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 #include <asm/set_memory.h>
  22
  23 extern void relocate_new_kernel(void);
  24 extern const unsigned int relocate_new_kernel_size;
  25
  26 extern unsigned long kexec_start_address;
  27 extern unsigned long kexec_indirection_page;
  28 extern unsigned long kexec_mach_type;
  29 extern unsigned long kexec_boot_atags;
  30
  31 static atomic_t waiting_for_crash_ipi;
  32
  33 static unsigned long dt_mem;
  34 /*
  35  * Provide a dummy crash_notes definition while crash dump arrives to arm.
  36  * This prevents breakage of crash_notes attribute in kernel/ksysfs.c.
  37  */
  38
  39 int machine_kexec_prepare(struct kimage *image)
  40 {
  41         struct kexec_segment *current_segment;
  42         __be32 header;
  43         int i, err;
  44
  45         /*
  46          * Validate that if the current HW supports SMP, then the SW supports
  47          * and implements CPU hotplug for the current HW. If not, we won't be
  48          * able to kexec reliably, so fail the prepare operation.
  49          */
  50         if (num_possible_cpus() > 1 && platform_can_secondary_boot() &&
  51             !platform_can_cpu_hotplug())
  52                 return -EINVAL;
  53
  54         /*
  55          * No segment at default ATAGs address. try to locate
  56          * a dtb using magic.
  57          */
  58         for (i = 0; i < image->nr_segments; i++) {
  59                 current_segment = &image->segment[i];
  60
  61                 if (!memblock_is_region_memory(idmap_to_phys(current_segment->mem),
  62                                                current_segment->memsz))
  63                         return -EINVAL;
  64
  65                 err = get_user(header, (__be32*)current_segment->buf);
  66                 if (err)
  67                         return err;
  68
  69                 if (be32_to_cpu(header) == OF_DT_HEADER)
  70                         dt_mem = current_segment->mem;
  71         }
  72         return 0;
  73 }
  74
  75 void machine_kexec_cleanup(struct kimage *image)
  76 {
  77 }
  78
  79 void machine_crash_nonpanic_core(void *unused)
  80 {
  81         struct pt_regs regs;
  82
  83         crash_setup_regs(&regs, NULL);
  84         printk(KERN_DEBUG "CPU %u will stop doing anything useful since another CPU has crashed\n",
  85                smp_processor_id());
  86         crash_save_cpu(&regs, smp_processor_id());
  87         flush_cache_all();
  88
  89         set_cpu_online(smp_processor_id(), false);
  90         atomic_dec(&waiting_for_crash_ipi);
  91         while (1)
  92                 cpu_relax();
  93 }
  94
  95 static void machine_kexec_mask_interrupts(void)
  96 {
  97         unsigned int i;
  98         struct irq_desc *desc;
  99
 100         for_each_irq_desc(i, desc) {
 101                 struct irq_chip *chip;
 102
 103                 chip = irq_desc_get_chip(desc);
 104                 if (!chip)
 105                         continue;
 106
 107                 if (chip->irq_eoi && irqd_irq_inprogress(&desc->irq_data))
 108                         chip->irq_eoi(&desc->irq_data);
 109
 110                 if (chip->irq_mask)
 111                         chip->irq_mask(&desc->irq_data);
 112
 113                 if (chip->irq_disable && !irqd_irq_disabled(&desc->irq_data))
 114                         chip->irq_disable(&desc->irq_data);
 115         }
 116 }
 117
 118 void machine_crash_shutdown(struct pt_regs *regs)
 119 {
 120         unsigned long msecs;
 121
 122         local_irq_disable();
 123
 124         atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
 125         smp_call_function(machine_crash_nonpanic_core, NULL, false);
 126         msecs = 1000; /* Wait at most a second for the other cpus to stop */
 127         while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
 128                 mdelay(1);
 129                 msecs--;
 130         }
 131         if (atomic_read(&waiting_for_crash_ipi) > 0)
 132                 pr_warn("Non-crashing CPUs did not react to IPI\n");
 133
 134         crash_save_cpu(regs, smp_processor_id());
 135         machine_kexec_mask_interrupts();
 136
 137         pr_info("Loading crashdump kernel...\n");
 138 }
 139
 140 /*
 141  * Function pointer to optional machine-specific reinitialization
 142  */
 143 void (*kexec_reinit)(void);
 144
 145 void machine_kexec(struct kimage *image)
 146 {
 147         unsigned long page_list, reboot_entry_phys;
 148         void (*reboot_entry)(void);
 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         reboot_code_buffer = page_address(image->control_code_page);
 162
 163         /* Prepare parameters for reboot_code_buffer*/
 164         set_kernel_text_rw();
 165         kexec_start_address = image->start;
 166         kexec_indirection_page = page_list;
 167         kexec_mach_type = machine_arch_type;
 168         kexec_boot_atags = dt_mem ?: image->start - KEXEC_ARM_ZIMAGE_OFFSET
 169                                      + KEXEC_ARM_ATAGS_OFFSET;
 170
 171         /* copy our kernel relocation code to the control code page */
 172         reboot_entry = fncpy(reboot_code_buffer,
 173                              &relocate_new_kernel,
 174                              relocate_new_kernel_size);
 175
 176         /* get the identity mapping physical address for the reboot code */
 177         reboot_entry_phys = virt_to_idmap(reboot_entry);
 178
 179         pr_info("Bye!\n");
 180
 181         if (kexec_reinit)
 182                 kexec_reinit();
 183
 184         soft_restart(reboot_entry_phys);
 185 }
 186
 187 void arch_crash_save_vmcoreinfo(void)
 188 {
 189 #ifdef CONFIG_ARM_LPAE
 190         VMCOREINFO_CONFIG(ARM_LPAE);
 191 #endif
 192 }