x86/resctrl: Split struct rdt_resource

resctrl is the defacto Linux ABI for SoC resource partitioning features.

To support it on another architecture, it needs to be abstracted from
the features provided by Intel RDT and AMD PQoS, and moved to /fs/.
struct rdt_resource contains a mix of architecture private details
and properties of the filesystem interface user-space uses.

Start by splitting struct rdt_resource, into an architecture private
'hw' struct, which contains the common resctrl structure that would be
used by any architecture. The foreach helpers are most commonly used by
the filesystem code, and should return the common resctrl structure.
for_each_rdt_resource() is changed to walk the common structure in its
parent arch private structure.

Move as much of the structure as possible into the common structure
in the core code's header file. The x86 hardware accessors remain
part of the architecture private code, as do num_closid, mon_scale
and mbm_width.

mon_scale and mbm_width are used to detect overflow of the hardware
counters, and convert them from their native size to bytes. Any
cross-architecture abstraction should be in terms of bytes, making
these properties private.

The hardware's num_closid is kept in the private structure to force the
filesystem code to use a helper to access it. MPAM would return a single
value for the system, regardless of the resource. Using the helper
prevents this field from being confused with the version of num_closid
that is being exposed to user-space (added in a later patch).

After this split, filesystem code touching a 'hw' struct indicates
where an abstraction is needed.

Splitting this structure only moves types around, and should not lead
to any change in behaviour.

Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Jamie Iles <jamie@nuviainc.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://lkml.kernel.org/r/20210728170637.25610-2-james.morse@arm.com

1 files changed, 110 insertions, 0 deletions

diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index 9b05af9b3e28..5ccf36b7dbbf 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -2,6 +2,8 @@
 #ifndef _RESCTRL_H
 #define _RESCTRL_H
 
+#include <linux/kernel.h>
+#include <linux/list.h>
 #include <linux/pid.h>
 
 #ifdef CONFIG_PROC_CPU_RESCTRL
@@ -13,4 +15,112 @@ int proc_resctrl_show(struct seq_file *m,
 
 #endif
 
+struct rdt_domain;
+
+/**
+ * struct resctrl_cache - Cache allocation related data
+ * @cbm_len:		Length of the cache bit mask
+ * @min_cbm_bits:	Minimum number of consecutive bits to be set
+ * @cbm_idx_mult:	Multiplier of CBM index
+ * @cbm_idx_offset:	Offset of CBM index. CBM index is computed by:
+ *			closid * cbm_idx_multi + cbm_idx_offset
+ *			in a cache bit mask
+ * @shareable_bits:	Bitmask of shareable resource with other
+ *			executing entities
+ * @arch_has_sparse_bitmaps:	True if a bitmap like f00f is valid.
+ * @arch_has_empty_bitmaps:	True if the '0' bitmap is valid.
+ * @arch_has_per_cpu_cfg:	True if QOS_CFG register for this cache
+ *				level has CPU scope.
+ */
+struct resctrl_cache {
+	unsigned int	cbm_len;
+	unsigned int	min_cbm_bits;
+	unsigned int	cbm_idx_mult;	// TODO remove this
+	unsigned int	cbm_idx_offset; // TODO remove this
+	unsigned int	shareable_bits;
+	bool		arch_has_sparse_bitmaps;
+	bool		arch_has_empty_bitmaps;
+	bool		arch_has_per_cpu_cfg;
+};
+
+/**
+ * enum membw_throttle_mode - System's memory bandwidth throttling mode
+ * @THREAD_THROTTLE_UNDEFINED:	Not relevant to the system
+ * @THREAD_THROTTLE_MAX:	Memory bandwidth is throttled at the core
+ *				always using smallest bandwidth percentage
+ *				assigned to threads, aka "max throttling"
+ * @THREAD_THROTTLE_PER_THREAD:	Memory bandwidth is throttled at the thread
+ */
+enum membw_throttle_mode {
+	THREAD_THROTTLE_UNDEFINED = 0,
+	THREAD_THROTTLE_MAX,
+	THREAD_THROTTLE_PER_THREAD,
+};
+
+/**
+ * struct resctrl_membw - Memory bandwidth allocation related data
+ * @min_bw:		Minimum memory bandwidth percentage user can request
+ * @bw_gran:		Granularity at which the memory bandwidth is allocated
+ * @delay_linear:	True if memory B/W delay is in linear scale
+ * @arch_needs_linear:	True if we can't configure non-linear resources
+ * @throttle_mode:	Bandwidth throttling mode when threads request
+ *			different memory bandwidths
+ * @mba_sc:		True if MBA software controller(mba_sc) is enabled
+ * @mb_map:		Mapping of memory B/W percentage to memory B/W delay
+ */
+struct resctrl_membw {
+	u32				min_bw;
+	u32				bw_gran;
+	u32				delay_linear;
+	bool				arch_needs_linear;
+	enum membw_throttle_mode	throttle_mode;
+	bool				mba_sc;
+	u32				*mb_map;
+};
+
+struct rdt_parse_data;
+
+/**
+ * struct rdt_resource - attributes of a resctrl resource
+ * @rid:		The index of the resource
+ * @alloc_enabled:	Is allocation enabled on this machine
+ * @mon_enabled:	Is monitoring enabled for this feature
+ * @alloc_capable:	Is allocation available on this machine
+ * @mon_capable:	Is monitor feature available on this machine
+ * @num_rmid:		Number of RMIDs available
+ * @cache_level:	Which cache level defines scope of this resource
+ * @cache:		Cache allocation related data
+ * @membw:		If the component has bandwidth controls, their properties.
+ * @domains:		All domains for this resource
+ * @name:		Name to use in "schemata" file.
+ * @data_width:		Character width of data when displaying
+ * @default_ctrl:	Specifies default cache cbm or memory B/W percent.
+ * @format_str:		Per resource format string to show domain value
+ * @parse_ctrlval:	Per resource function pointer to parse control values
+ * @evt_list:		List of monitoring events
+ * @fflags:		flags to choose base and info files
+ */
+struct rdt_resource {
+	int			rid;
+	bool			alloc_enabled;
+	bool			mon_enabled;
+	bool			alloc_capable;
+	bool			mon_capable;
+	int			num_rmid;
+	int			cache_level;
+	struct resctrl_cache	cache;
+	struct resctrl_membw	membw;
+	struct list_head	domains;
+	char			*name;
+	int			data_width;
+	u32			default_ctrl;
+	const char		*format_str;
+	int			(*parse_ctrlval)(struct rdt_parse_data *data,
+						 struct rdt_resource *r,
+						 struct rdt_domain *d);
+	struct list_head	evt_list;
+	unsigned long		fflags;
+
+};
+
 #endif /* _RESCTRL_H */