Commit Graph

948892 Commits (94dea151bf3651c01acb12a38ca75ba9d26ea4da)

Author SHA1 Message Date
Roman Li 8a488f5df3 drm/amd/display: Remove VSC infoframe dep on DMCU
[Why]
VSC infoframe is needed for PSR. Previously only DMCU controller
supported PSR. Now DMUB also implements PSR.

[How]
Remove VSC infoframe dependency on DMCU.

Signed-off-by: Roman Li <roman.li@amd.com>
Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Acked-by: Eryk Brol <eryk.brol@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
2020-07-08 09:01:51 -04:00
Jaehyun Chung 486b768046 drm/amd/display: Send VSIF on unsupported modes on DAL
[Why]
Current DAL behaviour is to not send VSIF if mode does not support VRR
(ie. FS range is < 10Hz). However, we should still set FS Native Color
Active bit in some unsupported mode cases.

[How]
Remove check for if VRR is supported before building infopacket.

Signed-off-by: Jaehyun Chung <jaehyun.chung@amd.com>
Reviewed-by: Anthony Koo <Anthony.Koo@amd.com>
Acked-by: Eryk Brol <eryk.brol@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
2020-07-08 09:01:45 -04:00
Igor Kravchenko cd9a180a29 drm/amd/display: Register init
[Why]
Driver re-initialize registers already set in FW

[How]
Transfer init to FW

Signed-off-by: Igor Kravchenko <Igor.Kravchenko@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Eryk Brol <eryk.brol@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
2020-07-08 09:01:38 -04:00
Dmytro Laktyushkin 3c0dcf9f2a drm/amd/display: Add diags scaling log by default
Print scaling parameters as they are calculated in diags.

Signed-off-by: Dmytro Laktyushkin <Dmytro.Laktyushkin@amd.com>
Reviewed-by: Eric Bernstein <Eric.Bernstein@amd.com>
Acked-by: Eryk Brol <eryk.brol@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
2020-07-08 09:01:31 -04:00
Likun Gao 1b0443b115 drm/amdgpu: fix coding error of mmhub pg enablement
MMHUB powergating should be disabled on navi12 and enabled on sienna
cichlid.

Signed-off-by: Likun Gao <Likun.Gao@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
2020-07-08 09:01:24 -04:00
Likun Gao 2373dd48fc drm/amdgpu: use RREG32_KIQ to read register when get cg state
Use RREG32_KIQ to read gfx register when try to get gfx/sdma
clockgating state instead of RREG32, as it will result
to system hard hang when GPU is enter into GFXOFF state.

Signed-off-by: Likun Gao <Likun.Gao@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
2020-07-08 09:01:18 -04:00
John Clements dcf9864d2d drm/amdgpu: updated ta ucode loading
add support for loading ucode with ta_firmware_header_v2_0

Reviewed-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: John Clements <john.clements@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
2020-07-08 09:01:11 -04:00
John Clements f893d74fb8 drm/amdgpu: updated ta ucode header
added definition for ta_firmware_header_v2_0

Reviewed-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: John Clements <john.clements@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
2020-07-08 09:01:04 -04:00
Huang Rui 90937420c4 drm/amdgpu: add TMR destory function for psp
TMR is required to be destoried with GFX_CMD_ID_DESTROY_TMR while the
system goes to suspend. Otherwise, PSP may return the failure state
(0xFFFF007) on Gfx-2-PSP command GFX_CMD_ID_SETUP_TMR after do multiple
times suspend/resume.

Signed-off-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
2020-07-08 09:00:55 -04:00
Huang Rui 429f3d2438 drm/amdgpu: asd function needs to be unloaded in suspend phase
Unload ASD function in suspend phase.

Signed-off-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
2020-07-08 09:00:09 -04:00
Gustavo A. R. Silva 74b76256f3 USB: serial: use fallthrough pseudo-keyword
Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
2020-07-08 14:55:35 +02:00
Daniel Baluta 4e7f8cac11
ASoC: SOF: imx: add min/max channels for SAI/ESAI on i.MX8/i.MX8M
This is identical with change for Intel platforms done with
commit 8c05246c0b ("ASoC: SOF: Intel: add min/max channels for SSP on Baytrail/Broadwell")
and fixes a regression on i.MX8/i.MX8M:

[   25.705750]  esai-Codec: ASoC: no backend playback stream
[   27.923378]  esai-Codec: ASoC: no users playback at close - state

This is root-caused to the introduction of the DAI capability checks
with snd_soc_dai_stream_valid(). Its use in soc-pcm.c makes it a
requirement for all DAIs to report at least a non-zero min_channels
field.

Fixes: 9b5db05936 ("ASoC: soc-pcm: dpcm: Only allow playback/capture if supported")
Signed-off-by: Daniel Baluta <daniel.baluta@nxp.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Link: https://lore.kernel.org/r/20200707210439.115300-4-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
2020-07-08 13:51:37 +01:00
Pierre-Louis Bossart fffebe8a83
ASoC: Intel: bdw-rt5677: fix non BE conversion
When SOF is used, the normal links are converted into DPCM ones. This
generates an error

[ 58.276668] bdw-rt5677 bdw-rt5677: CPU DAI spi-RT5677AA:00 for rtd
Wake on Voice does not support playback
[ 58.276676] bdw-rt5677 bdw-rt5677: ASoC: can't create pcm Wake on
Voice :-22

Fix by forcing the capture direction.

