arch/arm/kernel/machine_kexec.c

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