Commit 0a2f4d9b authored by James Morse's avatar James Morse Committed by Borislav Petkov (AMD)
Browse files

x86/resctrl: Make rdt_enable_key the arch's decision to switch 



rdt_enable_key is switched when resctrl is mounted. It was also previously used
to prevent a second mount of the filesystem.

Any other architecture that wants to support resctrl has to provide identical
static keys.

Now that there are helpers for enabling and disabling the alloc/mon keys,
resctrl doesn't need to switch this extra key, it can be done by the arch code.
Use the static-key increment and decrement helpers, and change resctrl to
ensure the calls are balanced.

Signed-off-by: default avatarJames Morse <james.morse@arm.com>
Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: default avatarShaopeng Tan <tan.shaopeng@fujitsu.com>
Reviewed-by: default avatarReinette Chatre <reinette.chatre@intel.com>
Reviewed-by: default avatarBabu Moger <babu.moger@amd.com>
Tested-by: default avatarShaopeng Tan <tan.shaopeng@fujitsu.com>
Tested-by: default avatarPeter Newman <peternewman@google.com>
Tested-by: default avatarBabu Moger <babu.moger@amd.com>
Tested-by: Carl Worth <carl@os.amperecomputing.com> # arm64
Link: https://lore.kernel.org/r/20240213184438.16675-19-james.morse@arm.com


Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
parent 5db6a4a7

arch/x86/include/asm/resctrl.h

+4 −0
Original line number Diff line number Diff line
@@ -45,21 +45,25 @@ DECLARE_STATIC_KEY_FALSE(rdt_mon_enable_key); 
static inline void resctrl_arch_enable_alloc(void)

{

	static_branch_enable_cpuslocked(&rdt_alloc_enable_key);

	static_branch_inc_cpuslocked(&rdt_enable_key);

}



static inline void resctrl_arch_disable_alloc(void)

{

	static_branch_disable_cpuslocked(&rdt_alloc_enable_key);

	static_branch_dec_cpuslocked(&rdt_enable_key);

}



static inline void resctrl_arch_enable_mon(void)

{

	static_branch_enable_cpuslocked(&rdt_mon_enable_key);

	static_branch_inc_cpuslocked(&rdt_enable_key);

}



static inline void resctrl_arch_disable_mon(void)

{

	static_branch_disable_cpuslocked(&rdt_mon_enable_key);

	static_branch_dec_cpuslocked(&rdt_enable_key);

}



/*

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

+5 −6
Original line number Diff line number Diff line
@@ -2672,10 +2672,8 @@ static int rdt_get_tree(struct fs_context *fc) 
	if (rdt_mon_capable)

		resctrl_arch_enable_mon();



	if (rdt_alloc_capable || rdt_mon_capable) {

		static_branch_enable_cpuslocked(&rdt_enable_key);

	if (rdt_alloc_capable || rdt_mon_capable)

		resctrl_mounted = true;

	}



	if (is_mbm_enabled()) {

		r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl;
@@ -2946,9 +2944,10 @@ static void rdt_kill_sb(struct super_block *sb) 
	rdtgroup_default.mode = RDT_MODE_SHAREABLE;

	schemata_list_destroy();

	rdtgroup_destroy_root();

	if (rdt_alloc_capable)

		resctrl_arch_disable_alloc();

	if (rdt_mon_capable)

		resctrl_arch_disable_mon();

	static_branch_disable_cpuslocked(&rdt_enable_key);

	resctrl_mounted = false;

	kernfs_kill_sb(sb);

	mutex_unlock(&rdtgroup_mutex);