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 int cpu; 229 230 /* All CPUs go to reboot_code_buffer */ 231 for_each_possible_cpu(cpu) 232 if (!cpu_online(cpu)) 233 cpu_device_up(get_cpu_device(cpu)); 234 235 #ifdef CONFIG_SMP 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