When the PHY fails on calibration we were previously skipping the ddi
initialization. However the driver is not really prepared for that,
ultimately leading to a NULL pointer dereference:
[ 75.748348] i915 0000:03:00.0: [drm:intel_modeset_init_nogem [i915]] SNPS PHY A failed to calibrate; output will not be used.
...
[ 75.750336] i915 0000:03:00.0: [drm:intel_modeset_setup_hw_state [i915]] [CRTC:80:pipe A] hw state readout: enabled
...
( no DDI A/PHY A )
[ 75.753080] i915 0000:03:00.0: [drm:intel_modeset_setup_hw_state [i915]] [ENCODER:235:DDI B/PHY B] hw state readout: disabled, pipe A
[ 75.753164] i915 0000:03:00.0: [drm:intel_modeset_setup_hw_state [i915]] [ENCODER:245:DDI C/PHY C] hw state readout: disabled, pipe A
...
[ 75.754425] i915 0000:03:00.0: [drm] *ERROR* crtc 80: Can't calculate constants, dotclock = 0!
[ 75.765558] i915 0000:03:00.0: drm_WARN_ON_ONCE(drm_drv_uses_atomic_modeset(dev))
[ 75.765569] WARNING: CPU: 5 PID: 1759 at drivers/gpu/drm/drm_vblank.c:728 drm_crtc_vblank_helper_get_vblank_timestamp_internal+0x347/0x360
...
[ 75.781230] BUG: kernel NULL pointer dereference, address: 000000000000007c
[ 75.788198] #PF: supervisor read access in kernel mode
[ 75.793347] #PF: error_code(0x0000) - not-present page
[ 75.798480] PGD 0 P4D 0
[ 75.801019] Oops: 0000 [#1] PREEMPT SMP NOPTI
[ 75.805377] CPU: 5 PID: 1759 Comm: modprobe Tainted: G W 5.18.0-rc1-demarchi+ #199
[ 75.827613] RIP: 0010:icl_aux_power_well_disable+0x3b/0x200 [i915]
[ 75.833890] Code: 83 ec 30 65 48 8b 04 25 28 00 00 00 48 89 44 24 28 48 8b 06 0f b6 70 1c f6 40 20 04 8d 56 fa 0f 45 f2 e8 88 bd ff ff 48 89 ef <8b> 70 7c e8 ed 67 ff ff 48 89 ef 89 c6 e8 73 67 ff ff 84 c0 75 0a
[ 75.852629] RSP: 0018:ffffc90003a7fb30 EFLAGS: 00010246
[ 75.857852] RAX: 0000000000000000 RBX: ffff8881145e8f10 RCX: 0000000000000000
[ 75.864978] RDX: ffff888115220840 RSI: 0000000000000000 RDI: ffff888115220000
[ 75.872106] RBP: ffff888115220000 R08: ffff88888effffe8 R09: 00000000fffdffff
[ 75.879234] R10: ffff88888e200000 R11: ffff88888ed00000 R12: ffff8881145e8f10
[ 75.886363] R13: 0000000000000001 R14: ffff888115223240 R15: 0000000000000000
[ 75.893490] FS: 00007ff6e753a740(0000) GS:ffff88888f680000(0000) knlGS:0000000000000000
[ 75.901573] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 75.907313] CR2: 000000000000007c CR3: 00000001216a6001 CR4: 0000000000770ee0
[ 75.914446] PKRU: 55555554
[ 75.917153] Call Trace:
[ 75.919603] <TASK>
[ 75.921709] intel_power_domains_sanitize_state+0x88/0xb0 [i915]
[ 75.927814] intel_modeset_init_nogem+0x317/0xef0 [i915]
[ 75.933205] i915_driver_probe+0x5f6/0xdf0 [i915]
[ 75.937976] i915_pci_probe+0x51/0x1d0 [i915]
We skip the initialization of PHY A, but later we try to find out what
is the phy for that power well and dereference dig_port, which is NULL.
Failing the PHY calibration could be left as a warning or error, like it
was before commit b4eb76d82a ("drm/i915/dg2: Skip output init on PHY
calibration failure"). However that often fails for outputs not being
used, which would make the warning/error appear on systems that have no
visible issues. Anyway, there is still a need to fix those failures,
but that is left for later.
