linux-kernel - [PATCH v3 32/38] x86/resctrl: Drop __init/_

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Message-Id: <20240614150033.10454-33-james.morse@arm.com>
Date: Fri, 14 Jun 2024 15:00:27 +0000
From: James Morse <james.morse@....com>
To: x86@...nel.org,
	linux-kernel@...r.kernel.org
Cc: Fenghua Yu <fenghua.yu@...el.com>,
	Reinette Chatre <reinette.chatre@...el.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>,
	H Peter Anvin <hpa@...or.com>,
	Babu Moger <Babu.Moger@....com>,
	James Morse <james.morse@....com>,
	shameerali.kolothum.thodi@...wei.com,
	D Scott Phillips OS <scott@...amperecomputing.com>,
	carl@...amperecomputing.com,
	lcherian@...vell.com,
	bobo.shaobowang@...wei.com,
	tan.shaopeng@...itsu.com,
	baolin.wang@...ux.alibaba.com,
	Jamie Iles <quic_jiles@...cinc.com>,
	Xin Hao <xhao@...ux.alibaba.com>,
	peternewman@...gle.com,
	dfustini@...libre.com,
	amitsinght@...vell.com,
	David Hildenbrand <david@...hat.com>,
	Rex Nie <rex.nie@...uarmicro.com>,
	Dave Martin <dave.martin@....com>,
	Shaopeng Tan <tan.shaopeng@...fujitsu.com>
Subject: [PATCH v3 32/38] x86/resctrl: Drop __init/__exit on assorted symbols

Because ARM's MPAM controls are probed using MMIO, resctrl can't be
initialised until enough CPUs are online to have determined the
system-wide supported num_closid. Arm64 also supports 'late onlined
secondaries', where only a subset of CPUs are online during boot.

These two combine to mean the MPAM driver may not be able to initialise
resctrl until user-space has brought 'enough' CPUs online.

To allow MPAM to initialise resctrl after __init text has been free'd,
remove all the __init markings from resctrl.

The existing __exit markings cause these functions to be removed by the
linker as it has never been possible to build resctrl as a module. MPAM
has an error interrupt which causes the driver to reset and disable
itself. Remove the __exit markings to allow the MPAM driver to tear down
resctrl when an error occurs.

Signed-off-by: James Morse <james.morse@....com>
Tested-by: Peter Newman <peternewman@...gle.com>
Tested-by: Shaopeng Tan <tan.shaopeng@...fujitsu.com>
---
 arch/x86/kernel/cpu/resctrl/rdtgroup.c | 8 ++++----
 include/linux/resctrl.h                | 4 ++--
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index ddf3d0a26517..0936a4cddc9e 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -2055,7 +2055,7 @@ static struct rftype *rdtgroup_get_rftype_by_name(const char *name)
 	return NULL;
 }
 
-static void __init thread_throttle_mode_init(void)
+static void thread_throttle_mode_init(void)
 {
 	struct rdt_resource *r = resctrl_arch_get_resource(RDT_RESOURCE_MBA);
 	struct rftype *rft;
@@ -4003,7 +4003,7 @@ static void rdtgroup_destroy_root(void)
 	rdtgroup_default.kn = NULL;
 }
 
-static void __init rdtgroup_setup_default(void)
+static void rdtgroup_setup_default(void)
 {
 	mutex_lock(&rdtgroup_mutex);
 
@@ -4196,7 +4196,7 @@ void resctrl_offline_cpu(unsigned int cpu)
  *
  * Return: 0 on success or -errno
  */
-int __init resctrl_init(void)
+int resctrl_init(void)
 {
 	int ret = 0;
 
@@ -4253,7 +4253,7 @@ int __init resctrl_init(void)
 	return ret;
 }
 
-void __exit resctrl_exit(void)
+void resctrl_exit(void)
 {
 	rdtgroup_destroy_root();
 	debugfs_remove_recursive(debugfs_resctrl);
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index 3fc5f760e041..31ae6d9a224e 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -452,7 +452,7 @@ void resctrl_arch_reset_rmid_all(struct rdt_resource *r, struct rdt_domain *d);
 extern unsigned int resctrl_rmid_realloc_threshold;
 extern unsigned int resctrl_rmid_realloc_limit;
 
-int __init resctrl_init(void);
-void __exit resctrl_exit(void);
+int resctrl_init(void);
+void resctrl_exit(void);
 
 #endif /* _RESCTRL_H */
-- 
2.39.2