Move the timer gsisters to the sysreg file. This will further help when
they are directly changed by a nesting hypervisor in the VNCR page.
This requires moving the initialisation of the timer struct so that some
of the helpers (such as arch_timer_ctx_index) can work correctly at an
early stage.
Signed-off-by: Marc Zyngier <maz@kernel.org>
kvm_timer_sync_hwstate() has nothing to do with the timer HW state,
but more to do with the state of a userspace interrupt controller.
Change the suffix from _hwstate to_user, in keeping with the rest
of the code.
Signed-off-by: Marc Zyngier <maz@kernel.org>
SPSR_EL1 being a VNCR-capable register with ARMv8.4-NV, move it to
the sysregs array and update the accessors.
Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
As we're about to move SPSR_EL1 into the VNCR page, we need to
disassociate it from the rest of the 32bit cruft. Let's break
the array into individual fields.
Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
SP_EL1 being a VNCR-capable register with ARMv8.4-NV, move it to the
system register array and update the accessors.
Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
As ELR-EL1 is a VNCR-capable register with ARMv8.4-NV, let's move it to
the sys_regs array and repaint the accessors. While we're at it, let's
kill the now useless accessors used only on the fault injection path.
Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
struct kvm_regs is used by userspace to indicate which register gets
accessed by the {GET,SET}_ONE_REG API. But as we're about to refactor
the layout of the in-kernel register structures, we need the kernel to
move away from it.
Let's make kvm_regs userspace only, and let the kernel map it to its own
internal representation.
Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
As part of the ongoing spring cleanup, remove the now useless
vcpu parameter that is passed around (host and guest contexts
give us everything we need).
Signed-off-by: Marc Zyngier <maz@kernel.org>
Switch the hypervisor code to using ctxt_sys_reg/__vcpu_sys_reg instead
of raw sys_regs accesses. No intended functionnal change.
Signed-off-by: Marc Zyngier <maz@kernel.org>
In order to allow the disintegration of the per-vcpu sysreg array,
let's introduce a new helper (ctxt_sys_reg()) that returns the
in-memory copy of a system register, picked from a given context.
__vcpu_sys_reg() is rewritten to use this helper.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Since we often have a precise idea of the level we're dealing with
when invalidating TLBs, we can provide it to as a hint to our
invalidation helper.
Reviewed-by: James Morse <james.morse@arm.com>
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
As we are about to reuse our stage 2 page table manipulation code for
shadow stage 2 page tables in the context of nested virtualization, we
are going to manage multiple stage 2 page tables for a single VM.
This requires some pretty invasive changes to our data structures,
which moves the vmid and pgd pointers into a separate structure and
change pretty much all of our mmu code to operate on this structure
instead.
The new structure is called struct kvm_s2_mmu.
There is no intended functional change by this patch alone.
Reviewed-by: James Morse <james.morse@arm.com>
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
[Designed data structure layout in collaboration]
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Co-developed-by: Marc Zyngier <maz@kernel.org>
[maz: Moved the last_vcpu_ran down to the S2 MMU structure as well]
Signed-off-by: Marc Zyngier <maz@kernel.org>
Add a level-hinted TLB invalidation helper that only gets used if
ARMv8.4-TTL gets detected.
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
In order to reduce the cost of TLB invalidation, the ARMv8.4 TTL
feature allows TLBs to be issued with a level allowing for quicker
invalidation.
Let's detect the feature for now. Further patches will implement
its actual usage.
Reviewed-by : Suzuki K Polose <suzuki.poulose@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
With VHE and nVHE executable code completely separated, remove build config
that disabled GCOV/KASAN/UBSAN/KCOV instrumentation for VHE as these now
execute under the same memory mappings as the rest of the kernel.
No violations are currently being reported by either KASAN or UBSAN.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200625131420.71444-16-dbrazdil@google.com
With nVHE code now fully separated from the rest of the kernel, the effects of
the __hyp_text macro (which had to be applied on all nVHE code) can be
achieved with build rules instead. The macro used to:
(a) move code to .hyp.text ELF section, now done by renaming .text using
`objcopy`, and
(b) `notrace` and `__noscs` would negate effects of CC_FLAGS_FTRACE and
CC_FLAGS_SCS, respectivelly, now those flags are erased from
KBUILD_CFLAGS (same way as in EFI stub).
