linux-stable.git/drivers/resctrl/mpam_internal.h, branch v7.0.10

arm_mpam: Pretend that NRDY is always hardware managed

2026-05-23T11:09:43+00:00

commit 4387970bbd84fd14e0c49c3089c5061ccd86b98a upstream.

Rule ZTXDS of the MPAM specification, IHI009 version B.b, states: "If a
monitor does not support automatic updates of NRDY, software can use that
bit for any purpose."

As software is not reliably informed whether or not the monitor supports
automatic updates of NRDY always assume that hardware may manage NRDY but
don't rely on it. When NRDY is truly untouched by hardware then, as it is
written to 0 on configuration, it will always read 0.

At probe it's checked if MSMON_CSU.NRDY and MSMON_MBWU.NRDY are hardware
managed but not MSMON_MBWU_L.NDRY. Specialize the checking for hardware
managed NRDY to CSU counters as this is the only case where hardware
management makes sense. Continue to inform the user if MSMON_CSU.NRDY
appears to be hardware managed but the firmware doesn't provide the
associated time limit for the automatic clearing of NRDY. Remove the NRDY
feature flags as they are now unused.

Fixes: 8c90dc68a5de ("arm_mpam: Probe the hardware features resctrl supports")
Cc: 
Signed-off-by: Ben Horgan 
Reviewed-by: James Morse 
Signed-off-by: Catalin Marinas 
Signed-off-by: Greg Kroah-Hartman

arm_mpam: Reset when feature configuration bit unset

2026-05-23T11:08:35+00:00

[ Upstream commit a1cb6577f575ba5ec2583caf4f791a86754dbf69 ]

To indicate that the configuration, of the controls used by resctrl, in a
RIS need resetting to driver defaults the reset flags in mpam_config are
set. However, these flags are only ever set temporarily at RIS scope in
mpam_reset_ris() and hence mpam_cpu_online() will never reset these
controls to default. As the hardware reset is unknown this leads to unknown
configuration when the control values haven't been configured away from the
defaults.

Use the policy that an unset feature configuration bit means reset. In this
way the mpam_config in the component can encode that it should be in reset
state and mpam_reprogram_msc() will reset controls as needed.

Fixes: 09b89d2a72f3 ("arm_mpam: Allow configuration to be applied and restored during cpu online")
Signed-off-by: Ben Horgan 
Reviewed-by: Gavin Shan 
Reviewed-by: James Morse 
Tested-by: Gavin Shan 
Tested-by: Shaopeng Tan 
Tested-by: Jesse Chick 
[ morse: Removed unused reset flags from config structure ]
Signed-off-by: James Morse 
Signed-off-by: Sasha Levin

arm_mpam: Use non-atomic bitops when modifying feature bitmap

2026-01-16T12:04:20+00:00

In the test__props_mismatch() kunit test we rely on the struct mpam_props
being packed to ensure memcmp doesn't consider packing. Making it packed
reduces the alignment of the features bitmap and so breaks a requirement
for the use of atomics. As we don't rely on the set/clear of these bits
being atomic, just make them non-atomic.

Reviewed-by: Jonathan Cameron 
Signed-off-by: Ben Horgan 
Fixes: 8c90dc68a5de ("arm_mpam: Probe the hardware features resctrl supports")
Reviewed-by: Gavin Shan 
Tested-by: Shaopeng Tan 
Tested-by: Peter Newman 
Signed-off-by: Catalin Marinas

arm_mpam: Remove duplicate linux/srcu.h header

2026-01-16T12:04:20+00:00

./drivers/resctrl/mpam_internal.h: linux/srcu.h is included more than once.

Reviewed-by: Jonathan Cameron 
Reported-by: Abaci Robot 
Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=27328
Signed-off-by: Jiapeng Chong 
Acked-by: James Morse 
[BH: Keep alphabetical order]
Signed-off-by: Ben Horgan 
Reviewed-by: Gavin Shan 
Reviewed-by: Fenghua Yu 
Tested-by: Shaopeng Tan 
Tested-by: Peter Newman 
Signed-off-by: Catalin Marinas

arm_mpam: Add kunit tests for props_mismatch()

2025-11-19T18:34:24+00:00

When features are mismatched between MSC the way features are combined
to the class determines whether resctrl can support this SoC.

Add some tests to illustrate the sort of thing that is expected to
work, and those that must be removed.

Signed-off-by: James Morse 
Reviewed-by: Ben Horgan 
Reviewed-by: Fenghua Yu 
Reviewed-by: Gavin Shan 
Reviewed-by: Shaopeng Tan 
Tested-by: Fenghua Yu 
Tested-by: Carl Worth 
Tested-by: Gavin Shan 
Tested-by: Zeng Heng 
Tested-by: Shaopeng Tan 
Tested-by: Hanjun Guo 
Signed-off-by: Ben Horgan 
Signed-off-by: Catalin Marinas

arm_mpam: Add helper to reset saved mbwu state

2025-11-19T18:34:24+00:00

resctrl expects to reset the bandwidth counters when the filesystem
is mounted.