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220410061537.4187383-1-lucas.demarchi@intel.com
If ret isn't zero, it is almost for sure ETIMEDOUT, because
we use it in wait_for macro which does continuous retries
until timeout is reached. If we still ran out of time and
retries, we most likely would be interested in getting status,
to understand what was the actual error propagated from PCode,
rather than to find out that we had a time out, which is anyway
quite obvious, if the function fails.
v2: Make it status ? status : ret(thanks Vinod for the hint)
Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Reviewed-by: Vinod Govindapillai <vinod.govindapillai@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220411081343.18099-1-stanislav.lisovskiy@intel.com
Currently skl_pcode_try_request function doesn't
properly handle return value it gets from
snb_pcode_rw, but treats status != 0 as success,
returning true, which basically doesn't allow
to use retry/timeout mechanisms if PCode happens
to be busy and returns EGAIN or some other status
code not equal to 0.
We saw this on real hw and also tried simulating this
by always returning -EAGAIN from snb_pcode_rw for 6 times, which
currently will just result in false success, while it should
have tried until timeout is reached:
[ 22.357729] i915 0000:00:02.0: [drm:intel_cdclk_dump_config [i915]] Changing CDCLK to
307200 kHz, VCO 614400 kHz, ref 38400 kHz, bypass 19200 kHz, voltage level 0
[ 22.357831] i915 0000:00:02.0: [drm:__snb_pcode_rw [i915]] Returning EAGAIN retry 1
[ 22.357892] i915 0000:00:02.0: [drm:skl_pcode_request [i915]] Success, exiting
[ 22.357936] i915 0000:00:02.0: [drm] ERROR Failed to inform PCU about cdclk change (err -11, freq 307200)
We see en error because higher level api, still notices that status was wrong,
however we still did try only once.
We fix it by requiring _both_ the status to be 0 and
request/reply match for success(true) and function
should return failure(false) if either status turns
out to be EAGAIN, EBUSY or whatever or reply/request
masks do not match.
So now we see this in the logs:
[ 22.318667] i915 0000:00:02.0: [drm:intel_cdclk_dump_config [i915]] Changing CDCLK to
307200 kHz, VCO 614400 kHz, ref 38400 kHz, bypass 19200 kHz, voltage level 0
[ 22.318782] i915 0000:00:02.0: [drm:__snb_pcode_rw [i915]] Returning EAGAIN retry 1
[ 22.318849] i915 0000:00:02.0: [drm:__snb_pcode_rw [i915]] Returning EAGAIN retry 2
[ 22.319006] i915 0000:00:02.0: [drm:__snb_pcode_rw [i915]] Returning EAGAIN retry 3
[ 22.319091] i915 0000:00:02.0: [drm:__snb_pcode_rw [i915]] Returning EAGAIN retry 4
[ 22.319158] i915 0000:00:02.0: [drm:__snb_pcode_rw [i915]] Returning EAGAIN retry 5
[ 22.319224] i915 0000:00:02.0: [drm:__snb_pcode_rw [i915]] Returning EAGAIN retry 6
Reviewed-by: Vinod Govindapillai <vinod.govindapillai@intel.com>
Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220408125200.9069-2-stanislav.lisovskiy@intel.com
Sync up with v5.18-rc1, in particular to get 5e3094cfd9
("drm/i915/xehpsdv: Add has_flat_ccs to device info").
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Since gen6 we use FPGA_DBG register to detect unclaimed MMIO registers.
This register is in the display engine IP and can only ever detect
unclaimed accesses to registers in this area. However sometimes there
are reports of this triggering for registers in other areas, which
should not be possible.
Right now we always warn after the read/write of registers going through
unclaimed_reg_debug(). However places using __raw_uncore_* may be
triggering the unclaimed access and those being later accounted to a
different register. Let's warn both before and after the read/write
with a slightly different message, so it's clear if the register
reported in the warning is actually the culprit.