Note that by removing __hyp_text from code shared with VHE, all VHE code is now
compiled into .text and without `notrace` and `__noscs`.
Use of '.pushsection .hyp.text' removed from assembly files as this is now also
covered by the build rules.
For MAINTAINERS: if needed to re-run, uses of macro were removed with the
following command. Formatting was fixed up manually.
find arch/arm64/kvm/hyp -type f -name '*.c' -o -name '*.h' \
-exec sed -i 's/ __hyp_text//g' {} +
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200625131420.71444-15-dbrazdil@google.com
The following files in hyp/ contain only code shared by VHE/nVHE:
vgic-v3-sr.c, aarch32.c, vgic-v2-cpuif-proxy.c, entry.S, fpsimd.S
Compile them under both configurations. Deletions in image-vars.h reflect
eliminated dependencies of nVHE code on the rest of the kernel.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200625131420.71444-14-dbrazdil@google.com
timer-sr.c contains a HVC handler for setting CNTVOFF_EL2 and two helper
functions for controlling access to physical counter. The former is used by
both VHE/nVHE and is duplicated, the latter are used only by nVHE and moved
to nvhe/timer-sr.c.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200625131420.71444-13-dbrazdil@google.com
sysreg-sr.c contains KVM's code for saving/restoring system registers, with
some code shared between VHE/nVHE. These common routines are moved to
a header file, VHE-specific code is moved to vhe/sysreg-sr.c and nVHE-specific
code to nvhe/sysreg-sr.c.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200625131420.71444-12-dbrazdil@google.com
debug-sr.c contains KVM's code for context-switching debug registers, with some
code shared between VHE/nVHE. These common routines are moved to a header file,
VHE-specific code is moved to vhe/debug-sr.c and nVHE-specific code to
nvhe/debug-sr.c.
Functions are slightly refactored to move code hidden behind `has_vhe()` checks
to the corresponding .c files.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200625131420.71444-11-dbrazdil@google.com
switch.c implements context-switching for KVM, with large parts shared between
VHE/nVHE. These common routines are moved to a header file, VHE-specific code
is moved to vhe/switch.c and nVHE-specific code is moved to nvhe/switch.c.
Previously __kvm_vcpu_run needed a different symbol name for VHE/nVHE. This
is cleaned up and the caller in arm.c simplified.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200625131420.71444-10-dbrazdil@google.com
hyp-entry.S contains implementation of KVM hyp vectors. This code is mostly
shared between VHE/nVHE, therefore compile it under both VHE and nVHE build
rules. nVHE-specific host HVC handler is hidden behind __KVM_NVHE_HYPERVISOR__.
Adjust code which selects which KVM hyp vecs to install to choose the correct
VHE/nVHE symbol.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200625131420.71444-7-dbrazdil@google.com
Once hyp functions are moved to a hyp object, they will have prefixed symbols.
This change declares and gets the address of the prefixed version for calls to
the hyp functions.
To aid migration, the hyp functions that have not yet moved have their prefixed
versions aliased to their non-prefixed version. This begins with all the hyp
functions being listed and will reduce to none of them once the migration is
complete.
Signed-off-by: Andrew Scull <ascull@google.com>
[David: Extracted kvm_call_hyp nVHE branches into own helper macros, added
comments around symbol aliases.]
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200625131420.71444-6-dbrazdil@google.com
Add new folders arch/arm64/kvm/hyp/{vhe,nvhe} and Makefiles for building code
that runs in EL2 under VHE/nVHE KVM, repsectivelly. Add an include folder for
hyp-specific header files which will include code common to VHE/nVHE.
Build nVHE code with -D__KVM_NVHE_HYPERVISOR__, VHE code with
-D__KVM_VHE_HYPERVISOR__.
Under nVHE compile each source file into a `.hyp.tmp.o` object first, then
prefix all its symbols with "__kvm_nvhe_" using `objcopy` and produce
a `.hyp.o`. Suffixes were chosen so that it would be possible for VHE and nVHE
to share some source files, but compiled with different CFLAGS.
