debugfs can now report an error code if something went wrong instead of
just NULL. So if the return value is to be used as a "real" dentry, it
needs to be checked if it is an error before dereferencing it.
This is now happening because of ff9fb72bc0 ("debugfs: return error
values, not NULL"). syzbot has found a way to trigger multiple debugfs
files attempting to be created, which fails, and then the error code
gets passed to dentry_path_raw() which obviously does not like it.
Reported-by: Eric Biggers <ebiggers@kernel.org>
Reported-and-tested-by: syzbot+7857962b4d45e602b8ad@syzkaller.appspotmail.com
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: kvm@vger.kernel.org
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
On the Fujitsu-A64FX cores ver(1.0, 1.1), memory access may cause
an undefined fault (Data abort, DFSC=0b111111). This fault occurs under
a specific hardware condition when a load/store instruction performs an
address translation. Any load/store instruction, except non-fault access
including Armv8 and SVE might cause this undefined fault.
The TCR_ELx.NFD1 bit is used by the kernel when CONFIG_RANDOMIZE_BASE
is enabled to mitigate timing attacks against KASLR where the kernel
address space could be probed using the FFR and suppressed fault on
SVE loads.
Since this erratum causes spurious exceptions, which may corrupt
the exception registers, we clear the TCR_ELx.NFDx=1 bits when
booting on an affected CPU.
Signed-off-by: Zhang Lei <zhang.lei@jp.fujitsu.com>
[Generated MIDR value/mask for __cpu_setup(), removed spurious-fault handler
and always disabled the NFDx bits on affected CPUs]
Signed-off-by: James Morse <james.morse@arm.com>
Tested-by: zhang.lei <zhang.lei@jp.fujitsu.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
We'll use this for the POLL implementation. Regular requests will
NOT be using references, so initialize it to 0. Any real use of
the io_kiocb ref will initialize it to at least 2.
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This enables an application to do IO, without ever entering the kernel.
By using the SQ ring to fill in new sqes and watching for completions
on the CQ ring, we can submit and reap IOs without doing a single system
call. The kernel side thread will poll for new submissions, and in case
of HIPRI/polled IO, it'll also poll for completions.
By default, we allow 1 second of active spinning. This can by changed
by passing in a different grace period at io_uring_register(2) time.
If the thread exceeds this idle time without having any work to do, it
will set:
sq_ring->flags |= IORING_SQ_NEED_WAKEUP.
The application will have to call io_uring_enter() to start things back
up again. If IO is kept busy, that will never be needed. Basically an
application that has this feature enabled will guard it's
io_uring_enter(2) call with:
read_barrier();
if (*sq_ring->flags & IORING_SQ_NEED_WAKEUP)
io_uring_enter(fd, 0, 0, IORING_ENTER_SQ_WAKEUP);
instead of calling it unconditionally.
It's mandatory to use fixed files with this feature. Failure to do so
will result in the application getting an -EBADF CQ entry when
submitting IO.
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We normally have to fget/fput for each IO we do on a file. Even with
the batching we do, the cost of the atomic inc/dec of the file usage
count adds up.
This adds IORING_REGISTER_FILES, and IORING_UNREGISTER_FILES opcodes
for the io_uring_register(2) system call. The arguments passed in must
be an array of __s32 holding file descriptors, and nr_args should hold
the number of file descriptors the application wishes to pin for the
duration of the io_uring instance (or until IORING_UNREGISTER_FILES is
called).
When used, the application must set IOSQE_FIXED_FILE in the sqe->flags
member. Then, instead of setting sqe->fd to the real fd, it sets sqe->fd
to the index in the array passed in to IORING_REGISTER_FILES.
Files are automatically unregistered when the io_uring instance is torn
down. An application need only unregister if it wishes to register a new
set of fds.
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We need this functionality for the io_uring file registration, but
we cannot rely on it since CONFIG_UNIX can be modular. Move the helpers
to a separate file, that's always builtin to the kernel if CONFIG_UNIX is
m/y.
No functional changes in this patch, just moving code around.
Reviewed-by: Hannes Reinecke <hare@suse.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we have fixed user buffers, we can map them into the kernel when we
setup the io_uring. That avoids the need to do get_user_pages() for
each and every IO.
