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2023-12-11 6778948f9de86c3cfaf36725a7c87dcff9ba247f 
 kernel/arch/riscv/kernel/smpboot.c
....@@ -1,3 +1,4 @@
1
+// SPDX-License-Identifier: GPL-2.0-only
12 /*
23  * SMP initialisation and IPI support
34  * Based on arch/arm64/kernel/smp.c
....@@ -5,17 +6,9 @@
56  * Copyright (C) 2012 ARM Ltd.
67  * Copyright (C) 2015 Regents of the University of California
78  * Copyright (C) 2017 SiFive
8
- *
9
- * This program is free software; you can redistribute it and/or modify
10
- * it under the terms of the GNU General Public License version 2 as
11
- * published by the Free Software Foundation.
12
- *
13
- * This program is distributed in the hope that it will be useful,
14
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
15
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16
- * GNU General Public License for more details.
179  */
1810 
11
+#include <linux/arch_topology.h>
1912 #include <linux/module.h>
2013 #include <linux/init.h>
2114 #include <linux/kernel.h>
....@@ -30,62 +23,117 @@
3023 #include <linux/irq.h>
3124 #include <linux/of.h>
3225 #include <linux/sched/task_stack.h>
26
+#include <linux/sched/mm.h>
27
+#include <asm/cpu_ops.h>
3328 #include <asm/irq.h>
3429 #include <asm/mmu_context.h>
3530 #include <asm/tlbflush.h>
3631 #include <asm/sections.h>
3732 #include <asm/sbi.h>
33
+#include <asm/smp.h>
3834 
39
-void *__cpu_up_stack_pointer[NR_CPUS];
40
-void *__cpu_up_task_pointer[NR_CPUS];
35
+#include "head.h"
36
+
37
+static DECLARE_COMPLETION(cpu_running);
4138 
4239 void __init smp_prepare_boot_cpu(void)
4340 {
41
+	init_cpu_topology();
4442 }
4543 
4644 void __init smp_prepare_cpus(unsigned int max_cpus)
4745 {
46
+	int cpuid;
47
+	int ret;
48
+
49
+	store_cpu_topology(smp_processor_id());
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+
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+	/* This covers non-smp usecase mandated by "nosmp" option */
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+	if (max_cpus == 0)
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+		return;
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+
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+	for_each_possible_cpu(cpuid) {
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+		if (cpuid == smp_processor_id())
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+			continue;
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+		if (cpu_ops[cpuid]->cpu_prepare) {
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+			ret = cpu_ops[cpuid]->cpu_prepare(cpuid);
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+			if (ret)
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+				continue;
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+		}
63
+		set_cpu_present(cpuid, true);
64
+	}
4865 }
4966 
5067 void __init setup_smp(void)
5168 {
52
-	struct device_node *dn = NULL;
53
-	int hart, im_okay_therefore_i_am = 0;
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+	struct device_node *dn;
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+	int hart;
71
+	bool found_boot_cpu = false;
72
+	int cpuid = 1;
5473 
55
-	while ((dn = of_find_node_by_type(dn, "cpu"))) {
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-		hart = riscv_of_processor_hart(dn);
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-		if (hart >= 0) {
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-			set_cpu_possible(hart, true);
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-			set_cpu_present(hart, true);
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-			if (hart == smp_processor_id()) {
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-				BUG_ON(im_okay_therefore_i_am);
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-				im_okay_therefore_i_am = 1;
63
-			}
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+	cpu_set_ops(0);
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+
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+	for_each_of_cpu_node(dn) {
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+		hart = riscv_of_processor_hartid(dn);
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+		if (hart < 0)
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+			continue;