Fixes: b73287f0b0 ('ASoC: soc-pcm: dpcm: fix playback/capture checks')
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Reviewed-by: Curtis Malainey <curtis@malainey.com>
Link: https://lore.kernel.org/r/20200707210439.115300-3-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
2020-07-08 13:51:36 +01:00
Pierre-Louis Bossart 25612477d2
ASoC: soc-dai: set dai_link dpcm_ flags with a helper
Add a helper to walk through all the DAIs and set dpcm_playback and
dpcm_capture flags based on the DAIs capabilities, and use this helper
to avoid setting these flags arbitrarily in generic cards.

The commit referenced in the Fixes tag did not introduce the
configuration issue but will prevent the card from probing when
detecting invalid configurations.

Fixes: b73287f0b0 ('ASoC: soc-pcm: dpcm: fix playback/capture checks')
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Link: https://lore.kernel.org/r/20200707210439.115300-2-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
2020-07-08 13:51:35 +01:00
Kamal Heib 04340645f6 RDMA/siw: Fix reporting vendor_part_id
Move the initialization of the vendor_part_id to be before calling
ib_register_device(), this is needed because the query_device() callback
is called from the context of ib_register_device() before initializing the
vendor_part_id, so the reported value is wrong.

Fixes: bdcf26bf9b ("rdma/siw: network and RDMA core interface")
Link: https://lore.kernel.org/r/20200707130931.444724-1-kamalheib1@gmail.com
Signed-off-by: Kamal Heib <kamalheib1@gmail.com>
Reviewed-by: Bernard Metzler <bmt@zurich.ibm.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
2020-07-08 09:24:45 -03:00
Desnes A. Nunes do Rosario 3337bf41e0 selftests/powerpc: Purge extra count_pmc() calls of ebb selftests
An extra count on ebb_state.stats.pmc_count[PMC_INDEX(pmc)] is being per-
formed when count_pmc() is used to reset PMCs on a few selftests. This
extra pmc_count can occasionally invalidate results, such as the ones from
cycles_test shown hereafter. The ebb_check_count() failed with an above
the upper limit error due to the extra value on ebb_state.stats.pmc_count.

Furthermore, this extra count is also indicated by extra PMC1 trace_log on
the output of the cycle test (as well as on pmc56_overflow_test):

==========
   ...
   [21]: counter = 8
   [22]: register SPRN_MMCR0 = 0x0000000080000080
   [23]: register SPRN_PMC1  = 0x0000000080000004
   [24]: counter = 9
   [25]: register SPRN_MMCR0 = 0x0000000080000080
   [26]: register SPRN_PMC1  = 0x0000000080000004
   [27]: counter = 10
   [28]: register SPRN_MMCR0 = 0x0000000080000080
   [29]: register SPRN_PMC1  = 0x0000000080000004
>> [30]: register SPRN_PMC1  = 0x000000004000051e
PMC1 count (0x280000546) above upper limit 0x2800003e8 (+0x15e)
[FAIL] Test FAILED on line 52
failure: cycles
==========

Signed-off-by: Desnes A. Nunes do Rosario <desnesn@linux.ibm.com>
Tested-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200626164737.21943-1-desnesn@linux.ibm.com
2020-07-08 22:09:31 +10:00
Michał Winiarski 9459fd5945 drm/i915/huc: Adjust HuC state accordingly after GuC fetch error
Firmware "Selected" state is a transient state - we don't expect to see
it after finishing driver probe, we even have asserts sprinkled over
i915 to confirm whether that's the case.
Unfortunately - we don't handle the transition out of "Selected" in case
of GuC fetch error, leading those asserts to fire when calling
"intel_huc_is_used()".

v2: Add dbg print when moving HuC into error state (Daniele)

Reported-by: Marcin Bernatowicz <marcin.bernatowicz@intel.com>
Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Marcin Bernatowicz <marcin.bernatowicz@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20200708100843.297655-2-michal@hardline.pl
2020-07-08 13:02:02 +01:00
Michał Winiarski 7f67deeb7f drm/i915/uc: Extract uc usage details into separate debugfs
It has been pointed out that information about HuC usage doesn't belong
in guc_info debugfs. Let's move "supported/used/wanted" matrix to a
separate debugfs file, keeping guc_info strictly about GuC.

Suggested-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Lukasz Fiedorowicz <lukasz.fiedorowicz@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20200708100843.297655-1-michal@hardline.pl
2020-07-08 13:02:01 +01:00
Miao-chen Chou 51b64c476a Bluetooth: Use whitelist for scan policy when suspending
Even with one advertisement monitor in place, the scan policy should use
the whitelist while the system is going to suspend to prevent waking by
random advertisement.

The following test was performed.
- With a paired device, register one advertisement monitor, suspend
the system and verify that the host was not awaken by random
advertisements.

Signed-off-by: Miao-chen Chou <mcchou@chromium.org>
Reviewed-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2020-07-08 13:59:06 +02:00
Rikard Falkeborn 82c8d38699 phy: allwinner: phy-sun6i-mipi-dphy: Constify structs
sun6i_dphy_ops and sun6i_dphy_regmap_config are not modified so make them
const structs to allow the compiler to put them in read-only memory.

