The code flow for the vclocks is convoluted as it requires the vclocks
which can be invalidated separately from the vsyscall_gtod_data sequence to
store the fact in a separate variable. That's inefficient.
Restructure the code so the vclock readout returns cycles and the
conversion to nanoseconds is handled at the call site.
If the clock gets invalidated or vclock is already VCLOCK_NONE, return
U64_MAX as the cycle value, which is invalid for all clocks and leave the
sequence loop immediately in that case by calling the fallback function
directly.
This allows to remove the gettimeofday fallback as it now uses the
clock_gettime() fallback and does the nanoseconds to microseconds
conversion in the same way as it does when the vclock is functional. It
does not make a difference whether the division by 1000 happens in the
kernel fallback or in userspace.
Generates way better code and gains a few cycles back.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Matt Rickard <matt@softrans.com.au>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: devel@linuxdriverproject.org
Cc: virtualization@lists.linux-foundation.org
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Juergen Gross <jgross@suse.com>
Link: https://lkml.kernel.org/r/20180917130707.657928937@linutronix.de
It's desired to support more clocks in the VDSO, e.g. CLOCK_TAI. This
results either in indirect calls due to the larger switch case, which then
requires retpolines or when the compiler is forced to avoid jump tables it
results in even more conditionals.
To avoid both variants which are bad for performance the high resolution
functions and the coarse grained functions will be collapsed into one for
each. That requires to store the clock specific base time in an array.
Introcude struct vgtod_ts for storage and convert the data store, the
update function and the individual clock functions over to use it.
The new storage does not longer use gtod_long_t for seconds depending on 32
or 64 bit compile because this needs to be the full 64bit value even for
32bit when a Y2038 function is added. No point in keeping the distinction
alive in the internal representation.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Matt Rickard <matt@softrans.com.au>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: devel@linuxdriverproject.org
Cc: virtualization@lists.linux-foundation.org
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Juergen Gross <jgross@suse.com>
Link: https://lkml.kernel.org/r/20180917130707.324679401@linutronix.de
The syscall fallbacks in the vDSO have incorrect asm constraints.
They are not marked as writing to their outputs -- instead, they are
marked as clobbering "memory", which is useless. In particular, gcc
is smart enough to know that the timespec parameter hasn't escaped,
so a memory clobber doesn't clobber it. And passing a pointer as an
asm *input* does not tell gcc that the pointed-to value is changed.
Add in the fact that the asm instructions weren't volatile, and gcc
was free to omit them entirely unless their sole output (the return
value) is used. Which it is (phew!), but that stops happening with
some upcoming patches.
As a trivial example, the following code:
void test_fallback(struct timespec *ts)
{
vdso_fallback_gettime(CLOCK_MONOTONIC, ts);
}
compiles to:
00000000000000c0 <test_fallback>:
c0: c3 retq
To add insult to injury, the RCX and R11 clobbers on 64-bit
builds were missing.
The "memory" clobber is also unnecessary -- no ordering with respect to
other memory operations is needed, but that's going to be fixed in a
separate not-for-stable patch.
Fixes: 2aae950b21 ("x86_64: Add vDSO for x86-64 with gettimeofday/clock_gettime/getcpu")
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/2c0231690551989d2fafa60ed0e7b5cc8b403908.1538422295.git.luto@kernel.org
Miguel writes:
"A trivial fix for auxdisplay
- MAINTAINERS reference fix for moved file
Reported by Joe Perches"
* tag 'auxdisplay-for-greg-v4.19-rc6' of https://github.com/ojeda/linux:
MAINTAINERS: fix reference to moved drivers/{misc => auxdisplay}/panel.c
Dan writes:
"filesystem-dax for 4.19-rc6
Fix a deadlock in the new for 4.19 dax_lock_mapping_entry() routine."