To utilize this feature, the application must call io_uring_register()
after having setup an io_uring instance, passing in
IORING_REGISTER_BUFFERS as the opcode. The argument must be a pointer to
an iovec array, and the nr_args should contain how many iovecs the
application wishes to map.
If successful, these buffers are now mapped into the kernel, eligible
for IO. To use these fixed buffers, the application must use the
IORING_OP_READ_FIXED and IORING_OP_WRITE_FIXED opcodes, and then
set sqe->index to the desired buffer index. sqe->addr..sqe->addr+seq->len
must point to somewhere inside the indexed buffer.
The application may register buffers throughout the lifetime of the
io_uring instance. It can call io_uring_register() with
IORING_UNREGISTER_BUFFERS as the opcode to unregister the current set of
buffers, and then register a new set. The application need not
unregister buffers explicitly before shutting down the io_uring
instance.
It's perfectly valid to setup a larger buffer, and then sometimes only
use parts of it for an IO. As long as the range is within the originally
mapped region, it will work just fine.
For now, buffers must not be file backed. If file backed buffers are
passed in, the registration will fail with -1/EOPNOTSUPP. This
restriction may be relaxed in the future.
RLIMIT_MEMLOCK is used to check how much memory we can pin. A somewhat
arbitrary 1G per buffer size is also imposed.
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
For an ITER_BVEC, we can just iterate the iov and add the pages
to the bio directly. For now, we grab a reference to those pages,
and release them normally on IO completion. This isn't really needed
for the normal case of O_DIRECT from/to a file, but some of the more
esoteric use cases (like splice(2)) will unconditionally put the
pipe buffer pages when the buffers are released. Until we can manage
that case properly, ITER_BVEC pages are treated like normal pages
in terms of reference counting.
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Similarly to how we use the state->ios_left to know how many references
to get to a file, we can use it to allocate the io_kiocb's we need in
bulk.
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add a separate io_submit_state structure, to cache some of the things
we need for IO submission.
One such example is file reference batching. io_submit_state. We get as
many references as the number of sqes we are submitting, and drop
unused ones if we end up switching files. The assumption here is that
we're usually only dealing with one fd, and if there are multiple,
hopefuly they are at least somewhat ordered. Could trivially be extended
to cover multiple fds, if needed.
On the completion side we do the same thing, except this is trivially
done just locally in io_iopoll_reap().
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Some uses cases repeatedly get and put references to the same file, but
the only exposed interface is doing these one at the time. As each of
these entail an atomic inc or dec on a shared structure, that cost can
add up.
Add fget_many(), which works just like fget(), except it takes an
argument for how many references to get on the file. Ditto fput_many(),
which can drop an arbitrary number of references to a file.
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add support for a polled io_uring instance. When a read or write is
submitted to a polled io_uring, the application must poll for
completions on the CQ ring through io_uring_enter(2). Polled IO may not
generate IRQ completions, hence they need to be actively found by the
application itself.
To use polling, io_uring_setup() must be used with the
IORING_SETUP_IOPOLL flag being set. It is illegal to mix and match
polled and non-polled IO on an io_uring.
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add a new fsync opcode, which either syncs a range if one is passed,
or the whole file if the offset and length fields are both cleared
to zero. A flag is provided to use fdatasync semantics, that is only
force out metadata which is required to retrieve the file data, but
not others like metadata.
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The submission queue (SQ) and completion queue (CQ) rings are shared
between the application and the kernel. This eliminates the need to
copy data back and forth to submit and complete IO.
IO submissions use the io_uring_sqe data structure, and completions
are generated in the form of io_uring_cqe data structures. The SQ
ring is an index into the io_uring_sqe array, which makes it possible
to submit a batch of IOs without them being contiguous in the ring.
The CQ ring is always contiguous, as completion events are inherently
unordered, and hence any io_uring_cqe entry can point back to an
arbitrary submission.
