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_secondary_boot() &&
  50             !platform_can_cpu_hotplug())
  51                 return -EINVAL;
  52
  53         /*
  54          * No segment at default ATAGs address. try to locate
  55          * a dtb using magic.
  56          */
  57         for (i = 0; i < image->nr_segments; i++) {
  58                 current_segment = &image->segment[i];
  59
  60                 if (!memblock_is_region_memory(idmap_to_phys(current_segment->mem),
  61                                                current_segment->memsz))
  62                         return -EINVAL;
  63
  64                 err = get_user(header, (__be32*)current_segment->buf);
  65                 if (err)
  66                         return err;
  67
  68                 if (be32_to_cpu(header) == OF_DT_HEADER)
  69                         dt_mem = current_segment->mem;
  70         }
  71         return 0;
  72 }
  73
  74 void machine_kexec_cleanup(struct kimage *image)
  75 {
  76 }
  77
  78 void machine_crash_nonpanic_core(void *unused)
  79 {
  80         struct pt_regs regs;
  81
  82         crash_setup_regs(&regs, NULL);
  83         printk(KERN_DEBUG "CPU %u will stop doing anything useful since another CPU has crashed\n",
  84                smp_processor_id());
  85         crash_save_cpu(&regs, smp_processor_id());
  86         flush_cache_all();
  87
  88         set_cpu_online(smp_processor_id(), false);
  89         atomic_dec(&waiting_for_crash_ipi);
  90         while (1)
  91                 cpu_relax();
  92 }
  93
  94 static void machine_kexec_mask_interrupts(void)
  95 {
  96         unsigned int i;
  97         struct irq_desc *desc;
  98
  99         for_each_irq_desc(i, desc) {
 100                 struct irq_chip *chip;
 101
 102                 chip = irq_desc_get_chip(desc);
 103                 if (!chip)
 104                         continue;
 105
 106                 if (chip->irq_eoi && irqd_irq_inprogress(&desc->irq_data))
 107                         chip->irq_eoi(&desc->irq_data);
 108
 109                 if (chip->irq_mask)
 110                         chip->irq_mask(&desc->irq_data);
 111
 112                 if (chip->irq_disable && !irqd_irq_disabled(&desc->irq_data))
 113                         chip->irq_disable(&desc->irq_data);
 114         }
 115 }
 116
 117 void machine_crash_shutdown(struct pt_regs *regs)
 118 {
 119         unsigned long msecs;
 120
 121         local_irq_disable();
 122
 123         atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
 124         smp_call_function(machine_crash_nonpanic_core, NULL, false);
 125         msecs = 1000; /* Wait at most a second for the other cpus to stop */
 126         while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
 127                 mdelay(1);
 128                 msecs--;
 129         }
 130         if (atomic_read(&waiting_for_crash_ipi) > 0)
 131                 pr_warn("Non-crashing CPUs did not react to IPI\n");
 132
 133         crash_save_cpu(regs, smp_processor_id());
 134         machine_kexec_mask_interrupts();
 135
 136         pr_info("Loading crashdump kernel...\n");
 137 }
 138
 139 /*
 140  * Function pointer to optional machine-specific reinitialization
 141  */
 142 void (*kexec_reinit)(void);
 143
 144 void machine_kexec(struct kimage *image)
 145 {
 146         unsigned long page_list, reboot_entry_phys;
 147         void (*reboot_entry)(void);
 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         reboot_code_buffer = page_address(image->control_code_page);
 161
 162         /* Prepare parameters for reboot_code_buffer*/
 163         set_kernel_text_rw();
 164         kexec_start_address = image->start;
 165         kexec_indirection_page = page_list;
 166         kexec_mach_type = machine_arch_type;
 167         kexec_boot_atags = dt_mem ?: image->start - KEXEC_ARM_ZIMAGE_OFFSET
 168                                      + KEXEC_ARM_ATAGS_OFFSET;
 169
 170         /* copy our kernel relocation code to the control code page */
 171         reboot_entry = fncpy(reboot_code_buffer,
 172                              &relocate_new_kernel,
 173                              relocate_new_kernel_size);
 174
 175         /* get the identity mapping physical address for the reboot code */
 176         reboot_entry_phys = virt_to_idmap(reboot_entry);
 177
 178         pr_info("Bye!\n");
 179
 180         if (kexec_reinit)
 181                 kexec_reinit();
 182
 183         soft_restart(reboot_entry_phys);
 184 }
 185
 186 void arch_crash_save_vmcoreinfo(void)
 187 {
 188 #ifdef CONFIG_ARM_LPAE
 189         VMCOREINFO_CONFIG(ARM_LPAE);
 190 #endif
 191 }