[PATCH v6 20/42] x86/resctrl: Change mon_event_config_{read,write}() to be arch helpers

[James Morse]

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
<linux/resctrl.h>.  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 <Dave.Martin@xxxxxxx>
Signed-off-by: Dave Martin <Dave.Martin@xxxxxxx>
Signed-off-by: James Morse <james.morse@xxxxxxx>
Tested-by: Carl Worth <carl@xxxxxxxxxxxxxxxxxxxxxx> # arm64
Tested-by: Shaopeng Tan <tan.shaopeng@xxxxxxxxxxxxxx>
Reviewed-by: Shaopeng Tan <tan.shaopeng@xxxxxxxxxxxxxx>
Reviewed-by: Tony Luck <tony.luck@xxxxxxxxx>
---
Changes since v5:
 * Renamed info to config_info.
 * Added description of which fields are read and written in the structure.
 * Clarified comment about which CPU this is called on for both kinds of
   reader.

Changes since v3:
 * Added comments over the read/write helper to explain the type of the void
   pointer.

Changes since v1:
 * [Whitespace only] Re-tabbed struct resctrl_mon_config_info in
   <linux/resctrl.h> to fit the prevailing style.

   Non-functional change.

 * [Commit message only] Reword to align with the actual naming of the
   definitions and destination header file.
---
 arch/x86/kernel/cpu/resctrl/rdtgroup.c | 46 +++++++++++++-------------
 include/linux/resctrl.h                | 31 +++++++++++++++++
 2 files changed, 54 insertions(+), 23 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index eb32fbc3abea..e7d1d8b6983d 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -1580,11 +1580,6 @@ static int rdtgroup_size_show(struct kernfs_open_file *of,
 	return ret;
 }
 
-struct mon_config_info {
-	u32 evtid;
-	u32 mon_config;
-};
-
 #define INVALID_CONFIG_INDEX   UINT_MAX
 
 /**
@@ -1609,31 +1604,32 @@ static inline unsigned int mon_event_config_index_get(u32 evtid)
 	}
 }
 
-static void mon_event_config_read(void *info)
+void resctrl_arch_mon_event_config_read(void *_config_info)
 {
-	struct mon_config_info *mon_info = info;
+	struct resctrl_mon_config_info *config_info = _config_info;
 	unsigned int index;
 	u64 msrval;
 
-	index = mon_event_config_index_get(mon_info->evtid);
+	index = mon_event_config_index_get(config_info->evtid);
 	if (index == INVALID_CONFIG_INDEX) {
-		pr_warn_once("Invalid event id %d\n", mon_info->evtid);
+		pr_warn_once("Invalid event id %d\n", config_info->evtid);
 		return;
 	}
 	rdmsrl(MSR_IA32_EVT_CFG_BASE + index, msrval);
 
 	/* Report only the valid event configuration bits */
-	mon_info->mon_config = msrval & MAX_EVT_CONFIG_BITS;
+	config_info->mon_config = msrval & MAX_EVT_CONFIG_BITS;
 }
 
-static void mondata_config_read(struct rdt_mon_domain *d, struct mon_config_info *mon_info)
+static void mondata_config_read(struct resctrl_mon_config_info *mon_info)
 {
-	smp_call_function_any(&d->hdr.cpu_mask, mon_event_config_read, mon_info, 1);
+	smp_call_function_any(&mon_info->d->hdr.cpu_mask,
+			      resctrl_arch_mon_event_config_read, mon_info, 1);
 }
 
 static int mbm_config_show(struct seq_file *s, struct rdt_resource *r, u32 evtid)
 {
-	struct mon_config_info mon_info;
+	struct resctrl_mon_config_info mon_info;
 	struct rdt_mon_domain *dom;
 	bool sep = false;
 
@@ -1644,9 +1640,11 @@ static int mbm_config_show(struct seq_file *s, struct rdt_resource *r, u32 evtid
 		if (sep)
 			seq_puts(s, ";");
 