Two new system calls are added for this:
io_uring_setup(entries, params)
Sets up an io_uring instance for doing async IO. On success,
returns a file descriptor that the application can mmap to
gain access to the SQ ring, CQ ring, and io_uring_sqes.
io_uring_enter(fd, to_submit, min_complete, flags, sigset, sigsetsize)
Initiates IO against the rings mapped to this fd, or waits for
them to complete, or both. The behavior is controlled by the
parameters passed in. If 'to_submit' is non-zero, then we'll
try and submit new IO. If IORING_ENTER_GETEVENTS is set, the
kernel will wait for 'min_complete' events, if they aren't
already available. It's valid to set IORING_ENTER_GETEVENTS
and 'min_complete' == 0 at the same time, this allows the
kernel to return already completed events without waiting
for them. This is useful only for polling, as for IRQ
driven IO, the application can just check the CQ ring
without entering the kernel.
With this setup, it's possible to do async IO with a single system
call. Future developments will enable polled IO with this interface,
and polled submission as well. The latter will enable an application
to do IO without doing ANY system calls at all.
For IRQ driven IO, an application only needs to enter the kernel for
completions if it wants to wait for them to occur.
Each io_uring is backed by a workqueue, to support buffered async IO
as well. We will only punt to an async context if the command would
need to wait for IO on the device side. Any data that can be accessed
directly in the page cache is done inline. This avoids the slowness
issue of usual threadpools, since cached data is accessed as quickly
as a sync interface.
Sample application: http://git.kernel.dk/cgit/fio/plain/t/io_uring.c
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add support for suspend/resume and runtime PM to stm32-vrefbuf driver.
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
This patch fixes a bug that prevents freeing the reset gpio on unloading
the module.
aic3x_i2c_probe is called when loading the module and it calls list_add
with a probably uninitialized list entry aic3x->list (next = prev = NULL)).
So even if list_del is called it does nothing and in the end the gpio_reset
is not freed. Then a repeated module probing fails silently because
gpio_request fails.
When moving INIT_LIST_HEAD to aic3x_i2c_probe we also have to move
list_del to aic3x_i2c_remove because aic3x_remove may be called
multiple times without aic3x_i2c_remove being called which leads to
a NULL pointer dereference.
Signed-off-by: Philipp Puschmann <philipp.puschmann@emlix.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
CONFIG_DEBUG_INFO_SPLIT and CONFIG_DEBUG_INFO_DWARF4 enable extra
dwarf options if supported. You never know if they are really enabled
since Makefile may silently turn them off.
The actual behavior will match to the kernel configuration by
testing those compiler flags in the Kconfig stage.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
DPKG_FLAGS variable lets user to add more flags to dpkg-buildpackage
command in deb-pkg and bindeb-pkg.
Signed-off-by: Kacper Kołodziej <kacper@kolodziej.it>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
mp_bvec_for_each_segment() is a bit big for the iteration, so introduce
a light-weight helper for iterating over pages, then 32bytes stack
space can be saved.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add support of cancellation request to the TEE kernel internal
client interface. Can be used by software TPM drivers, that leverage
TEE under the hood (for instance TPM2.0 mobile profile), for requesting
cancellation of time-consuming operations (RSA key-pair generation etc.).
Signed-off-by: Igor Opaniuk <igor.opaniuk@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
Another batch of changes for ASoC, no big core changes - it's mainly
small fixes and improvements for individual drivers.
- A big refresh and cleanup of the Samsung drivers, fixing a number of
issues which allow the driver to be used with a wider range of
userspaces.
- Fixes for the Intel drivers to make them more standard so less likely
to get bitten by core issues.
- New driver for Cirrus Logic CS35L26.
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Merge tag 'asoc-v5.1-2' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-next
ASoC: More changes for v5.1
Another batch of changes for ASoC, no big core changes - it's mainly
small fixes and improvements for individual drivers.
- A big refresh and cleanup of the Samsung drivers, fixing a number of
issues which allow the driver to be used with a wider range of
userspaces.
- Fixes for the Intel drivers to make them more standard so less likely
to get bitten by core issues.
- New driver for Cirrus Logic CS35L26.
Add __cpu_to_le16/32/64 and __le16/32/64_to_cpu where needed according to
sparse.
