missing, they ended
being included twice.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
This API is the equivalent of alloc_pages, except that the returned memory
is guaranteed to be DMA addressable by the passed in device. The
implementation will also be used to provide a more sensible replacement
for DMA_ATTR_NON_CONSISTENT flag.
Additionally dma_alloc_noncoherent is switched over to use dma_alloc_pages
as its backend.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> (MIPS part)
Add a new API to allocate and free memory that is guaranteed to be
addressable by a device, but which potentially is not cache coherent
for DMA.
To transfer ownership to and from the device, the existing streaming
DMA API calls dma_sync_single_for_device and dma_sync_single_for_cpu
must be used.
For now the new calls are implemented on top of dma_alloc_attrs just
like the old-noncoherent API, but once all drivers are switched to
the new API it will be replaced with a better working implementation
that is available on all architectures.
Signed-off-by: Christoph Hellwig <hch@lst.de>
dma_declare_coherent_memory should not be in a DMA API guide aimed
at driver writers (that is consumers of the API). Move it to a comment
near the function instead.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Pull documentation fixes from Jonathan Corbet:
"A handful of obvious fixes that wandered in during the merge window"
* tag 'docs-5.9-2' of git://git.lwn.net/linux:
Documentation/locking/locktypes: fix the typo
doc/zh_CN: resolve undefined label warning in admin-guide index
doc/zh_CN: fix title heading markup in admin-guide cpu-load
docs: remove the 2.6 "Upgrading I2C Drivers" guide
docs: Correct the release date of 5.2 stable
mailmap: Update comments for with format and more detalis
docs: cdrom: Fix a typo and rst markup
Doc: admin-guide: use correct legends in kernel-parameters.txt
Documentation/features: refresh RISC-V arch support files
documentation: coccinelle: Improve command example for make C={1,2}
Core-api: Documentation: Replace deprecated :c:func: Usage
Dev-tools: Documentation: Replace deprecated :c:func: Usage
Filesystems: Documentation: Replace deprecated :c:func: Usage
docs: trace: fix a typo
Pull powerpc updates from Michael Ellerman:
- Add support for (optionally) using queued spinlocks & rwlocks.
- Support for a new faster system call ABI using the scv instruction on
Power9 or later.
- Drop support for the PROT_SAO mmap/mprotect flag as it will be
unsupported on Power10 and future processors, leaving us with no way
to implement the functionality it requests. This risks breaking
userspace, though we believe it is unused in practice.
- A bug fix for, and then the removal of, our custom stack expansion
checking. We now allow stack expansion up to the rlimit, like other
architectures.
- Remove the remnants of our (previously disabled) topology update
code, which tried to react to NUMA layout changes on virtualised
systems, but was prone to crashes and other problems.
- Add PMU support for Power10 CPUs.
- A change to our signal trampoline so that we don't unbalance the link
stack (branch return predictor) in the signal delivery path.
- Lots of other cleanups, refactorings, smaller features and so on as
usual.
Thanks to: Abhishek Goel, Alastair D'Silva, Alexander A. Klimov, Alexey
Kardashevskiy, Alistair Popple, Andrew Donnellan, Aneesh Kumar K.V, Anju
T Sudhakar, Anton Blanchard, Arnd Bergmann, Athira Rajeev, Balamuruhan
S, Bharata B Rao, Bill Wendling, Bin Meng, Cédric Le Goater, Chris
Packham, Christophe Leroy, Christoph Hellwig, Daniel Axtens, Dan
Williams, David Lamparter, Desnes A. Nunes do Rosario, Erhard F., Finn
Thain, Frederic Barrat, Ganesh Goudar, Gautham R. Shenoy, Geoff Levand,
Greg Kurz, Gustavo A. R. Silva, Hari Bathini, Harish, Imre Kaloz, Joel
Stanley, Joe Perches, John Crispin, Jordan Niethe, Kajol Jain, Kamalesh
Babulal, Kees Cook, Laurent Dufour, Leonardo Bras, Li RongQing, Madhavan
Srinivasan, Mahesh Salgaonkar, Mark Cave-Ayland, Michal Suchanek, Milton
Miller, Mimi Zohar, Murilo Opsfelder Araujo, Nathan Chancellor, Nathan
Lynch, Naveen N. Rao, Nayna Jain, Nicholas Piggin, Oliver O'Halloran,
Palmer Dabbelt, Pedro Miraglia Franco de Carvalho, Philippe Bergheaud,
Pingfan Liu, Pratik Rajesh Sampat, Qian Cai, Qinglang Miao, Randy
Dunlap, Ravi Bangoria, Sachin Sant, Sam Bobroff, Sandipan Das, Santosh
Sivaraj, Satheesh Rajendran, Shirisha Ganta, Sourabh Jain, Srikar
Dronamraju, Stan Johnson, Stephen Rothwell, Thadeu Lima de Souza
Cascardo, Thiago Jung Bauermann, Tom Lane, Vaibhav Jain, Vladis Dronov,
Wei Yongjun, Wen Xiong, YueHaibing.