Commit dda960335e ("drm/i915: Just clear the mmiodebug before a
register access") attempted to solve the same issue by removing the
warning when if FPGA_DBG flags before the mmio read/write. However, it
doesn't solve it completely as FPGA_DBG may remain set when reading
registers outside display. So in the end the check after the mmio
read/write triggers the warning pointing to the wrong register.
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220405001149.2675226-1-lucas.demarchi@intel.com
Accessing the DDI_BUF_CTL register without the port's DDI clock being
enabled (to set/clear the TypeC PHY ownership for the port) can lead to
a corrupted value read during any i915 register access right after the
DDI clock is enabled.
The root cause is the way clock synchronization works for this register,
controlled by the CHICKEN_DCPR_1 DDI_CLOCK_REG_ACCESS flag. Correctly
this flag should be cleared on ADLP (see the Bspec link below), however
after bootup the flag is set.
One easily reproducible issue is an unclaimed register access of the
PWR_WELL_CTL_DDI2 register, programmed right after DDI clock enabling to
enable the port's DDI_IO power well (see the HSDES, VLK links below).
With the correct setting above this problem can't be reproduced.
Bspec: 49189
HSDES: 18019028154
VLK: 28328, 28655
Cc: Jouni Högander <jouni.hogander@intel.com>
Cc: Arthur J Runyan <arthur.j.runyan@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Acked-by: Arthur J Runyan <arthur.j.runyan@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220323201749.288566-1-imre.deak@intel.com
Instead of exit PSR when a frontbuffer invalidation happens, we can
enable the PSR2 selective fetch continuous full frame, that will keep
the panel updated like PSR was disabled but without keeping PSR active.
So as soon as the frontbuffer flush happens we can disable the
continuous full frame and start to do selective fetches much quicker
than the path that would enable PSR, that will wait a few frames
to actually activate PSR.
Also this approach has proven to fix some glitches found in Alderlake-P
when there are a lot of invalidations happening together with page
flips.
Some may ask why it is writing to CURSURFLIVE(), it is because
that is the way that hardware team provided us to poke display to
handle PSR updates, and it is being used since display 9.
v2:
- handling possible race conditions between frontbuffer rendering and
page flips
Reviewed-by: Jouni Högander <jouni.hogander@intel.com>
Cc: Khaled Almahallawy <khaled.almahallawy@intel.com>
Cc: Shawn C Lee <shawn.c.lee@intel.com>
Cc: Jouni Högander <jouni.hogander@intel.com>
Cc: Mika Kahola <mika.kahola@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220405155344.47219-3-jose.souza@intel.com
Frontbuffer rendering and page flips can race with each other
and this can potentialy cause issues with PSR2 selective fetch.
And because pipe/crtc updates are time sentive we can't grab the
PSR lock after intel_pipe_update_start() and before
intel_pipe_update_end().
So here adding the lock and unlock functions and calls, the
proper PSR2 selective fetch handling will come in a separated patch.
v2:
- fixed new functions documentation
Reviewed-by: Jouni Högander <jouni.hogander@intel.com>
Cc: Jouni Högander <jouni.hogander@intel.com>
Cc: Mika Kahola <mika.kahola@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220405155344.47219-2-jose.souza@intel.com
Following up what was done in commit 804f468853 ("drm/i915/psr: Set
"SF Partial Frame Enable" also on full update") and also setting
partial frame enable when psr_force_hw_tracking_exit() is called.
Also as PSR2_MAN_TRK_CTL is a double buffered registers do a RMW
is not a good idea so here also setting the man_trk_ctl_enable_bit()
that is required in TGL and only doing a register write.
v2:
- not doing a rmw
v3:
- removing the inline from functions that return PSR2_MAN_TRK_CTL
bits
Reviewed-by: Jouni Högander <jouni.hogander@intel.com>
Cc: Jouni Högander <jouni.hogander@intel.com>
Cc: Mika Kahola <mika.kahola@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220405155344.47219-1-jose.souza@intel.com
The request to aqquire gem resources is failing for DSB in rare
scenario where it is busy and the register programming will be done
through mmio fallback path.
DSB has extra advantage of faster register programming which may
go away through mmio path. Adding wait for gem resource also may
not be right as anyways losing time.
