[PATCH v3 36/38] fs/resctrl: Add boiler plate for external resctrl code

[James Morse <james.morse@arm.com>]

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
depend on this.

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

Co-developed-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Tested-by: Peter Newman <peternewman@google.com>
Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
---
Changes since v2:
 * Dropped KERNFS dependency from arch side Kconfig.
 * Added empty trace.h file.
 * Merged asm->linux includes from Dave's patch to decouple those
   patches from this series.

Changes since v1:
 * Rename new file psuedo_lock.c to pseudo_lock.c, to match the name
   of the original file (and to be less surprising).

 * [Whitespace only] Under RESCTRL_FS in fs/resctrl/Kconfig, delete
   alignment space in orphaned select ... if (which has nothing to line
   up with any more).

 * [Whitespace only] Reflow and re-tab Kconfig additions.
---
 MAINTAINERS                               |  1 +
 arch/Kconfig                              |  8 +++++
 arch/x86/Kconfig                          |  5 ++--
 arch/x86/kernel/cpu/resctrl/internal.h    |  3 +-
 arch/x86/kernel/cpu/resctrl/monitor.c     |  2 +-
 arch/x86/kernel/cpu/resctrl/pseudo_lock.c |  2 +-
 arch/x86/kernel/cpu/resctrl/rdtgroup.c    |  2 +-
 fs/Kconfig                                |  1 +
 fs/Makefile                               |  1 +
 fs/resctrl/Kconfig                        | 36 +++++++++++++++++++++++
 fs/resctrl/Makefile                       |  3 ++
 fs/resctrl/ctrlmondata.c                  |  0
 fs/resctrl/internal.h                     |  0
 fs/resctrl/monitor.c                      |  0
 fs/resctrl/pseudo_lock.c                  |  0
 fs/resctrl/rdtgroup.c                     |  0
 fs/resctrl/trace.h                        |  0
 include/linux/resctrl.h                   |  4 +++
 18 files changed, 61 insertions(+), 7 deletions(-)
 create mode 100644 fs/resctrl/Kconfig
 create mode 100644 fs/resctrl/Makefile
 create mode 100644 fs/resctrl/ctrlmondata.c
 create mode 100644 fs/resctrl/internal.h
 create mode 100644 fs/resctrl/monitor.c
 create mode 100644 fs/resctrl/pseudo_lock.c
 create mode 100644 fs/resctrl/rdtgroup.c
 create mode 100644 fs/resctrl/trace.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 441b039068d8..64195c298baf 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -18859,6 +18859,7 @@ S:	Supported
 F:	Documentation/arch/x86/resctrl*
 F:	arch/x86/include/asm/resctrl.h
 F:	arch/x86/kernel/cpu/resctrl/
+F:	fs/resctrl/
 F:	include/linux/resctrl*.h
 F:	tools/testing/selftests/resctrl/
 
diff --git a/arch/Kconfig b/arch/Kconfig
index 975dd22a2dbd..4156604dd926 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -1431,6 +1431,14 @@ config STRICT_MODULE_RWX
 config ARCH_HAS_PHYS_TO_DMA
 	bool
 
+config ARCH_HAS_CPU_RESCTRL
+	bool
+	help
+	  An architecture selects this option to indicate that the necessary
+	  hooks are provided to support the common memory system usage
+	  monitoring and control interfaces provided by the 'resctrl'
+	  filesystem (see RESCTRL_FS).
+
 config HAVE_ARCH_COMPILER_H
 	bool
 	help
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 446984277b45..e4dd4097e10f 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -490,8 +490,9 @@ config X86_MPPARSE
 config X86_CPU_RESCTRL
 	bool "x86 CPU resource control support"
 	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
-	select KERNFS
-	select PROC_CPU_RESCTRL		if PROC_FS
+	depends on MISC_FILESYSTEMS
+	select ARCH_HAS_CPU_RESCTRL
+	select RESCTRL_FS
 	select RESCTRL_FS_PSEUDO_LOCK
 	help
 	  Enable x86 CPU resource control support.
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index bad103f20663..6f6785a31efe 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -7,10 +7,9 @@
 #include <linux/kernfs.h>
 #include <linux/fs_context.h>
 #include <linux/jump_label.h>
+#include <linux/resctrl.h>
 #include <linux/tick.h>
 
-#include <asm/resctrl.h>
-
 #define L3_QOS_CDP_ENABLE		0x01ULL
 
 #define L2_QOS_CDP_ENABLE		0x01ULL
diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index 145bd05eafa5..a1539edb25fa 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -17,11 +17,11 @@
 
 #include <linux/cpu.h>
 #include <linux/module.h>
+#include <linux/resctrl.h>
 #include <linux/sizes.h>
 #include <linux/slab.h>
 
 #include <asm/cpu_device_id.h>
-#include <asm/resctrl.h>
 
 #include "internal.h"
 #include "trace.h"
diff --git a/arch/x86/kernel/cpu/resctrl/pseudo_lock.c b/arch/x86/kernel/cpu/resctrl/pseudo_lock.c
index c096fa106b80..97e901009c91 100644
--- a/arch/x86/kernel/cpu/resctrl/pseudo_lock.c
+++ b/arch/x86/kernel/cpu/resctrl/pseudo_lock.c
@@ -19,12 +19,12 @@
 #include <linux/mman.h>
 #include <linux/perf_event.h>
 #include <linux/pm_qos.h>
+#include <linux/resctrl.h>
 #include <linux/slab.h>
 #include <linux/uaccess.h>
 