Before:
   text    data     bss     dec     hex filename
   4407    1944      64    6415    190f drivers/phy/allwinner/phy-sun6i-mipi-dphy.o

After:
   text    data     bss     dec     hex filename
   4835    1496      64    6395    18fb drivers/phy/allwinner/phy-sun6i-mipi-dphy.o

Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Acked-by: Maxime Ripard <mripard@kernel.org>
Link: https://lore.kernel.org/r/20200629195727.9717-1-rikard.falkeborn@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
2020-07-08 16:46:08 +05:30
Vinod Koul 3cc4502ce8 phy: ti-pipe3: remove set but unused variable
ti_pipe3_power_on() sets variable 'ret' but never uses it, so remove it.

drivers/phy/ti/phy-ti-pipe3.c:340:6: warning: variable ‘ret’ set but not
used [-Wunused-but-set-variable]

Link: https://lore.kernel.org/r/20200629145010.122675-4-vkoul@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>
2020-07-08 16:40:28 +05:30
Vinod Koul 3b0163bb34 phy: ti: dm816x: remove set but unused variable
dm816x_usb_phy_init() sets variable 'error' but never uses it, so remove
it.

drivers/phy/ti/phy-dm816x-usb.c:85:6: warning: variable ‘error’ set but
not used [-Wunused-but-set-variable]

Link: https://lore.kernel.org/r/20200629145010.122675-3-vkoul@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>
2020-07-08 16:40:24 +05:30
Vinod Koul aad075c155 phy: core: Document function args
Some function arguments are missing from documentation prompting
validation kernel doc script to complain:

drivers/phy/phy-core.c:1078: warning: Function parameter or member
'children' not described in '__devm_of_phy_provider_register'
drivers/phy/phy-core.c:1125: warning: Function parameter or member
'phy_provider' not described in 'devm_of_phy_provider_unregister'

Add the documentation for these

Link: https://lore.kernel.org/r/20200629145010.122675-2-vkoul@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>
2020-07-08 16:40:21 +05:30
Vinod Koul b555f35f2f phy: core: fix code style in devm_of_phy_provider_unregister
Documentation/process/coding-style.rst says:
"functions: they have the opening brace at the beginning of the next
line"

devm_of_phy_provider_unregister() function has opening brace at same
line, so fix it up.

Link: https://lore.kernel.org/r/20200629145010.122675-1-vkoul@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>
2020-07-08 16:40:13 +05:30
Vinod Koul 02dca8c981 phy: qcom: remove ufs qmp phy driver
The UFS specific QMP PHY driver started off supporting the 14nm and
20nm hardware. With the 20nm support marked broken for a long time and
the 14nm support added to the common QMP PHY, this driver has not been
used in a while. So delete it

Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20200629145452.123035-1-vkoul@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>
2020-07-08 16:37:05 +05:30
Nicholas Piggin 4557ac6b34 powerpc/64s/exception: Fix 0x1500 interrupt handler crash
A typo caused the interrupt handler to branch immediately to the
common "unknown interrupt" handler and skip the special case test for
denormal cause.

This does not affect KVM softpatch handling (e.g., for POWER9 TM
assist) because the KVM test was moved to common code by commit
9600f261ac ("powerpc/64s/exception: Move KVM test to common code")
just before this bug was introduced.

Fixes: 3f7fbd97d0 ("powerpc/64s/exception: Clean up SRR specifiers")
Reported-by: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Tested-by: Paul Menzel <pmenzel@molgen.mpg.de>
[mpe: Split selftest into a separate patch]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200708074942.1713396-1-npiggin@gmail.com
2020-07-08 20:41:06 +10:00
Mark Brown 31cf2c3b6f
Merge branch 'topic/devnode' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap into regmap-5.9 2020-07-08 11:20:59 +01:00
Michael Walle 5cc2013bfe
regmap-irq: use fwnode instead of device node in add_irq_chip()
Convert the argument to the newer fwnode_handle instead a device tree
node. Fortunately, there are no users for now. So this is an easy
change.

Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20200706175353.16404-2-michael@walle.cc
Signed-off-by: Mark Brown <broonie@kernel.org>
2020-07-08 11:15:12 +01:00
Ramalingam C 018532e940 drm/i915/hdcp: Fix the return handling of drm_hdcp_check_ksvs_revoked
drm_hdcp_check_ksvs_revoked() returns the number of revoked keys and
error codes when the SRM parsing is failed.

Errors in SRM parsing can't affect the HDCP auth, hence with this patch,
I915 will look out for revoked key count alone.

Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
cc: Sean Paul <seanpaul@chromium.org>
Reviewed-by: Sean Paul <sean@poorly.run>
Link: https://patchwork.freedesktop.org/patch/msgid/20200429134555.22106-1-ramalingam.c@intel.com
2020-07-08 15:20:01 +05:30
Marek Vasut ebd267b2e3 drm/stm: repair runtime power management
Add missing pm_runtime_get_sync() into ltdc_crtc_atomic_enable() to
match pm_runtime_put_sync() in ltdc_crtc_atomic_disable(), otherwise
the LTDC might suspend via runtime PM, disable clock, and then fail
to resume later on.

The test which triggers it is roughly -- run qt5 application which
uses eglfs platform and etnaviv, stop the application, sleep for 15
minutes, run the application again. This leads to a timeout waiting
for vsync, because the LTDC has suspended, but did not resume.

Fixes: 35ab6cfbf2 ("drm/stm: support runtime power management")
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Yannick Fertré <yannick.fertre@st.com>
Cc: Philippe Cornu <philippe.cornu@st.com>
Cc: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Cc: Vincent Abriou <vincent.abriou@st.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
To: dri-devel@lists.freedesktop.org
Cc: linux-stm32@st-md-mailman.stormreply.com
Cc: linux-arm-kernel@lists.infradead.org
Acked-by: Philippe Cornu <philippe.cornu@st.com>
Tested-by: Yannick Fertre <yannick.fertre@st.com>
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200229221649.90813-1-marex@denx.de
2020-07-08 11:47:01 +02:00
Yannick Fertre a790ababbe drm/stm: ltdc: remove call of pm-runtime functions
It is not necessary to suspend or stop the ltdc clocks
to modify the pixel clock.

