arch/arm/kernel/machine_kexec.c

   1 /*
   2  * machine_kexec.c - handle transition of Linux booting another kernel
   3  */
   4
   5 #include <linux/mm.h>
   6 #include <linux/kexec.h>
   7 #include <linux/delay.h>
   8 #include <linux/reboot.h>
   9 #include <linux/io.h>
  10 #include <linux/irq.h>
  11 #include <linux/memblock.h>
  12 #include <asm/pgtable.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/mach-types.h>
  18 #include <asm/system_misc.h>
  19
  20 extern const unsigned char relocate_new_kernel[];
  21 extern const unsigned int relocate_new_kernel_size;
  22
  23 extern unsigned long kexec_start_address;
  24 extern unsigned long kexec_indirection_page;
  25 extern unsigned long kexec_mach_type;
  26 extern unsigned long kexec_boot_atags;
  27
  28 static atomic_t waiting_for_crash_ipi;
  29
  30 /*
  31  * Provide a dummy crash_notes definition while crash dump arrives to arm.
  32  * This prevents breakage of crash_notes attribute in kernel/ksysfs.c.
  33  */
  34
  35 int machine_kexec_prepare(struct kimage *image)
  36 {
  37         struct kexec_segment *current_segment;
  38         __be32 header;
  39         int i, err;
  40
  41         /*
  42          * No segment at default ATAGs address. try to locate
  43          * a dtb using magic.
  44          */
  45         for (i = 0; i < image->nr_segments; i++) {
  46                 current_segment = &image->segment[i];
  47
  48                 if (!memblock_is_region_memory(current_segment->mem,
  49                                                current_segment->memsz))
  50                         return -EINVAL;
  51
  52                 err = get_user(header, (__be32*)current_segment->buf);
  53                 if (err)
  54                         return err;
  55
  56                 if (be32_to_cpu(header) == OF_DT_HEADER)
  57                         kexec_boot_atags = current_segment->mem;
  58         }
  59         return 0;
  60 }
  61
  62 void machine_kexec_cleanup(struct kimage *image)
  63 {
  64 }
  65
  66 void machine_crash_nonpanic_core(void *unused)
  67 {
  68         struct pt_regs regs;
  69
  70         crash_setup_regs(&regs, NULL);
  71         printk(KERN_DEBUG "CPU %u will stop doing anything useful since another CPU has crashed\n",
  72                smp_processor_id());
  73         crash_save_cpu(&regs, smp_processor_id());
  74         flush_cache_all();
  75
  76         atomic_dec(&waiting_for_crash_ipi);
  77         while (1)
  78                 cpu_relax();
  79 }
  80
  81 static void machine_kexec_mask_interrupts(void)
  82 {
  83         unsigned int i;
  84         struct irq_desc *desc;
  85
  86         for_each_irq_desc(i, desc) {
  87                 struct irq_chip *chip;
  88
  89                 chip = irq_desc_get_chip(desc);
  90                 if (!chip)
  91                         continue;
  92
  93                 if (chip->irq_eoi && irqd_irq_inprogress(&desc->irq_data))
  94                         chip->irq_eoi(&desc->irq_data);
  95
  96                 if (chip->irq_mask)
  97                         chip->irq_mask(&desc->irq_data);
  98
  99                 if (chip->irq_disable && !irqd_irq_disabled(&desc->irq_data))
 100                         chip->irq_disable(&desc->irq_data);
 101         }
 102 }
 103
 104 void machine_crash_shutdown(struct pt_regs *regs)
 105 {
 106         unsigned long msecs;
 107
 108         local_irq_disable();
 109
 110         atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
 111         smp_call_function(machine_crash_nonpanic_core, NULL, false);
 112         msecs = 1000; /* Wait at most a second for the other cpus to stop */
 113         while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
 114                 mdelay(1);
 115                 msecs--;
 116         }
 117         if (atomic_read(&waiting_for_crash_ipi) > 0)
 118                 printk(KERN_WARNING "Non-crashing CPUs did not react to IPI\n");
 119
 120         crash_save_cpu(regs, smp_processor_id());
 121         machine_kexec_mask_interrupts();
 122
 123         printk(KERN_INFO "Loading crashdump kernel...\n");
 124 }
 125
 126 /*
 127  * Function pointer to optional machine-specific reinitialization
 128  */
 129 void (*kexec_reinit)(void);
 130
 131 void machine_kexec(struct kimage *image)
 132 {
 133         unsigned long page_list;
 134         unsigned long reboot_code_buffer_phys;
 135         void *reboot_code_buffer;
 136
 137         if (num_online_cpus() > 1) {
 138                 pr_err("kexec: error: multiple CPUs still online\n");
 139                 return;
 140         }
 141
 142         page_list = image->head & PAGE_MASK;
 143
 144         /* we need both effective and real address here */
 145         reboot_code_buffer_phys =
 146             page_to_pfn(image->control_code_page) << PAGE_SHIFT;
 147         reboot_code_buffer = page_address(image->control_code_page);
 148
 149         /* Prepare parameters for reboot_code_buffer*/
 150         kexec_start_address = image->start;
 151         kexec_indirection_page = page_list;
 152         kexec_mach_type = machine_arch_type;
 153         if (!kexec_boot_atags)
 154                 kexec_boot_atags = image->start - KEXEC_ARM_ZIMAGE_OFFSET + KEXEC_ARM_ATAGS_OFFSET;
 155
 156
 157         /* copy our kernel relocation code to the control code page */
 158         memcpy(reboot_code_buffer,
 159                relocate_new_kernel, relocate_new_kernel_size);
 160
 161
 162         flush_icache_range((unsigned long) reboot_code_buffer,
 163                            (unsigned long) reboot_code_buffer + KEXEC_CONTROL_PAGE_SIZE);
 164         printk(KERN_INFO "Bye!\n");
 165
 166         if (kexec_reinit)
 167                 kexec_reinit();
 168
 169         soft_restart(reboot_code_buffer_phys);
 170 }