The nVHE ELF symbol prefix is added to kallsyms.c as ignored. EL2-only symbols
will never appear in EL1 stack traces.
Due to symbol prefixing, add a section in image-vars.h for aliases of symbols
that are defined in nVHE EL2 and accessed by kernel in EL1 or vice versa.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200625131420.71444-4-dbrazdil@google.com
__hyp_call_panic_nvhe contains inline assembly which did not declare
its dependency on the __hyp_panic_string symbol.
The static-declared string has previously been kept alive because of a use in
__hyp_call_panic_vhe. Fix this in preparation for separating the source files
between VHE and nVHE when the two users land in two different compilation
units. The static variable otherwise gets dropped when compiling the nVHE
source file, causing an undefined symbol linker error later.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200625131420.71444-2-dbrazdil@google.com
Pull ARM OMAP fixes from Arnd Bergmann:
"The OMAP developers are particularly active at hunting down
regressions, so this is a separate branch with OMAP specific
fixes for v5.8:
As Tony explains
"The recent display subsystem (DSS) related platform data changes
caused display related regressions for suspend and resume. Looks
like I only tested suspend and resume before dropping the legacy
platform data, and forgot to test it after dropping it. Turns out
the main issue was that we no longer have platform code calling
pm_runtime_suspend for DSS like we did for the legacy platform data
case, and that fix is still being discussed on the dri-devel list
and will get merged separately. The DSS related testing exposed a
pile other other display related issues that also need fixing
though":
- Fix ti-sysc optional clock handling and reset status checks for
devices that reset automatically in idle like DSS
- Ignore ti-sysc clockactivity bit unless separately requested to
avoid unexpected performance issues
- Init ti-sysc framedonetv_irq to true and disable for am4
- Avoid duplicate DSS reset for legacy mode with dts data
- Remove LCD timings for am4 as they cause warnings now that we're
using generic panels
Other OMAP changes from Tony include:
- Fix omap_prm reset deassert as we still have drivers setting the
pm_runtime_irq_safe() flag
- Flush posted write for ti-sysc enable and disable
- Fix droid4 spi related errors with spi flags
- Fix am335x USB range and a typo for softreset
- Fix dra7 timer nodes for clocks for IPU and DSP
- Drop duplicate mailboxes after mismerge for dra7
- Prevent pocketgeagle header line signal from accidentally setting
micro-SD write protection signal by removing the default mux
- Fix NFSroot flakeyness after resume for duover by switching the
smsc911x gpio interrupt to back to level sensitive
- Fix regression for omap4 clockevent source after recent system
timer changes
- Yet another ethernet regression fix for the "rgmii" vs "rgmii-rxid"
phy-mode
- One patch to convert am3/am4 DT files to use the regular sdhci-omap
driver instead of the old hsmmc driver, this was meant for the
merge window but got lost in the process"
* tag 'arm-omap-fixes-5.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: (21 commits)
ARM: dts: am5729: beaglebone-ai: fix rgmii phy-mode
ARM: dts: Fix omap4 system timer source clocks
ARM: dts: Fix duovero smsc interrupt for suspend
ARM: dts: am335x-pocketbeagle: Fix mmc0 Write Protect
Revert "bus: ti-sysc: Increase max softreset wait"
ARM: dts: am437x-epos-evm: remove lcd timings
ARM: dts: am437x-gp-evm: remove lcd timings
ARM: dts: am437x-sk-evm: remove lcd timings
ARM: dts: dra7-evm-common: Fix duplicate mailbox nodes
ARM: dts: dra7: Fix timer nodes properly for timer_sys_ck clocks
ARM: dts: Fix am33xx.dtsi ti,sysc-mask wrong softreset flag
ARM: dts: Fix am33xx.dtsi USB ranges length
bus: ti-sysc: Increase max softreset wait
ARM: OMAP2+: Fix legacy mode dss_reset
bus: ti-sysc: Fix uninitialized framedonetv_irq
bus: ti-sysc: Ignore clockactivity unless specified as a quirk
bus: ti-sysc: Use optional clocks on for enable and wait for softreset bit
ARM: dts: omap4-droid4: Fix spi configuration and increase rate
bus: ti-sysc: Flush posted write on enable and disable
soc: ti: omap-prm: use atomic iopoll instead of sleeping one
...