Signed-off-by: Yannick Fertre <yannick.fertre@st.com>
Acked-by: Philippe Cornu <philippe.cornu@st.com>
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200701120402.6444-1-yannick.fertre@st.com
2020-07-08 11:46:26 +02:00
Anshuman Gupta 33f9a623bf drm/i915/hdcp: Update CP as per the kernel internal state
Content Protection property should be updated as per the kernel
internal state. Let's say if Content protection is disabled
by userspace, CP property should be set to UNDESIRED so that
reauthentication will not happen until userspace request it again,
but when kernel disables the HDCP due to any DDI disabling sequences
like modeset/DPMS operation, kernel should set the property to
DESIRED, so that when opportunity arises, kernel will start the
HDCP authentication on its own.

Somewhere in the line, state machine to set content protection to
DESIRED from kernel was broken and IGT coverage was missing for it.
This patch fixes it.

v2:
- Fixing hdcp CP state in connector atomic check function
  intel_hdcp_atomic_check(). [Maarten]
  This will require to check hdcp->value in intel_hdcp_update_pipe()
  in order to avoid enabling hdcp, if it was already enabled.

v3:
- Rebased.

Cc: Ramalingam C <ramalingam.c@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
Link: https://patchwork.freedesktop.org/patch/350962/?series=72664&rev=2 #v1
Link: https://patchwork.freedesktop.org/patch/359396/?series=72251&rev=3 #v2
Reviewed-by: Ramalingam C <ramalingam.c@intel.com>
Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200630082048.22308-1-anshuman.gupta@intel.com
2020-07-08 15:14:18 +05:30
Phil Auld 9d246053a6 sched: Add a tracepoint to track rq->nr_running
Add a bare tracepoint trace_sched_update_nr_running_tp which tracks
->nr_running CPU's rq. This is used to accurately trace this data and
provide a visualization of scheduler imbalances in, for example, the
form of a heat map.  The tracepoint is accessed by loading an external
kernel module. An example module (forked from Qais' module and including
the pelt related tracepoints) can be found at:

  https://github.com/auldp/tracepoints-helpers.git

A script to turn the trace-cmd report output into a heatmap plot can be
found at:

  https://github.com/jirvoz/plot-nr-running

The tracepoints are added to add_nr_running() and sub_nr_running() which
are in kernel/sched/sched.h. In order to avoid CREATE_TRACE_POINTS in
the header a wrapper call is used and the trace/events/sched.h include
is moved before sched.h in kernel/sched/core.

Signed-off-by: Phil Auld <pauld@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200629192303.GC120228@lorien.usersys.redhat.com
2020-07-08 11:39:02 +02:00
Alex Belits 07bbecb341 net: Restrict receive packets queuing to housekeeping CPUs
With the existing implementation of store_rps_map(), packets are queued
in the receive path on the backlog queues of other CPUs irrespective of
whether they are isolated or not. This could add a latency overhead to
any RT workload that is running on the same CPU.

Ensure that store_rps_map() only uses available housekeeping CPUs for
storing the rps_map.

Signed-off-by: Alex Belits <abelits@marvell.com>
Signed-off-by: Nitesh Narayan Lal <nitesh@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200625223443.2684-4-nitesh@redhat.com
2020-07-08 11:39:02 +02:00
Alex Belits 69a18b1869 PCI: Restrict probe functions to housekeeping CPUs
pci_call_probe() prevents the nesting of work_on_cpu() for a scenario
where a VF device is probed from work_on_cpu() of the PF.

Replace the cpumask used in pci_call_probe() from all online CPUs to only
housekeeping CPUs. This is to ensure that there are no additional latency
overheads caused due to the pinning of jobs on isolated CPUs.

Signed-off-by: Alex Belits <abelits@marvell.com>
Signed-off-by: Nitesh Narayan Lal <nitesh@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lkml.kernel.org/r/20200625223443.2684-3-nitesh@redhat.com
2020-07-08 11:39:01 +02:00
Alex Belits 1abdfe706a lib: Restrict cpumask_local_spread to houskeeping CPUs
The current implementation of cpumask_local_spread() does not respect the
isolated CPUs, i.e., even if a CPU has been isolated for Real-Time task,
it will return it to the caller for pinning of its IRQ threads. Having
these unwanted IRQ threads on an isolated CPU adds up to a latency
overhead.

Restrict the CPUs that are returned for spreading IRQs only to the
available housekeeping CPUs.

Signed-off-by: Alex Belits <abelits@marvell.com>
Signed-off-by: Nitesh Narayan Lal <nitesh@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200625223443.2684-2-nitesh@redhat.com
2020-07-08 11:39:01 +02:00
Qais Yousef 46609ce227 sched/uclamp: Protect uclamp fast path code with static key
There is a report that when uclamp is enabled, a netperf UDP test
regresses compared to a kernel compiled without uclamp.

https://lore.kernel.org/lkml/20200529100806.GA3070@suse.de/

While investigating the root cause, there were no sign that the uclamp
code is doing anything particularly expensive but could suffer from bad
cache behavior under certain circumstances that are yet to be
understood.

https://lore.kernel.org/lkml/20200616110824.dgkkbyapn3io6wik@e107158-lin/

To reduce the pressure on the fast path anyway, add a static key that is
by default will skip executing uclamp logic in the
enqueue/dequeue_task() fast path until it's needed.

