Maxime Ripard [Fri, 21 Jun 2024 15:20:52 +0000 (16:20 +0100)]
drm/vc4: hvs: Change prototype of __vc4_hvs_alloc to pass registers
The BCM2712 HVS has registers to report the size of the various SRAM the
driver uses, and their size actually differ depending on the stepping.
The initialisation of the memory pools happen in the __vc4_hvs_alloc()
function that also allocates the main HVS structure, that will then hold
the pointer to the memory mapping of the registers.
This creates some kind of circular dependency that we can break by
passing the mapping pointer as an argument for __vc4_hvs_alloc() to use
to query to get the SRAM sizes and initialise the memory pools
accordingly.
Maxime Ripard [Fri, 21 Jun 2024 15:20:51 +0000 (16:20 +0100)]
drm/vc4: hvs: Rework LBM alignment
With the introduction of the support for BCM2712, the check of whether
we're running on vc5 or not to compute the LBM alignment requirement
doesn't work anymore.
Moreover, the LBM size will need to be computed in words for the
BCM2712, while we've had sizes in bytes so far.
Aligning on either 64 or 32 words is thus fairly harmful on BCM2712, so
let's just explicitly align the size when needed, and then call
drm_mm_insert_node_generic() with an alignment of 1.
Maxime Ripard [Fri, 21 Jun 2024 15:20:47 +0000 (16:20 +0100)]
drm/vc4: hvs: Create hw_init function
Since the BCM2712 will feature a significantly different HVS, let's move
the hardware initialisation part of our bind function into a separate
function.
That way, it will be easier to extend in the future.
Maxime Ripard [Fri, 21 Jun 2024 15:20:44 +0000 (16:20 +0100)]
drm/vc4: Introduce generation number enum
With the introduction of the BCM2712 support, we will get yet another
generation of display engine to support.
The binary check of whether it's VC5 or not thus doesn't work anymore,
especially since some parts of the driver will have changed with BCM2711,
and some others with BCM2712.
Let's introduce an enum to store the generation the driver is running
on, which should provide more flexibility.
Dom Cobley [Fri, 21 Jun 2024 15:20:43 +0000 (16:20 +0100)]
drm/vc4: hvs: Remove ABORT_ON_EMPTY flag
ABORT_ON_EMPTY chooses whether the HVS abandons the current frame
when it experiences an underflow, or attempts to continue.
In theory the frame should be black from the point of underflow,
compared to a shift of sebsequent pixels to the left.
Unfortunately it seems to put the HVS is a bad state where it is not
possible to recover simply. This typically requires a reboot
following the 'flip done timed out message'.
Discussion with Broadcom has suggested we don't use this flag.
All their testing is done with it disabled.
Additionally setting BLANK_INSERT_EN causes the HDMI to output
blank pixels on an underflow which avoids it losing sync.
After this change a 'flip done timed out' due to sdram bandwidth
starvation or too low a clock is recoverable once the situation improves.
Dave Stevenson [Fri, 21 Jun 2024 15:20:41 +0000 (16:20 +0100)]
drm/vc4: hvs: Fix dlist debug not resetting the next entry pointer
The debug function to display the dlists didn't reset next_entry_start
when starting each display, so resulting in not stopping the
list at the correct place.
Dom Cobley [Fri, 21 Jun 2024 15:20:40 +0000 (16:20 +0100)]
drm/vc4: hdmi: Avoid hang with debug registers when suspended
Trying to read /sys/kernel/debug/dri/1/hdmi1_regs
when the hdmi is disconnected results in a fatal system hang.
This is due to the pm suspend code disabling the dvp clock.
That is just a gate of the 108MHz clock in DVP_HT_RPI_MISC_CONFIG,
which results in accesses hanging AXI bus.
Dave Stevenson [Fri, 21 Jun 2024 15:20:39 +0000 (16:20 +0100)]
drm/vc4: plane: YUV planes require vertical scaling to always be enabled
It has been observed that a YUV422 unity scaled plane isn't displayed.
Enabling vertical scaling on the UV planes solves this. There is
already a similar clause to always enable horizontal scaling on the
UV planes.
Maxime Ripard [Fri, 21 Jun 2024 15:20:37 +0000 (16:20 +0100)]
drm/vc4: crtc: Move assigned_channel to a variable
We access multiple times the vc4_crtc_state->assigned_channel variable
in the vc4_crtc_get_scanout_position() function, so let's store it in a
local variable.
Maxime Ripard [Fri, 21 Jun 2024 15:20:34 +0000 (16:20 +0100)]
drm/vc4: hvs: Print error if we fail an allocation
We need to allocate a few additional structures when checking our
atomic_state, especially related to hardware SRAM that will hold the
plane descriptors (DLIST) and the current line context (LBM) during
composition.
Since those allocation can fail, let's add some error message in that
case to help debug what goes wrong.
Maxime Ripard [Fri, 21 Jun 2024 15:20:32 +0000 (16:20 +0100)]
drm/vc4: hdmi: Warn if writing to an unknown HDMI register
The VC4 HDMI driver has a bunch of accessors to read from a register.
The read accessor was warning when accessing an unknown register, but
the write one was just returning silently.
Let's make sure we warn also when writing to an unknown register.
Dave Stevenson [Fri, 21 Jun 2024 15:20:30 +0000 (16:20 +0100)]
drm/vc4: hvs: Set AXI panic modes for the HVS
The HVS can change AXI request mode based on how full the COB
FIFOs are.
Until now the vc4 driver has been relying on the firmware to
have set these to sensible values.
With HVS channel 2 now being used for live video, change the
panic mode for all channels to be explicitly set by the driver,
and the same for all channels.
Dom Cobley [Fri, 21 Jun 2024 15:20:28 +0000 (16:20 +0100)]
drm/vc4: hdmi: Avoid log spam for audio start failure
We regularly get dmesg error reports of:
[ 18.184066] hdmi-audio-codec hdmi-audio-codec.3.auto: ASoC: error at snd_soc_dai_startup on i2s-hifi: -19
[ 18.184098] MAI: soc_pcm_open() failed (-19)
These are generated for any disconnected hdmi interface when pulseaudio
attempts to open the associated ALSA device (numerous times). Each open
generates a kernel error message, generating general log spam.
