thread_throttle_mode_init() is called from the architecture specific code
to make the 'thread_throttle_mode' file visible. The architecture specific
code has already set the membw.throttle_mode in the rdt_resource.

This doesn't need to be specific to the architecture, the throttle_mode
can be used by resctrl to determine if the 'thread_throttle_mode' file
should be visible.

Call thread_throttle_mode_init() from resctrl_setup(), check the
membw.throttle_mode on the MBA resource. This avoids publishing an
extra function between the architecture and filesystem code.

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>
---
 arch/x86/kernel/cpu/resctrl/core.c     | 1 -
 arch/x86/kernel/cpu/resctrl/internal.h | 1 -
 arch/x86/kernel/cpu/resctrl/rdtgroup.c | 9 ++++++++-
 3 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index 252201eefdd0..d932e03f129f 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -222,7 +222,6 @@ static bool __get_mem_config_intel(struct rdt_resource *r)
 		r->membw.throttle_mode = THREAD_THROTTLE_PER_THREAD;
 	else
 		r->membw.throttle_mode = THREAD_THROTTLE_MAX;
-	thread_throttle_mode_init();
 
 	r->alloc_capable = true;
 
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 38d3aab9b684..fc837d144894 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -480,7 +480,6 @@ void cqm_handle_limbo(struct work_struct *work);
 bool has_busy_rmid(struct rdt_domain *d);
 void __check_limbo(struct rdt_domain *d, bool force_free);
 void rdt_domain_reconfigure_cdp(struct rdt_resource *r);
-void __init thread_throttle_mode_init(void);
 void mbm_config_rftype_init(const char *config);
 void rdt_staged_configs_clear(void);
 bool closid_allocated(unsigned int closid);
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 7957edcfc97d..8066d0e51a73 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -2055,10 +2055,15 @@ static struct rftype *rdtgroup_get_rftype_by_name(const char *name)
 	return NULL;
 }
 
-void __init thread_throttle_mode_init(void)
+static void __init thread_throttle_mode_init(void)
 {
+	struct rdt_resource *r = resctrl_arch_get_resource(RDT_RESOURCE_MBA);
 	struct rftype *rft;
 
+	if (!r->alloc_capable ||
+	    r->membw.throttle_mode == THREAD_THROTTLE_UNDEFINED)
+		return;
+
 	rft = rdtgroup_get_rftype_by_name("thread_throttle_mode");
 	if (!rft)
 		return;
@@ -4200,6 +4205,8 @@ int __init resctrl_init(void)
 
 	rdtgroup_setup_default();
 
+	thread_throttle_mode_init();
+
 	ret = resctrl_mon_resource_init();
 	if (ret)
 		return ret;
-- 
2.39.2