As soon as the user start using util clamp by:

	1. Changing uclamp value of a task with sched_setattr()
	2. Modifying the default sysctl_sched_util_clamp_{min, max}
	3. Modifying the default cpu.uclamp.{min, max} value in cgroup

We flip the static key now that the user has opted to use util clamp.
Effectively re-introducing uclamp logic in the enqueue/dequeue_task()
fast path. It stays on from that point forward until the next reboot.

This should help minimize the effect of util clamp on workloads that
don't need it but still allow distros to ship their kernels with uclamp
compiled in by default.

SCHED_WARN_ON() in uclamp_rq_dec_id() was removed since now we can end
up with unbalanced call to uclamp_rq_dec_id() if we flip the key while
a task is running in the rq. Since we know it is harmless we just
quietly return if we attempt a uclamp_rq_dec_id() when
rq->uclamp[].bucket[].tasks is 0.

In schedutil, we introduce a new uclamp_is_enabled() helper which takes
the static key into account to ensure RT boosting behavior is retained.

The following results demonstrates how this helps on 2 Sockets Xeon E5
2x10-Cores system.

                                   nouclamp                 uclamp      uclamp-static-key
Hmean     send-64         162.43 (   0.00%)      157.84 *  -2.82%*      163.39 *   0.59%*
Hmean     send-128        324.71 (   0.00%)      314.78 *  -3.06%*      326.18 *   0.45%*
Hmean     send-256        641.55 (   0.00%)      628.67 *  -2.01%*      648.12 *   1.02%*
Hmean     send-1024      2525.28 (   0.00%)     2448.26 *  -3.05%*     2543.73 *   0.73%*
Hmean     send-2048      4836.14 (   0.00%)     4712.08 *  -2.57%*     4867.69 *   0.65%*
Hmean     send-3312      7540.83 (   0.00%)     7425.45 *  -1.53%*     7621.06 *   1.06%*
Hmean     send-4096      9124.53 (   0.00%)     8948.82 *  -1.93%*     9276.25 *   1.66%*
Hmean     send-8192     15589.67 (   0.00%)    15486.35 *  -0.66%*    15819.98 *   1.48%*
Hmean     send-16384    26386.47 (   0.00%)    25752.25 *  -2.40%*    26773.74 *   1.47%*

The perf diff between nouclamp and uclamp-static-key when uclamp is
disabled in the fast path:

     8.73%     -1.55%  [kernel.kallsyms]        [k] try_to_wake_up
     0.07%     +0.04%  [kernel.kallsyms]        [k] deactivate_task
     0.13%     -0.02%  [kernel.kallsyms]        [k] activate_task

The diff between nouclamp and uclamp-static-key when uclamp is enabled
in the fast path:

     8.73%     -0.72%  [kernel.kallsyms]        [k] try_to_wake_up
     0.13%     +0.39%  [kernel.kallsyms]        [k] activate_task
     0.07%     +0.38%  [kernel.kallsyms]        [k] deactivate_task

Fixes: 69842cba9a ("sched/uclamp: Add CPU's clamp buckets refcounting")
Reported-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Qais Yousef <qais.yousef@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Lukasz Luba <lukasz.luba@arm.com>
Link: https://lkml.kernel.org/r/20200630112123.12076-3-qais.yousef@arm.com
2020-07-08 11:39:01 +02:00
Qais Yousef d81ae8aac8 sched/uclamp: Fix initialization of struct uclamp_rq
struct uclamp_rq was zeroed out entirely in assumption that in the first
call to uclamp_rq_inc() they'd be initialized correctly in accordance to
default settings.

But when next patch introduces a static key to skip
uclamp_rq_{inc,dec}() until userspace opts in to use uclamp, schedutil
will fail to perform any frequency changes because the
rq->uclamp[UCLAMP_MAX].value is zeroed at init and stays as such. Which
means all rqs are capped to 0 by default.

Fix it by making sure we do proper initialization at init without
relying on uclamp_rq_inc() doing it later.

Fixes: 69842cba9a ("sched/uclamp: Add CPU's clamp buckets refcounting")
Signed-off-by: Qais Yousef <qais.yousef@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Tested-by: Lukasz Luba <lukasz.luba@arm.com>
Link: https://lkml.kernel.org/r/20200630112123.12076-2-qais.yousef@arm.com
2020-07-08 11:39:01 +02:00
Peter Zijlstra 85c2ce9104 sched, vmlinux.lds: Increase STRUCT_ALIGNMENT to 64 bytes for GCC-4.9
For some mysterious reason GCC-4.9 has a 64 byte section alignment for
structures, all other GCC versions (and Clang) tested (including 4.8
and 5.0) are fine with the 32 bytes alignment.

Getting this right is important for the new SCHED_DATA macro that
creates an explicitly ordered array of 'struct sched_class' in the
linker script and expect pointer arithmetic to work.

Fixes: c3a340f7e7 ("sched: Have sched_class_highest define by vmlinux.lds.h")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200630144905.GX4817@hirez.programming.kicks-ass.net
2020-07-08 11:39:00 +02:00
Peter Zijlstra faa2fd7cba Merge branch 'sched/urgent' 2020-07-08 11:38:59 +02:00
Kan Liang c085fb8774 perf/x86/intel/lbr: Support XSAVES for arch LBR read
Reading LBR registers in a perf NMI handler for a non-PEBS event
causes a high overhead because the number of LBR registers is huge.
To reduce the overhead, the XSAVES instruction should be used to replace
the LBR registers' reading method.