To make the CI execution happy replaced drm_err() to drm_info()
for printing debug info during dsb buffer preparation.
v1: Initial version.
v2: Added print for mmio fallback at out label. [Nirmoy]
v3: Improved debug message. [Nirmoy]
Cc: Nirmoy Das <nirmoy.das@linux.intel.com>
Signed-off-by: Animesh Manna <animesh.manna@intel.com>
Signed-off-by: Uma Shankar <uma.shankar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220325161140.11906-1-animesh.manna@intel.com
Reviewed-by: Nirmoy Das <nirmoy.das@intel.com>
Pull more tracing updates from Steven Rostedt:
- Rename the staging files to give them some meaning. Just
stage1,stag2,etc, does not show what they are for
- Check for NULL from allocation in bootconfig
- Hold event mutex for dyn_event call in user events
- Mark user events to broken (to work on the API)
- Remove eBPF updates from user events
- Remove user events from uapi header to keep it from being installed.
- Move ftrace_graph_is_dead() into inline as it is called from hot
paths and also convert it into a static branch.
* tag 'trace-v5.18-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Move user_events.h temporarily out of include/uapi
ftrace: Make ftrace_graph_is_dead() a static branch
tracing: Set user_events to BROKEN
tracing/user_events: Remove eBPF interfaces
tracing/user_events: Hold event_mutex during dyn_event_add
proc: bootconfig: Add null pointer check
tracing: Rename the staging files for trace_events
Pull clk fix from Stephen Boyd:
"A single revert to fix a boot regression seen when clk_put() started
dropping rate range requests. It's best to keep various systems
booting so we'll kick this out and try again next time"
* tag 'clk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
Revert "clk: Drop the rate range on clk_put()"
Pull x86 fixes from Thomas Gleixner:
"A set of x86 fixes and updates:
- Make the prctl() for enabling dynamic XSTATE components correct so
it adds the newly requested feature to the permission bitmap
instead of overwriting it. Add a selftest which validates that.
- Unroll string MMIO for encrypted SEV guests as the hypervisor
cannot emulate it.
- Handle supervisor states correctly in the FPU/XSTATE code so it
takes the feature set of the fpstate buffer into account. The
feature sets can differ between host and guest buffers. Guest
buffers do not contain supervisor states. So far this was not an
issue, but with enabling PASID it needs to be handled in the buffer
offset calculation and in the permission bitmaps.
- Avoid a gazillion of repeated CPUID invocations in by caching the
values early in the FPU/XSTATE code.
- Enable CONFIG_WERROR in x86 defconfig.
- Make the X86 defconfigs more useful by adapting them to Y2022
reality"
* tag 'x86-urgent-2022-04-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/fpu/xstate: Consolidate size calculations
x86/fpu/xstate: Handle supervisor states in XSTATE permissions
x86/fpu/xsave: Handle compacted offsets correctly with supervisor states
x86/fpu: Cache xfeature flags from CPUID
x86/fpu/xsave: Initialize offset/size cache early
x86/fpu: Remove unused supervisor only offsets
x86/fpu: Remove redundant XCOMP_BV initialization
x86/sev: Unroll string mmio with CC_ATTR_GUEST_UNROLL_STRING_IO
x86/config: Make the x86 defconfigs a bit more usable
x86/defconfig: Enable WERROR
selftests/x86/amx: Update the ARCH_REQ_XCOMP_PERM test
x86/fpu/xstate: Fix the ARCH_REQ_XCOMP_PERM implementation
Pull RT signal fix from Thomas Gleixner:
"Revert the RT related signal changes. They need to be reworked and
generalized"
* tag 'core-urgent-2022-04-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
Revert "signal, x86: Delay calling signals in atomic on RT enabled kernels"
Pull more dma-mapping updates from Christoph Hellwig:
- fix a regression in dma remap handling vs AMD memory encryption (me)
- finally kill off the legacy PCI DMA API (Christophe JAILLET)
* tag 'dma-mapping-5.18-1' of git://git.infradead.org/users/hch/dma-mapping:
dma-mapping: move pgprot_decrypted out of dma_pgprot
PCI/doc: cleanup references to the legacy PCI DMA API
PCI: Remove the deprecated "pci-dma-compat.h" API
Pull more perf tools updates from Arnaldo Carvalho de Melo:
- Avoid SEGV if core.cpus isn't set in 'perf stat'.
