1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * machine_kexec.c - handle transition of Linux booting another kernel
4 */
5
6 #include <linux/mm.h>
7 #include <linux/kexec.h>
8 #include <linux/delay.h>
9 #include <linux/reboot.h>
10 #include <linux/io.h>
11 #include <linux/irq.h>
12 #include <linux/memblock.h>
13 #include <linux/of_fdt.h>
14 #include <asm/mmu_context.h>
15 #include <asm/cacheflush.h>
16 #include <asm/kexec-internal.h>
17 #include <asm/fncpy.h>
18 #include <asm/mach-types.h>
19 #include <asm/smp_plat.h>
20 #include <asm/system_misc.h>
21 #include <asm/set_memory.h>
22
23 extern void relocate_new_kernel(void);
24 extern const unsigned int relocate_new_kernel_size;
25
26 static atomic_t waiting_for_crash_ipi;
27
28 /*
29 * Provide a dummy crash_notes definition while crash dump arrives to arm.
30 * This prevents breakage of crash_notes attribute in kernel/ksysfs.c.
31 */
32
machine_kexec_prepare(struct kimage * image)33 int machine_kexec_prepare(struct kimage *image)
34 {
35 struct kexec_segment *current_segment;
36 __be32 header;
37 int i, err;
38
39 image->arch.kernel_r2 = image->start - KEXEC_ARM_ZIMAGE_OFFSET
40 + KEXEC_ARM_ATAGS_OFFSET;
41
42 /*
43 * Validate that if the current HW supports SMP, then the SW supports
44 * and implements CPU hotplug for the current HW. If not, we won't be
45 * able to kexec reliably, so fail the prepare operation.
46 */
47 if (num_possible_cpus() > 1 && platform_can_secondary_boot() &&
48 !platform_can_cpu_hotplug())
49 return -EINVAL;
50
51 /*
52 * No segment at default ATAGs address. try to locate
53 * a dtb using magic.
54 */
55 for (i = 0; i < image->nr_segments; i++) {
56 current_segment = &image->segment[i];
57
58 if (!memblock_is_region_memory(idmap_to_phys(current_segment->mem),
59 current_segment->memsz))
60 return -EINVAL;
61
62 err = get_user(header, (__be32*)current_segment->buf);
63 if (err)
64 return err;
65
66 if (header == cpu_to_be32(OF_DT_HEADER))
67 image->arch.kernel_r2 = current_segment->mem;
68 }
69 return 0;
70 }
71
machine_kexec_cleanup(struct kimage * image)72 void machine_kexec_cleanup(struct kimage *image)
73 {
74 }
75
machine_crash_nonpanic_core(void * unused)76 void machine_crash_nonpanic_core(void *unused)
77 {
78 struct pt_regs regs;
79
80 crash_setup_regs(®s, get_irq_regs());
81 printk(KERN_DEBUG "CPU %u will stop doing anything useful since another CPU has crashed\n",
82 smp_processor_id());
83 crash_save_cpu(®s, smp_processor_id());
84 flush_cache_all();
85
86 set_cpu_online(smp_processor_id(), false);
87 atomic_dec(&waiting_for_crash_ipi);
88
89 while (1) {
90 cpu_relax();
91 wfe();
92 }
93 }
94
95 static DEFINE_PER_CPU(call_single_data_t, cpu_stop_csd) =
96 CSD_INIT(machine_crash_nonpanic_core, NULL);
97
crash_smp_send_stop(void)98 void crash_smp_send_stop(void)
99 {
100 static int cpus_stopped;
101 unsigned long msecs;
102 call_single_data_t *csd;
103 int cpu, this_cpu = raw_smp_processor_id();
104
105 if (cpus_stopped)
106 return;
107
108 atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
109 for_each_online_cpu(cpu) {
110 if (cpu == this_cpu)
111 continue;
112
113 csd = &per_cpu(cpu_stop_csd, cpu);
114 smp_call_function_single_async(cpu, csd);
115 }
116
117 msecs = 1000; /* Wait at most a second for the other cpus to stop */
118 while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
119 mdelay(1);
120 msecs--;
121 }
122 if (atomic_read(&waiting_for_crash_ipi) > 0)
123 pr_warn("Non-crashing CPUs did not react to IPI\n");
124
125 cpus_stopped = 1;
126 }
127
machine_kexec_mask_interrupts(void)128 static void machine_kexec_mask_interrupts(void)
129 {
130 unsigned int i;
131 struct irq_desc *desc;
132
133 for_each_irq_desc(i, desc) {
134 struct irq_chip *chip;
135
136 chip = irq_desc_get_chip(desc);
137 if (!chip)
138 continue;
139
140 if (chip->irq_eoi && irqd_irq_inprogress(&desc->irq_data))
141 chip->irq_eoi(&desc->irq_data);
142
143 if (chip->irq_mask)
144 chip->irq_mask(&desc->irq_data);
145
146 if (chip->irq_disable && !irqd_irq_disabled(&desc->irq_data))
147 chip->irq_disable(&desc->irq_data);
148 }
149 }
150
machine_crash_shutdown(struct pt_regs * regs)151 void machine_crash_shutdown(struct pt_regs *regs)
152 {
153 local_irq_disable();
154 crash_smp_send_stop();
155
156 crash_save_cpu(regs, smp_processor_id());
157 machine_kexec_mask_interrupts();
158
159 pr_info("Loading crashdump kernel...\n");
160 }
161
machine_kexec(struct kimage * image)162 void machine_kexec(struct kimage *image)
163 {
164 unsigned long page_list, reboot_entry_phys;
165 struct kexec_relocate_data *data;
166 void (*reboot_entry)(void);
167 void *reboot_code_buffer;
168
169 /*
170 * This can only happen if machine_shutdown() failed to disable some
171 * CPU, and that can only happen if the checks in
172 * machine_kexec_prepare() were not correct. If this fails, we can't
173 * reliably kexec anyway, so BUG_ON is appropriate.
174 */
175 BUG_ON(num_online_cpus() > 1);
176
177 page_list = image->head & PAGE_MASK;
178
179 reboot_code_buffer = page_address(image->control_code_page);
180
181 /* copy our kernel relocation code to the control code page */
182 reboot_entry = fncpy(reboot_code_buffer,
183 &relocate_new_kernel,
184 relocate_new_kernel_size);
185
186 data = reboot_code_buffer + relocate_new_kernel_size;
187 data->kexec_start_address = image->start;
188 data->kexec_indirection_page = page_list;
189 data->kexec_mach_type = machine_arch_type;
190 data->kexec_r2 = image->arch.kernel_r2;
191
192 /* get the identity mapping physical address for the reboot code */
193 reboot_entry_phys = virt_to_idmap(reboot_entry);
194
195 pr_info("Bye!\n");
196
197 soft_restart(reboot_entry_phys);
198 }
199
arch_crash_save_vmcoreinfo(void)200 void arch_crash_save_vmcoreinfo(void)
201 {
202 #ifdef CONFIG_ARM_LPAE
203 VMCOREINFO_CONFIG(ARM_LPAE);
204 #endif
205 }
206