The XSAVES buffer used for LBR read has to be per-CPU because the NMI
handler invoked the lbr_read(). The existing task_ctx_data buffer
cannot be used which is per-task and only be allocated for the LBR call
stack mode. A new lbr_xsave pointer is introduced in the cpu_hw_events
as an XSAVES buffer for LBR read.

The XSAVES buffer should be allocated only when LBR is used by a
non-PEBS event on the CPU because the total size of the lbr_xsave is
not small (~1.4KB).

The XSAVES buffer is allocated when a non-PEBS event is added, but it
is lazily released in x86_release_hardware() when perf releases the
entire PMU hardware resource, because perf may frequently schedule the
event, e.g. high context switch. The lazy release method reduces the
overhead of frequently allocate/free the buffer.

If the lbr_xsave fails to be allocated, roll back to normal Arch LBR
lbr_read().

Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Link: https://lkml.kernel.org/r/1593780569-62993-24-git-send-email-kan.liang@linux.intel.com
2020-07-08 11:38:57 +02:00
Kan Liang ce711ea3ca perf/x86/intel/lbr: Support XSAVES/XRSTORS for LBR context switch
In the LBR call stack mode, LBR information is used to reconstruct a
call stack. To get the complete call stack, perf has to save/restore
all LBR registers during a context switch. Due to a large number of the
LBR registers, this process causes a high CPU overhead. To reduce the
CPU overhead during a context switch, use the XSAVES/XRSTORS
instructions.

Every XSAVE area must follow a canonical format: the legacy region, an
XSAVE header and the extended region. Although the LBR information is
only kept in the extended region, a space for the legacy region and
XSAVE header is still required. Add a new dedicated structure for LBR
XSAVES support.

Before enabling XSAVES support, the size of the LBR state has to be
sanity checked, because:
- the size of the software structure is calculated from the max number
of the LBR depth, which is enumerated by the CPUID leaf for Arch LBR.
The size of the LBR state is enumerated by the CPUID leaf for XSAVE
support of Arch LBR. If the values from the two CPUID leaves are not
consistent, it may trigger a buffer overflow. For example, a hypervisor
may unconsciously set inconsistent values for the two emulated CPUID.
- unlike other state components, the size of an LBR state depends on the
max number of LBRs, which may vary from generation to generation.

Expose the function xfeature_size() for the sanity check.
The LBR XSAVES support will be disabled if the size of the LBR state
enumerated by CPUID doesn't match with the size of the software
structure.

The XSAVE instruction requires 64-byte alignment for state buffers. A
new macro is added to reflect the alignment requirement. A 64-byte
aligned kmem_cache is created for architecture LBR.

Currently, the structure for each state component is maintained in
fpu/types.h. The structure for the new LBR state component should be
maintained in the same place. Move structure lbr_entry to fpu/types.h as
well for broader sharing.

Add dedicated lbr_save/lbr_restore functions for LBR XSAVES support,
which invokes the corresponding xstate helpers to XSAVES/XRSTORS LBR
information at the context switch when the call stack mode is enabled.
Since the XSAVES/XRSTORS instructions will be eventually invoked, the
dedicated functions is named with '_xsaves'/'_xrstors' postfix.

Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Link: https://lkml.kernel.org/r/1593780569-62993-23-git-send-email-kan.liang@linux.intel.com
2020-07-08 11:38:56 +02:00
Kan Liang 50f408d96d x86/fpu/xstate: Add helpers for LBR dynamic supervisor feature
The perf subsystem will only need to save/restore the LBR state.
However, the existing helpers save all supported supervisor states to a
kernel buffer, which will be unnecessary. Two helpers are introduced to
only save/restore requested dynamic supervisor states. The supervisor
features in XFEATURE_MASK_SUPERVISOR_SUPPORTED and
XFEATURE_MASK_SUPERVISOR_UNSUPPORTED mask cannot be saved/restored using
these helpers.

The helpers will be used in the following patch.

Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Link: https://lkml.kernel.org/r/1593780569-62993-22-git-send-email-kan.liang@linux.intel.com
2020-07-08 11:38:56 +02:00
Kan Liang f0dccc9da4 x86/fpu/xstate: Support dynamic supervisor feature for LBR
Last Branch Records (LBR) registers are used to log taken branches and
other control flows. In perf with call stack mode, LBR information is
used to reconstruct a call stack. To get the complete call stack, perf
has to save/restore all LBR registers during a context switch. Due to
the large number of the LBR registers, e.g., the current platform has
96 LBR registers, this process causes a high CPU overhead. To reduce
the CPU overhead during a context switch, an LBR state component that
contains all the LBR related registers is introduced in hardware. All
LBR registers can be saved/restored together using one XSAVES/XRSTORS
instruction.

However, the kernel should not save/restore the LBR state component at
each context switch, like other state components, because of the
following unique features of LBR:
- The LBR state component only contains valuable information when LBR
  is enabled in the perf subsystem, but for most of the time, LBR is
  disabled.
- The size of the LBR state component is huge. For the current
  platform, it's 808 bytes.
If the kernel saves/restores the LBR state at each context switch, for
most of the time, it is just a waste of space and cycles.

To efficiently support the LBR state component, it is desired to have:
- only context-switch the LBR when the LBR feature is enabled in perf.
- only allocate an LBR-specific XSAVE buffer on demand.
  (Besides the LBR state, a legacy region and an XSAVE header have to be
   included in the buffer as well. There is a total of (808+576) byte
   overhead for the LBR-specific XSAVE buffer. The overhead only happens
   when the perf is actively using LBRs. There is still a space-saving,
   on average, when it replaces the constant 808 bytes of overhead for
   every task, all the time on the systems that support architectural
   LBR.)
- be able to use XSAVES/XRSTORS for accessing LBR at run time.
  However, the IA32_XSS should not be adjusted at run time.
  (The XCR0 | IA32_XSS are used to determine the requested-feature
  bitmap (RFBM) of XSAVES.)