The error messages all come from _soc_pcm_ret in sound/soc/soc-pcm.c#L39
which suggests returning ENOTSUPP, rather that ENODEV will be quiet.
And indeed it is.
Merge tag 'timers_urgent_for_v6.11_rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fixes from Borislav Petkov:
- Remove percpu irq related code in the timer-of initialization routine
as it is broken but also unused (Daniel Lezcano)
- Fix return -ETIME when delta exceeds INT_MAX and the next event not
taking effect sometimes (Jacky Bai)
* tag 'timers_urgent_for_v6.11_rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
clocksource/drivers/imx-tpm: Fix next event not taking effect sometime
clocksource/drivers/imx-tpm: Fix return -ETIME when delta exceeds INT_MAX
clocksource/drivers/timer-of: Remove percpu irq related code
Merge tag 'perf_urgent_for_v6.11_rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Borislav Petkov:
- Fix perf's AUX buffer serialization
- Prevent uninitialized struct members in perf's uprobes handling
* tag 'perf_urgent_for_v6.11_rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/aux: Fix AUX buffer serialization
uprobes: Use kzalloc to allocate xol area
Merge tag 'char-misc-6.11-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
Pull char/misc driver fixes from Greg KH:
"Here are some small char/misc/other driver fixes for 6.11-rc7. It's
nothing huge, just a bunch of small fixes of reported problems,
including:
- lots of tiny iio driver fixes
- nvmem driver fixex
- binder UAF bugfix
- uio driver crash fix
- other small fixes
All of these have been in linux-next this week with no reported
problems"
* tag 'char-misc-6.11-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (21 commits)
VMCI: Fix use-after-free when removing resource in vmci_resource_remove()
Drivers: hv: vmbus: Fix rescind handling in uio_hv_generic
uio_hv_generic: Fix kernel NULL pointer dereference in hv_uio_rescind
misc: keba: Fix sysfs group creation
dt-bindings: nvmem: Use soc-nvmem node name instead of nvmem
nvmem: Fix return type of devm_nvmem_device_get() in kerneldoc
nvmem: u-boot-env: error if NVMEM device is too small
misc: fastrpc: Fix double free of 'buf' in error path
binder: fix UAF caused by offsets overwrite
iio: imu: inv_mpu6050: fix interrupt status read for old buggy chips
iio: adc: ad7173: fix GPIO device info
iio: adc: ad7124: fix DT configuration parsing
iio: adc: ad_sigma_delta: fix irq_flags on irq request
iio: adc: ads1119: Fix IRQ flags
iio: fix scale application in iio_convert_raw_to_processed_unlocked
iio: adc: ad7124: fix config comparison
iio: adc: ad7124: fix chip ID mismatch
iio: adc: ad7173: Fix incorrect compatible string
iio: buffer-dmaengine: fix releasing dma channel on error
iio: adc: ad7606: remove frstdata check for serial mode
...
Merge tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux
Pull clk fixes from Stephen Boyd:
"A pile of Qualcomm clk driver fixes with two main themes: the alpha
PLL driver and shared RCGs, and one fix for the Starfive JH7110 SoC.
- The Alpha PLL clk_ops had multiple problems around setting rates.
There are a handful of patches here that fix masks and skip
enabling the clk from set_rate() when the PLL is disabled. The PLLs
are crucial to operation of the system as almost all frequencies in
the system are derived from them.
- Parking shared RCGs at a slow always on clk at registration time
breaks stuff.
USB host mode can't handle such a slow frequency and the serial
console gets all garbled when the UART clk is handed over to the
kernel. There's a few patches that don't use the shared clk_ops for
the UART clks and another one to skip parking the USB clk at
registration time.
- The Starfive PLL driver used for the CPU was busted causing cpufreq
to fail because the clk didn't change to a safe parent during
set_rate().
The fix is to register a notifier and switch to a safe parent so
the PLL can change rate in a glitch free manner"
* tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
clk: qcom: gcc-sc8280xp: don't use parking clk_ops for QUPs
clk: starfive: jh7110-sys: Add notifier for PLL0 clock
clk: qcom: gcc-sm8650: Don't use shared clk_ops for QUPs
clk: qcom: gcc-sm8550: Don't park the USB RCG at registration time
clk: qcom: gcc-sm8550: Don't use parking clk_ops for QUPs
clk: qcom: gcc-x1e80100: Don't use parking clk_ops for QUPs
clk: qcom: ipq9574: Update the alpha PLL type for GPLLs
clk: qcom: gcc-x1e80100: Fix USB 0 and 1 PHY GDSC pwrsts flags
clk: qcom: clk-alpha-pll: Update set_rate for Zonda PLL
clk: qcom: clk-alpha-pll: Fix zonda set_rate failure when PLL is disabled
clk: qcom: clk-alpha-pll: Fix the trion pll postdiv set rate API
clk: qcom: clk-alpha-pll: Fix the pll post div mask
Merge tag 'pinctrl-v6.11-3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl
Pull pin control fix from Linus Walleij:
"A single fix for Qualcomm laptops that are affected by
missing wakeup IRQs"
* tag 'pinctrl-v6.11-3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl:
pinctrl: qcom: x1e80100: Bypass PDC wakeup parent for now
Merge tag 'linux_kselftest-kunit-fixes-6.11-rc7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest
PullKUnit fix from Shuah Khan:
"Fix to a missing function parameter warning found during documentation
build in linux-next"
* tag 'linux_kselftest-kunit-fixes-6.11-rc7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
kunit: Fix missing kerneldoc comment
Merge tag 'pci-v6.11-fixes-3' of git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci
Pull pci fixes from Bjorn Helgaas:
- Unregister platform devices for child nodes when stopping a PCI
device, even if the PCI core has already cleared the OF_POPULATED bit
and of_platform_depopulate() doesn't do anything (Bartosz
Golaszewski)
- Rescan the bus from a separate thread so we don't deadlock when
triggering rescan from sysfs (Bartosz Golaszewski)
* tag 'pci-v6.11-fixes-3' of git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci:
PCI/pwrctl: Rescan bus on a separate thread
PCI: Don't rely on of_platform_depopulate() for reused OF-nodes
Merge tag 'v6.11-rc6-cifs-client-fixes' of git://git.samba.org/sfrench/cifs-2.6
Pull smb client fixes from Steve French:
- fix potential mount hang
- fix retry problem in two types of compound operations
- important netfs integration fix in SMB1 read paths
- fix potential uninitialized zero point of inode
- minor patch to improve debugging for potential crediting problems
* tag 'v6.11-rc6-cifs-client-fixes' of git://git.samba.org/sfrench/cifs-2.6:
netfs, cifs: Improve some debugging bits
cifs: Fix SMB1 readv/writev callback in the same way as SMB2/3
cifs: Fix zero_point init on inode initialisation
smb: client: fix double put of @cfile in smb2_set_path_size()
smb: client: fix double put of @cfile in smb2_rename_path()
smb: client: fix hang in wait_for_response() for negproto
KVM: x86: don't fall through case statements without annotations
clang warns on this because it has an unannotated fall-through between
cases:
arch/x86/kvm/x86.c:4819:2: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
and while we could annotate it as a fallthrough, the proper fix is to
just add the break for this case, instead of falling through to the
default case and the break there.