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+
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+		if (hart == cpuid_to_hartid_map(0)) {
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+			BUG_ON(found_boot_cpu);
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+			found_boot_cpu = 1;
84
+			continue;
6485 		}
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+		if (cpuid >= NR_CPUS) {
87
+			pr_warn("Invalid cpuid [%d] for hartid [%d]\n",
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+				cpuid, hart);
89
+			break;
90
+		}
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+
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+		cpuid_to_hartid_map(cpuid) = hart;
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+		cpuid++;
6594 	}
6695 
67
-	BUG_ON(!im_okay_therefore_i_am);
96
+	BUG_ON(!found_boot_cpu);
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+
98
+	if (cpuid > nr_cpu_ids)
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+		pr_warn("Total number of cpus [%d] is greater than nr_cpus option value [%d]\n",
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+			cpuid, nr_cpu_ids);
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+
102
+	for (cpuid = 1; cpuid < nr_cpu_ids; cpuid++) {
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+		if (cpuid_to_hartid_map(cpuid) != INVALID_HARTID) {
104
+			cpu_set_ops(cpuid);
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+			set_cpu_possible(cpuid, true);
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+		}
107
+	}
108
+}
109
+
110
+static int start_secondary_cpu(int cpu, struct task_struct *tidle)
111
+{
112
+	if (cpu_ops[cpu]->cpu_start)
113
+		return cpu_ops[cpu]->cpu_start(cpu, tidle);
114
+
115
+	return -EOPNOTSUPP;
68116 }
69117 
70118 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
71119 {
120
+	int ret = 0;
72121 	tidle->thread_info.cpu = cpu;
73122 
74
-	/*
75
-	 * On RISC-V systems, all harts boot on their own accord.  Our _start
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-	 * selects the first hart to boot the kernel and causes the remainder
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-	 * of the harts to spin in a loop waiting for their stack pointer to be
78
-	 * setup by that main hart.  Writing __cpu_up_stack_pointer signals to
79
-	 * the spinning harts that they can continue the boot process.
80
-	 */
81
-	smp_mb();
82
-	__cpu_up_stack_pointer[cpu] = task_stack_page(tidle) + THREAD_SIZE;
83
-	__cpu_up_task_pointer[cpu] = tidle;
123
+	ret = start_secondary_cpu(cpu, tidle);
124
+	if (!ret) {
125
+		wait_for_completion_timeout(&cpu_running,
126
+					    msecs_to_jiffies(1000));
84127 
85
-	while (!cpu_online(cpu))
86
-		cpu_relax();
128
+		if (!cpu_online(cpu)) {
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+			pr_crit("CPU%u: failed to come online\n", cpu);
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+			ret = -EIO;
131
+		}
132
+	} else {
133
+		pr_crit("CPU%u: failed to start\n", cpu);
134
+	}
87135 
88
-	return 0;
136
+	return ret;
89137 }
90138 
91139 void __init smp_cpus_done(unsigned int max_cpus)
....@@ -95,19 +143,31 @@
95143 /*
96144  * C entry point for a secondary processor.
97145  */
98
-asmlinkage void __init smp_callin(void)
146
+asmlinkage __visible void smp_callin(void)
99147 {
100148 	struct mm_struct *mm = &init_mm;
149
+	unsigned int curr_cpuid = smp_processor_id();
150
+
151
+	riscv_clear_ipi();
101152 
102153 	/* All kernel threads share the same mm context.  */
103
-	atomic_inc(&mm->mm_count);
154
+	mmgrab(mm);
104155 	current->active_mm = mm;
105156 
106
-	trap_init();
107
-	notify_cpu_starting(smp_processor_id());
108
-	set_cpu_online(smp_processor_id(), 1);
157
+	store_cpu_topology(curr_cpuid);
158
+	notify_cpu_starting(curr_cpuid);
159
+	set_cpu_online(curr_cpuid, 1);
160
+
161
+	/*
162
+	 * Remote TLB flushes are ignored while the CPU is offline, so emit
163
+	 * a local TLB flush right now just in case.
164
+	 */
109165 	local_flush_tlb_all();
166
+	complete(&cpu_running);
167
+	/*
168
+	 * Disable preemption before enabling interrupts, so we don't try to
169
+	 * schedule a CPU that hasn't actually started yet.
170
+	 */
110171 	local_irq_enable();
111
-	preempt_disable();
112172 	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
113173 }