From: David Woodhouse <dwmw@amazon.co.uk>
Date: Tue, 14 Dec 2021 19:58:54 +0000 (+0000)
Subject: parallel part 2
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=5a3f1ac5adb28c7ff6f2c90c6146adc5dde489bb;p=users%2Fdwmw2%2Flinux.git

parallel part 2
---

diff --git a/arch/x86/include/asm/cpumask.h b/arch/x86/include/asm/cpumask.h
index c5aed9e9226c6..3156b3d6f9913 100644
--- a/arch/x86/include/asm/cpumask.h
+++ b/arch/x86/include/asm/cpumask.h
@@ -7,6 +7,7 @@
 extern cpumask_var_t cpu_callin_mask;
 extern cpumask_var_t cpu_callout_mask;
 extern cpumask_var_t cpu_initialized_mask;
+extern cpumask_var_t cpu_finishup_mask;
 extern cpumask_var_t cpu_sibling_setup_mask;
 
 extern void setup_cpu_local_masks(void);
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index cf1a4eff7a765..0f120047cfb55 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -71,6 +71,7 @@ u32 elf_hwcap2 __read_mostly;
 cpumask_var_t cpu_initialized_mask;
 cpumask_var_t cpu_callout_mask;
 cpumask_var_t cpu_callin_mask;
+cpumask_var_t cpu_finishup_mask;
 
 /* representing cpus for which sibling maps can be computed */
 cpumask_var_t cpu_sibling_setup_mask;
@@ -174,6 +175,7 @@ void __init setup_cpu_local_masks(void)
 	alloc_bootmem_cpumask_var(&cpu_initialized_mask);
 	alloc_bootmem_cpumask_var(&cpu_callin_mask);
 	alloc_bootmem_cpumask_var(&cpu_callout_mask);
+	alloc_bootmem_cpumask_var(&cpu_finishup_mask);
 	alloc_bootmem_cpumask_var(&cpu_sibling_setup_mask);
 }
 
@@ -2230,6 +2232,7 @@ void cpu_init(void)
 
 	wait_for_master_cpu(cpu);
 
+	/* XXX: Make sure siblings don't call this at the same time */
 	ucode_cpu_init(cpu);
 
 #ifdef CONFIG_NUMA
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index f53a060a899b7..638dc63bc1d11 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -204,15 +204,20 @@ static void smp_callin(void)
 	wmb();
 
 	/*
-	 * This runs the AP through all the cpuhp states to its target
-	 * state (CPUHP_ONLINE in the case of serial bringup).
+	 * Allow the master to continue.
 	 */
-	notify_cpu_starting(cpuid);
+	cpumask_set_cpu(cpuid, cpu_callin_mask);
+	while (!cpumask_test_cpu(cpuid, cpu_finishup_mask))
+		cpu_relax();
 
 	/*
-	 * Allow the master to continue.
+	 * This runs the AP through all the cpuhp states to its target
+	 * state (CPUHP_ONLINE in the case of serial bringup).
 	 */
-	cpumask_set_cpu(cpuid, cpu_callin_mask);
+	static arch_spinlock_t cpuhp_lock = __ARCH_SPIN_LOCK_UNLOCKED;
+	arch_spin_lock(&cpuhp_lock);
+	notify_cpu_starting(cpuid);
+	arch_spin_unlock(&cpuhp_lock);
 }
 
 static int cpu0_logical_apicid;
@@ -1250,7 +1255,11 @@ static int do_wait_cpu_callin(unsigned int cpu)
 	/*
 	 * Wait till AP completes initial initialization.
 	 */
-	return do_wait_cpu_cpumask(cpu, cpu_callin_mask);
+	if (do_wait_cpu_cpumask(cpu, cpu_callin_mask))
+		return -1;
+
+	cpumask_set_cpu(cpu, cpu_finishup_mask);
+	return 0;
 }
 
 /*
@@ -1353,11 +1362,11 @@ int native_cpu_up(unsigned int cpu, struct task_struct *tidle)
 		ret = do_cpu_up(cpu, tidle);
 		if (ret)
 			return ret;
-	}
 
-	ret = do_wait_cpu_initialized(cpu);
-	if (ret)
-		return ret;
+		ret = do_wait_cpu_initialized(cpu);
+		if (ret)
+			return ret;
+	}
 
 	ret = do_wait_cpu_callin(cpu);
 	if (ret)
@@ -1569,9 +1578,12 @@ void __init native_smp_prepare_cpus(unsigned int max_cpus)
 	    cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT))
 		do_parallel_bringup = false;
 
-	if (do_parallel_bringup)
+	if (do_parallel_bringup) {
 		cpuhp_setup_state_nocalls(CPUHP_BP_PARALLEL_DYN, "x86/cpu:kick",
 					  native_cpu_kick, NULL);
+		cpuhp_setup_state_nocalls(CPUHP_BP_PARALLEL_DYN, "x86/cpu:wait-init",
+					  do_wait_cpu_initialized, NULL);
+	}
 
 	snp_set_wakeup_secondary_cpu();
 }
@@ -1599,6 +1611,7 @@ void __init native_smp_prepare_boot_cpu(void)
 
 	/* already set me in cpu_online_mask in boot_cpu_init() */
 	cpumask_set_cpu(me, cpu_callout_mask);
+	cpumask_set_cpu(me, cpu_finishup_mask);
 	cpu_set_state_online(me);
 	native_pv_lock_init();
 }
@@ -1782,6 +1795,7 @@ static void remove_cpu_from_maps(int cpu)
 {
 	set_cpu_online(cpu, false);
 	cpumask_clear_cpu(cpu, cpu_callout_mask);
+	cpumask_clear_cpu(cpu, cpu_finishup_mask);
 	cpumask_clear_cpu(cpu, cpu_callin_mask);
 	/* was set by cpu_init() */
 	cpumask_clear_cpu(cpu, cpu_initialized_mask);
diff --git a/arch/x86/xen/smp_pv.c b/arch/x86/xen/smp_pv.c
index 09f94f9406895..c797c0ff4401f 100644
--- a/arch/x86/xen/smp_pv.c
+++ b/arch/x86/xen/smp_pv.c
@@ -254,6 +254,7 @@ cpu_initialize_context(unsigned int cpu, struct task_struct *idle)
 
 	/* used to tell cpu_init() that it can proceed with initialization */
 	cpumask_set_cpu(cpu, cpu_callout_mask);
+	cpumask_set_cpu(cpu, cpu_finishup_mask);
 	if (cpumask_test_and_set_cpu(cpu, xen_cpu_initialized_map))
 		return 0;