gcc also has that warning, but it looks like gcc only warns for the
cases where they fall through to "real code", rather than to just a
break. Odd.
Fixes: d30d9ee94cc0 ("KVM: x86: Only advertise KVM_CAP_READONLY_MEM when supported by VM") Cc: Paolo Bonzini <[email protected]> Cc: Tom Dohrmann <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 fix from Catalin Marinas:
"Fix the arm64 usage of ftrace_graph_ret_addr() to pass the
&state->graph_idx pointer instead of NULL, otherwise this function
just returns early"
* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
arm64: stacktrace: fix the usage of ftrace_graph_ret_addr()
Merge tag 'riscv-for-linus-6.11-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux
Pull RISC-V fixes from Palmer Dabbelt:
- A revert for the mmap() change that ties the allocation range to the
hint adress, as what we tried to do ended up regressing on other
userspace workloads.
- A fix to avoid a kernel memory leak when emulating misaligned
accesses from userspace.
- A Kconfig fix for toolchain vector detection, which now correctly
detects vector support on toolchains where the V extension depends on
the M extension.
- A fix to avoid failing the linear mapping bootmem bounds check on
NOMMU systems.
- A fix for early alternatives on relocatable kernels.
* tag 'riscv-for-linus-6.11-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
riscv: Fix RISCV_ALTERNATIVE_EARLY
riscv: Do not restrict memory size because of linear mapping on nommu
riscv: Fix toolchain vector detection
riscv: misaligned: Restrict user access to kernel memory
riscv: mm: Do not restrict mmap address based on hint
riscv: selftests: Remove mmap hint address checks
Revert "RISC-V: mm: Document mmap changes"
Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull x86 kvm fixes from Paolo Bonzini:
"Many small fixes that accumulated while I was on vacation...
- Fixup missed comments from the REMOVED_SPTE => FROZEN_SPTE rename
- Ensure a root is successfully loaded when pre-faulting SPTEs
- Grab kvm->srcu when handling KVM_SET_VCPU_EVENTS to guard against
accessing memslots if toggling SMM happens to force a VM-Exit
- Emulate MSR_{FS,GS}_BASE on SVM even though interception is always
disabled, so that KVM does the right thing if KVM's emulator
encounters {RD,WR}MSR
- Explicitly clear BUS_LOCK_DETECT from KVM's caps on AMD, as KVM
doesn't yet virtualize BUS_LOCK_DETECT on AMD
- Cleanup the help message for CONFIG_KVM_AMD_SEV, and call out that
KVM now supports SEV-SNP too
- Specialize return value of
KVM_CHECK_EXTENSION(KVM_CAP_READONLY_MEM), based on VM type
- Remove unnecessary dependency on CONFIG_HIGH_RES_TIMERS
- Note an RCU quiescent state on guest exit. This avoids a call to
rcu_core() if there was a grace period request while guest was
running"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: Remove HIGH_RES_TIMERS dependency
kvm: Note an RCU quiescent state on guest exit
KVM: x86: Only advertise KVM_CAP_READONLY_MEM when supported by VM
KVM: SEV: Update KVM_AMD_SEV Kconfig entry and mention SEV-SNP
KVM: SVM: Don't advertise Bus Lock Detect to guest if SVM support is missing
KVM: SVM: fix emulation of msr reads/writes of MSR_FS_BASE and MSR_GS_BASE
KVM: x86: Acquire kvm->srcu when handling KVM_SET_VCPU_EVENTS
KVM: x86/mmu: Check that root is valid/loaded when pre-faulting SPTEs
KVM: x86/mmu: Fixup comments missed by the REMOVED_SPTE=>FROZEN_SPTE rename
Merge tag 'pm-6.11-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management fix from Rafael Wysocki:
"Fix an incorrect warning emitted by the amd-pstate driver on
processors that don't support X86_FEATURE_CPPC (Gautham Shenoy)"
* tag 'pm-6.11-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
cpufreq/amd-pstate: Remove warning for X86_FEATURE_CPPC on certain Zen models
Merge tag 'block-6.11-20240906' of git://git.kernel.dk/linux
Pull block fixes from Jens Axboe:
"Mostly just some fixlets for NVMe, but also a bug fix for the ublk
driver and an integrity fix"
* tag 'block-6.11-20240906' of git://git.kernel.dk/linux:
bio-integrity: don't restrict the size of integrity metadata
ublk_drv: fix NULL pointer dereference in ublk_ctrl_start_recovery()
nvmet: Identify-Active Namespace ID List command should reject invalid nsid
nvme: set BLK_FEAT_ZONED for ZNS multipath disks
nvme-pci: Add sleep quirk for Samsung 990 Evo
nvme-pci: allocate tagset on reset if necessary
nvmet-tcp: fix kernel crash if commands allocation fails
nvme: use better description for async reset reason
nvmet: Make nvmet_debugfs static
Merge tag 'sound-6.11-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound
Pull sound fixes from Takashi Iwai:
"Hopefully the last PR for 6.11, at least for this level of amount.