Pull ARM SoC fixes from Arnd Bergmann:
"Here are a couple of bug fixes, mostly for devicetree files
NXP i.MX:
- Use correct voltage on some i.MX8M board device trees to avoid
hardware damage
- Code fixes for a compiler warning and incorrect reference counting,
both harmless.
- Fix the i.MX8M SoC driver to correctly identify imx8mp
- Fix watchdog configuration in imx6ul-kontron device tree.
Broadcom:
- A small regression fix for the Raspberry-Pi firmware driver
- A Kconfig change to use the correct timer driver on Northstar
- A DT fix for the Luxul XWC-2000 machine
- Two more DT fixes for NSP SoCs
STmicroelectronics STI
- Revert one broken patch for L2 cache configuration
ARM Versatile Express:
- Fix a regression by reverting a broken DT cleanup
TEE drivers:
- MAINTAINERS: change tee mailing list"
* tag 'arm-fixes-5.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc:
Revert "ARM: sti: Implement dummy L2 cache's write_sec"
soc: imx8m: fix build warning
ARM: imx6: add missing put_device() call in imx6q_suspend_init()
ARM: imx5: add missing put_device() call in imx_suspend_alloc_ocram()
soc: imx8m: Correct i.MX8MP UID fuse offset
ARM: dts: imx6ul-kontron: Change WDOG_ANY signal from push-pull to open-drain
ARM: dts: imx6ul-kontron: Move watchdog from Kontron i.MX6UL/ULL board to SoM
arm64: dts: imx8mm-beacon: Fix voltages on LDO1 and LDO2
arm64: dts: imx8mn-ddr4-evk: correct ldo1/ldo2 voltage range
arm64: dts: imx8mm-evk: correct ldo1/ldo2 voltage range
ARM: dts: NSP: Correct FA2 mailbox node
ARM: bcm2835: Fix integer overflow in rpi_firmware_print_firmware_revision()
MAINTAINERS: change tee mailing list
ARM: dts: NSP: Disable PL330 by default, add dma-coherent property
ARM: bcm: Select ARM_TIMER_SP804 for ARCH_BCM_NSP
ARM: dts: BCM5301X: Add missing memory "device_type" for Luxul XWC-2000
arm: dts: vexpress: Move mcc node back into motherboard node
Pull timer fix from Ingo Molnar:
"A single DocBook fix"
* tag 'timers-urgent-2020-06-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
timekeeping: Fix kerneldoc system_device_crosststamp & al
Pull perf fix from Ingo Molnar:
"A single Kbuild dependency fix"
* tag 'perf-urgent-2020-06-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86/rapl: Fix RAPL config variable bug
Pull EFI fixes from Ingo Molnar:
- Fix build regression on v4.8 and older
- Robustness fix for TPM log parsing code
- kobject refcount fix for the ESRT parsing code
- Two efivarfs fixes to make it behave more like an ordinary file
system
- Style fixup for zero length arrays
- Fix a regression in path separator handling in the initrd loader
- Fix a missing prototype warning
- Add some kerneldoc headers for newly introduced stub routines
- Allow support for SSDT overrides via EFI variables to be disabled
- Report CPU mode and MMU state upon entry for 32-bit ARM
- Use the correct stack pointer alignment when entering from mixed mode
* tag 'efi-urgent-2020-06-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
efi/libstub: arm: Print CPU boot mode and MMU state at boot
efi/libstub: arm: Omit arch specific config table matching array on arm64
efi/x86: Setup stack correctly for efi_pe_entry
efi: Make it possible to disable efivar_ssdt entirely
efi/libstub: Descriptions for stub helper functions
efi/libstub: Fix path separator regression
efi/libstub: Fix missing-prototype warning for skip_spaces()
efi: Replace zero-length array and use struct_size() helper
efivarfs: Don't return -EINTR when rate-limiting reads
efivarfs: Update inode modification time for successful writes
efi/esrt: Fix reference count leak in esre_create_sysfs_entry.
efi/tpm: Verify event log header before parsing
efi/x86: Fix build with gcc 4
Pull scheduler fixes from Borislav Petkov:
"The most anticipated fix in this pull request is probably the horrible
build fix for the RANDSTRUCT fail that didn't make -rc2. Also included
is the cleanup that removes those BUILD_BUG_ON()s and replaces it with
ugly unions.
