linux-kernel - [patch 10/37] x86/cpu/cacheinfo: Remove cpu_callout

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Date:   Sat, 15 Apr 2023 01:44:29 +0200 (CEST)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     x86@...nel.org, David Woodhouse <dwmw@...radead.org>,
        Andrew Cooper <andrew.cooper3@...rix.com>,
        Brian Gerst <brgerst@...il.com>,
        "Arjan van de Veen" <arjan@...ux.intel.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Paul McKenney <paulmck@...nel.org>,
        Tom Lendacky <thomas.lendacky@....com>,
        Sean Christopherson <seanjc@...gle.com>,
        Oleksandr Natalenko <oleksandr@...alenko.name>,
        Paul Menzel <pmenzel@...gen.mpg.de>,
        "Guilherme G. Piccoli" <gpiccoli@...lia.com>,
        Piotr Gorski <lucjan.lucjanov@...il.com>,
        David Woodhouse <dwmw@...zon.co.uk>,
        Usama Arif <usama.arif@...edance.com>,
        Juergen Gross <jgross@...e.com>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        xen-devel@...ts.xenproject.org,
        Russell King <linux@...linux.org.uk>,
        Arnd Bergmann <arnd@...db.de>,
        linux-arm-kernel@...ts.infradead.org,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>, Guo Ren <guoren@...nel.org>,
        linux-csky@...r.kernel.org,
        Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        linux-mips@...r.kernel.org,
        "James E.J. Bottomley" <James.Bottomley@...senPartnership.com>,
        Helge Deller <deller@....de>, linux-parisc@...r.kernel.org,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        linux-riscv@...ts.infradead.org,
        Mark Rutland <mark.rutland@....com>,
        Sabin Rapan <sabrapan@...zon.com>
Subject: [patch 10/37] x86/cpu/cacheinfo: Remove cpu_callout_mask dependency

cpu_callout_mask is used for the stop machine based MTRR/PAT init.

In preparation of moving the BP/AP synchronization to the core hotplug
code, use a private CPU mask for cacheinfo and manage it in the
starting/dying hotplug state.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
 arch/x86/kernel/cpu/cacheinfo.c |   21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

--- a/arch/x86/kernel/cpu/cacheinfo.c
+++ b/arch/x86/kernel/cpu/cacheinfo.c
@@ -39,6 +39,8 @@ DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t
 /* Shared L2 cache maps */
 DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_l2c_shared_map);
 
+static cpumask_var_t cpu_cacheinfo_mask;
+
 /* Kernel controls MTRR and/or PAT MSRs. */
 unsigned int memory_caching_control __ro_after_init;
 
@@ -1172,8 +1174,10 @@ void cache_bp_restore(void)
 		cache_cpu_init();
 }
 
-static int cache_ap_init(unsigned int cpu)
+static int cache_ap_online(unsigned int cpu)
 {
+	cpumask_set_cpu(cpu, cpu_cacheinfo_mask);
+
 	if (!memory_caching_control || get_cache_aps_delayed_init())
 		return 0;
 
@@ -1191,11 +1195,17 @@ static int cache_ap_init(unsigned int cp
 	 *      lock to prevent MTRR entry changes
 	 */
 	stop_machine_from_inactive_cpu(cache_rendezvous_handler, NULL,
-				       cpu_callout_mask);
+				       cpu_cacheinfo_mask);
 
 	return 0;
 }
 
+static int cache_ap_offline(unsigned int cpu)
+{
+	cpumask_clear_cpu(cpu, cpu_cacheinfo_mask);
+	return 0;
+}
+
 /*
  * Delayed cache initialization for all AP's
  */
@@ -1210,9 +1220,12 @@ void cache_aps_init(void)
 
 static int __init cache_ap_register(void)
 {
+	zalloc_cpumask_var(&cpu_cacheinfo_mask, GFP_KERNEL);
+	cpumask_set_cpu(smp_processor_id(), cpu_cacheinfo_mask);
+
 	cpuhp_setup_state_nocalls(CPUHP_AP_CACHECTRL_STARTING,
 				  "x86/cachectrl:starting",
-				  cache_ap_init, NULL);
+				  cache_ap_online, cache_ap_offline);
 	return 0;
 }
-core_initcall(cache_ap_register);
+early_initcall(cache_ap_register);