1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * machine_kexec.c for kexec
4 *
5 * Copyright (C) 2022 Loongson Technology Corporation Limited
6 */
7 #include <linux/compiler.h>
8 #include <linux/cpu.h>
9 #include <linux/kexec.h>
10 #include <linux/crash_dump.h>
11 #include <linux/delay.h>
12 #include <linux/irq.h>
13 #include <linux/libfdt.h>
14 #include <linux/mm.h>
15 #include <linux/of_fdt.h>
16 #include <linux/reboot.h>
17 #include <linux/sched.h>
18 #include <linux/sched/task_stack.h>
19
20 #include <asm/bootinfo.h>
21 #include <asm/cacheflush.h>
22 #include <asm/page.h>
23
24 /* 0x100000 ~ 0x200000 is safe */
25 #define KEXEC_CONTROL_CODE TO_CACHE(0x100000UL)
26 #define KEXEC_CMDLINE_ADDR TO_CACHE(0x108000UL)
27
28 static unsigned long reboot_code_buffer;
29 static cpumask_t cpus_in_crash = CPU_MASK_NONE;
30
31 #ifdef CONFIG_SMP
32 static void (*relocated_kexec_smp_wait)(void *);
33 atomic_t kexec_ready_to_reboot = ATOMIC_INIT(0);
34 #endif
35
36 static unsigned long efi_boot;
37 static unsigned long cmdline_ptr;
38 static unsigned long systable_ptr;
39 static unsigned long start_addr;
40 static unsigned long first_ind_entry;
41
42 static void kexec_image_info(const struct kimage *kimage)
43 {
44 unsigned long i;
45
46 pr_debug("kexec kimage info:\n");
47 pr_debug("\ttype: %d\n", kimage->type);
48 pr_debug("\tstart: %lx\n", kimage->start);
49 pr_debug("\thead: %lx\n", kimage->head);
50 pr_debug("\tnr_segments: %lu\n", kimage->nr_segments);
51
52 for (i = 0; i < kimage->nr_segments; i++) {
53 pr_debug("\t segment[%lu]: %016lx - %016lx", i,
54 kimage->segment[i].mem,
55 kimage->segment[i].mem + kimage->segment[i].memsz);
56 pr_debug("\t\t0x%lx bytes, %lu pages\n",
57 (unsigned long)kimage->segment[i].memsz,
58 (unsigned long)kimage->segment[i].memsz / PAGE_SIZE);
59 }
60 }
61
62 int machine_kexec_prepare(struct kimage *kimage)
63 {
64 int i;
65 char *bootloader = "kexec";
66 void *cmdline_ptr = (void *)KEXEC_CMDLINE_ADDR;
67
68 kexec_image_info(kimage);
69
70 kimage->arch.efi_boot = fw_arg0;
71 kimage->arch.systable_ptr = fw_arg2;
72
73 /* Find the command line */
74 for (i = 0; i < kimage->nr_segments; i++) {
75 if (!strncmp(bootloader, (char __user *)kimage->segment[i].buf, strlen(bootloader))) {
76 if (!copy_from_user(cmdline_ptr, kimage->segment[i].buf, COMMAND_LINE_SIZE))
77 kimage->arch.cmdline_ptr = (unsigned long)cmdline_ptr;
78 break;
79 }
80 }
81
82 if (!kimage->arch.cmdline_ptr) {
83 pr_err("Command line not included in the provided image\n");
84 return -EINVAL;
85 }
86
87 /* kexec/kdump need a safe page to save reboot_code_buffer */
88 kimage->control_code_page = virt_to_page((void *)KEXEC_CONTROL_CODE);
89
90 reboot_code_buffer = (unsigned long)page_address(kimage->control_code_page);
91 memcpy((void *)reboot_code_buffer, relocate_new_kernel, relocate_new_kernel_size);
92
93 #ifdef CONFIG_SMP
94 /* All secondary cpus now may jump to kexec_smp_wait cycle */
95 relocated_kexec_smp_wait = reboot_code_buffer + (void *)(kexec_smp_wait - relocate_new_kernel);
96 #endif
97
98 return 0;
99 }
100
101 void machine_kexec_cleanup(struct kimage *kimage)
102 {
103 }
104
105 void kexec_reboot(void)
106 {
107 do_kexec_t do_kexec = NULL;
108
109 /*
110 * We know we were online, and there will be no incoming IPIs at
111 * this point. Mark online again before rebooting so that the crash
112 * analysis tool will see us correctly.
113 */
114 set_cpu_online(smp_processor_id(), true);
115
116 /* Ensure remote CPUs observe that we're online before rebooting. */
117 smp_mb__after_atomic();
118
119 /*
120 * Make sure we get correct instructions written by the
121 * machine_kexec_prepare() CPU.
