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 static unsigned long dt_mem;
  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         /*
  45          * Validate that if the current HW supports SMP, then the SW supports
  46          * and implements CPU hotplug for the current HW. If not, we won't be
  47          * able to kexec reliably, so fail the prepare operation.
  48          */
  49         if (num_possible_cpus() > 1 && !platform_can_cpu_hotplug())
  50                 return -EINVAL;
  51
  52         /*
  53          * No segment at default ATAGs address. try to locate
  54          * a dtb using magic.
  55          */
  56         for (i = 0; i < image->nr_segments; i++) {
  57                 current_segment = &image->segment[i];
  58
  59                 if (!memblock_is_region_memory(current_segment->mem,
  60                                                current_segment->memsz))
  61                         return -EINVAL;
  62
  63                 err = get_user(header, (__be32*)current_segment->buf);
  64                 if (err)
  65                         return err;
  66
  67                 if (be32_to_cpu(header) == OF_DT_HEADER)
  68                         dt_mem = current_segment->mem;
  69         }
  70         return 0;
  71 }
  72
  73 void machine_kexec_cleanup(struct kimage *image)
  74 {
  75 }
  76
  77 void machine_crash_nonpanic_core(void *unused)
  78 {
  79         struct pt_regs regs;
  80
  81         crash_setup_regs(&regs, NULL);
  82         printk(KERN_DEBUG "CPU %u will stop doing anything useful since another CPU has crashed\n",
  83                smp_processor_id());
  84         crash_save_cpu(&regs, smp_processor_id());
  85         flush_cache_all();
  86
  87         set_cpu_online(smp_processor_id(), false);
  88         atomic_dec(&waiting_for_crash_ipi);
  89         while (1)
  90                 cpu_relax();
  91 }
  92
  93 static void machine_kexec_mask_interrupts(void)
  94 {
  95         unsigned int i;
  96         struct irq_desc *desc;
  97
  98         for_each_irq_desc(i, desc) {
  99                 struct irq_chip *chip;
 100
 101                 chip = irq_desc_get_chip(desc);
 102                 if (!chip)
 103                         continue;
 104
 105                 if (chip->irq_eoi && irqd_irq_inprogress(&desc->irq_data))
 106                         chip->irq_eoi(&desc->irq_data);
 107
 108                 if (chip->irq_mask)
 109                         chip->irq_mask(&desc->irq_data);
 110
 111                 if (chip->irq_disable && !irqd_irq_disabled(&desc->irq_data))
 112                         chip->irq_disable(&desc->irq_data);
 113         }
 114 }
 115
 116 void machine_crash_shutdown(struct pt_regs *regs)
 117 {
 118         unsigned long msecs;
 119
 120         local_irq_disable();
 121
 122         atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
 123         smp_call_function(machine_crash_nonpanic_core, NULL, false);
 124         msecs = 1000; /* Wait at most a second for the other cpus to stop */
 125         while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
 126                 mdelay(1);
 127                 msecs--;
 128         }
 129         if (atomic_read(&waiting_for_crash_ipi) > 0)
 130                 pr_warn("Non-crashing CPUs did not react to IPI\n");
 131
 132         crash_save_cpu(regs, smp_processor_id());
 133         machine_kexec_mask_interrupts();
 134
 135         pr_info("Loading crashdump kernel...\n");
 136 }
 137
 138 /*
 139  * Function pointer to optional machine-specific reinitialization
 140  */
 141 void (*kexec_reinit)(void);
 142
 143 void machine_kexec(struct kimage *image)
 144 {
 145         unsigned long page_list;
 146         unsigned long reboot_code_buffer_phys;
 147         unsigned long reboot_entry = (unsigned long)relocate_new_kernel;
 148         unsigned long reboot_entry_phys;
 149         void *reboot_code_buffer;
 150
 151         /*
 152          * This can only happen if machine_shutdown() failed to disable some
 153          * CPU, and that can only happen if the checks in
 154          * machine_kexec_prepare() were not correct. If this fails, we can't
 155          * reliably kexec anyway, so BUG_ON is appropriate.
 156          */
 157         BUG_ON(num_online_cpus() > 1);
 158
 159         page_list = image->head & PAGE_MASK;
 160
 161         /* we need both effective and real address here */
 162         reboot_code_buffer_phys =
 163             page_to_pfn(image->control_code_page) << PAGE_SHIFT;
 164         reboot_code_buffer = page_address(image->control_code_page);
 165
 166         /* Prepare parameters for reboot_code_buffer*/
 167         set_kernel_text_rw();
 168         kexec_start_address = image->start;
 169         kexec_indirection_page = page_list;
 170         kexec_mach_type = machine_arch_type;
 171         kexec_boot_atags = dt_mem ?: image->start - KEXEC_ARM_ZIMAGE_OFFSET
 172                                      + KEXEC_ARM_ATAGS_OFFSET;
 173
 174         /* copy our kernel relocation code to the control code page */
 175         reboot_entry = fncpy(reboot_code_buffer,
 176                              reboot_entry,
 177                              relocate_new_kernel_size);
 178         reboot_entry_phys = (unsigned long)reboot_entry +
 179                 (reboot_code_buffer_phys - (unsigned long)reboot_code_buffer);
 180
 181         pr_info("Bye!\n");
 182
 183         if (kexec_reinit)
 184                 kexec_reinit();
 185
 186         soft_restart(reboot_entry_phys);
 187 }
 188
 189 void arch_crash_save_vmcoreinfo(void)
 190 {
 191 #ifdef CONFIG_ARM_LPAE
 192         VMCOREINFO_CONFIG(ARM_LPAE);
 193 #endif
 194 }