1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * machine_kexec.c - handle transition of Linux booting another kernel 4 */ 5 6 #include <linux/mm.h> 7 #include <linux/kexec.h> 8 #include <linux/delay.h> 9 #include <linux/reboot.h> 10 #include <linux/io.h> 11 #include <linux/irq.h> 12 #include <linux/memblock.h> 13 #include <linux/of_fdt.h> 14 #include <asm/mmu_context.h> 15 #include <asm/cacheflush.h> 16 #include <asm/kexec-internal.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 static atomic_t waiting_for_crash_ipi; 27 28 /* 29 * Provide a dummy crash_notes definition while crash dump arrives to arm. 30 * This prevents breakage of crash_notes attribute in kernel/ksysfs.c. 31 */ 32 33 int machine_kexec_prepare(struct kimage *image) 34 { 35 struct kexec_segment *current_segment; 36 __be32 header; 37 int i, err; 38 39 image->arch.kernel_r2 = image->start - KEXEC_ARM_ZIMAGE_OFFSET 40 + KEXEC_ARM_ATAGS_OFFSET; 41 42 /* 43 * Validate that if the current HW supports SMP, then the SW supports 44 * and implements CPU hotplug for the current HW. If not, we won't be 45 * able to kexec reliably, so fail the prepare operation. 46 */ 47 if (num_possible_cpus() > 1 && platform_can_secondary_boot() && 48 !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(idmap_to_phys(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 (header == cpu_to_be32(OF_DT_HEADER)) 67 image->arch.kernel_r2 = current_segment->mem; 68 } 69 return 0; 70 } 71 72 void machine_kexec_cleanup(struct kimage *image) 73 { 74 } 75 76 static void machine_crash_nonpanic_core(void *unused) 77 { 78 struct pt_regs regs; 79 80 local_fiq_disable(); 81 82 crash_setup_regs(®s, get_irq_regs()); 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(®s, smp_processor_id()); 86 flush_cache_all(); 87 88 set_cpu_online(smp_processor_id(), false); 89 atomic_dec(&waiting_for_crash_ipi); 90 91 while (1) { 92 cpu_relax(); 93 wfe(); 94 } 95 } 96 97 void crash_smp_send_stop(void) 98 { 99 static int cpus_stopped; 100 unsigned long msecs; 101 102 if (cpus_stopped) 103 return; 104 105 atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1); 106 smp_call_function(machine_crash_nonpanic_core, NULL, false); 107 msecs = 1000; /* Wait at most a second for the other cpus to stop */ 108 while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) { 109 mdelay(1); 110 msecs--; 111 } 112 if (atomic_read(&waiting_for_crash_ipi) > 0) 113 pr_warn("Non-crashing CPUs did not react to IPI\n"); 114 115 cpus_stopped = 1; 116 } 117 118 static void machine_kexec_mask_interrupts(void) 119 { 120 unsigned int i; 121 struct irq_desc *desc; 122 123 for_each_irq_desc(i, desc) { 124 struct irq_chip *chip; 125 126 chip = irq_desc_get_chip(desc); 127 if (!chip) 128 continue; 129 130 if (chip->irq_eoi && irqd_irq_inprogress(&desc->irq_data)) 131 chip->irq_eoi(&desc->irq_data); 132 133 if (chip->irq_mask) 134 chip->irq_mask(&desc->irq_data); 135 136 if (chip->irq_disable && !irqd_irq_disabled(&desc->irq_data)) 137 chip->irq_disable(&desc->irq_data); 138 } 139 } 140 141 void machine_crash_shutdown(struct pt_regs *regs) 142 { 143 local_irq_disable(); 144 crash_smp_send_stop(); 145 146 crash_save_cpu(regs, smp_processor_id()); 147 machine_kexec_mask_interrupts(); 148 149 pr_info("Loading crashdump kernel...\n"); 150 } 151 152 void machine_kexec(struct kimage *image) 153 { 154 unsigned long page_list, reboot_entry_phys; 155 struct kexec_relocate_data *data; 156 void (*reboot_entry)(void); 157 void *reboot_code_buffer; 158 159 /* 160 * This can only happen if machine_shutdown() failed to disable some 161 * CPU, and that can only happen if the checks in 162 * machine_kexec_prepare() were not correct. If this fails, we can't 163 * reliably kexec anyway, so BUG_ON is appropriate. 164 */ 165 BUG_ON(num_online_cpus() > 1); 166 167 page_list = image->head & PAGE_MASK; 168 169 reboot_code_buffer = page_address(image->control_code_page); 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 data = reboot_code_buffer + relocate_new_kernel_size; 177 data->kexec_start_address = image->start; 178 data->kexec_indirection_page = page_list; 179 data->kexec_mach_type = machine_arch_type; 180 data->kexec_r2 = image->arch.kernel_r2; 181 182 /* get the identity mapping physical address for the reboot code */ 183 reboot_entry_phys = virt_to_idmap(reboot_entry); 184 185 pr_info("Bye!\n"); 186 187 soft_restart(reboot_entry_phys); 188 } 189 190 void arch_crash_save_vmcoreinfo(void) 191 { 192 #ifdef CONFIG_ARM_LPAE 193 VMCOREINFO_CONFIG(ARM_LPAE); 194 #endif 195 } 196