In addition to the usual HD-audio quirks, there are more changes in
ASoC, but all look small and device-specific fixes, and nothing stands
out. The only slightly big change is sunxi I2S fix, which looks quite
safe to apply, too"
* tag 'sound-6.11-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: (21 commits)
ALSA: hda/realtek - Fix inactive headset mic jack for ASUS Vivobook 15 X1504VAP
ALSA: hda/realtek: Support mute LED on HP Laptop 14-dq2xxx
ALSA: hda/realtek: Enable Mute Led for HP Victus 15-fb1xxx
ALSA: hda/realtek: extend quirks for Clevo V5[46]0
ASoC: codecs: lpass-va-macro: set the default codec version for sm8250
ALSA: hda: add HDMI codec ID for Intel PTL
ALSA: hda/realtek: add patch for internal mic in Lenovo V145
ASoC: sunxi: sun4i-i2s: fix LRCLK polarity in i2s mode
ASoC: amd: yc: Add a quirk for MSI Bravo 17 (D7VEK)
ASoC: mediatek: mt8188-mt6359: Modify key
ASoc: SOF: topology: Clear SOF link platform name upon unload
ALSA: hda/conexant: Add pincfg quirk to enable top speakers on Sirius devices
ASoC: SOF: ipc: replace "enum sof_comp_type" field with "uint32_t"
ASoC: fix module autoloading
ASoC: tda7419: fix module autoloading
ASoC: google: fix module autoloading
ASoC: intel: fix module autoloading
ASoC: tegra: Fix CBB error during probe()
ASoC: dapm: Fix UAF for snd_soc_pcm_runtime object
ASoC: Intel: soc-acpi-cht: Make Lenovo Yoga Tab 3 X90F DMI match less strict
...
Merge tag 'mmc-v6.11-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc
Pull MMC fixes from Ulf Hansson:
"MMC core:
- Apply SD quirks earlier during probe so they become relevant
MMC host:
- cqhci: Fix checking of CQHCI_HALT state
- dw_mmc: Fix IDMAC operation with pages bigger than 4K
- sdhci-of-aspeed: Fix module autoloading"
* tag 'mmc-v6.11-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc:
mmc: cqhci: Fix checking of CQHCI_HALT state
mmc: dw_mmc: Fix IDMAC operation with pages bigger than 4K
mmc: sdhci-of-aspeed: fix module autoloading
mmc: core: apply SD quirks earlier during probe
Merge tag 'gpio-fixes-for-v6.11-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux
Pull gpio fixes from Bartosz Golaszewski:
- fix an OF node reference leak in gpio-rockchip
- add the missing module device table to gpio-modepin
* tag 'gpio-fixes-for-v6.11-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux:
gpio: modepin: Enable module autoloading
gpio: rockchip: fix OF node leak in probe()
Merge tag 'pmdomain-v6.11-rc2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/linux-pm
Pull pmdomain fix from Ulf Hansson:
- Fix support for required OPPs for multiple PM domains
* tag 'pmdomain-v6.11-rc2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/linux-pm:
OPP: Fix support for required OPPs for multiple PM domains
Merge tag 'pwm/for-6.11-rc7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/ukleinek/linux
Pull pwm fix from Uwe Kleine-König:
"Fix an off-by-one in the stm32 driver.
Hardware engineers tend to start counting at 1 while the software guys
usually start with 0. This isn't so nice because that results in
drivers where pwm device #2 needs to use the hardware registers with
index 3.
This was noticed by Fabrice Gasnier.
A small patch fixing that mismatch is the only change included here"
* tag 'pwm/for-6.11-rc7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/ukleinek/linux:
pwm: stm32: Use the right CCxNP bit in stm32_pwm_enable()
Merge tag 'drm-fixes-2024-09-06' of https://gitlab.freedesktop.org/drm/kernel
Pull drm fixes from Dave Airlie:
"This has a fair few patches in it, but I reviewed them all and they
seem like real things, amdgpu, i915 and xe each have a bunch of fixes
for various things, then there is a some bridge suspend/resume
ordering fixes for a recent rework, and then some single driver
changes in a few others.
Nothing looks too serious, hopefully next week is quiet.
amdgpu:
- IPS workaround
- Fix compatibility with older MES firmware
- Fix CPU spikes when clearing VRAM
- Backlight fix
- PMO fix
- Revert SWSMU change to fix regression
i915:
- Do not attempt to load the GSC multiple times
- Fix readout degamma_lut mismatch on ilk/snb
- Mark debug_fence_init_onstack() with __maybe_unused
- fence: Mark debug_fence_free() with __maybe_unused
- display: Add mechanism to use sink model when applying quirk
- display: Increase Fast Wake Sync length as a quirk
komeda:
- zpos normalization fix
nouveau:
- incorrect register fix
imagination:
- memory leak fix
bridge:
- hdmi/bridge rework fixes
panthor:
- cache coherency fix
- hi priority access fix
panel:
- change of compatible string
fbdev:
- deferred-io init with no struct page fix"
* tag 'drm-fixes-2024-09-06' of https://gitlab.freedesktop.org/drm/kernel: (29 commits)
Revert "drm/amdgpu: align pp_power_profile_mode with kernel docs"
drm/fbdev-dma: Only install deferred I/O if necessary
drm/panthor: flush FW AS caches in slow reset path
drm: panel: nv3052c: Correct WL-355608-A8 panel compatible
dt-bindings: display: panel: Rename WL-355608-A8 panel to rg35xx-*-panel
drm/panthor: Restrict high priorities on group_create
drm/xe/display: Avoid encoder_suspend at runtime suspend
drm/xe: Suspend/resume user access only during system s/r
drm/xe/display: Match i915 driver suspend/resume sequences better
drm/xe: Add missing runtime reference to wedged upon gt_reset
drm/xe/pcode: Treat pcode as per-tile rather than per-GT
drm/xe/gsc: Do not attempt to load the GSC multiple times
drm/bridge-connector: reset the HDMI connector state
drm/bridge-connector: move to DRM_DISPLAY_HELPER module
drm/display: stop depending on DRM_DISPLAY_HELPER
drm/i915/display: Increase Fast Wake Sync length as a quirk
drm/i915/display: Add mechanism to use sink model when applying quirk
drm/amd/display: Block timing sync for different signals in PMO
drm/amd/display: Lock DC and exit IPS when changing backlight
drm/amdgpu: always allocate cleared VRAM for GEM allocations
...
get_stashed_dentry() tries to optimistically retrieve a stashed dentry
from a provided location. It needs to ensure to hold rcu lock before it
dereference the stashed location to prevent UAF issues. Use
rcu_dereference() instead of READ_ONCE() it's effectively equivalent
with some lockdep bells and whistles and it communicates clearly that
this expects rcu protection.
