x86/resctrl: Move RFTYPE flags to be managed by resctrl

resctrl_file_fflags_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 forces the RFTYPE flags used by resctrl to be exposed to the architecture
specific code.

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. This allows the RFTYPE flags to be private to resctrl.

Add thread_throttle_mode_init(), and use it to call resctrl_file_fflags_init()
from resctrl_init(). This avoids publishing an extra function between the
architecture and filesystem code.

Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Fenghua Yu <fenghuay@nvidia.com>
Reviewed-by: Babu Moger <babu.moger@amd.com>
Reviewed-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Tested-by: Peter Newman <peternewman@google.com>
Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.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/20250311183715.16445-28-james.morse@arm.com

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

@@ -227,9 +227,6 @@ static __init bool __get_mem_config_intel(struct rdt_resource *r)
 	else
 		r->membw.throttle_mode = THREAD_THROTTLE_MAX;
 
-	resctrl_file_fflags_init("thread_throttle_mode",
-				 RFTYPE_CTRL_INFO | RFTYPE_RES_MB);
-
 	r->alloc_capable = true;
 
 	return true;

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

@@ -2064,6 +2064,16 @@ static struct rftype *rdtgroup_get_rftype_by_name(const char *name)
 	return NULL;
 }
 
+static void thread_throttle_mode_init(void)
+{
+	struct rdt_resource *r_mba;
+
+	r_mba = resctrl_arch_get_resource(RDT_RESOURCE_MBA);
+	if (r_mba->membw.throttle_mode != THREAD_THROTTLE_UNDEFINED)
+		resctrl_file_fflags_init("thread_throttle_mode",
+					 RFTYPE_CTRL_INFO | RFTYPE_RES_MB);
+}
+
 void resctrl_file_fflags_init(const char *config, unsigned long fflags)
 {
 	struct rftype *rft;
@@ -4277,6 +4287,8 @@ int __init resctrl_init(void)
 
 	rdtgroup_setup_default();
 
+	thread_throttle_mode_init();
+
 	ret = resctrl_mon_resource_init();
 	if (ret)
 		return ret;