A solution, called dynamic supervisor feature, is introduced to address
this issue, which
- does not allocate a buffer in each task->fpu;
- does not save/restore a state component at each context switch;
- sets the bit corresponding to the dynamic supervisor feature in
  IA32_XSS at boot time, and avoids setting it at run time.
- dynamically allocates a specific buffer for a state component
  on demand, e.g. only allocates LBR-specific XSAVE buffer when LBR is
  enabled in perf. (Note: The buffer has to include the LBR state
  component, a legacy region and a XSAVE header space.)
  (Implemented in a later patch)
- saves/restores a state component on demand, e.g. manually invokes
  the XSAVES/XRSTORS instruction to save/restore the LBR state
  to/from the buffer when perf is active and a call stack is required.
  (Implemented in a later patch)

A new mask XFEATURE_MASK_DYNAMIC and a helper xfeatures_mask_dynamic()
are introduced to indicate the dynamic supervisor feature. For the
systems which support the Architecture LBR, LBR is the only dynamic
supervisor feature for now. For the previous systems, there is no
dynamic supervisor feature available.

Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Link: https://lkml.kernel.org/r/1593780569-62993-21-git-send-email-kan.liang@linux.intel.com
2020-07-08 11:38:56 +02:00
Kan Liang a063bf249b x86/fpu: Use proper mask to replace full instruction mask
When saving xstate to a kernel/user XSAVE area with the XSAVE family of
instructions, the current code applies the 'full' instruction mask (-1),
which tries to XSAVE all possible features. This method relies on
hardware to trim 'all possible' down to what is enabled in the
hardware. The code works well for now. However, there will be a
problem, if some features are enabled in hardware, but are not suitable
to be saved into all kernel XSAVE buffers, like task->fpu, due to
performance consideration.

One such example is the Last Branch Records (LBR) state. The LBR state
only contains valuable information when LBR is explicitly enabled by
the perf subsystem, and the size of an LBR state is large (808 bytes
for now). To avoid both CPU overhead and space overhead at each context
switch, the LBR state should not be saved into task->fpu like other
state components. It should be saved/restored on demand when LBR is
enabled in the perf subsystem. Current copy_xregs_to_* will trigger a
buffer overflow for such cases.

Three sites use the '-1' instruction mask which must be updated.

Two are saving/restoring the xstate to/from a kernel-allocated XSAVE
buffer and can use 'xfeatures_mask_all', which will save/restore all of
the features present in a normal task FPU buffer.

The last one saves the register state directly to a user buffer. It
could
also use 'xfeatures_mask_all'. Just as it was with the '-1' argument,
any supervisor states in the mask will be filtered out by the hardware
and not saved to the buffer.  But, to be more explicit about what is
expected to be saved, use xfeatures_mask_user() for the instruction
mask.

KVM includes the header file fpu/internal.h. To avoid 'undefined
xfeatures_mask_all' compiling issue, move copy_fpregs_to_fpstate() to
fpu/core.c and export it, because:
- The xfeatures_mask_all is indirectly used via copy_fpregs_to_fpstate()
  by KVM. The function which is directly used by other modules should be
  exported.
- The copy_fpregs_to_fpstate() is a function, while xfeatures_mask_all
  is a variable for the "internal" FPU state. It's safer to export a
  function than a variable, which may be implicitly changed by others.
- The copy_fpregs_to_fpstate() is a big function with many checks. The
  removal of the inline keyword should not impact the performance.

Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Link: https://lkml.kernel.org/r/1593780569-62993-20-git-send-email-kan.liang@linux.intel.com
2020-07-08 11:38:56 +02:00
Kan Liang 5a09928d33 perf/x86: Remove task_ctx_size
A new kmem_cache method has replaced the kzalloc() to allocate the PMU
specific data. The task_ctx_size is not required anymore.

Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/1593780569-62993-19-git-send-email-kan.liang@linux.intel.com
2020-07-08 11:38:55 +02:00
Kan Liang 33cad28449 perf/x86/intel/lbr: Create kmem_cache for the LBR context data
A new kmem_cache method is introduced to allocate the PMU specific data
task_ctx_data, which requires the PMU specific code to create a
kmem_cache.

Currently, the task_ctx_data is only used by the Intel LBR call stack
feature, which is introduced since Haswell. The kmem_cache should be
only created for Haswell and later platforms. There is no alignment
requirement for the existing platforms.

Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/1593780569-62993-18-git-send-email-kan.liang@linux.intel.com
2020-07-08 11:38:55 +02:00
Kan Liang 217c2a633e perf/core: Use kmem_cache to allocate the PMU specific data
Currently, the PMU specific data task_ctx_data is allocated by the
function kzalloc() in the perf generic code. When there is no specific
alignment requirement for the task_ctx_data, the method works well for
now. However, there will be a problem once a specific alignment
requirement is introduced in future features, e.g., the Architecture LBR
XSAVE feature requires 64-byte alignment. If the specific alignment
requirement is not fulfilled, the XSAVE family of instructions will fail
to save/restore the xstate to/from the task_ctx_data.

