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(®s, 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(®s, 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 } 187