- Stop depending on .git files for building PERF-VERSION-FILE, used in
'perf --version', fixing some perf tools build scenarios.
- Convert tracepoint.py example to python3.
- Update UAPI header copies from the kernel sources: socket,
mman-common, msr-index, KVM, i915 and cpufeatures.
- Update copy of libbpf's hashmap.c.
- Directly return instead of using local ret variable in
evlist__create_syswide_maps(), found by coccinelle.
* tag 'perf-tools-for-v5.18-2022-04-02' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux:
perf python: Convert tracepoint.py example to python3
perf evlist: Directly return instead of using local ret variable
perf cpumap: More cpu map reuse by merge.
perf cpumap: Add is_subset function
perf evlist: Rename cpus to user_requested_cpus
perf tools: Stop depending on .git files for building PERF-VERSION-FILE
tools headers cpufeatures: Sync with the kernel sources
tools headers UAPI: Sync drm/i915_drm.h with the kernel sources
tools headers UAPI: Sync linux/kvm.h with the kernel sources
tools kvm headers arm64: Update KVM headers from the kernel sources
tools arch x86: Sync the msr-index.h copy with the kernel sources
tools headers UAPI: Sync asm-generic/mman-common.h with the kernel
perf beauty: Update copy of linux/socket.h with the kernel sources
perf tools: Update copy of libbpf's hashmap.c
perf stat: Avoid SEGV if core.cpus isn't set
Pull Kbuild fixes from Masahiro Yamada:
- Fix empty $(PYTHON) expansion.
- Fix UML, which got broken by the attempt to suppress Clang warnings.
- Fix warning message in modpost.
* tag 'kbuild-fixes-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
modpost: restore the warning message for missing symbol versions
Revert "um: clang: Strip out -mno-global-merge from USER_CFLAGS"
kbuild: Remove '-mno-global-merge'
kbuild: fix empty ${PYTHON} in scripts/link-vmlinux.sh
kconfig: remove stale comment about removed kconfig_print_symbol()
Pull MIPS fixes from Thomas Bogendoerfer:
- build fix for gpio
- fix crc32 build problems
- check for failed memory allocations
* tag 'mips_5.18_1' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux:
MIPS: crypto: Fix CRC32 code
MIPS: rb532: move GPIOD definition into C-files
MIPS: lantiq: check the return value of kzalloc()
mips: sgi-ip22: add a check for the return of kzalloc()
Pull kvm fixes from Paolo Bonzini:
- Only do MSR filtering for MSRs accessed by rdmsr/wrmsr
- Documentation improvements
- Prevent module exit until all VMs are freed
- PMU Virtualization fixes
- Fix for kvm_irq_delivery_to_apic_fast() NULL-pointer dereferences
- Other miscellaneous bugfixes
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (42 commits)
KVM: x86: fix sending PV IPI
KVM: x86/mmu: do compare-and-exchange of gPTE via the user address
KVM: x86: Remove redundant vm_entry_controls_clearbit() call
KVM: x86: cleanup enter_rmode()
KVM: x86: SVM: fix tsc scaling when the host doesn't support it
kvm: x86: SVM: remove unused defines
KVM: x86: SVM: move tsc ratio definitions to svm.h
KVM: x86: SVM: fix avic spec based definitions again
KVM: MIPS: remove reference to trap&emulate virtualization
KVM: x86: document limitations of MSR filtering
KVM: x86: Only do MSR filtering when access MSR by rdmsr/wrmsr
KVM: x86/emulator: Emulate RDPID only if it is enabled in guest
KVM: x86/pmu: Fix and isolate TSX-specific performance event logic
KVM: x86: mmu: trace kvm_mmu_set_spte after the new SPTE was set
KVM: x86/svm: Clear reserved bits written to PerfEvtSeln MSRs
KVM: x86: Trace all APICv inhibit changes and capture overall status
KVM: x86: Add wrappers for setting/clearing APICv inhibits
KVM: x86: Make APICv inhibit reasons an enum and cleanup naming
KVM: X86: Handle implicit supervisor access with SMAP
KVM: X86: Rename variable smap to not_smap in permission_fault()
...