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch fixes the following sparse warnings:
drivers/misc/habanalabs/hwmon.c:20:56: warning: Using plain integer as NULL pointer
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch fix a bug in the driver, where if the TPC or MME remains in
non-IDLE even after all the command submissions are done (due to user bug
or malicious user), then future command submissions will fail in the
context-switch stage and the driver will remain in "stuck" mode.
The fix is to do a soft-reset of the device in case the context-switch
fails, because the device should be IDLE during context-switch. If it is
not IDLE, then something is wrong and we should reset the compute engines.
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Don't cast pointer to u64 to print it. Instead, print the pointer using
%p.
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch fix a bug when a command buffer with unaligned size (with
regard to PAGE_SIZE) was used. The accounting for the unmap operation
wasn't done correctly and could result in a memory leak.
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch fix a bug where EINVAL was returned instead of -EINVAL.
Signed-off-by: Omer Shpigelman <oshpigelman@habana.ai>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add comment about minimum and maximum size of command buffer.
Add some text about the expected input of CS IOCTL.
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch fix a bug where the timeout for sending a job on QMAN0 by KMD
wasn't enough in palladium environment.
Signed-off-by: Omer Shpigelman <oshpigelman@habana.ai>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch fix a bug where DMA channel 0 completion address wasn't
initialized by the driver.
The patch sets the address to Sync Object no. 1007
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch fix a bug in the validation of WREG32 in DMA queues. The
validation was too strict. It allowed the user to set the completion
address only for DMA channel 1.
The fix allows the user to set the completion address for all 5 DMA
channels.
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch fix an incorrect initialization of the MMU cache registers. The
shift operation was done in the wrong direction.
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch provides a workaround for a bug in the F/W where the response
time for a request from KMD may take more then 100ms. This could cause the
queue between KMD and the F/W to get out of sync.
The WA is to:
1. Increase the timeout of ALL requests to 1s.
2. In case a request isn't answered in time, mark the state as
"cpu_disabled" and prevent sending further requests from KMD to the F/W.
This will eventually lead to a heartbeat failure and hard reset of the
device.
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch provides a workaround for a H/W bug in Goya, where access to
RAZWI from TPC can cause PCI completion timeout.
The WA is to use the device MMU to map any unmapped DRAM memory to a
default page in the DRAM. That way, the TPC will never reach RAZWI upon
accessing a bad address in the DRAM.
When a DRAM page is mapped by the user, its default mapping is
overwritten. Once that page is unmapped, the MMU driver will map that page
to the default page.
To help debugging, the driver will set the default page area to 0x99 on
device initialization.
Signed-off-by: Omer Shpigelman <oshpigelman@habana.ai>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch provides a workaround for a H/W bug in the RAZWI logger in
Goya. The logger doesn't recognize the initiator correctly and as a
result, accesses from one initiator are reported that were coming from a
different initiator.
The WA is to print the error information from the event entries we receive
without looking at the RAZWI logger at all.
Signed-off-by: Tomer Tayar <ttayar@habana.ai>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mei driver for the me hdcp client, for use by drm/i915.
Including the following prep work:
- whitelist hdcp client in mei bus
- merge to include char-misc-next
- drm/i915 side of the mei_hdcp/i915 component interface
- component prep work (including one patch touching i915&snd-hda)
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Merge tag 'topic/mei-hdcp-2019-02-26' of git://anongit.freedesktop.org/drm/drm-intel into char-misc-next
Daniel writes:
mei-hdcp driver
mei driver for the me hdcp client, for use by drm/i915.