Christian König [Mon, 26 Aug 2024 12:25:40 +0000 (14:25 +0200)]
drm/doc: Document submission error signaling
Different approaches have been tried to signal resets and other errors in
vendor specific ways which not only resulted in a wide variety of
implementations but also repeating the same bugs and problems over different
drivers.
Document that drivers should use dma_fence based error signaling which is
vendor agnostic and allows userspace to query submission errors in generic
non-vendor specific code.
Christian König [Mon, 26 Aug 2024 12:25:38 +0000 (14:25 +0200)]
drm/sched: add optional errno to drm_sched_start()
The current implementation of drm_sched_start uses a hardcoded
-ECANCELED to dispose of a job when the parent/hw fence is NULL.
This results in drm_sched_job_done being called with -ECANCELED for
each job with a NULL parent in the pending list, making it difficult
to distinguish between recovery methods, whether a queue reset or a
full GPU reset was used.
To improve this, we first try a soft recovery for timeout jobs and
use the error code -ENODATA. If soft recovery fails, we proceed with
a queue reset, where the error code remains -ENODATA for the job.
Finally, for a full GPU reset, we use error codes -ECANCELED or
-ETIME. This patch adds an error code parameter to drm_sched_start,
allowing us to differentiate between queue reset and GPU reset
failures. This enables user mode and test applications to validate
the expected correctness of the requested operation. After a
successful queue reset, the only way to continue normal operation is
to call drm_sched_job_done with the specific error code -ENODATA.
v1: Initial implementation by Jesse utilized amdgpu_device_lock_reset_domain
and amdgpu_device_unlock_reset_domain to allow user mode to track
the queue reset status and distinguish between queue reset and
GPU reset.
v2: Christian suggested using the error codes -ENODATA for queue reset
and -ECANCELED or -ETIME for GPU reset, returned to
amdgpu_cs_wait_ioctl.
v3: To meet the requirements, we introduce a new function
drm_sched_start_ex with an additional parameter to set
dma_fence_set_error, allowing us to handle the specific error
codes appropriately and dispose of bad jobs with the selected
error code depending on whether it was a queue reset or GPU reset.
v4: Alex suggested using a new name, drm_sched_start_with_recovery_error,
which more accurately describes the function's purpose.
Additionally, it was recommended to add documentation details
about the new method.
v5: Fixed declaration of new function drm_sched_start_with_recovery_error.(Alex)
v6 (chk): rebase on upstream changes, cleanup the commit message,
drop the new function again and update all callers,
apply the errno also to scheduler fences with hw fences
v7 (chk): rebased
drm/bochs: Use GEM SHMEM helpers for memory management
Replace GEM VRAM with GEM SHMEM in bochs. The new memory manager
stores buffer objects in system memory. Makes the driver's memory
management more reliably.
Most of the changes are hidden in external helpers that allocate
buffers. Replacing DRM_GEM_VRAM_DRIVER with DRM_GEM_SHMEM_DRIVER_OPS
swaps these. With GEM VRAM, the video memory was updated directly by
the DRM client. The biggest change within bochs is in atomic_update,
which now updates video memory via memcpy() from the BO in system
memory. Shadow-plane helpers maintaining the pointers to the buffer's
data, so bochs doesn't have to. The update is triggered by each page
flip's call to the framebuffer's dirty helper. The driver supports
damage clipping to minimize memcpy() overhead.
The advantage of GEM SHMEM is that it makes memory management
more reliable. Given DRM's double buffering during page flips, the
minimum amount of video memory is three times the maximum consumption
in some pathological cases. For example, if the maximum size of a GEM
buffer is 1920x1080-32 (i.e., 32-bit FullHD), the buffer size is
8 MiB. Display hardware has to provide at lease 24 MiB to reliably
page flip such configurations. This cannot always be guaranteed and
bochs already contains code to rule out <4 MiB configurations. With
GEM SHMEM, only 8 MiB of video memory are required for the given
example. Unsupported modes can be sorted out easily.
Remove the simple display pipeline in favor of the regular atomic
helpers in bochs. The simple-pipe helpers are considered deprecated
in DRM.
This effectivly inlines the simple-pipe code for plane and CRTC
support. Instead of a single update helper, there's now a mode-set
helper for the CRTC and an update helper for the plane. The encoder
changes type from NONE ot VIRTUAL.
Removing simple-pipe helpers from bochs will allow for related
cleanups in GEM VRAM helpers.
drm/bochs: Allocate DRM device in struct bochs_device
Allocate an instance of struct drm_device in struct bochs_device. Also
remove all uses of dev_private from bochs and upcast from the embedded
instance if necessary.
Implement a read function for struct drm_edid and read the EDID data
with drm_edit_read_custom(). Update the connector data accordingly.
The EDID data comes from the emulator itself and the connector stores
a copy in its EDID property. The drm_edid field in struct bochs_device
is therefore not required. Remove it.
If qemu provides no EDID data, install default display modes as before.
'struct exynos_drm_ipp_funcs' are not modified in these drivers.
Constifying this structure moves some data to a read-only section, so
increase overall security.