Also included is the try_to_wake_up() race fix that was first
triggered by Paul's RCU-torture runs, but was independently hit by
Dave Chinner's fstest runs as well"
* tag 'sched_urgent_for_5.8_rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/cfs: change initial value of runnable_avg
smp, irq_work: Continue smp_call_function*() and irq_work*() integration
sched/core: s/WF_ON_RQ/WQ_ON_CPU/
sched/core: Fix ttwu() race
sched/core: Fix PI boosting between RT and DEADLINE tasks
sched/deadline: Initialize ->dl_boosted
sched/core: Check cpus_mask, not cpus_ptr in __set_cpus_allowed_ptr(), to fix mask corruption
sched/core: Fix CONFIG_GCC_PLUGIN_RANDSTRUCT build fail
Pull x86 fixes from Borislav Petkov:
- AMD Memory bandwidth counter width fix, by Babu Moger.
- Use the proper length type in the 32-bit truncate() syscall variant,
by Jiri Slaby.
- Reinit IA32_FEAT_CTL during wakeup to fix the case where after
resume, VMXON would #GP due to VMX not being properly enabled, by
Sean Christopherson.
- Fix a static checker warning in the resctrl code, by Dan Carpenter.
- Add a CR4 pinning mask for bits which cannot change after boot, by
Kees Cook.
- Align the start of the loop of __clear_user() to 16 bytes, to improve
performance on AMD zen1 and zen2 microarchitectures, by Matt Fleming.
* tag 'x86_urgent_for_5.8_rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/asm/64: Align start of __clear_user() loop to 16-bytes
x86/cpu: Use pinning mask for CR4 bits needing to be 0
x86/resctrl: Fix a NULL vs IS_ERR() static checker warning in rdt_cdp_peer_get()
x86/cpu: Reinitialize IA32_FEAT_CTL MSR on BSP during wakeup
syscalls: Fix offset type of ksys_ftruncate()
x86/resctrl: Fix memory bandwidth counter width for AMD
Pull RCU-vs-KCSAN fixes from Borislav Petkov:
"A single commit that uses "arch_" atomic operations to avoid the
instrumentation that comes with the non-"arch_" versions.
In preparation for that commit, it also has another commit that makes
these "arch_" atomic operations available to generic code.
Without these commits, KCSAN uses can see pointless errors"
* tag 'rcu_urgent_for_5.8_rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
rcu: Fixup noinstr warnings
locking/atomics: Provide the arch_atomic_ interface to generic code
Pull objtool fixes from Borislav Petkov:
"Three fixes from Peter Zijlstra suppressing KCOV instrumentation in
noinstr sections.
Peter Zijlstra says:
"Address KCOV vs noinstr. There is no function attribute to
selectively suppress KCOV instrumentation, instead teach objtool
to NOP out the calls in noinstr functions"
This cures a bunch of KCOV crashes (as used by syzcaller)"
* tag 'objtool_urgent_for_5.8_rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
objtool: Fix noinstr vs KCOV
objtool: Provide elf_write_{insn,reloc}()
objtool: Clean up elf_write() condition
Pull x86 entry fixes from Borislav Petkov:
"This is the x86/entry urgent pile which has accumulated since the
merge window.
It is not the smallest but considering the almost complete entry core
rewrite, the amount of fixes to follow is somewhat higher than usual,
which is to be expected.
Peter Zijlstra says:
'These patches address a number of instrumentation issues that were
found after the x86/entry overhaul. When combined with rcu/urgent
and objtool/urgent, these patches make UBSAN/KASAN/KCSAN happy
again.
Part of making this all work is bumping the minimum GCC version for
KASAN builds to gcc-8.3, the reason for this is that the
__no_sanitize_address function attribute is broken in GCC releases
before that.