Including the following prep work:
- whitelist hdcp client in mei bus
- merge to include char-misc-next
- drm/i915 side of the mei_hdcp/i915 component interface
- component prep work (including one patch touching i915&snd-hda)
* tag 'topic/mei-hdcp-2019-02-26' of git://anongit.freedesktop.org/drm/drm-intel: (23 commits)
misc/mei/hdcp: Component framework for I915 Interface
misc/mei/hdcp: Closing wired HDCP2.2 Tx Session
misc/mei/hdcp: Enabling the HDCP authentication
misc/mei/hdcp: Verify M_prime
misc/mei/hdcp: Repeater topology verification and ack
misc/mei/hdcp: Prepare Session Key
misc/mei/hdcp: Verify L_prime
misc/mei/hdcp: Initiate Locality check
misc/mei/hdcp: Store the HDCP Pairing info
misc/mei/hdcp: Verify H_prime
misc/mei/hdcp: Verify Receiver Cert and prepare km
misc/mei/hdcp: Initiate Wired HDCP2.2 Tx Session
misc/mei/hdcp: Define ME FW interface for HDCP2.2
misc/mei/hdcp: Client driver for HDCP application
mei: bus: whitelist hdcp client
drm/audio: declaration of struct device
drm: helper functions for hdcp2 seq_num to from u32
drm/i915: MEI interface definition
drm/i915: header for i915 - MEI_HDCP interface
drm/i915: enum port definition is moved into i915_drm.h
...
EFI systems do not necessarily provide a legacy ROM. If the ROM is missing
the memory is not mapped at all.
Trying to dereference values in the legacy ROM area leads to a crash on
Macbook Pro.
Only look for values in the legacy ROM area for non-EFI system.
Fixes: 3548e131ec ("x86/boot/compressed/64: Find a place for 32-bit trampoline")
Reported-by: Pitam Mitra <pitamm@gmail.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Bockjoo Kim <bockjoo@phys.ufl.edu>
Cc: bp@alien8.de
Cc: hpa@zytor.com
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20190219075224.35058-1-kirill.shutemov@linux.intel.com
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202351
From networking side, there are numerous attempts to get rid of indirect
calls in fast-path wherever feasible in order to avoid the cost of
retpolines, for example, just to name a few:
* 283c16a2df ("indirect call wrappers: helpers to speed-up indirect calls of builtin")
* aaa5d90b39 ("net: use indirect call wrappers at GRO network layer")
* 028e0a4766 ("net: use indirect call wrappers at GRO transport layer")
* 356da6d0cd ("dma-mapping: bypass indirect calls for dma-direct")
* 09772d92cd ("bpf: avoid retpoline for lookup/update/delete calls on maps")
* 10870dd89e ("netfilter: nf_tables: add direct calls for all builtin expressions")
[...]
Recent work on XDP from Björn and Magnus additionally found that manually
transforming the XDP return code switch statement with more than 5 cases
into if-else combination would result in a considerable speedup in XDP
layer due to avoidance of indirect calls in CONFIG_RETPOLINE enabled
builds. On i40e driver with XDP prog attached, a 20-26% speedup has been
observed [0]. Aside from XDP, there are many other places later in the
networking stack's critical path with similar switch-case
processing. Rather than fixing every XDP-enabled driver and locations in
stack by hand, it would be good to instead raise the limit where gcc would
emit expensive indirect calls from the switch under retpolines and stick
with the default as-is in case of !retpoline configured kernels. This would
also have the advantage that for archs where this is not necessary, we let
compiler select the underlying target optimization for these constructs and
avoid potential slow-downs by if-else hand-rewrite.
In case of gcc, this setting is controlled by case-values-threshold which
has an architecture global default that selects 4 or 5 (latter if target
does not have a case insn that compares the bounds) where some arch back
ends like arm64 or s390 override it with their own target hooks, for
example, in gcc commit db7a90aa0de5 ("S/390: Disable prediction of indirect
branches") the threshold pretty much disables jump tables by limit of 20
under retpoline builds. Comparing gcc's and clang's default code
generation on x86-64 under O2 level with retpoline build results in the
following outcome for 5 switch cases:
* gcc with -mindirect-branch=thunk-inline -mindirect-branch-register:
# gdb -batch -ex 'disassemble dispatch' ./c-switch
Dump of assembler code for function dispatch:
0x0000000000400be0 <+0>: cmp $0x4,%edi
0x0000000000400be3 <+3>: ja 0x400c35 <dispatch+85>
0x0000000000400be5 <+5>: lea 0x915f8(%rip),%rdx # 0x4921e4
0x0000000000400bec <+12>: mov %edi,%edi
0x0000000000400bee <+14>: movslq (%rdx,%rdi,4),%rax
0x0000000000400bf2 <+18>: add %rdx,%rax
0x0000000000400bf5 <+21>: callq 0x400c01 <dispatch+33>
0x0000000000400bfa <+26>: pause
0x0000000000400bfc <+28>: lfence
0x0000000000400bff <+31>: jmp 0x400bfa <dispatch+26>
0x0000000000400c01 <+33>: mov %rax,(%rsp)
0x0000000000400c05 <+37>: retq
0x0000000000400c06 <+38>: nopw %cs:0x0(%rax,%rax,1)
0x0000000000400c10 <+48>: jmpq 0x400c90 <fn_3>
0x0000000000400c15 <+53>: nopl (%rax)
0x0000000000400c18 <+56>: jmpq 0x400c70 <fn_2>
0x0000000000400c1d <+61>: nopl (%rax)
0x0000000000400c20 <+64>: jmpq 0x400c50 <fn_1>
0x0000000000400c25 <+69>: nopl (%rax)
0x0000000000400c28 <+72>: jmpq 0x400c40 <fn_0>
0x0000000000400c2d <+77>: nopl (%rax)
0x0000000000400c30 <+80>: jmpq 0x400cb0 <fn_4>
0x0000000000400c35 <+85>: push %rax
0x0000000000400c36 <+86>: callq 0x40dd80 <abort>
End of assembler dump.