* tag 'libnvdimm-fixes2-4.19-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
dax: Fix deadlock in dax_lock_mapping_entry()
Jens writes:
"Block fixes for 4.19-rc6
A set of fixes that should go into this release. This pull request
contains:
- A fix (hopefully) for the persistent grants for xen-blkfront. A
previous fix from this series wasn't complete, hence reverted, and
this one should hopefully be it. (Boris Ostrovsky)
- Fix for an elevator drain warning with SMR devices, which is
triggered when you switch schedulers (Damien)
- bcache deadlock fix (Guoju Fang)
- Fix for the block unplug tracepoint, which has had the
timer/explicit flag reverted since 4.11 (Ilya)
- Fix a regression in this series where the blk-mq timeout hook is
invoked with the RCU read lock held, hence preventing it from
blocking (Keith)
- NVMe pull from Christoph, with a single multipath fix (Susobhan Dey)"
* tag 'for-linus-20180929' of git://git.kernel.dk/linux-block:
xen/blkfront: correct purging of persistent grants
Revert "xen/blkfront: When purging persistent grants, keep them in the buffer"
blk-mq: I/O and timer unplugs are inverted in blktrace
bcache: add separate workqueue for journal_write to avoid deadlock
xen/blkfront: When purging persistent grants, keep them in the buffer
block: fix deadline elevator drain for zoned block devices
blk-mq: Allow blocking queue tag iter callbacks
nvme: properly propagate errors in nvme_mpath_init
Thomas writes:
"A single fix for the AMD memory encryption boot code so it does not
read random garbage instead of the cached encryption bit when a kexec
kernel is allocated above the 32bit address limit."
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/boot: Fix kexec booting failure in the SEV bit detection code
Thomas writes:
"Three small fixes for clocksource drivers:
- Proper error handling in the Atmel PIT driver
- Add CLOCK_SOURCE_SUSPEND_NONSTOP for TI SoCs so suspend works again
- Fix the next event function for Facebook Backpack-CMM BMC chips so
usleep(100) doesnt sleep several milliseconds"
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
clocksource/drivers/timer-atmel-pit: Properly handle error cases
clocksource/drivers/fttmr010: Fix set_next_event handler
clocksource/drivers/ti-32k: Add CLOCK_SOURCE_SUSPEND_NONSTOP flag for non-am43 SoCs
Thomas writes:
"A single fix for a missing sanity check when a pinned event is tried
to be read on the wrong CPU due to a legit event scheduling failure."
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/core: Add sanity check to deal with pinned event failure
Rafael writes:
"Power management fix for 4.19-rc6
Fix incorrect __init and __exit annotations in the Qualcomm
Kryo cpufreq driver (Nathan Chancellor)."
* tag 'pm-4.19-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
cpufreq: qcom-kryo: Fix section annotations
There is currently a warning when building the Kryo cpufreq driver into
the kernel image:
WARNING: vmlinux.o(.text+0x8aa424): Section mismatch in reference from
the function qcom_cpufreq_kryo_probe() to the function
.init.text:qcom_cpufreq_kryo_get_msm_id()
The function qcom_cpufreq_kryo_probe() references
the function __init qcom_cpufreq_kryo_get_msm_id().
This is often because qcom_cpufreq_kryo_probe lacks a __init
annotation or the annotation of qcom_cpufreq_kryo_get_msm_id is wrong.
Remove the '__init' annotation from qcom_cpufreq_kryo_get_msm_id
so that there is no more mismatch warning.
Additionally, Nick noticed that the remove function was marked as
'__init' when it should really be marked as '__exit'.
Fixes: 46e2856b8e (cpufreq: Add Kryo CPU scaling driver)
Fixes: 5ad7346b4a (cpufreq: kryo: Add module remove and exit)
Reported-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: 4.18+ <stable@vger.kernel.org> # 4.18+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Christoph writes:
"dma mapping fix for 4.19-rc6
fix a missing Kconfig symbol for commits introduced in 4.19-rc"
* tag 'dma-mapping-4.19-3' of git://git.infradead.org/users/hch/dma-mapping:
dma-mapping: add the missing ARCH_HAS_SYNC_DMA_FOR_CPU_ALL declaration
Dmitry writes:
"Input updates for v4.19-rc5
Just a few driver fixes"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
Input: uinput - allow for max == min during input_absinfo validation
Input: elantech - enable middle button of touchpad on ThinkPad P72
Input: atakbd - fix Atari CapsLock behaviour
Input: atakbd - fix Atari keymap
Input: egalax_ts - add system wakeup support
Input: gpio-keys - fix a documentation index issue
Mark writes:
"spi: Fixes for v4.19
Quite a few fixes for the Renesas drivers in here, plus a fix for the
Tegra driver and some documentation fixes for the recently added
spi-mem code. The Tegra fix is relatively large but fairly
straightforward and mechanical, it runs on probe so it's been
reasonably well covered in -next testing."
