linux.git/include/linux/resctrl.h, branch v6.16-rc2

x86/resctrl: Move pseudo lock prototypes to include/linux/resctrl.h

2025-05-16T10:21:00+00:00

The resctrl pseudo-lock feature allows an architecture to allocate data
into particular cache portions, which are then treated as reserved to
avoid that data ever being evicted. Setting this up is deeply architecture
specific as it involves disabling prefetchers etc. It is not possible
to support this kind of feature on arm64. Risc-V is assumed to be the
same.

The prototypes for the architecture code were added to x86's asm/resctrl.h,
with other architectures able to provide stubs for their architecture. This
forces other architectures to provide identical stubs.

Move the prototypes and stubs to linux/resctrl.h, and switch between them
using the existing Kconfig symbol.

Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Reinette Chatre 
Reviewed-by: Fenghua Yu 
Tested-by: Fenghua Yu 
Tested-by: Babu Moger 
Tested-by: Shaopeng Tan 
Tested-by: Tony Luck 
Link: https://lore.kernel.org/20250515165855.31452-20-james.morse@arm.com

x86/resctrl: Move enum resctrl_event_id to resctrl.h

2025-05-16T10:10:20+00:00

resctrl_types.h contains common types and constants to enable architectures
to use these types in their definitions within asm/resctrl.h.

enum resctrl_event_id was placed in resctrl_types.h for
resctrl_arch_get_cdp_enabled() and resctrl_arch_set_cdp_enabled(), but
these two functions are no longer inlined by any architecture.

Move enum resctrl_event_id to resctrl.h.

Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Reinette Chatre 
Reviewed-by: Fenghua Yu 
Tested-by: Fenghua Yu 
Tested-by: Babu Moger 
Tested-by: Shaopeng Tan 
Tested-by: Tony Luck 
Link: https://lore.kernel.org/20250515165855.31452-18-james.morse@arm.com

x86/resctrl: Move the filesystem bits to headers visible to fs/resctrl

2025-05-16T09:35:23+00:00

Once the filesystem parts of resctrl move to fs/resctrl, it cannot rely
on definitions in x86's internal.h.

Move definitions in internal.h that need to be shared between the
filesystem and architecture code to header files that fs/resctrl can
include.

Doing this separately means the filesystem code only moves between files
of the same name, instead of having these changes mixed in too.

Co-developed-by: Dave Martin 
Signed-off-by: Dave Martin 
Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Shaopeng Tan 
Reviewed-by: Tony Luck 
Reviewed-by: Fenghua Yu 
Reviewed-by: Reinette Chatre 
Tested-by: Fenghua Yu 
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 
Tested-by: Tony Luck 
Link: https://lore.kernel.org/20250515165855.31452-17-james.morse@arm.com

fs/resctrl: Add boiler plate for external resctrl code

2025-05-16T09:05:40+00:00

Add Makefile and Kconfig for fs/resctrl. Add ARCH_HAS_CPU_RESCTRL
for the common parts of the resctrl interface and make X86_CPU_RESCTRL
select this.

Adding an include of asm/resctrl.h to linux/resctrl.h allows the
/fs/resctrl files to switch over to using this header instead.

Co-developed-by: Dave Martin 
Signed-off-by: Dave Martin 
Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Shaopeng Tan 
Reviewed-by: Tony Luck 
Reviewed-by: Fenghua Yu 
Reviewed-by: Reinette Chatre 
Tested-by: Fenghua Yu 
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 
Tested-by: Tony Luck 
Link: https://lore.kernel.org/20250515165855.31452-16-james.morse@arm.com

x86/resctrl: Drop init/exit on assorted symbols

2025-05-15T19:06:02+00:00

Because ARM's MPAM controls are probed using MMIO, resctrl can't be
initialised until enough CPUs are online to have determined the system-wide
supported num_closid. Arm64 also supports 'late onlined secondaries', where
only a subset of CPUs are online during boot.

These two combine to mean the MPAM driver may not be able to initialise
resctrl until user-space has brought 'enough' CPUs online.

To allow MPAM to initialise resctrl after __init text has been free'd, remove
all the __init markings from resctrl.

The existing __exit markings cause these functions to be removed by the linker
as it has never been possible to build resctrl as a module. MPAM has an error
interrupt which causes the driver to reset and disable itself. Remove the
__exit markings to allow the MPAM driver to tear down resctrl when an error
occurs.

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 
Tested-by: Fenghua Yu 
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 
Tested-by: Tony Luck 
Link: https://lore.kernel.org/20250515165855.31452-10-james.morse@arm.com

x86/resctrl: Move get_config_index() to a header

2025-03-12T11:24:54+00:00

get_config_index() is used by the architecture specific code to map
a CLOSID+type pair to an index in the configuration arrays.

MPAM needs to do this too to preserve the ABI to user-space, there is no
reason to do it differently.

Move the helper to a header file to allow all architectures that either
use or emulate CDP to use the same pattern of CLOSID values. Moving
this to a header file means it must be marked inline, which matches
the existing compiler choice for this static function.

Co-developed-by: Dave Martin 
Signed-off-by: Dave Martin 
Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Shaopeng Tan 
Reviewed-by: Tony Luck 
Reviewed-by: Fenghua Yu 
Reviewed-by: Reinette Chatre 
Reviewed-by: Babu Moger 
Tested-by: Carl Worth  # arm64
Tested-by: Shanker Donthineni  # arm64
Tested-by: Shaopeng Tan 
Tested-by: Peter Newman 
Tested-by: Amit Singh Tomar  # arm64
Tested-by: Babu Moger 
Link: https://lore.kernel.org/r/20250311183715.16445-30-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: 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: Change mon_event_config_{read,write}() to be arch helpers

2025-03-12T11:23:49+00:00

mon_event_config_{read,write}() are called via IPI and access model specific
registers to do their work.

To support another architecture, this needs abstracting.

Rename mon_event_config_{read,write}() to have a "resctrl_arch_" prefix, and
move their struct mon_config_info parameter into .  This
allows another architecture to supply an implementation of these.

As struct mon_config_info is now exposed globally, give it a 'resctrl_'
prefix. MPAM systems need access to the domain to do this work, add the
resource and domain to struct resctrl_mon_config_info.

Co-developed-by: Dave Martin 
Signed-off-by: Dave Martin 
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/20250311183715.16445-21-james.morse@arm.com

x86/resctrl: Add resctrl_arch_is_evt_configurable() to abstract BMEC

2025-03-12T11:23:45+00:00

When BMEC is supported the resctrl event can be configured in a number of
ways. This depends on architecture support. rdt_get_mon_l3_config() modifies
the struct mon_evt and calls resctrl_file_fflags_init() to create the files
that allow the configuration.

Splitting this into separate architecture and filesystem parts would require
the struct mon_evt and resctrl_file_fflags_init() to be exposed.

Instead, add resctrl_arch_is_evt_configurable(), and use this from
resctrl_mon_resource_init() to initialise struct mon_evt and call
resctrl_file_fflags_init().

resctrl_arch_is_evt_configurable() calls rdt_cpu_has() so it doesn't obviously
benefit from being inlined. Putting it in core.c will allow rdt_cpu_has() to
eventually become static.

Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Shaopeng Tan 
Reviewed-by: Tony Luck 
Reviewed-by: Fenghua Yu 
Reviewed-by: Reinette Chatre 
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/20250311183715.16445-20-james.morse@arm.com