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/smp_plat.h>
  19 #include <asm/system_misc.h>
  20
  21 extern const unsigned char relocate_new_kernel[];
  22 extern const unsigned int relocate_new_kernel_size;
  23
  24 extern unsigned long kexec_start_address;
  25 extern unsigned long kexec_indirection_page;
  26 extern unsigned long kexec_mach_type;
  27 extern unsigned long kexec_boot_atags;
  28
  29 static atomic_t waiting_for_crash_ipi;
  30
  31 /*
  32  * Provide a dummy crash_notes definition while crash dump arrives to arm.
  33  * This prevents breakage of crash_notes attribute in kernel/ksysfs.c.
  34  */
  35
  36 int machine_kexec_prepare(struct kimage *image)
  37 {
  38         struct kexec_segment *current_segment;
  39         __be32 header;
  40         int i, err;
  41
  42         /*
  43          * Validate that if the current HW supports SMP, then the SW supports
  44          * and implements CPU hotplug for the current HW. If not, we won't be
  45          * able to kexec reliably, so fail the prepare operation.
  46          */
  47         if (num_possible_cpus() > 1 && !platform_can_cpu_hotplug())
  48                 return -EINVAL;
  49
  50         /*
  51          * No segment at default ATAGs address. try to locate
  52          * a dtb using magic.
  53          */
  54         for (i = 0; i < image->nr_segments; i++) {
  55                 current_segment = &image->segment[i];
  56
  57                 if (!memblock_is_region_memory(current_segment->mem,
  58                                                current_segment->memsz))
  59                         return -EINVAL;
  60
  61                 err = get_user(header, (__be32*)current_segment->buf);
  62                 if (err)
  63                         return err;
  64
  65                 if (be32_to_cpu(header) == OF_DT_HEADER)
  66                         kexec_boot_atags = current_segment->mem;
  67         }
  68         return 0;
  69 }
  70
  71 void machine_kexec_cleanup(struct kimage *image)
  72 {
  73 }
  74
  75 void machine_crash_nonpanic_core(void *unused)
  76 {
  77         struct pt_regs regs;
  78
  79         crash_setup_regs(&regs, NULL);
  80         printk(KERN_DEBUG "CPU %u will stop doing anything useful since another CPU has crashed\n",
  81                smp_processor_id());
  82         crash_save_cpu(&regs, smp_processor_id());
  83         flush_cache_all();
  84
  85         set_cpu_online(smp_processor_id(), false);
  86         atomic_dec(&waiting_for_crash_ipi);
  87         while (1)
  88                 cpu_relax();
  89 }
  90
  91 static void machine_kexec_mask_interrupts(void)
  92 {
  93         unsigned int i;
  94         struct irq_desc *desc;
  95
  96         for_each_irq_desc(i, desc) {
  97                 struct irq_chip *chip;
  98
  99                 chip = irq_desc_get_chip(desc);
 100                 if (!chip)
 101                         continue;
 102
 103                 if (chip->irq_eoi && irqd_irq_inprogress(&desc->irq_data))
 104                         chip->irq_eoi(&desc->irq_data);
 105
 106                 if (chip->irq_mask)
 107                         chip->irq_mask(&desc->irq_data);
 108
 109                 if (chip->irq_disable && !irqd_irq_disabled(&desc->irq_data))
 110                         chip->irq_disable(&desc->irq_data);
 111         }
 112 }
 113
 114 void machine_crash_shutdown(struct pt_regs *regs)
 115 {
 116         unsigned long msecs;
 117
 118         local_irq_disable();
 119
 120         atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
 121         smp_call_function(machine_crash_nonpanic_core, NULL, false);
 122         msecs = 1000; /* Wait at most a second for the other cpus to stop */
 123         while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
 124                 mdelay(1);
 125                 msecs--;
 126         }
 127         if (atomic_read(&waiting_for_crash_ipi) > 0)
 128                 printk(KERN_WARNING "Non-crashing CPUs did not react to IPI\n");
 129
 130         crash_save_cpu(regs, smp_processor_id());
 131         machine_kexec_mask_interrupts();
 132
 133         printk(KERN_INFO "Loading crashdump kernel...\n");
 134 }
 135
 136 /*
 137  * Function pointer to optional machine-specific reinitialization
 138  */
 139 void (*kexec_reinit)(void);
 140
 141 void machine_kexec(struct kimage *image)
 142 {
 143         unsigned long page_list;
 144         unsigned long reboot_code_buffer_phys;
 145         void *reboot_code_buffer;
 146
 147         /*
 148          * This can only happen if machine_shutdown() failed to disable some
 149          * CPU, and that can only happen if the checks in
 150          * machine_kexec_prepare() were not correct. If this fails, we can't
 151          * reliably kexec anyway, so BUG_ON is appropriate.
 152          */
 153         BUG_ON(num_online_cpus() > 1);
 154
 155         page_list = image->head & PAGE_MASK;
 156
 157         /* we need both effective and real address here */
 158         reboot_code_buffer_phys =
 159             page_to_pfn(image->control_code_page) << PAGE_SHIFT;
 160         reboot_code_buffer = page_address(image->control_code_page);
 161
 162         /* Prepare parameters for reboot_code_buffer*/
 163         kexec_start_address = image->start;
 164         kexec_indirection_page = page_list;
 165         kexec_mach_type = machine_arch_type;
 166         if (!kexec_boot_atags)
 167                 kexec_boot_atags = image->start - KEXEC_ARM_ZIMAGE_OFFSET + KEXEC_ARM_ATAGS_OFFSET;
 168
 169
 170         /* copy our kernel relocation code to the control code page */
 171         memcpy(reboot_code_buffer,
 172                relocate_new_kernel, relocate_new_kernel_size);
 173
 174
 175         flush_icache_range((unsigned long) reboot_code_buffer,
 176                            (unsigned long) reboot_code_buffer + KEXEC_CONTROL_PAGE_SIZE);
 177         printk(KERN_INFO "Bye!\n");
 178
 179         if (kexec_reinit)
 180                 kexec_reinit();
 181
 182         soft_restart(reboot_code_buffer_phys);
 183 }