122 */
123 __asm__ __volatile__ ("\tibar 0\n"::);
124
125 #ifdef CONFIG_SMP
126 /* All secondary cpus go to kexec_smp_wait */
127 if (smp_processor_id() > 0) {
128 relocated_kexec_smp_wait(NULL);
129 unreachable();
130 }
131 #endif
132
133 do_kexec = (void *)reboot_code_buffer;
134 do_kexec(efi_boot, cmdline_ptr, systable_ptr, start_addr, first_ind_entry);
135
136 unreachable();
137 }
138
139
140 #ifdef CONFIG_SMP
141 static void kexec_shutdown_secondary(void *regs)
142 {
143 int cpu = smp_processor_id();
144
145 if (!cpu_online(cpu))
146 return;
147
148 /* We won't be sent IPIs any more. */
149 set_cpu_online(cpu, false);
150
151 local_irq_disable();
152 while (!atomic_read(&kexec_ready_to_reboot))
153 cpu_relax();
154
155 kexec_reboot();
156 }
157
158 static void crash_shutdown_secondary(void *passed_regs)
159 {
160 int cpu = smp_processor_id();
161 struct pt_regs *regs = passed_regs;
162
163 /*
164 * If we are passed registers, use those. Otherwise get the
165 * regs from the last interrupt, which should be correct, as
166 * we are in an interrupt. But if the regs are not there,
167 * pull them from the top of the stack. They are probably
168 * wrong, but we need something to keep from crashing again.
169 */
170 if (!regs)
171 regs = get_irq_regs();
172 if (!regs)
173 regs = task_pt_regs(current);
174
175 if (!cpu_online(cpu))
176 return;
177
178 /* We won't be sent IPIs any more. */
179 set_cpu_online(cpu, false);
180
181 local_irq_disable();
182 if (!cpumask_test_cpu(cpu, &cpus_in_crash))
183 crash_save_cpu(regs, cpu);
184 cpumask_set_cpu(cpu, &cpus_in_crash);
185
186 while (!atomic_read(&kexec_ready_to_reboot))
187 cpu_relax();
188
189 kexec_reboot();
190 }
191
192 void crash_smp_send_stop(void)
193 {
194 unsigned int ncpus;
195 unsigned long timeout;
196 static int cpus_stopped;
197
198 /*
199 * This function can be called twice in panic path, but obviously
200 * we should execute this only once.
201 */
202 if (cpus_stopped)
203 return;
204
205 cpus_stopped = 1;
206
207 /* Excluding the panic cpu */
208 ncpus = num_online_cpus() - 1;
209
210 smp_call_function(crash_shutdown_secondary, NULL, 0);
211 smp_wmb();
212
213 /*
214 * The crash CPU sends an IPI and wait for other CPUs to
215 * respond. Delay of at least 10 seconds.
216 */
217 timeout = MSEC_PER_SEC * 10;
218 pr_emerg("Sending IPI to other cpus...\n");
219 while ((cpumask_weight(&cpus_in_crash) < ncpus) && timeout--) {
220 mdelay(1);
221 cpu_relax();
222 }
223 }
224 #endif /* defined(CONFIG_SMP) */
225
226 void machine_shutdown(void)
227 {
228 #ifdef CONFIG_SMP
229 int cpu;
230
231 /* All CPUs go to reboot_code_buffer */
232 for_each_possible_cpu(cpu)
233 if (!cpu_online(cpu))
234 cpu_device_up(get_cpu_device(cpu));
235
236 smp_call_function(kexec_shutdown_secondary, NULL, 0);
237 #endif
238 }
239
240 void machine_crash_shutdown(struct pt_regs *regs)
241 {
242 int crashing_cpu;
243
244 local_irq_disable();
245
246 crashing_cpu = smp_processor_id();
247 crash_save_cpu(regs, crashing_cpu);
248
249 #ifdef CONFIG_SMP
250 crash_smp_send_stop();
251 #endif
252 cpumask_set_cpu(crashing_cpu, &cpus_in_crash);
253
254 pr_info("Starting crashdump kernel...\n");
255 }
256
257 void machine_kexec(struct kimage *image)
258 {
259 unsigned long entry, *ptr;
260 struct kimage_arch *internal = &image->arch;
261
262 efi_boot = internal->efi_boot;
263 cmdline_ptr = internal->cmdline_ptr;
264 systable_ptr = internal->systable_ptr;
265
266 start_addr = (unsigned long)phys_to_virt(image->start);
267
268 first_ind_entry = (image->type == KEXEC_TYPE_DEFAULT) ?
269 (unsigned long)phys_to_virt(image->head & PAGE_MASK) : 0;
270
271 /*
272 * The generic kexec code builds a page list with physical
273 * addresses. they are directly accessible through XKPRANGE
274 * hence the phys_to_virt() call.
275 */
276 for (ptr = &image->head; (entry = *ptr) && !(entry & IND_DONE);
277 ptr = (entry & IND_INDIRECTION) ?
278 phys_to_virt(entry & PAGE_MASK) : ptr + 1) {
279 if (*ptr & IND_SOURCE || *ptr & IND_INDIRECTION ||
280 *ptr & IND_DESTINATION)
281 *ptr = (unsigned long) phys_to_virt(*ptr);
282 }
283
284 /* Mark offline before disabling local irq. */
285 set_cpu_online(smp_processor_id(), false);
286
287 /* We do not want to be bothered. */
288 local_irq_disable();
289
290 pr_notice("EFI boot flag 0x%lx\n", efi_boot);
291 pr_notice("Command line at 0x%lx\n", cmdline_ptr);
292 pr_notice("System table at 0x%lx\n", systable_ptr);
293 pr_notice("We will call new kernel at 0x%lx\n", start_addr);
294 pr_notice("Bye ...\n");
295
296 /* Make reboot code buffer available to the boot CPU. */
297 flush_cache_all();
298
299 #ifdef CONFIG_SMP
300 atomic_set(&kexec_ready_to_reboot, 1);
301 #endif
302
303 kexec_reboot();
304 }
305
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.