Pull block driver fix from Jens Axboe:
"Got two reports on nbd spewing warnings on load now, which is a
regression from a commit that went into your tree yesterday.
Revert the problematic change for now"
* tag 'for-5.18/drivers-2022-04-02' of git://git.kernel.dk/linux-block:
Revert "nbd: fix possible overflow on 'first_minor' in nbd_dev_add()"
Pull pci fix from Bjorn Helgaas:
- Fix Hyper-V "defined but not used" build issue added during merge
window (YueHaibing)
* tag 'pci-v5.18-changes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
PCI: hv: Remove unused hv_set_msi_entry_from_desc()
Pull chrome platform updates from Benson Leung:
"cros_ec_typec:
- Check for EC device - Fix a crash when using the cros_ec_typec
driver on older hardware not capable of typec commands
- Make try power role optional
- Mux configuration reorganization series from Prashant
cros_ec_debugfs:
- Fix use after free. Thanks Tzung-bi
sensorhub:
- cros_ec_sensorhub fixup - Split trace include file
misc:
- Add new mailing list for chrome-platform development:
chrome-platform@lists.linux.dev
Now with patchwork!"
* tag 'tag-chrome-platform-for-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/chrome-platform/linux:
platform/chrome: cros_ec_debugfs: detach log reader wq from devm
platform: chrome: Split trace include file
platform/chrome: cros_ec_typec: Update mux flags during partner removal
platform/chrome: cros_ec_typec: Configure muxes at start of port update
platform/chrome: cros_ec_typec: Get mux state inside configure_mux
platform/chrome: cros_ec_typec: Move mux flag checks
platform/chrome: cros_ec_typec: Check for EC device
platform/chrome: cros_ec_typec: Make try power role optional
MAINTAINERS: platform-chrome: Add new chrome-platform@lists.linux.dev list
This reverts commit 6d35d04a9e.
Both Gabriel and Borislav report that this commit casues a regression
with nbd:
sysfs: cannot create duplicate filename '/dev/block/43:0'
Revert it before 5.18-rc1 and we'll investigage this separately in
due time.
Link: https://lore.kernel.org/all/YkiJTnFOt9bTv6A2@zn.tnic/
Reported-by: Gabriel L. Somlo <somlo@cmu.edu>
Reported-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
After being merged, user_events become more visible to a wider audience
that have concerns with the current API.
It is too late to fix this for this release, but instead of a full
revert, just mark it as BROKEN (which prevents it from being selected in
make config). Then we can work finding a better API. If that fails,
then it will need to be completely reverted.
To not have the code silently bitrot, still allow building it with
COMPILE_TEST.
And to prevent the uapi header from being installed, then later changed,
and then have an old distro user space see the old version, move the
header file out of the uapi directory.
Surround the include with CONFIG_COMPILE_TEST to the current location,
but when the BROKEN tag is taken off, it will use the uapi directory,
and fail to compile. This is a good way to remind us to move the header
back.
Link: https://lore.kernel.org/all/20220330155835.5e1f6669@gandalf.local.home
Link: https://lkml.kernel.org/r/20220330201755.29319-1-mathieu.desnoyers@efficios.com
Suggested-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ftrace_graph_is_dead() is used on hot paths, it just reads a variable
in memory and is not worth suffering function call constraints.
For instance, at entry of prepare_ftrace_return(), inlining it avoids
saving prepare_ftrace_return() parameters to stack and restoring them
after calling ftrace_graph_is_dead().
While at it using a static branch is even more performant and is
rather well adapted considering that the returned value will almost
never change.
Inline ftrace_graph_is_dead() and replace 'kill_ftrace_graph' bool
by a static branch.
The performance improvement is noticeable.
Link: https://lkml.kernel.org/r/e0411a6a0ed3eafff0ad2bc9cd4b0e202b4617df.1648623570.git.christophe.leroy@csgroup.eu
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
