Commit 30f89e52 authored by Juergen Gross's avatar Juergen Gross Committed by Borislav Petkov
Browse files

x86/cacheinfo: Switch cache_ap_init() to hotplug callback 



Instead of explicitly calling cache_ap_init() in
identify_secondary_cpu() use a CPU hotplug callback instead. By
registering the callback only after having started the non-boot CPUs
and initializing cache_aps_delayed_init with "true", calling
set_cache_aps_delayed_init() at boot time can be dropped.

It should be noted that this change results in cache_ap_init() being
called a little bit later when hotplugging CPUs. By using a new
hotplug slot right at the start of the low level bringup this is not
problematic, as no operations requiring a specific caching mode are
performed that early in CPU initialization.

Suggested-by: default avatarBorislav Petkov <bp@alien8.de>
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20221102074713.21493-15-jgross@suse.com


Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
parent adfe7512

arch/x86/include/asm/cacheinfo.h

+0 −1
Original line number Diff line number Diff line
@@ -16,7 +16,6 @@ void set_cache_aps_delayed_init(bool val); 
bool get_cache_aps_delayed_init(void);

void cache_bp_init(void);

void cache_bp_restore(void);

void cache_ap_init(void);

void cache_aps_init(void);



#endif /* _ASM_X86_CACHEINFO_H */

arch/x86/kernel/cpu/cacheinfo.c

+15 −3
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
#include <linux/slab.h>

#include <linux/cacheinfo.h>

#include <linux/cpu.h>

#include <linux/cpuhotplug.h>

#include <linux/sched.h>

#include <linux/capability.h>

#include <linux/sysfs.h>
@@ -1139,7 +1140,7 @@ static void cache_cpu_init(void) 
	local_irq_restore(flags);

}



static bool cache_aps_delayed_init;

static bool cache_aps_delayed_init = true;



void set_cache_aps_delayed_init(bool val)

{
@@ -1174,10 +1175,10 @@ void cache_bp_restore(void) 
		cache_cpu_init();

}



void cache_ap_init(void)

static int cache_ap_init(unsigned int cpu)

{

	if (!memory_caching_control || get_cache_aps_delayed_init())

		return;

		return 0;



	/*

	 * Ideally we should hold mtrr_mutex here to avoid MTRR entries
@@ -1194,6 +1195,8 @@ void cache_ap_init(void) 
	 */

	stop_machine_from_inactive_cpu(cache_rendezvous_handler, NULL,

				       cpu_callout_mask);



	return 0;

}



/*
@@ -1207,3 +1210,12 @@ void cache_aps_init(void) 
	stop_machine(cache_rendezvous_handler, NULL, cpu_online_mask);

	set_cache_aps_delayed_init(false);

}



static int __init cache_ap_register(void)

{

	cpuhp_setup_state_nocalls(CPUHP_AP_CACHECTRL_STARTING,

				  "x86/cachectrl:starting",

				  cache_ap_init, NULL);

	return 0;

}

core_initcall(cache_ap_register);

arch/x86/kernel/cpu/common.c

+0 −1
Original line number Diff line number Diff line
@@ -1949,7 +1949,6 @@ void identify_secondary_cpu(struct cpuinfo_x86 *c) 
#ifdef CONFIG_X86_32

	enable_sep_cpu();

#endif

	cache_ap_init();

	validate_apic_and_package_id(c);

	x86_spec_ctrl_setup_ap();

	update_srbds_msr();

arch/x86/kernel/smpboot.c

+0 −2
Original line number Diff line number Diff line
@@ -1429,8 +1429,6 @@ void __init native_smp_prepare_cpus(unsigned int max_cpus) 


	uv_system_init();



	set_cache_aps_delayed_init(true);



	smp_quirk_init_udelay();



	speculative_store_bypass_ht_init();

include/linux/cpuhotplug.h

+1 −0
Original line number Diff line number Diff line
@@ -140,6 +140,7 @@ enum cpuhp_state { 
	 */

	CPUHP_AP_IDLE_DEAD,

	CPUHP_AP_OFFLINE,

	CPUHP_AP_CACHECTRL_STARTING,

	CPUHP_AP_SCHED_STARTING,

	CPUHP_AP_RCUTREE_DYING,

	CPUHP_AP_CPU_PM_STARTING,