No known GCC version has a working __no_sanitize_undefined, however
because the only noinstr violation that results from this happens
when an UB is found, we treat it like WARN. That is, we allow it to
violate the noinstr rules in order to get the warning out'"
* tag 'x86_entry_for_5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/entry: Fix #UD vs WARN more
x86/entry: Increase entry_stack size to a full page
x86/entry: Fixup bad_iret vs noinstr
objtool: Don't consider vmlinux a C-file
kasan: Fix required compiler version
compiler_attributes.h: Support no_sanitize_undefined check with GCC 4
x86/entry, bug: Comment the instrumentation_begin() usage for WARN()
x86/entry, ubsan, objtool: Whitelist __ubsan_handle_*()
x86/entry, cpumask: Provide non-instrumented variant of cpu_is_offline()
compiler_types.h: Add __no_sanitize_{address,undefined} to noinstr
kasan: Bump required compiler version
x86, kcsan: Add __no_kcsan to noinstr
kcsan: Remove __no_kcsan_or_inline
x86, kcsan: Remove __no_kcsan_or_inline usage
Some performance regression on reaim benchmark have been raised with
commit 070f5e860e ("sched/fair: Take into account runnable_avg to classify group")
The problem comes from the init value of runnable_avg which is initialized
with max value. This can be a problem if the newly forked task is finally
a short task because the group of CPUs is wrongly set to overloaded and
tasks are pulled less agressively.
Set initial value of runnable_avg equals to util_avg to reflect that there
is no waiting time so far.
Fixes: 070f5e860e ("sched/fair: Take into account runnable_avg to classify group")
Reported-by: kernel test robot <rong.a.chen@intel.com>
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200624154422.29166-1-vincent.guittot@linaro.org
Paul reported rcutorture occasionally hitting a NULL deref:
sched_ttwu_pending()
ttwu_do_wakeup()
check_preempt_curr() := check_preempt_wakeup()
find_matching_se()
is_same_group()
if (se->cfs_rq == pse->cfs_rq) <-- *BOOM*
Debugging showed that this only appears to happen when we take the new
code-path from commit:
2ebb177175 ("sched/core: Offload wakee task activation if it the wakee is descheduling")
and only when @cpu == smp_processor_id(). Something which should not
be possible, because p->on_cpu can only be true for remote tasks.
Similarly, without the new code-path from commit:
c6e7bd7afa ("sched/core: Optimize ttwu() spinning on p->on_cpu")
this would've unconditionally hit:
smp_cond_load_acquire(&p->on_cpu, !VAL);
and if: 'cpu == smp_processor_id() && p->on_cpu' is possible, this
would result in an instant live-lock (with IRQs disabled), something
that hasn't been reported.
The NULL deref can be explained however if the task_cpu(p) load at the
beginning of try_to_wake_up() returns an old value, and this old value
happens to be smp_processor_id(). Further assume that the p->on_cpu
load accurately returns 1, it really is still running, just not here.
Then, when we enqueue the task locally, we can crash in exactly the
observed manner because p->se.cfs_rq != rq->cfs_rq, because p's cfs_rq
is from the wrong CPU, therefore we'll iterate into the non-existant
parents and NULL deref.
The closest semi-plausible scenario I've managed to contrive is
somewhat elaborate (then again, actual reproduction takes many CPU
hours of rcutorture, so it can't be anything obvious):
X->cpu = 1
rq(1)->curr = X
CPU0 CPU1 CPU2
// switch away from X
LOCK rq(1)->lock
smp_mb__after_spinlock
dequeue_task(X)
X->on_rq = 9
switch_to(Z)
X->on_cpu = 0
UNLOCK rq(1)->lock
// migrate X to cpu 0
LOCK rq(1)->lock
dequeue_task(X)
set_task_cpu(X, 0)
X->cpu = 0
UNLOCK rq(1)->lock
LOCK rq(0)->lock
enqueue_task(X)
X->on_rq = 1
UNLOCK rq(0)->lock
// switch to X
LOCK rq(0)->lock
smp_mb__after_spinlock
switch_to(X)
X->on_cpu = 1
UNLOCK rq(0)->lock
// X goes sleep
X->state = TASK_UNINTERRUPTIBLE
smp_mb(); // wake X
ttwu()
LOCK X->pi_lock
smp_mb__after_spinlock
if (p->state)
cpu = X->cpu; // =? 1
smp_rmb()
// X calls schedule()
LOCK rq(0)->lock
smp_mb__after_spinlock
dequeue_task(X)
X->on_rq = 0
if (p->on_rq)
smp_rmb();
if (p->on_cpu && ttwu_queue_wakelist(..)) [*]
smp_cond_load_acquire(&p->on_cpu, !VAL)
cpu = select_task_rq(X, X->wake_cpu, ...)