The function kzalloc() itself only guarantees a natural alignment. A
new method to allocate the task_ctx_data has to be introduced, which
has to meet the requirements as below:
- must be a generic method can be used by different architectures,
  because the allocation of the task_ctx_data is implemented in the
  perf generic code;
- must be an alignment-guarantee method (The alignment requirement is
  not changed after the boot);
- must be able to allocate/free a buffer (smaller than a page size)
  dynamically;
- should not cause extra CPU overhead or space overhead.

Several options were considered as below:
- One option is to allocate a larger buffer for task_ctx_data. E.g.,
    ptr = kmalloc(size + alignment, GFP_KERNEL);
    ptr &= ~(alignment - 1);
  This option causes space overhead.
- Another option is to allocate the task_ctx_data in the PMU specific
  code. To do so, several function pointers have to be added. As a
  result, both the generic structure and the PMU specific structure
  will become bigger. Besides, extra function calls are added when
  allocating/freeing the buffer. This option will increase both the
  space overhead and CPU overhead.
- The third option is to use a kmem_cache to allocate a buffer for the
  task_ctx_data. The kmem_cache can be created with a specific alignment
  requirement by the PMU at boot time. A new pointer for kmem_cache has
  to be added in the generic struct pmu, which would be used to
  dynamically allocate a buffer for the task_ctx_data at run time.
  Although the new pointer is added to the struct pmu, the existing
  variable task_ctx_size is not required anymore. The size of the
  generic structure is kept the same.

The third option which meets all the aforementioned requirements is used
to replace kzalloc() for the PMU specific data allocation. A later patch
will remove the kzalloc() method and the related variables.

Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/1593780569-62993-17-git-send-email-kan.liang@linux.intel.com
2020-07-08 11:38:55 +02:00
Kan Liang ff9ff92688 perf/core: Factor out functions to allocate/free the task_ctx_data
The method to allocate/free the task_ctx_data is going to be changed in
the following patch. Currently, the task_ctx_data is allocated/freed in
several different places. To avoid repeatedly modifying the same codes
in several different places, alloc_task_ctx_data() and
free_task_ctx_data() are factored out to allocate/free the
task_ctx_data. The modification only needs to be applied once.

Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/1593780569-62993-16-git-send-email-kan.liang@linux.intel.com
2020-07-08 11:38:54 +02:00
Kan Liang 47125db27e perf/x86/intel/lbr: Support Architectural LBR
Last Branch Records (LBR) enables recording of software path history by
logging taken branches and other control flows within architectural
registers now. Intel CPUs have had model-specific LBR for quite some
time, but this evolves them into an architectural feature now.

The main improvements of Architectural LBR implemented includes:
- Linux kernel can support the LBR features without knowing the model
  number of the current CPU.
- Architectural LBR capabilities can be enumerated by CPUID. The
  lbr_ctl_map is based on the CPUID Enumeration.
- The possible LBR depth can be retrieved from CPUID enumeration. The
  max value is written to the new MSR_ARCH_LBR_DEPTH as the number of
  LBR entries.
- A new IA32_LBR_CTL MSR is introduced to enable and configure LBRs,
  which replaces the IA32_DEBUGCTL[bit 0] and the LBR_SELECT MSR.
- Each LBR record or entry is still comprised of three MSRs,
  IA32_LBR_x_FROM_IP, IA32_LBR_x_TO_IP and IA32_LBR_x_TO_IP.
  But they become the architectural MSRs.
- Architectural LBR is stack-like now. Entry 0 is always the youngest
  branch, entry 1 the next youngest... The TOS MSR has been removed.

The way to enable/disable Architectural LBR is similar to the previous
model-specific LBR. __intel_pmu_lbr_enable/disable() can be reused, but
some modifications are required, which include:
- MSR_ARCH_LBR_CTL is used to enable and configure the Architectural
  LBR.
- When checking the value of the IA32_DEBUGCTL MSR, ignoring the
  DEBUGCTLMSR_LBR (bit 0) for Architectural LBR, which has no meaning
  and always return 0.
- The FREEZE_LBRS_ON_PMI has to be explicitly set/clear, because
  MSR_IA32_DEBUGCTLMSR is not touched in __intel_pmu_lbr_disable() for
  Architectural LBR.
- Only MSR_ARCH_LBR_CTL is cleared in __intel_pmu_lbr_disable() for
  Architectural LBR.

Some Architectural LBR dedicated functions are implemented to
reset/read/save/restore LBR.
- For reset, writing to the ARCH_LBR_DEPTH MSR clears all Arch LBR
  entries, which is a lot faster and can improve the context switch
  latency.
- For read, the branch type information can be retrieved from
  the MSR_ARCH_LBR_INFO_*. But it's not fully compatible due to
  OTHER_BRANCH type. The software decoding is still required for the
  OTHER_BRANCH case.
  LBR records are stored in the age order as well. Reuse
  intel_pmu_store_lbr(). Check the CPUID enumeration before accessing
  the corresponding bits in LBR_INFO.
- For save/restore, applying the fast reset (writing ARCH_LBR_DEPTH).
  Reading 'lbr_from' of entry 0 instead of the TOS MSR to check if the
  LBR registers are reset in the deep C-state. If 'the deep C-state
  reset' bit is not set in CPUID enumeration, ignoring the check.
  XSAVE support for Architectural LBR will be implemented later.

The number of LBR entries cannot be hardcoded anymore, which should be
retrieved from CPUID enumeration. A new structure
x86_perf_task_context_arch_lbr is introduced for Architectural LBR.

Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/1593780569-62993-15-git-send-email-kan.liang@linux.intel.com
2020-07-08 11:38:54 +02:00