* tag 'spi-fix-v4.19-rc5' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi:
spi: spi-mem: Move the DMA-able constraint doc to the kerneldoc header
spi: spi-mem: Add missing description for data.nbytes field
spi: rspi: Fix interrupted DMA transfers
spi: rspi: Fix invalid SPI use during system suspend
spi: sh-msiof: Fix handling of write value for SISTR register
spi: sh-msiof: Fix invalid SPI use during system suspend
spi: gpio: Fix copy-and-paste error
spi: tegra20-slink: explicitly enable/disable clock
Mark writes:
"regulator: Fixes for 4.19
A collection of fairly minor bug fixes here, a couple of driver
specific ones plus two core fixes. There's one fix for the new
suspend state code which fixes some confusion with constant values
that are supposed to indicate noop operation and another fixing a
race condition with the creation of sysfs files on new regulators."
* tag 'regulator-v4.19-rc5' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator:
regulator: fix crash caused by null driver data
regulator: Fix 'do-nothing' value for regulators without suspend state
regulator: da9063: fix DT probing with constraints
regulator: bd71837: Disable voltage monitoring for LDO3/4
Michael writes:
"powerpc fixes for 4.19 #3
A reasonably big batch of fixes due to me being away for a few weeks.
A fix for the TM emulation support on Power9, which could result in
corrupting the guest r11 when running under KVM.
Two fixes to the TM code which could lead to userspace GPR corruption
if we take an SLB miss at exactly the wrong time.
Our dynamic patching code had a bug that meant we could patch freed
__init text, which could lead to corrupting userspace memory.
csum_ipv6_magic() didn't work on little endian platforms since we
optimised it recently.
A fix for an endian bug when reading a device tree property telling
us how many storage keys the machine has available.
Fix a crash seen on some configurations of PowerVM when migrating the
partition from one machine to another.
A fix for a regression in the setup of our CPU to NUMA node mapping
in KVM guests.
A fix to our selftest Makefiles to make them work since a recent
change to the shared Makefile logic."
* tag 'powerpc-4.19-3' of https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
selftests/powerpc: Fix Makefiles for headers_install change
powerpc/numa: Use associativity if VPHN hcall is successful
powerpc/tm: Avoid possible userspace r1 corruption on reclaim
powerpc/tm: Fix userspace r13 corruption
powerpc/pseries: Fix unitialized timer reset on migration
powerpc/pkeys: Fix reading of ibm, processor-storage-keys property
powerpc: fix csum_ipv6_magic() on little endian platforms
powerpc/powernv/ioda2: Reduce upper limit for DMA window size (again)
powerpc: Avoid code patching freed init sections
KVM: PPC: Book3S HV: Fix guest r11 corruption with POWER9 TM workarounds
Dave writes:
"drm fixes for 4.19-rc6
Looks like a pretty normal week for graphics,
core: syncobj fix, panel link regression revert
amd: suspend/resume fixes, EDID emulation fix
mali-dp: NV12 writeback and vblank reset fixes
etnaviv: DMA setup fix"
* tag 'drm-fixes-2018-09-28' of git://anongit.freedesktop.org/drm/drm:
drm/amd/display: Fix Edid emulation for linux
drm/amd/display: Fix Vega10 lightup on S3 resume
drm/amdgpu: Fix vce work queue was not cancelled when suspend
Revert "drm/panel: Add device_link from panel device to DRM device"
drm/syncobj: Don't leak fences when WAIT_FOR_SUBMIT is set
drm/malidp: Fix writeback in NV12
drm: mali-dp: Call drm_crtc_vblank_reset on device init
drm/etnaviv: add DMA configuration for etnaviv platform device
Palmer writes:
"A Single RISC-V Update for 4.19-rc6
The Debian guys have been pushing on our port and found some
unversioned symbols leaking into modules. This PR contains a single
fix for that issue."
* tag 'riscv-for-linus-4.19-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/palmer/riscv-linux:
RISC-V: include linux/ftrace.h in asm-prototypes.h
Commit a46b53672b ("xen/blkfront: cleanup
stale persistent grants") introduced a regression as purged persistent
grants were not pu into the list of free grants again. Correct that.
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Commit b2d35fa5fc ("selftests: add headers_install to lib.mk")
introduced a requirement that Makefiles more than one level below the
selftests directory need to define top_srcdir, but it didn't update
any of the powerpc Makefiles.
