linux.git/arch/x86/kernel/cpu/resctrl/internal.h, branch v6.15

Merge tag 'driver-core-6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2025-04-01T18:02:03+00:00

Pull driver core updatesk from Greg KH:
 "Here is the big set of driver core updates for 6.15-rc1. Lots of stuff
  happened this development cycle, including:

   - kernfs scaling changes to make it even faster thanks to rcu

   - bin_attribute constify work in many subsystems

   - faux bus minor tweaks for the rust bindings

   - rust binding updates for driver core, pci, and platform busses,
     making more functionaliy available to rust drivers. These are all
     due to people actually trying to use the bindings that were in
     6.14.

   - make Rafael and Danilo full co-maintainers of the driver core
     codebase

   - other minor fixes and updates"

* tag 'driver-core-6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (52 commits)
  rust: platform: require Send for Driver trait implementers
  rust: pci: require Send for Driver trait implementers
  rust: platform: impl Send + Sync for platform::Device
  rust: pci: impl Send + Sync for pci::Device
  rust: platform: fix unrestricted &mut platform::Device
  rust: pci: fix unrestricted &mut pci::Device
  rust: device: implement device context marker
  rust: pci: use to_result() in enable_device_mem()
  MAINTAINERS: driver core: mark Rafael and Danilo as co-maintainers
  rust/kernel/faux: mark Registration methods inline
  driver core: faux: only create the device if probe() succeeds
  rust/faux: Add missing parent argument to Registration::new()
  rust/faux: Drop #[repr(transparent)] from faux::Registration
  rust: io: fix devres test with new io accessor functions
  rust: io: rename `io::Io` accessors
  kernfs: Move dput() outside of the RCU section.
  efi: rci2: mark bin_attribute as __ro_after_init
  rapidio: constify 'struct bin_attribute'
  firmware: qemu_fw_cfg: constify 'struct bin_attribute'
  powerpc/perf/hv-24x7: Constify 'struct bin_attribute'
  ...

x86/resctrl: Move get_{mon,ctrl}_domain_from_cpu() to live with their callers

2025-03-12T11:24:58+00:00

Each of get_{mon,ctrl}_domain_from_cpu() only has one caller.

Once the filesystem code is moved to /fs/, there is no equivalent to
core.c.

Move these functions to each live next to their caller. This allows
them to be made static and the header file entries to be removed.

Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Fenghua Yu 
Reviewed-by: Reinette Chatre 
Reviewed-by: Babu Moger 
Reviewed-by: Shaopeng Tan 
Tested-by: Peter Newman 
Tested-by: Shaopeng Tan 
Tested-by: Amit Singh Tomar  # arm64
Tested-by: Shanker Donthineni  # arm64
Tested-by: Babu Moger 
Link: https://lore.kernel.org/r/20250311183715.16445-31-james.morse@arm.com

x86/resctrl: Make resctrl_arch_pseudo_lock_fn() take a plr

2025-03-12T11:24:33+00:00

resctrl_arch_pseudo_lock_fn() has architecture specific behaviour,
and takes a struct rdtgroup as an argument.

After the filesystem code moves to /fs/, the definition of struct
rdtgroup will not be available to the architecture code.

The only reason resctrl_arch_pseudo_lock_fn() wants the rdtgroup is
for the CLOSID. Embed that in the pseudo_lock_region as a closid,
and move the definition of struct pseudo_lock_region to resctrl.h.

Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Shaopeng Tan 
Reviewed-by: Tony Luck 
Reviewed-by: Reinette Chatre 
Reviewed-by: Fenghua Yu 
Reviewed-by: Babu Moger 
Tested-by: Carl Worth  # arm64
Tested-by: Shaopeng Tan 
Tested-by: Peter Newman 
Tested-by: Amit Singh Tomar  # arm64
Tested-by: Shanker Donthineni  # arm64
Tested-by: Babu Moger 
Link: https://lore.kernel.org/r/20250311183715.16445-27-james.morse@arm.com

x86/resctrl: Allow an architecture to disable pseudo lock

2025-03-12T11:24:25+00:00

Pseudo-lock relies on knowledge of the micro-architecture to disable
prefetchers etc.

On arm64 these controls are typically secure only, meaning Linux can't access
them. Arm's cache-lockdown feature works in a very different way. Resctrl's
pseudo-lock isn't going to be used on arm64 platforms.