To allow this, add a helper that clears the saved mbwu state. Instead
of cross calling to each CPU that can access the component MSC to
write to the counter, set a flag that causes it to be zero'd on the
the next read. This is easily done by forcing a configuration update.

Signed-off-by: James Morse 
Cc: Peter Newman 
Reviewed-by: Fenghua Yu 
Reviewed-by: Gavin Shan 
Reviewed-by: Jonathan Cameron 
Reviewed-by: Shaopeng Tan 
Tested-by: Fenghua Yu 
Tested-by: Carl Worth 
Tested-by: Gavin Shan 
Tested-by: Zeng Heng 
Tested-by: Shaopeng Tan 
Tested-by: Hanjun Guo 
Signed-off-by: Ben Horgan 
Signed-off-by: Catalin Marinas

arm_mpam: Probe for long/lwd mbwu counters

2025-11-19T18:34:23+00:00

mpam v0.1 and versions above v1.0 support optional long counter for
memory bandwidth monitoring. The MPAMF_MBWUMON_IDR register has fields
indicating support for long counters.

Probe these feature bits.

The mpam_feat_msmon_mbwu feature is used to indicate that bandwidth
monitors are supported, instead of muddling this with which size of
bandwidth monitors, add an explicit 31 bit counter feature.

Signed-off-by: Rohit Mathew 
[ morse: Added 31bit counter feature to simplify later logic ]
Signed-off-by: James Morse 
Reviewed-by: Ben Horgan 
Reviewed-by: Jonathan Cameron 
Reviewed-by: Gavin Shan 
Reviewed-by: Shaopeng Tan 
Reviewed-by: Fenghua Yu 
Tested-by: Fenghua Yu 
Tested-by: Shaopeng Tan 
Tested-by: Peter Newman 
Tested-by: Carl Worth 
Tested-by: Gavin Shan 
Tested-by: Zeng Heng 
Tested-by: Hanjun Guo 
Signed-off-by: Ben Horgan 
Signed-off-by: Catalin Marinas

arm_mpam: Consider overflow in bandwidth counter state

2025-11-19T18:34:23+00:00

Use the overflow status bit to track overflow on each bandwidth counter
read and add the counter size to the correction when overflow is detected.

This assumes that only a single overflow has occurred since the last read
of the counter. Overflow interrupts, on hardware that supports them could
be used to remove this limitation.

Cc: Zeng Heng 
Reviewed-by: Gavin Shan 
Reviewed-by: Zeng Heng 
Reviewed-by: Jonathan Cameron 
Reviewed-by: Shaopeng Tan 
Reviewed-by: Fenghua Yu 
Tested-by: Carl Worth 
Tested-by: Gavin Shan 
Tested-by: Zeng Heng 
Tested-by: Shaopeng Tan 
Tested-by: Hanjun Guo 
Signed-off-by: Ben Horgan 
Signed-off-by: Catalin Marinas

arm_mpam: Track bandwidth counter state for power management

2025-11-19T18:34:23+00:00

Bandwidth counters need to run continuously to correctly reflect the
bandwidth.

Save the counter state when the hardware is reset due to CPU hotplug.
Add struct mbwu_state to track the bandwidth counter. Support for
tracking overflow with the same structure will be added in a
subsequent commit.

Cc: Zeng Heng 
Reviewed-by: Gavin Shan 
Reviewed-by: Zeng Heng 
Reviewed-by: Jonathan Cameron 
Reviewed-by: Shaopeng Tan 
Reviewed-by: Fenghua Yu 
Tested-by: Carl Worth 
Tested-by: Gavin Shan 
Tested-by: Zeng Heng 
Tested-by: Shaopeng Tan 
Tested-by: Hanjun Guo 
Signed-off-by: James Morse 
Signed-off-by: Ben Horgan 
Signed-off-by: Catalin Marinas

arm_mpam: Add mpam_msmon_read() to read monitor value

2025-11-19T18:34:23+00:00

Reading a monitor involves configuring what you want to monitor, and
reading the value. Components made up of multiple MSC may need values
from each MSC. MSCs may take time to configure, returning 'not ready'.
The maximum 'not ready' time should have been provided by firmware.

Add mpam_msmon_read() to hide all this. If (one of) the MSC returns
not ready, then wait the full timeout value before trying again.

CC: Shanker Donthineni 
Cc: Shaopeng Tan (Fujitsu) 
Reviewed-by: Jonathan Cameron 
Reviewed-by: Gavin Shan 
Reviewed-by: Shaopeng Tan 
Reviewed-by: Fenghua Yu 
Tested-by: Shaopeng Tan 
Tested-by: Peter Newman 
Tested-by: Carl Worth 
Tested-by: Gavin Shan 
Tested-by: Zeng Heng 
Tested-by: Hanjun Guo 
Signed-off-by: James Morse 
Signed-off-by: Ben Horgan 
Signed-off-by: Catalin Marinas