if (X->cpu != cpu)
switch_to(Y)
X->on_cpu = 0
UNLOCK rq(0)->lock
However I'm having trouble convincing myself that's actually possible
on x86_64 -- after all, every LOCK implies an smp_mb() there, so if ttwu
observes ->state != RUNNING, it must also observe ->cpu != 1.
(Most of the previous ttwu() races were found on very large PowerPC)
Nevertheless, this fully explains the observed failure case.
Fix it by ordering the task_cpu(p) load after the p->on_cpu load,
which is easy since nothing actually uses @cpu before this.
Fixes: c6e7bd7afa ("sched/core: Optimize ttwu() spinning on p->on_cpu")
Reported-by: Paul E. McKenney <paulmck@kernel.org>
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20200622125649.GC576871@hirez.programming.kicks-ass.net
syzbot reported the following warning:
WARNING: CPU: 1 PID: 6351 at kernel/sched/deadline.c:628
enqueue_task_dl+0x22da/0x38a0 kernel/sched/deadline.c:1504
At deadline.c:628 we have:
623 static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se)
624 {
625 struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
626 struct rq *rq = rq_of_dl_rq(dl_rq);
627
628 WARN_ON(dl_se->dl_boosted);
629 WARN_ON(dl_time_before(rq_clock(rq), dl_se->deadline));
[...]
}
Which means that setup_new_dl_entity() has been called on a task
currently boosted. This shouldn't happen though, as setup_new_dl_entity()
is only called when the 'dynamic' deadline of the new entity
is in the past w.r.t. rq_clock and boosted tasks shouldn't verify this
condition.
Digging through the PI code I noticed that what above might in fact happen
if an RT tasks blocks on an rt_mutex hold by a DEADLINE task. In the
first branch of boosting conditions we check only if a pi_task 'dynamic'
deadline is earlier than mutex holder's and in this case we set mutex
holder to be dl_boosted. However, since RT 'dynamic' deadlines are only
initialized if such tasks get boosted at some point (or if they become
DEADLINE of course), in general RT 'dynamic' deadlines are usually equal
to 0 and this verifies the aforementioned condition.
Fix it by checking that the potential donor task is actually (even if
temporary because in turn boosted) running at DEADLINE priority before
using its 'dynamic' deadline value.
Fixes: 2d3d891d33 ("sched/deadline: Add SCHED_DEADLINE inheritance logic")
Reported-by: syzbot+119ba87189432ead09b4@syzkaller.appspotmail.com
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Tested-by: Daniel Wagner <dwagner@suse.de>
Link: https://lkml.kernel.org/r/20181119153201.GB2119@localhost.localdomain
syzbot reported the following warning triggered via SYSC_sched_setattr():
WARNING: CPU: 0 PID: 6973 at kernel/sched/deadline.c:593 setup_new_dl_entity /kernel/sched/deadline.c:594 [inline]
WARNING: CPU: 0 PID: 6973 at kernel/sched/deadline.c:593 enqueue_dl_entity /kernel/sched/deadline.c:1370 [inline]
WARNING: CPU: 0 PID: 6973 at kernel/sched/deadline.c:593 enqueue_task_dl+0x1c17/0x2ba0 /kernel/sched/deadline.c:1441
This happens because the ->dl_boosted flag is currently not initialized by
__dl_clear_params() (unlike the other flags) and setup_new_dl_entity()
rightfully complains about it.
Initialize dl_boosted to 0.
Fixes: 2d3d891d33 ("sched/deadline: Add SCHED_DEADLINE inheritance logic")
Reported-by: syzbot+5ac8bac25f95e8b221e7@syzkaller.appspotmail.com
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Daniel Wagner <dwagner@suse.de>
Link: https://lkml.kernel.org/r/20200617072919.818409-1-juri.lelli@redhat.com