Add a Kconfig symbol that can be selected by the architecture. This enables or
disables building of the pseudo_lock.c file, and replaces the functions with
stubs. An additional IS_ENABLED() check is needed in rdtgroup_mode_write() so
that attempting to enable pseudo-lock reports an "Unknown or unsupported mode"
to user-space via the last_cmd_status file.

Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Shaopeng Tan 
Reviewed-by: Tony Luck 
Reviewed-by: Reinette Chatre 
Reviewed-by: Fenghua Yu 
Reviewed-by: Babu Moger 
Tested-by: Carl Worth  # arm64
Tested-by: Shaopeng Tan 
Tested-by: Peter Newman 
Tested-by: Amit Singh Tomar  # arm64
Tested-by: Shanker Donthineni  # arm64
Tested-by: Babu Moger 
Link: https://lore.kernel.org/r/20250311183715.16445-25-james.morse@arm.com

x86/resctrl: Move mbm_cfg_mask to struct rdt_resource

2025-03-12T11:24:09+00:00

The mbm_cfg_mask field lists the bits that user-space can set when configuring
an event. This value is output via the last_cmd_status file.

Once the filesystem parts of resctrl are moved to live in /fs/, the struct
rdt_hw_resource is inaccessible to the filesystem code. Because this value is
output to user-space, it has to be accessible to the filesystem code.

Move it to struct rdt_resource.

Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Shaopeng Tan 
Reviewed-by: Tony Luck 
Reviewed-by: Reinette Chatre 
Reviewed-by: Fenghua Yu 
Reviewed-by: Babu Moger 
Tested-by: Carl Worth  # arm64
Tested-by: Shaopeng Tan 
Tested-by: Peter Newman 
Tested-by: Amit Singh Tomar  # arm64
Tested-by: Shanker Donthineni  # arm64
Tested-by: Babu Moger 
Link: https://lore.kernel.org/r/20250311183715.16445-23-james.morse@arm.com

x86/resctrl: Move the is_mbm_*_enabled() helpers to asm/resctrl.h

2025-03-12T11:23:33+00:00

The architecture specific parts of resctrl provide helpers like
is_mbm_total_enabled() and is_mbm_local_enabled() to hide accesses to the
rdt_mon_features bitmap.

Exposing a group of helpers between the architecture and filesystem code is
preferable to a single unsigned-long like rdt_mon_features. Helpers can be more
readable and have a well defined behaviour, while allowing architectures to hide
more complex behaviour.

Once the filesystem parts of resctrl are moved, these existing helpers can no
longer live in internal.h. Move them to include/linux/resctrl.h Once these are
exposed to the wider kernel, they should have a 'resctrl_arch_' prefix, to fit
the rest of the arch<->fs interface.

Move and rename the helpers that touch rdt_mon_features directly. is_mbm_event()
and is_mbm_enabled() are only called from rdtgroup.c, so can be moved into that
file.

Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Tony Luck 
Reviewed-by: Fenghua Yu 
Reviewed-by: Reinette Chatre 
Reviewed-by: Babu Moger 
Reviewed-by: Shaopeng Tan 
Tested-by: Carl Worth  # arm64
Tested-by: Shaopeng Tan 
Tested-by: Peter Newman 
Tested-by: Amit Singh Tomar  # arm64
Tested-by: Shanker Donthineni  # arm64
Tested-by: Babu Moger 
Link: https://lore.kernel.org/r/20250311183715.16445-19-james.morse@arm.com

x86/resctrl: Rewrite and move the for_each_*_rdt_resource() walkers

2025-03-12T11:23:30+00:00

The for_each_*_rdt_resource() helpers walk the architecture's array of
structures, using the resctrl visible part as an iterator. These became
over-complex when the structures were split into a filesystem and
architecture-specific struct. This approach avoided the need to touch every
call site, and was done before there was a helper to retrieve a resource by
rid.

Once the filesystem parts of resctrl are moved to /fs/, both the arch's
resource array, and the definition of those structures is no longer
accessible. To support resctrl, each architecture would have to provide
equally complex macros.

Rewrite the macro to make use of resctrl_arch_get_resource(), and move these
to include/linux/resctrl.h so existing x86 arch code continues to use them.

Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Shaopeng Tan 
Reviewed-by: Tony Luck 
Reviewed-by: Reinette Chatre 
Reviewed-by: Fenghua Yu 
Reviewed-by: Babu Moger 
Tested-by: Shaopeng Tan 
Tested-by: Peter Newman 
Tested-by: Amit Singh Tomar  # arm64
Tested-by: Shanker Donthineni  # arm64
Tested-by: Babu Moger 
Link: https://lore.kernel.org/r/20250311183715.16445-18-james.morse@arm.com

x86/resctrl: Move monitor init work to a resctrl init call

2025-03-12T11:23:21+00:00

rdt_get_mon_l3_config() is called from the arch's resctrl_arch_late_init(),
and initialises both architecture specific fields, such as hw_res->mon_scale
and resctrl filesystem fields by calling dom_data_init().

To separate the filesystem and architecture parts of resctrl, this function
needs splitting up.

Add resctrl_mon_resource_init() to do the filesystem specific work, and call
it from resctrl_init(). This runs later, but is still before the filesystem is
mounted and the rmid_ptrs[] array can be used.

  [ bp: Massage commit message. ]

Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Shaopeng Tan 
Reviewed-by: Tony Luck 
Reviewed-by: Reinette Chatre 
Reviewed-by: Fenghua Yu 
Reviewed-by: Babu Moger 
Tested-by: Carl Worth  # arm64
Tested-by: Shaopeng Tan 
Tested-by: Peter Newman 
Tested-by: Amit Singh Tomar  # arm64
Tested-by: Shanker Donthineni  # arm64
Tested-by: Babu Moger 
Link: https://lore.kernel.org/r/20250311183715.16445-17-james.morse@arm.com

x86/resctrl: Move monitor exit work to a resctrl exit call

2025-03-12T11:23:13+00:00

rdt_put_mon_l3_config() is called via the architecture's resctrl_arch_exit()
call, and appears to free the rmid_ptrs[] and closid_num_dirty_rmid[] arrays.
In reality this code is marked __exit, and is removed by the linker as resctrl
can't be built as a module.

To separate the filesystem and architecture parts of resctrl, this free()ing
work needs to be triggered by the filesystem, as these structures belong to
the filesystem code.

Rename rdt_put_mon_l3_config() to resctrl_mon_resource_exit() and call it from
resctrl_exit(). The kfree() is currently dependent on r->mon_capable.

Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Shaopeng Tan 
Reviewed-by: Tony Luck 
Reviewed-by: Reinette Chatre 
Reviewed-by: Fenghua Yu 
Reviewed-by: Babu Moger 
Tested-by: Carl Worth  # arm64
Tested-by: Shaopeng Tan 
Tested-by: Peter Newman 
Tested-by: Amit Singh Tomar  # arm64
Tested-by: Shanker Donthineni  # arm64
Tested-by: Babu Moger 
Link: https://lore.kernel.org/r/20250311183715.16445-16-james.morse@arm.com

x86/resctrl: Move resctrl types to a separate header

2025-03-12T11:23:00+00:00

When resctrl is fully factored into core and per-arch code, each arch will
need to use some resctrl common definitions in order to define its own
specializations and helpers.  Following conventional practice, it would be
desirable to put the dependent arch definitions in an  header
that is included by the common  header.  However, this can
make it awkward to avoid a circular dependency between  and
the arch header.

To avoid such dependencies, move the affected common types and constants into
a new header that does not need to depend on  or on the arch
headers.

The same logic applies to the monitor-configuration defines, move these too.

Some kind of enumeration for events is needed between the filesystem and
architecture code. Take the x86 definition as its convenient for x86.

The definition of enum resctrl_event_id is needed to allow the architecture
code to define resctrl_arch_mon_ctx_alloc() and resctrl_arch_mon_ctx_free().

The definition of enum resctrl_res_level is needed to allow the architecture
code to define resctrl_arch_set_cdp_enabled() and
resctrl_arch_get_cdp_enabled().

The bits for mbm_local_bytes_config et al are ABI, and must be the same on all
architectures. These are documented in Documentation/arch/x86/resctrl.rst

The maintainers entry for these headers was missed when resctrl.h was created.
Add a wildcard entry to match both resctrl.h and resctrl_types.h.

Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Shaopeng Tan 
Reviewed-by: Tony Luck 
Reviewed-by: Reinette Chatre 
Reviewed-by: Fenghua Yu 
Reviewed-by: Babu Moger 
Tested-by: Carl Worth  # arm64
Tested-by: Shaopeng Tan 
Tested-by: Peter Newman 
Tested-by: Amit Singh Tomar  # arm64
Tested-by: Shanker Donthineni  # arm64
Tested-by: Babu Moger 
Link: https://lore.kernel.org/r/20250311183715.16445-14-james.morse@arm.com