 #include <asm/cacheflush.h>
 #include <asm/cpu_device_id.h>
-#include <asm/resctrl.h>
 #include <asm/perf_event.h>
 
 #include "../../events/perf_event.h" /* For X86_CONFIG() */
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 969c454b67f1..c7cbd30ac0f2 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -19,6 +19,7 @@
 #include <linux/fs_parser.h>
 #include <linux/sysfs.h>
 #include <linux/kernfs.h>
+#include <linux/resctrl.h>
 #include <linux/seq_buf.h>
 #include <linux/seq_file.h>
 #include <linux/sched/signal.h>
@@ -29,7 +30,6 @@
 
 #include <uapi/linux/magic.h>
 
-#include <asm/resctrl.h>
 #include "internal.h"
 
 DEFINE_STATIC_KEY_FALSE(rdt_enable_key);
diff --git a/fs/Kconfig b/fs/Kconfig
index a46b0cbc4d8f..d8a36383b6dc 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -331,6 +331,7 @@ source "fs/omfs/Kconfig"
 source "fs/hpfs/Kconfig"
 source "fs/qnx4/Kconfig"
 source "fs/qnx6/Kconfig"
+source "fs/resctrl/Kconfig"
 source "fs/romfs/Kconfig"
 source "fs/pstore/Kconfig"
 source "fs/sysv/Kconfig"
diff --git a/fs/Makefile b/fs/Makefile
index 6ecc9b0a53f2..da6e2d028722 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -129,3 +129,4 @@ obj-$(CONFIG_EFIVAR_FS)		+= efivarfs/
 obj-$(CONFIG_EROFS_FS)		+= erofs/
 obj-$(CONFIG_VBOXSF_FS)		+= vboxsf/
 obj-$(CONFIG_ZONEFS_FS)		+= zonefs/
+obj-$(CONFIG_RESCTRL_FS)	+= resctrl/
diff --git a/fs/resctrl/Kconfig b/fs/resctrl/Kconfig
new file mode 100644
index 000000000000..a5fbda54d32f
--- /dev/null
+++ b/fs/resctrl/Kconfig
@@ -0,0 +1,36 @@
+config RESCTRL_FS
+	bool "CPU Resource Control Filesystem (resctrl)"
+	depends on ARCH_HAS_CPU_RESCTRL
+	select KERNFS
+	select PROC_CPU_RESCTRL if PROC_FS
+	help
+	  Some architectures provide hardware facilities to group tasks and
+	  monitor and control their usage of memory system resources such as
+	  caches and memory bandwidth.  Examples of such facilities include
+	  Intel's Resource Director Technology (Intel(R) RDT) and AMD's
+	  Platform Quality of Service (AMD QoS).
+
+	  If your system has the necessary support and you want to be able to
+	  assign tasks to groups and manipulate the associated resource
+	  monitors and controls from userspace, say Y here to get a mountable
+	  'resctrl' filesystem that lets you do just that.
+
+	  If nothing mounts or prods the 'resctrl' filesystem, resource
+	  controls and monitors are left in a quiescent, permissive state.
+
+	  If unsure, it is safe to say N.
+
+	  See <file:Documentation/arch/x86/resctrl.rst> for more information.
+
+config RESCTRL_FS_PSEUDO_LOCK
+	bool
+	help
+	  Software mechanism to pin data in a cache portion using
+	  micro-architecture specific knowledge.
+
+config RESCTRL_RMID_DEPENDS_ON_CLOSID
+	bool
+	help
+	  Enable by the architecture when the RMID values depend on the CLOSID.
+	  This causes the closid allocator to search for CLOSID with clean
+	  RMID.
diff --git a/fs/resctrl/Makefile b/fs/resctrl/Makefile
new file mode 100644
index 000000000000..ee8c4463317a
--- /dev/null
+++ b/fs/resctrl/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_RESCTRL_FS)		+= rdtgroup.o ctrlmondata.o monitor.o
+obj-$(CONFIG_RESCTRL_FS_PSEUDO_LOCK)	+= pseudo_lock.o
diff --git a/fs/resctrl/ctrlmondata.c b/fs/resctrl/ctrlmondata.c
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/fs/resctrl/internal.h b/fs/resctrl/internal.h
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/fs/resctrl/monitor.c b/fs/resctrl/monitor.c
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/fs/resctrl/pseudo_lock.c b/fs/resctrl/pseudo_lock.c
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/fs/resctrl/trace.h b/fs/resctrl/trace.h
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index 31ae6d9a224e..268e17276412 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -8,6 +8,10 @@
 #include <linux/pid.h>
 #include <linux/resctrl_types.h>
 
+#ifdef CONFIG_ARCH_HAS_CPU_RESCTRL
+#include <asm/resctrl.h>
+#endif
+
 /* CLOSID, RMID value used by the default control group */
 #define RESCTRL_RESERVED_CLOSID		0
 #define RESCTRL_RESERVED_RMID		0
-- 
2.39.2