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