* tag 'powerpc-5.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (337 commits)
selftests/powerpc: Fix pkey syscall redefinitions
powerpc: Fix circular dependency between percpu.h and mmu.h
powerpc/powernv/sriov: Fix use of uninitialised variable
selftests/powerpc: Skip vmx/vsx/tar/etc tests on older CPUs
powerpc/40x: Fix assembler warning about r0
powerpc/papr_scm: Add support for fetching nvdimm 'fuel-gauge' metric
powerpc/papr_scm: Fetch nvdimm performance stats from PHYP
cpuidle: pseries: Fixup exit latency for CEDE(0)
cpuidle: pseries: Add function to parse extended CEDE records
cpuidle: pseries: Set the latency-hint before entering CEDE
selftests/powerpc: Fix online CPU selection
powerpc/perf: Consolidate perf_callchain_user_[64|32]()
powerpc/pseries/hotplug-cpu: Remove double free in error path
powerpc/pseries/mobility: Add pr_debug() for device tree changes
powerpc/pseries/mobility: Set pr_fmt()
powerpc/cacheinfo: Warn if cache object chain becomes unordered
powerpc/cacheinfo: Improve diagnostics about malformed cache lists
powerpc/cacheinfo: Use name@unit instead of full DT path in debug messages
powerpc/cacheinfo: Set pr_fmt()
powerpc: fix function annotations to avoid section mismatch warnings with gcc-10
...
Pull documentation updates from Jonathan Corbet:
"It's been a busy cycle for documentation - hopefully the busiest for a
while to come. Changes include:
- Some new Chinese translations
- Progress on the battle against double words words and non-HTTPS
URLs
- Some block-mq documentation
- More RST conversions from Mauro. At this point, that task is
essentially complete, so we shouldn't see this kind of churn again
for a while. Unless we decide to switch to asciidoc or
something...:)
- Lots of typo fixes, warning fixes, and more"
* tag 'docs-5.9' of git://git.lwn.net/linux: (195 commits)
scripts/kernel-doc: optionally treat warnings as errors
docs: ia64: correct typo
mailmap: add entry for <alobakin@marvell.com>
doc/zh_CN: add cpu-load Chinese version
Documentation/admin-guide: tainted-kernels: fix spelling mistake
MAINTAINERS: adjust kprobes.rst entry to new location
devices.txt: document rfkill allocation
PCI: correct flag name
docs: filesystems: vfs: correct flag name
docs: filesystems: vfs: correct sync_mode flag names
docs: path-lookup: markup fixes for emphasis
docs: path-lookup: more markup fixes
docs: path-lookup: fix HTML entity mojibake
CREDITS: Replace HTTP links with HTTPS ones
docs: process: Add an example for creating a fixes tag
doc/zh_CN: add Chinese translation prefer section
doc/zh_CN: add clearing-warn-once Chinese version
doc/zh_CN: add admin-guide index
doc:it_IT: process: coding-style.rst: Correct __maybe_unused compiler label
futex: MAINTAINERS: Re-add selftests directory
...
Pull printk updates from Petr Mladek:
- Herbert Xu made printk header file self-contained.
- Andy Shevchenko and Sergey Senozhatsky cleaned up console->setup()
error handling.
- Andy Shevchenko did some cleanups (e.g. sparse warning) in vsprintf
code.
- Minor documentation updates.