On a x86_64, with allmodconfig, as an example:
Before:
======
text data bss dec hex filename
20446 1746 16 22208 56c0 drivers/gpu/drm/exynos/exynos_drm_fimc.o
After:
=====
text data bss dec hex filename
20446 1714 16 22176 56a0 drivers/gpu/drm/exynos/exynos_drm_fimc.o
dt-bindings: MAINTAINERS: drop stale exynos file pattern
With last TXT binding converted to DT schema, all Samsung Exynos display
bindings are in "samsung" directory, already present in maintainers
entry. Drop old "exynos" directory to fix get_maintainers.pl self-test
warning:
./MAINTAINERS:7539: warning: no file matches F: Documentation/devicetree/bindings/display/exynos/
Fixes: ad6d17e10306 ("dt-bindings: display: samsung,exynos5-dp: convert to DT Schema") Signed-off-by: Krzysztof Kozlowski <[email protected]> Signed-off-by: Inki Dae <[email protected]>
Merge tag 'asoc-fix-v6.11-rc6' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus
ASoC: Fixes for v6.11
A larger set of fixes than I'd like at this point, but mainly due to
people working on fixing module autoloading by adding missing exports of
ID tables rather than anything particularly concerning. There are some
other runtime fixes and quirks, and a tweak to the ABI definition for
SOF which ensures that a struct layout doesn't vary depending on the
architecture of the host.
Dave Airlie [Fri, 6 Sep 2024 06:02:05 +0000 (16:02 +1000)]
Merge tag 'mediatek-drm-next-6.12' of https://git.kernel.org/pub/scm/linux/kernel/git/chunkuang.hu/linux into drm-next
Mediatek DRM Next for Linux 6.12
1. Support alpha blending
2. Remove cl in struct cmdq_pkt
3. Fixup for ovl adaptor
4. Declare Z Position for all planes
5. Drop unnecessary check for property presence
6. Add dsi per-frame lp code for mt8188
7. Fix missing configuration flags in mtk_crtc_ddp_config()
8. Use spin_lock_irqsave() for CRTC event lock
9. Add power domain binding to the mediatek DPI controller
Merge tag 'bpf-6.11-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf
Pull bpf fixes from Alexei Starovoitov:
- Fix crash when btf_parse_base() returns an error (Martin Lau)
- Fix out of bounds access in btf_name_valid_section() (Jeongjun Park)
* tag 'bpf-6.11-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
selftests/bpf: Add a selftest to check for incorrect names
bpf: add check for invalid name in btf_name_valid_section()
bpf: Fix a crash when btf_parse_base() returns an error pointer
Dave Airlie [Fri, 6 Sep 2024 01:25:38 +0000 (11:25 +1000)]
Merge tag 'drm-misc-fixes-2024-09-05' of https://gitlab.freedesktop.org/drm/misc/kernel into drm-fixes
A zpos normalization fix for komeda, a register bitmask fix for nouveau,
a memory leak fix for imagination, three fixes for the recent bridge
HDMI work, a potential DoS fix and a cache coherency for panthor, a
change of panel compatible and a deferred-io fix when used with
non-highmem memory.
Dave Airlie [Fri, 6 Sep 2024 01:24:37 +0000 (11:24 +1000)]
Merge tag 'drm-intel-next-2024-09-03' of https://gitlab.freedesktop.org/drm/i915/kernel into drm-next
- Fix probe on 'nomodeset and deprecate i915.modeset=0 (Jani)
- Update new entries in VBT BDB block definitions (Dnyaneshwar)
- Fix clang build (Andy Shevchenko)
- More clean up on drvdata usage in display code (Jani)
- Increase fastwake DP sync pulse count as a quirk (Jouni)
Merge tag 'net-6.11-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Pull networking fixes from Jakub Kicinski:
"Including fixes from can, bluetooth and wireless.
No known regressions at this point. Another calm week, but chances are
that has more to do with vacation season than the quality of our work.
Current release - new code bugs:
- smc: prevent NULL pointer dereference in txopt_get
- eth: ti: am65-cpsw: number of XDP-related fixes
Previous releases - regressions:
- Revert "Bluetooth: MGMT/SMP: Fix address type when using SMP over
BREDR/LE", it breaks existing user space
- Bluetooth: qca: if memdump doesn't work, re-enable IBS to avoid
later problems with suspend
- can: mcp251x: fix deadlock if an interrupt occurs during
mcp251x_open
- eth: r8152: fix the firmware communication error due to use of bulk
write
- ptp: ocp: fix serial port information export
- eth: igb: fix not clearing TimeSync interrupts for 82580
- Revert "wifi: ath11k: support hibernation", fix suspend on Lenovo
Previous releases - always broken:
- eth: intel: fix crashes and bugs when reconfiguration and resets
happening in parallel
- wifi: ath11k: fix NULL dereference in ath11k_mac_get_eirp_power()
Misc:
- docs: netdev: document guidance on cleanup.h"
* tag 'net-6.11-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (61 commits)
ila: call nf_unregister_net_hooks() sooner
tools/net/ynl: fix cli.py --subscribe feature
MAINTAINERS: fix ptp ocp driver maintainers address
selftests: net: enable bind tests
net: dsa: vsc73xx: fix possible subblocks range of CAPT block
sched: sch_cake: fix bulk flow accounting logic for host fairness
docs: netdev: document guidance on cleanup.h
net: xilinx: axienet: Fix race in axienet_stop
net: bridge: br_fdb_external_learn_add(): always set EXT_LEARN
r8152: fix the firmware doesn't work
fou: Fix null-ptr-deref in GRO.
bareudp: Fix device stats updates.
net: mana: Fix error handling in mana_create_txq/rxq's NAPI cleanup
bpf, net: Fix a potential race in do_sock_getsockopt()
net: dqs: Do not use extern for unused dql_group
sch/netem: fix use after free in netem_dequeue
usbnet: modern method to get random MAC
MAINTAINERS: wifi: cw1200: add net-cw1200.h
ice: do not bring the VSI up, if it was down before the XDP setup
ice: remove ICE_CFG_BUSY locking from AF_XDP code
...
