arch/loongarch/kernel/machine_kexec.c

   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 }