This broke building all the powerpc selftests with eg:
make[1]: Entering directory '/src/linux/tools/testing/selftests/powerpc'
BUILD_TARGET=/src/linux/tools/testing/selftests/powerpc/alignment; mkdir -p $BUILD_TARGET; make OUTPUT=$BUILD_TARGET -k -C alignment all
make[2]: Entering directory '/src/linux/tools/testing/selftests/powerpc/alignment'
../../lib.mk:20: ../../../../scripts/subarch.include: No such file or directory
make[2]: *** No rule to make target '../../../../scripts/subarch.include'.
make[2]: Failed to remake makefile '../../../../scripts/subarch.include'.
Makefile:38: recipe for target 'alignment' failed
Fix it by setting top_srcdir in the affected Makefiles.
Fixes: b2d35fa5fc ("selftests: add headers_install to lib.mk")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Jason writes:
"Second RDMA rc pull request
- Fix a long standing race bug when destroying comp_event file descriptors
- srp, hfi1, bnxt_re: Various driver crashes from missing validation
and other cases
- Fixes for regressions in patches merged this window in the gid
cache, devx, ucma and uapi."
* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma:
RDMA/core: Set right entry state before releasing reference
IB/mlx5: Destroy the DEVX object upon error flow
IB/uverbs: Free uapi on destroy
RDMA/bnxt_re: Fix system crash during RDMA resource initialization
IB/hfi1: Fix destroy_qp hang after a link down
IB/hfi1: Fix context recovery when PBC has an UnsupportedVL
IB/hfi1: Invalid user input can result in crash
IB/hfi1: Fix SL array bounds check
RDMA/uverbs: Fix validity check for modify QP
IB/srp: Avoid that sg_reset -d ${srp_device} triggers an infinite loop
ucma: fix a use-after-free in ucma_resolve_ip()
RDMA/uverbs: Atomically flush and mark closed the comp event queue
cxgb4: fix abort_req_rss6 struct
Jan writes:
"an ext2 patch fixing fsync(2) for DAX mounts."
* tag 'for_v4.19-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
ext2, dax: set ext2_dax_aops for dax files
trace_block_unplug() takes true for explicit unplugs and false for
implicit unplugs. schedule() unplugs are implicit and should be
reported as timer unplugs. While correct in the legacy code, this has
been inverted in blk-mq since 4.11.
Cc: stable@vger.kernel.org
Fixes: bd166ef183 ("blk-mq-sched: add framework for MQ capable IO schedulers")
Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When dax_lock_mapping_entry() has to sleep to obtain entry lock, it will
fail to unlock mapping->i_pages spinlock and thus immediately deadlock
against itself when retrying to grab the entry lock again. Fix the
problem by unlocking mapping->i_pages before retrying.
Fixes: c2a7d2a115 ("filesystem-dax: Introduce dax_lock_mapping_entry()")
Reported-by: Barret Rhoden <brho@google.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Commit
1958b5fc40 ("x86/boot: Add early boot support when running with SEV active")
can occasionally cause system resets when kexec-ing a second kernel even
if SEV is not active.
That's because get_sev_encryption_bit() uses 32-bit rIP-relative
addressing to read the value of enc_bit - a variable which caches a
previously detected encryption bit position - but kexec may allocate
the early boot code to a higher location, beyond the 32-bit addressing
limit.
In this case, garbage will be read and get_sev_encryption_bit() will
return the wrong value, leading to accessing memory with the wrong
encryption setting.
Therefore, remove enc_bit, and thus get rid of the need to do 32-bit
rIP-relative addressing in the first place.
[ bp: massage commit message heavily. ]
Fixes: 1958b5fc40 ("x86/boot: Add early boot support when running with SEV active")
Suggested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Kairui Song <kasong@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Cc: linux-kernel@vger.kernel.org
Cc: tglx@linutronix.de
Cc: mingo@redhat.com
Cc: hpa@zytor.com
Cc: brijesh.singh@amd.com
Cc: kexec@lists.infradead.org
Cc: dyoung@redhat.com
Cc: bhe@redhat.com
Cc: ghook@redhat.com
Link: https://lkml.kernel.org/r/20180927123845.32052-1-kasong@redhat.com
After write SSD completed, bcache schedules journal_write work to
system_wq, which is a public workqueue in system, without WQ_MEM_RECLAIM
flag. system_wq is also a bound wq, and there may be no idle kworker on
current processor. Creating a new kworker may unfortunately need to
reclaim memory first, by shrinking cache and slab used by vfs, which
depends on bcache device. That's a deadlock.
This patch create a new workqueue for journal_write with WQ_MEM_RECLAIM
flag. It's rescuer thread will work to avoid the deadlock.
Signed-off-by: Guoju Fang <fangguoju@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