Merge tag 'spi-fix-v6.11-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi
Pull spi fixes from Mark Brown:
"A few small driver specific fixes (including some of the widespread
work on fixing missing ID tables for module autoloading and the revert
of some problematic PM work in spi-rockchip), some improvements to the
MAINTAINERS information for the NXP drivers and the addition of a new
device ID to spidev"
* tag 'spi-fix-v6.11-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi:
MAINTAINERS: SPI: Add mailing list [email protected] for nxp spi drivers
MAINTAINERS: SPI: Add freescale lpspi maintainer information
spi: spi-fsl-lpspi: Fix off-by-one in prescale max
spi: spidev: Add missing spi_device_id for jg10309-01
spi: bcm63xx: Enable module autoloading
spi: intel: Add check devm_kasprintf() returned value
spi: spidev: Add an entry for elgin,jg10309-01
spi: rockchip: Resolve unbalanced runtime PM / system PM handling
Dave Airlie [Thu, 5 Sep 2024 23:45:52 +0000 (09:45 +1000)]
Merge tag 'drm-intel-fixes-2024-09-05' of https://gitlab.freedesktop.org/drm/i915/kernel into drm-fixes
- drm/i915: Do not attempt to load the GSC multiple times (Daniele Ceraolo Spurio)
- drm/i915: Fix readout degamma_lut mismatch on ilk/snb (Ville Syrjälä)
- drm/i915/fence: Mark debug_fence_init_onstack() with __maybe_unused (Andy Shevchenko)
- drm/i915/fence: Mark debug_fence_free() with __maybe_unused (Andy Shevchenko)
- drm/i915/display: Add mechanism to use sink model when applying quirk [display] (Jouni Högander)
- drm/i915/display: Increase Fast Wake Sync length as a quirk [display] (Jouni Högander)
Merge tag 'regulator-fix-v6.11-stub' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator
Pull regulator fix from Mark Brown:
"A fix from Doug Anderson for a missing stub, required to fix the build
for some newly added users of devm_regulator_bulk_get_const() in
!REGULATOR configurations"
* tag 'regulator-fix-v6.11-stub' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator:
regulator: core: Stub devm_regulator_bulk_get_const() if !CONFIG_REGULATOR
Merge tag 'rust-fixes-6.11-2' of https://github.com/Rust-for-Linux/linux
Pull Rust fixes from Miguel Ojeda:
"Toolchain and infrastructure:
- Fix builds for nightly compiler users now that 'new_uninit' was
split into new features by using an alternative approach for the
code that used what is now called the 'box_uninit_write' feature
- Allow the 'stable_features' lint to preempt upcoming warnings about
them, since soon there will be unstable features that will become
stable in nightly compilers
- Export bss symbols too
'kernel' crate:
- 'block' module: fix wrong usage of lockdep API
'macros' crate:
- Provide correct provenance when constructing 'THIS_MODULE'
Documentation:
- Remove unintended indentation (blockquotes) in generated output
- Fix a couple typos
MAINTAINERS:
- Remove Wedson as Rust maintainer
- Update Andreas' email"
* tag 'rust-fixes-6.11-2' of https://github.com/Rust-for-Linux/linux:
MAINTAINERS: update Andreas Hindborg's email address
MAINTAINERS: Remove Wedson as Rust maintainer
rust: macros: provide correct provenance when constructing THIS_MODULE
rust: allow `stable_features` lint
docs: rust: remove unintended blockquote in Quick Start
rust: alloc: eschew `Box<MaybeUninit<T>>::write`
rust: kernel: fix typos in code comments
docs: rust: remove unintended blockquote in Coding Guidelines
rust: block: fix wrong usage of lockdep API
rust: kbuild: fix export of bss symbols
Merge tag 'trace-v6.11-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing fixes from Steven Rostedt:
- Fix adding a new fgraph callback after function graph tracing has
already started.
If the new caller does not initialize its hash before registering the
fgraph_ops, it can cause a NULL pointer dereference. Fix this by
adding a new parameter to ftrace_graph_enable_direct() passing in the
newly added gops directly and not rely on using the fgraph_array[],
as entries in the fgraph_array[] must be initialized.
Assign the new gops to the fgraph_array[] after it goes through
ftrace_startup_subops() as that will properly initialize the
gops->ops and initialize its hashes.
- Fix a memory leak in fgraph storage memory test.
If the "multiple fgraph storage on a function" boot up selftest fails
in the registering of the function graph tracer, it will not free the
memory it allocated for the filter. Break the loop up into two where
it allocates the filters first and then registers the functions where
any errors will do the appropriate clean ups.
- Only clear the timerlat timers if it has an associated kthread.
In the rtla tool that uses timerlat, if it was killed just as it was
shutting down, the signals can free the kthread and the timer. But
the closing of the timerlat files could cause the hrtimer_cancel() to
be called on the already freed timer. As the kthread variable is is
set to NULL when the kthreads are stopped and the timers are freed it
can be used to know not to call hrtimer_cancel() on the timer if the
kthread variable is NULL.
- Use a cpumask to keep track of osnoise/timerlat kthreads
The timerlat tracer can use user space threads for its analysis. With
the killing of the rtla tool, the kernel can get confused between if
it is using a user space thread to analyze or one of its own kernel
threads. When this confusion happens, kthread_stop() can be called on
a user space thread and bad things happen. As the kernel threads are
per-cpu, a bitmask can be used to know when a kernel thread is used
or when a user space thread is used.
- Add missing interface_lock to osnoise/timerlat stop_kthread()
The stop_kthread() function in osnoise/timerlat clears the osnoise
kthread variable, and if it was a user space thread does a put_task
on it. But this can race with the closing of the timerlat files that
also does a put_task on the kthread, and if the race happens the task
will have put_task called on it twice and oops.
- Add cond_resched() to the tracing_iter_reset() loop.
The latency tracers keep writing to the ring buffer without resetting
when it issues a new "start" event (like interrupts being disabled).
When reading the buffer with an iterator, the tracing_iter_reset()
sets its pointer to that start event by walking through all the
events in the buffer until it gets to the time stamp of the start
event. In the case of a very large buffer, the loop that looks for
the start event has been reported taking a very long time with a non
preempt kernel that it can trigger a soft lock up warning. Add a
cond_resched() into that loop to make sure that doesn't happen.
