x86/resctrl: Add resctrl_arch_ prefix to pseudo lock functions

resctrl's pseudo lock has some copy-to-cache and measurement functions that
are micro-architecture specific.

For example, pseudo_lock_fn() is not at all portable.

Label these 'resctrl_arch_' so they stay under /arch/x86.  To expose these
functions to the filesystem code they need an entry in a header file, and
can't be marked static.

Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Fenghua Yu <fenghuay@nvidia.com>
Reviewed-by: Babu Moger <babu.moger@amd.com>
Tested-by: Carl Worth <carl@os.amperecomputing.com> # arm64
Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Tested-by: Peter Newman <peternewman@google.com>
Tested-by: Amit Singh Tomar <amitsinght@marvell.com> # arm64
Tested-by: Shanker Donthineni <sdonthineni@nvidia.com> # arm64
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://lore.kernel.org/r/20250311183715.16445-24-james.morse@arm.com

Author: James Morse

arch/x86/include/asm/resctrl.h

@@ -203,6 +203,11 @@ static inline void *resctrl_arch_mon_ctx_alloc(struct rdt_resource *r, int evtid
 static inline void resctrl_arch_mon_ctx_free(struct rdt_resource *r, int evtid,
 					     void *ctx) { };
 
+u64 resctrl_arch_get_prefetch_disable_bits(void);
+int resctrl_arch_pseudo_lock_fn(void *_rdtgrp);
+int resctrl_arch_measure_cycles_lat_fn(void *_plr);
+int resctrl_arch_measure_l2_residency(void *_plr);
+int resctrl_arch_measure_l3_residency(void *_plr);
 void resctrl_cpu_detect(struct cpuinfo_x86 *c);
 
 #else

arch/x86/kernel/cpu/resctrl/pseudo_lock.c

@@ -61,7 +61,8 @@ static const struct class pseudo_lock_class = {
 };
 
 /**
- * get_prefetch_disable_bits - prefetch disable bits of supported platforms
+ * resctrl_arch_get_prefetch_disable_bits - prefetch disable bits of supported
+ *                                          platforms
  * @void: It takes no parameters.
  *
  * Capture the list of platforms that have been validated to support
@@ -75,13 +76,13 @@ static const struct class pseudo_lock_class = {
  * in the SDM.
  *
  * When adding a platform here also add support for its cache events to
- * measure_cycles_perf_fn()
+ * resctrl_arch_measure_l*_residency()
  *
  * Return:
  * If platform is supported, the bits to disable hardware prefetchers, 0
  * if platform is not supported.
  */
-static u64 get_prefetch_disable_bits(void)
+u64 resctrl_arch_get_prefetch_disable_bits(void)
 {
 	if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL ||
 	    boot_cpu_data.x86 != 6)
@@ -408,7 +409,7 @@ static void pseudo_lock_free(struct rdtgroup *rdtgrp)
 }
 
 /**
- * pseudo_lock_fn - Load kernel memory into cache
+ * resctrl_arch_pseudo_lock_fn - Load kernel memory into cache
  * @_rdtgrp: resource group to which pseudo-lock region belongs
  *
  * This is the core pseudo-locking flow.
@@ -426,7 +427,7 @@ static void pseudo_lock_free(struct rdtgroup *rdtgrp)
  *
  * Return: 0. Waiter on waitqueue will be woken on completion.
  */
-static int pseudo_lock_fn(void *_rdtgrp)
+int resctrl_arch_pseudo_lock_fn(void *_rdtgrp)
 {
 	struct rdtgroup *rdtgrp = _rdtgrp;
 	struct pseudo_lock_region *plr = rdtgrp->plr;
@@ -712,7 +713,7 @@ int rdtgroup_locksetup_enter(struct rdtgroup *rdtgrp)
 	 * Not knowing the bits to disable prefetching implies that this
 	 * platform does not support Cache Pseudo-Locking.
 	 */
-	prefetch_disable_bits = get_prefetch_disable_bits();
+	prefetch_disable_bits = resctrl_arch_get_prefetch_disable_bits();
 	if (prefetch_disable_bits == 0) {
 		rdt_last_cmd_puts("Pseudo-locking not supported\n");
 		return -EINVAL;
@@ -872,7 +873,8 @@ bool rdtgroup_pseudo_locked_in_hierarchy(struct rdt_ctrl_domain *d)
 }
 
 /**
- * measure_cycles_lat_fn - Measure cycle latency to read pseudo-locked memory
+ * resctrl_arch_measure_cycles_lat_fn - Measure cycle latency to read
+ *                                      pseudo-locked memory
  * @_plr: pseudo-lock region to measure
  *
  * There is no deterministic way to test if a memory region is cached. One
@@ -885,7 +887,7 @@ bool rdtgroup_pseudo_locked_in_hierarchy(struct rdt_ctrl_domain *d)
  *
  * Return: 0. Waiter on waitqueue will be woken on completion.
  */
-static int measure_cycles_lat_fn(void *_plr)
+int resctrl_arch_measure_cycles_lat_fn(void *_plr)
 {
 	struct pseudo_lock_region *plr = _plr;
 	u32 saved_low, saved_high;
@@ -1069,7 +1071,7 @@ static int measure_residency_fn(struct perf_event_attr *miss_attr,
 	return 0;
 }
 
-static int measure_l2_residency(void *_plr)
+int resctrl_arch_measure_l2_residency(void *_plr)
 {
 	struct pseudo_lock_region *plr = _plr;
 	struct residency_counts counts = {0};
@@ -1107,7 +1109,7 @@ static int measure_l2_residency(void *_plr)
 	return 0;
 }
 
-static int measure_l3_residency(void *_plr)
+int resctrl_arch_measure_l3_residency(void *_plr)
 {
 	struct pseudo_lock_region *plr = _plr;
 	struct residency_counts counts = {0};
@@ -1205,14 +1207,14 @@ static int pseudo_lock_measure_cycles(struct rdtgroup *rdtgrp, int sel)
 	plr->cpu = cpu;
 
 	if (sel == 1)
-		thread = kthread_run_on_cpu(measure_cycles_lat_fn, plr,
-					    cpu, "pseudo_lock_measure/%u");
+		thread = kthread_run_on_cpu(resctrl_arch_measure_cycles_lat_fn,
+					    plr, cpu, "pseudo_lock_measure/%u");
 	else if (sel == 2)
-		thread = kthread_run_on_cpu(measure_l2_residency, plr,
-					    cpu, "pseudo_lock_measure/%u");
+		thread = kthread_run_on_cpu(resctrl_arch_measure_l2_residency,
+					    plr, cpu, "pseudo_lock_measure/%u");
 	else if (sel == 3)
-		thread = kthread_run_on_cpu(measure_l3_residency, plr,
-					    cpu, "pseudo_lock_measure/%u");
+		thread = kthread_run_on_cpu(resctrl_arch_measure_l3_residency,
+					    plr, cpu, "pseudo_lock_measure/%u");
 	else
 		goto out;
 
@@ -1307,7 +1309,7 @@ int rdtgroup_pseudo_lock_create(struct rdtgroup *rdtgrp)
 
 	plr->thread_done = 0;
 
-	thread = kthread_run_on_cpu(pseudo_lock_fn, rdtgrp,
+	thread = kthread_run_on_cpu(resctrl_arch_pseudo_lock_fn, rdtgrp,
 				    plr->cpu, "pseudo_lock/%u");
 	if (IS_ERR(thread)) {
 		ret = PTR_ERR(thread);