* clang with -mretpoline emitting search tree:
# gdb -batch -ex 'disassemble dispatch' ./c-switch
Dump of assembler code for function dispatch:
0x0000000000400b30 <+0>: cmp $0x1,%edi
0x0000000000400b33 <+3>: jle 0x400b44 <dispatch+20>
0x0000000000400b35 <+5>: cmp $0x2,%edi
0x0000000000400b38 <+8>: je 0x400b4d <dispatch+29>
0x0000000000400b3a <+10>: cmp $0x3,%edi
0x0000000000400b3d <+13>: jne 0x400b52 <dispatch+34>
0x0000000000400b3f <+15>: jmpq 0x400c50 <fn_3>
0x0000000000400b44 <+20>: test %edi,%edi
0x0000000000400b46 <+22>: jne 0x400b5c <dispatch+44>
0x0000000000400b48 <+24>: jmpq 0x400c20 <fn_0>
0x0000000000400b4d <+29>: jmpq 0x400c40 <fn_2>
0x0000000000400b52 <+34>: cmp $0x4,%edi
0x0000000000400b55 <+37>: jne 0x400b66 <dispatch+54>
0x0000000000400b57 <+39>: jmpq 0x400c60 <fn_4>
0x0000000000400b5c <+44>: cmp $0x1,%edi
0x0000000000400b5f <+47>: jne 0x400b66 <dispatch+54>
0x0000000000400b61 <+49>: jmpq 0x400c30 <fn_1>
0x0000000000400b66 <+54>: push %rax
0x0000000000400b67 <+55>: callq 0x40dd20 <abort>
End of assembler dump.
For sake of comparison, clang without -mretpoline:
# gdb -batch -ex 'disassemble dispatch' ./c-switch
Dump of assembler code for function dispatch:
0x0000000000400b30 <+0>: cmp $0x4,%edi
0x0000000000400b33 <+3>: ja 0x400b57 <dispatch+39>
0x0000000000400b35 <+5>: mov %edi,%eax
0x0000000000400b37 <+7>: jmpq *0x492148(,%rax,8)
0x0000000000400b3e <+14>: jmpq 0x400bf0 <fn_0>
0x0000000000400b43 <+19>: jmpq 0x400c30 <fn_4>
0x0000000000400b48 <+24>: jmpq 0x400c10 <fn_2>
0x0000000000400b4d <+29>: jmpq 0x400c20 <fn_3>
0x0000000000400b52 <+34>: jmpq 0x400c00 <fn_1>
0x0000000000400b57 <+39>: push %rax
0x0000000000400b58 <+40>: callq 0x40dcf0 <abort>
End of assembler dump.
Raising the cases to a high number (e.g. 100) will still result in similar
code generation pattern with clang and gcc as above, in other words clang
generally turns off jump table emission by having an extra expansion pass
under retpoline build to turn indirectbr instructions from their IR into
switch instructions as a built-in -mno-jump-table lowering of a switch (in
this case, even if IR input already contained an indirect branch).