- Use list_del_rcu() for eventfs ei->list variable
It was reported that running loops of creating and deleting kprobe
events could cause a crash due to the eventfs list iteration hitting
a LIST_POISON variable. This is because the list is protected by SRCU
but when an item is deleted from the list, it was using list_del()
which poisons the "next" pointer. This is what list_del_rcu() was to
prevent.
* tag 'trace-v6.11-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing/timerlat: Add interface_lock around clearing of kthread in stop_kthread()
tracing/timerlat: Only clear timer if a kthread exists
tracing/osnoise: Use a cpumask to know what threads are kthreads
eventfs: Use list_del_rcu() for SRCU protected list variable
tracing: Avoid possible softlockup in tracing_iter_reset()
tracing: Fix memory leak in fgraph storage selftest
tracing: fgraph: Fix to add new fgraph_ops to array after ftrace_startup_subops()
Memory state around the buggy address: ffff88806461ff00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88806461ff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888064620000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^ ffff888064620080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888064620100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
Execution of command:
./tools/net/ynl/cli.py --spec Documentation/netlink/specs/dpll.yaml /
--subscribe "monitor" --sleep 10
fails with:
File "/repo/./tools/net/ynl/cli.py", line 109, in main
ynl.check_ntf()
File "/repo/tools/net/ynl/lib/ynl.py", line 924, in check_ntf
op = self.rsp_by_value[nl_msg.cmd()]
KeyError: 19
Parsing Generic Netlink notification messages performs lookup for op in
the message. The message was not yet decoded, and is not yet considered
GenlMsg, thus msg.cmd() returns Generic Netlink family id (19) instead of
proper notification command id (i.e.: DPLL_CMD_PIN_CHANGE_NTF=13).
Allow the op to be obtained within NetlinkProtocol.decode(..) itself if the
op was not passed to the decode function, thus allow parsing of Generic
Netlink notifications without causing the failure.
Merge tag 'platform-drivers-x86-v6.11-6' of git://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86
Pull x86 platform driver fixes from Ilpo Järvinen:
- amd/pmf: ASUS GA403 quirk matching tweak
- dell-smbios: Fix to the init function rollback path
* tag 'platform-drivers-x86-v6.11-6' of git://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86:
platform/x86/amd: pmf: Make ASUS GA403 quirk generic
platform/x86: dell-smbios: Fix error path in dell_smbios_init()
Merge tag 'linux_kselftest-kunit-fixes-6.11-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest
Pull kunit fix fromShuah Khan:
"One single fix to a use-after-free bug resulting from
kunit_driver_create() failing to copy the driver name leaving it on
the stack or freeing it"
* tag 'linux_kselftest-kunit-fixes-6.11-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
kunit: Device wrappers should also manage driver name
Steven Rostedt [Wed, 21 Aug 2024 13:51:27 +0000 (09:51 -0400)]
KVM: Remove HIGH_RES_TIMERS dependency
Commit 92b5265d38f6a ("KVM: Depend on HIGH_RES_TIMERS") added a dependency
to high resolution timers with the comment:
KVM lapic timer and tsc deadline timer based on hrtimer,
setting a leftmost node to rb tree and then do hrtimer reprogram.
If hrtimer not configured as high resolution, hrtimer_enqueue_reprogram
do nothing and then make kvm lapic timer and tsc deadline timer fail.
That was back in 2012, where hrtimer_start_range_ns() would do the
reprogramming with hrtimer_enqueue_reprogram(). But as that was a nop with
high resolution timers disabled, this did not work. But a lot has changed
in the last 12 years.
For example, commit 49a2a07514a3a ("hrtimer: Kick lowres dynticks targets on
timer enqueue") modifies __hrtimer_start_range_ns() to work with low res
timers. There's been lots of other changes that make low res work.
ChromeOS has tested this before as well, and it hasn't seen any issues
with running KVM with high res timers disabled. There could be problems,
especially at low HZ, for guests that do not support kvmclock and rely
on precise delivery of periodic timers to keep their clock running.
This can be the APIC timer (provided by the kernel), the RTC (provided
by userspace), or the i8254 (choice of kernel/userspace). These guests
are few and far between these days, and in the case of the APIC timer +
Intel hosts we can use the preemption timer (which is TSC-based and has
better latency _and_ accuracy).
In KVM, only x86 is requiring CONFIG_HIGH_RES_TIMERS; perhaps a "depends
on HIGH_RES_TIMERS || EXPERT" could be added to virt/kvm, or a pr_warn
could be added to kvm_init if HIGH_RES_TIMERS are not enabled. But in
general, it seems that there must be other code in the kernel (maybe
sound/?) that is relying on having high-enough HZ or hrtimers but that's
not documented anywhere. Whenever you disable it you probably need to
know what you're doing and what your workload is; so the dependency is
not particularly interesting, and we can just remove it.
Signed-off-by: Steven Rostedt (Google) <[email protected]>
Message-ID: <20240821095127.45d17b19@gandalf.local.home>
[Added the last two paragraphs to the commit message. - Paolo] Signed-off-by: Paolo Bonzini <[email protected]>
Steven Rostedt [Thu, 5 Sep 2024 15:33:59 +0000 (11:33 -0400)]
tracing/timerlat: Add interface_lock around clearing of kthread in stop_kthread()
The timerlat interface will get and put the task that is part of the
"kthread" field of the osn_var to keep it around until all references are
released. But here's a race in the "stop_kthread()" code that will call
put_task_struct() on the kthread if it is not a kernel thread. This can
race with the releasing of the references to that task struct and the
put_task_struct() can be called twice when it should have been called just
once.
Take the interface_lock() in stop_kthread() to synchronize this change.
But to do so, the function stop_per_cpu_kthreads() needs to change the
loop from for_each_online_cpu() to for_each_possible_cpu() and remove the
cpu_read_lock(), as the interface_lock can not be taken while the cpu
locks are held. The only side effect of this change is that it may do some
extra work, as the per_cpu variables of the offline CPUs would not be set
anyway, and would simply be skipped in the loop.