-		memset(&mon_info, 0, sizeof(struct mon_config_info));
+		memset(&mon_info, 0, sizeof(struct resctrl_mon_config_info));
+		mon_info.r = r;
+		mon_info.d = dom;
 		mon_info.evtid = evtid;
-		mondata_config_read(dom, &mon_info);
+		mondata_config_read(&mon_info);
 
 		seq_printf(s, "%d=0x%02x", dom->hdr.id, mon_info.mon_config);
 		sep = true;
@@ -1679,30 +1677,32 @@ static int mbm_local_bytes_config_show(struct kernfs_open_file *of,
 	return 0;
 }
 
-static void mon_event_config_write(void *info)
+void resctrl_arch_mon_event_config_write(void *_config_info)
 {
-	struct mon_config_info *mon_info = info;
+	struct resctrl_mon_config_info *config_info = _config_info;
 	unsigned int index;
 
-	index = mon_event_config_index_get(mon_info->evtid);
+	index = mon_event_config_index_get(config_info->evtid);
 	if (index == INVALID_CONFIG_INDEX) {
-		pr_warn_once("Invalid event id %d\n", mon_info->evtid);
+		pr_warn_once("Invalid event id %d\n", config_info->evtid);
 		return;
 	}
-	wrmsr(MSR_IA32_EVT_CFG_BASE + index, mon_info->mon_config, 0);
+	wrmsr(MSR_IA32_EVT_CFG_BASE + index, config_info->mon_config, 0);
 }
 
 static void mbm_config_write_domain(struct rdt_resource *r,
 				    struct rdt_mon_domain *d, u32 evtid, u32 val)
 {
-	struct mon_config_info mon_info = {0};
+	struct resctrl_mon_config_info mon_info = {0};
 
 	/*
 	 * Read the current config value first. If both are the same then
 	 * no need to write it again.
 	 */
+	mon_info.r = r;
+	mon_info.d = d;
 	mon_info.evtid = evtid;
-	mondata_config_read(d, &mon_info);
+	mondata_config_read(&mon_info);
 	if (mon_info.mon_config == val)
 		return;
 
@@ -1714,7 +1714,7 @@ static void mbm_config_write_domain(struct rdt_resource *r,
 	 * are scoped at the domain level. Writing any of these MSRs
 	 * on one CPU is observed by all the CPUs in the domain.
 	 */
-	smp_call_function_any(&d->hdr.cpu_mask, mon_event_config_write,
+	smp_call_function_any(&d->hdr.cpu_mask, resctrl_arch_mon_event_config_write,
 			      &mon_info, 1);
 
 	/*
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index 5c7b9760b63a..59d944e139f8 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -270,6 +270,13 @@ struct resctrl_cpu_defaults {
 	u32 rmid;
 };
 
+struct resctrl_mon_config_info {
+	struct rdt_resource	*r;
+	struct rdt_mon_domain	*d;
+	u32			evtid;
+	u32			mon_config;
+};
+
 /**
  * resctrl_arch_sync_cpu_closid_rmid() - Refresh this CPU's CLOSID and RMID.
  *					 Call via IPI.
@@ -311,6 +318,30 @@ int resctrl_arch_update_domains(struct rdt_resource *r, u32 closid);
 
 bool __init resctrl_arch_is_evt_configurable(enum resctrl_event_id evt);
 
+/**
+ * resctrl_arch_mon_event_config_write() - Write the config for an event.
+ * @config_info: struct resctrl_mon_config_info describing the resource, domain
+ *		 and event.
+ *
+ * Reads resource, domain and eventid from @config_info and writes the
+ * event config_info->mon_config into hardware.
+ *
+ * Called via IPI to reach a CPU that is a member of the specified domain.
+ */
+void resctrl_arch_mon_event_config_write(void *config_info);
+
+/**
+ * resctrl_arch_mon_event_config_read() - Read the config for an event.
+ * @config_info: struct resctrl_mon_config_info describing the resource, domain
+ *		 and event.
+ *
+ * Reads resource, domain and eventid from @config_info and reads the
+ * hardware config value into config_info->mon_config.
+ *
+ * Called via IPI to reach a CPU that is a member of the specified domain.
+ */
+void resctrl_arch_mon_event_config_read(void *config_info);
+
 /*
  * Update the ctrl_val and apply this config right now.
  * Must be called on one of the domain's CPUs.
-- 
2.39.2