For gcc, adding --param=case-values-threshold=20 as in similar fashion as
s390 in order to raise the limit for x86 retpoline enabled builds results
in a small vmlinux size increase of only 0.13% (before=18,027,528
after=18,051,192). For clang this option is ignored due to i) not being
needed as mentioned and ii) not having above cmdline
parameter. Non-retpoline-enabled builds with gcc continue to use the
default case-values-threshold setting, so nothing changes here.
[0] https://lore.kernel.org/netdev/20190129095754.9390-1-bjorn.topel@gmail.com/
and "The Path to DPDK Speeds for AF_XDP", LPC 2018, networking track:
- http://vger.kernel.org/lpc_net2018_talks/lpc18_pres_af_xdp_perf-v3.pdf
- http://vger.kernel.org/lpc_net2018_talks/lpc18_paper_af_xdp_perf-v2.pdf
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Björn Töpel <bjorn.topel@intel.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: netdev@vger.kernel.org
Cc: David S. Miller <davem@davemloft.net>
Cc: Magnus Karlsson <magnus.karlsson@intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Link: https://lkml.kernel.org/r/20190221221941.29358-1-daniel@iogearbox.net
Support for "%pCr" was removed, but a reference in a comment was
forgotten.
Fixes: 666902e42f ("lib/vsprintf: Remove atomic-unsafe support for %pCr")
Link: http://lkml.kernel.org/r/20190228105315.744-1-geert+renesas@glider.be
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Petr Mladek <pmladek@suse.com>
The TIMER_IRQSAFE usage was introduced in commit 22597dc3d9 ("kthread:
initial support for delayed kthread work") which modelled the delayed
kthread code after workqueue's code. The workqueue code requires the flag
TIMER_IRQSAFE for synchronisation purpose. This is not true for kthread's
delay timer since all operations occur under a lock.
Remove TIMER_IRQSAFE from the timer initialisation and use timer_setup()
for initialisation purpose which is the official function.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lkml.kernel.org/r/20190212162554.19779-2-bigeasy@linutronix.de
In order to enable the queuing of kthread work items from hardirq context
even when PREEMPT_RT_FULL is enabled, convert the worker spin_lock to a
raw_spin_lock.
This is only acceptable to do because the work performed under the lock is
well-bounded and minimal.
Reported-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Reported-by: Tim Sander <tim@krieglstein.org>
Signed-off-by: Julia Cartwright <julia@ni.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Link: https://lkml.kernel.org/r/20190212162554.19779-1-bigeasy@linutronix.de
This patch is to add Hyper-V IOMMU driver file into Hyper-V CORE and
DRIVERS scope.
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Lan Tianyu <Tianyu.Lan@microsoft.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
On the bare metal, enabling X2APIC mode requires interrupt remapping
function which helps to deliver irq to cpu with 32-bit APIC ID.
Hyper-V doesn't provide interrupt remapping function so far and Hyper-V
MSI protocol already supports to deliver interrupt to the CPU whose
virtual processor index is more than 255. IO-APIC interrupt still has
8-bit APIC ID limitation.
This patch is to add Hyper-V stub IOMMU driver in order to enable
X2APIC mode successfully in Hyper-V Linux guest. The driver returns X2APIC
interrupt remapping capability when X2APIC mode is available. Otherwise,
it creates a Hyper-V irq domain to limit IO-APIC interrupts' affinity
and make sure cpus assigned with IO-APIC interrupt have 8-bit APIC ID.
Define 24 IO-APIC remapping entries because Hyper-V only expose one
single IO-APIC and one IO-APIC has 24 pins according IO-APIC spec(
https://pdos.csail.mit.edu/6.828/2016/readings/ia32/ioapic.pdf).
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Lan Tianyu <Tianyu.Lan@microsoft.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Hyper-V doesn't provide irq remapping for IO-APIC. To enable x2apic,
set x2apic destination mode to physcial mode when x2apic is available
and Hyper-V IOMMU driver makes sure cpus assigned with IO-APIC irqs have
8-bit APIC id.
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Lan Tianyu <Tianyu.Lan@microsoft.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