* tag 'printk-for-5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
lib/vsprintf: Force type of flags value for gfp_t
lib/vsprintf: Replace custom spec to print decimals with generic one
lib/vsprintf: Replace hidden BUILD_BUG_ON() with static_assert()
printk: Make linux/printk.h self-contained
doc:kmsg: explicitly state the return value in case of SEEK_CUR
Replace HTTP links with HTTPS ones: vsprintf
hvc: unify console setup naming
console: Fix trivia typo 'change' -> 'chance'
console: Propagate error code from console ->setup()
tty: hvc: Return proper error code from console ->setup() hook
serial: sunzilog: Return proper error code from console ->setup() hook
serial: sunsab: Return proper error code from console ->setup() hook
mips: Return proper error code from console ->setup() hook
Pull crypto updates from Herbert Xu:
"API:
- Add support for allocating transforms on a specific NUMA Node
- Introduce the flag CRYPTO_ALG_ALLOCATES_MEMORY for storage users
Algorithms:
- Drop PMULL based ghash on arm64
- Fixes for building with clang on x86
- Add sha256 helper that does the digest in one go
- Add SP800-56A rev 3 validation checks to dh
Drivers:
- Permit users to specify NUMA node in hisilicon/zip
- Add support for i.MX6 in imx-rngc
- Add sa2ul crypto driver
- Add BA431 hwrng driver
- Add Ingenic JZ4780 and X1000 hwrng driver
- Spread IRQ affinity in inside-secure and marvell/cesa"
* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (157 commits)
crypto: sa2ul - Fix inconsistent IS_ERR and PTR_ERR
hwrng: core - remove redundant initialization of variable ret
crypto: x86/curve25519 - Remove unused carry variables
crypto: ingenic - Add hardware RNG for Ingenic JZ4780 and X1000
dt-bindings: RNG: Add Ingenic RNG bindings.
crypto: caam/qi2 - add module alias
crypto: caam - add more RNG hw error codes
crypto: caam/jr - remove incorrect reference to caam_jr_register()
crypto: caam - silence .setkey in case of bad key length
crypto: caam/qi2 - create ahash shared descriptors only once
crypto: caam/qi2 - fix error reporting for caam_hash_alloc
crypto: caam - remove deadcode on 32-bit platforms
crypto: ccp - use generic power management
crypto: xts - Replace memcpy() invocation with simple assignment
crypto: marvell/cesa - irq balance
crypto: inside-secure - irq balance
crypto: ecc - SP800-56A rev 3 local public key validation
crypto: dh - SP800-56A rev 3 local public key validation
crypto: dh - check validity of Z before export
lib/mpi: Add mpi_sub_ui()
...
Changelog of commit dcda9b0471 ("mm, tree wide: replace __GFP_REPEAT by
__GFP_RETRY_MAYFAIL with more useful semantic") has very nice description
of GFP flags that affect reclaim behaviour of the page allocator.
It would be pity to keep this description buried in the log so let's expose
it in the Documentation/ as well.
Cc: Michal Hocko <mhocko@suse.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Link: https://lore.kernel.org/r/20200719153641.231131-1-rppt@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
This effectively reverts commit 3aa565f53c ("powerpc/pseries: Add
hooks to put the CPU into an appropriate offline state"), which added
an offline mode for CPUs which uses the H_CEDE hcall instead of the
architected stop-self RTAS function in order to facilitate "folding"
of dedicated mode processors on PowerVM platforms to achieve energy
savings. This has been the default offline mode since its
introduction.
There's nothing about stop-self that would prevent the hypervisor from
achieving the energy savings available via H_CEDE, so the original
premise of this change appears to be flawed.
I also have encountered the claim that the transition to and from
ceded state is much faster than stop-self/start-cpu. Certainly we
would not want to use stop-self as an *idle* mode. That is what H_CEDE
is for. However, this difference is insignificant in the context of
Linux CPU hotplug, where the latency of an offline or online operation
on current systems is on the order of 100ms, mainly attributable to
all the various subsystems' cpuhp callbacks.
The cede offline mode also prevents accurate accounting, as discussed
before:
https://lore.kernel.org/linuxppc-dev/1571740391-3251-1-git-send-email-ego@linux.vnet.ibm.com/
Unconditionally use stop-self to offline processor threads. This is
the architected method for offlining CPUs on PAPR systems.
The "cede_offline" boot parameter is rendered obsolete.
Removing this code enables the removal of the partition suspend code
which temporarily onlines all present CPUs.
Fixes: 3aa565f53c ("powerpc/pseries: Add hooks to put the CPU into an appropriate offline state")
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200612051238.1007764-2-nathanl@linux.ibm.com
