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/fncpy.h>
  18 #include <asm/mach-types.h>
  19 #include <asm/smp_plat.h>
  20 #include <asm/system_misc.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         /*
  44          * Validate that if the current HW supports SMP, then the SW supports
  45          * and implements CPU hotplug for the current HW. If not, we won't be
  46          * able to kexec reliably, so fail the prepare operation.
  47          */
  48         if (num_possible_cpus() > 1 && !platform_can_cpu_hotplug())
  49                 return -EINVAL;
  50
  51         /*
  52          * No segment at default ATAGs address. try to locate
  53          * a dtb using magic.
  54          */
  55         for (i = 0; i < image->nr_segments; i++) {
  56                 current_segment = &image->segment[i];
  57
  58                 if (!memblock_is_region_memory(current_segment->mem,
  59                                                current_segment->memsz))
  60                         return -EINVAL;
  61
  62                 err = get_user(header, (__be32*)current_segment->buf);
  63                 if (err)
  64                         return err;
  65
  66                 if (be32_to_cpu(header) == OF_DT_HEADER)
  67                         kexec_boot_atags = current_segment->mem;
  68         }
  69         return 0;
  70 }
  71
  72 void machine_kexec_cleanup(struct kimage *image)
  73 {
  74 }
  75
  76 void machine_crash_nonpanic_core(void *unused)
  77 {
  78         struct pt_regs regs;
  79
  80         crash_setup_regs(&regs, NULL);
  81         printk(KERN_DEBUG "CPU %u will stop doing anything useful since another CPU has crashed\n",
  82                smp_processor_id());
  83         crash_save_cpu(&regs, smp_processor_id());
  84         flush_cache_all();
  85
  86         set_cpu_online(smp_processor_id(), false);
  87         atomic_dec(&waiting_for_crash_ipi);
  88         while (1)
  89                 cpu_relax();
  90 }
  91
  92 static void machine_kexec_mask_interrupts(void)
  93 {
  94         unsigned int i;
  95         struct irq_desc *desc;
  96
  97         for_each_irq_desc(i, desc) {
  98                 struct irq_chip *chip;
  99
 100                 chip = irq_desc_get_chip(desc);
 101                 if (!chip)
 102                         continue;
 103
 104                 if (chip->irq_eoi && irqd_irq_inprogress(&desc->irq_data))
 105                         chip->irq_eoi(&desc->irq_data);
 106
 107                 if (chip->irq_mask)
 108                         chip->irq_mask(&desc->irq_data);
 109
 110                 if (chip->irq_disable && !irqd_irq_disabled(&desc->irq_data))
 111                         chip->irq_disable(&desc->irq_data);
 112         }
 113 }
 114
 115 void machine_crash_shutdown(struct pt_regs *regs)
 116 {
 117         unsigned long msecs;
 118
 119         local_irq_disable();
 120
 121         atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
 122         smp_call_function(machine_crash_nonpanic_core, NULL, false);
 123         msecs = 1000; /* Wait at most a second for the other cpus to stop */
 124         while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
 125                 mdelay(1);
 126                 msecs--;
 127         }
 128         if (atomic_read(&waiting_for_crash_ipi) > 0)
 129                 printk(KERN_WARNING "Non-crashing CPUs did not react to IPI\n");
 130
 131         crash_save_cpu(regs, smp_processor_id());
 132         machine_kexec_mask_interrupts();
 133
 134         printk(KERN_INFO "Loading crashdump kernel...\n");
 135 }
 136
 137 /*
 138  * Function pointer to optional machine-specific reinitialization
 139  */
 140 void (*kexec_reinit)(void);
 141
 142 void machine_kexec(struct kimage *image)
 143 {
 144         unsigned long page_list;
 145         unsigned long reboot_code_buffer_phys;
 146         unsigned long reboot_entry = (unsigned long)relocate_new_kernel;
 147         unsigned long reboot_entry_phys;
 148         void *reboot_code_buffer;
 149
 150         /*
 151          * This can only happen if machine_shutdown() failed to disable some
 152          * CPU, and that can only happen if the checks in
 153          * machine_kexec_prepare() were not correct. If this fails, we can't
 154          * reliably kexec anyway, so BUG_ON is appropriate.
 155          */
 156         BUG_ON(num_online_cpus() > 1);
 157
 158         page_list = image->head & PAGE_MASK;
 159
 160         /* we need both effective and real address here */
 161         reboot_code_buffer_phys =
 162             page_to_pfn(image->control_code_page) << PAGE_SHIFT;
 163         reboot_code_buffer = page_address(image->control_code_page);
 164
 165         /* Prepare parameters for reboot_code_buffer*/
 166         kexec_start_address = image->start;
 167         kexec_indirection_page = page_list;
 168         kexec_mach_type = machine_arch_type;
 169         if (!kexec_boot_atags)
 170                 kexec_boot_atags = image->start - KEXEC_ARM_ZIMAGE_OFFSET + KEXEC_ARM_ATAGS_OFFSET;
 171
 172
 173         /* copy our kernel relocation code to the control code page */
 174         reboot_entry = fncpy(reboot_code_buffer,
 175                              reboot_entry,
 176                              relocate_new_kernel_size);
 177         reboot_entry_phys = (unsigned long)reboot_entry +
 178                 (reboot_code_buffer_phys - (unsigned long)reboot_code_buffer);
 179
 180         printk(KERN_INFO "Bye!\n");
 181
 182         if (kexec_reinit)
 183                 kexec_reinit();
 184
 185         soft_restart(reboot_entry_phys);
 186 }