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 machine_kexec_prepare(struct kimage * image)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 machine_kexec_cleanup(struct kimage * image)72 void machine_kexec_cleanup(struct kimage *image) 73 { 74 } 75 machine_crash_nonpanic_core(void * unused)76 void machine_crash_nonpanic_core(void *unused) 77 { 78 struct pt_regs regs; 79 80 crash_setup_regs(®s, get_irq_regs()); 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 89 while (1) { 90 cpu_relax(); 91 wfe(); 92 } 93 } 94 crash_smp_send_stop(void)95 void crash_smp_send_stop(void) 96 { 97 static int cpus_stopped; 98 unsigned long msecs; 99 100 if (cpus_stopped) 101 return; 102 103 atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1); 104 smp_call_function(machine_crash_nonpanic_core, NULL, false); 105 msecs = 1000; /* Wait at most a second for the other cpus to stop */ 106 while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) { 107 mdelay(1); 108 msecs--; 109 } 110 if (atomic_read(&waiting_for_crash_ipi) > 0) 111 pr_warn("Non-crashing CPUs did not react to IPI\n"); 112 113 cpus_stopped = 1; 114 } 115 machine_kexec_mask_interrupts(void)116 static void machine_kexec_mask_interrupts(void) 117 { 118 unsigned int i; 119 struct irq_desc *desc; 120 121 for_each_irq_desc(i, desc) { 122 struct irq_chip *chip; 123 124 chip = irq_desc_get_chip(desc); 125 if (!chip) 126 continue; 127 128 if (chip->irq_eoi && irqd_irq_inprogress(&desc->irq_data)) 129 chip->irq_eoi(&desc->irq_data); 130 131 if (chip->irq_mask) 132 chip->irq_mask(&desc->irq_data); 133 134 if (chip->irq_disable && !irqd_irq_disabled(&desc->irq_data)) 135 chip->irq_disable(&desc->irq_data); 136 } 137 } 138 machine_crash_shutdown(struct pt_regs * regs)139 void machine_crash_shutdown(struct pt_regs *regs) 140 { 141 local_irq_disable(); 142 crash_smp_send_stop(); 143 144 crash_save_cpu(regs, smp_processor_id()); 145 machine_kexec_mask_interrupts(); 146 147 pr_info("Loading crashdump kernel...\n"); 148 } 149 machine_kexec(struct kimage * image)150 void machine_kexec(struct kimage *image) 151 { 152 unsigned long page_list, reboot_entry_phys; 153 struct kexec_relocate_data *data; 154 void (*reboot_entry)(void); 155 void *reboot_code_buffer; 156 157 /* 158 * This can only happen if machine_shutdown() failed to disable some 159 * CPU, and that can only happen if the checks in 160 * machine_kexec_prepare() were not correct. If this fails, we can't 161 * reliably kexec anyway, so BUG_ON is appropriate. 162 */ 163 BUG_ON(num_online_cpus() > 1); 164 165 page_list = image->head & PAGE_MASK; 166 167 reboot_code_buffer = page_address(image->control_code_page); 168 169 /* copy our kernel relocation code to the control code page */ 170 reboot_entry = fncpy(reboot_code_buffer, 171 &relocate_new_kernel, 172 relocate_new_kernel_size); 173 174 data = reboot_code_buffer + relocate_new_kernel_size; 175 data->kexec_start_address = image->start; 176 data->kexec_indirection_page = page_list; 177 data->kexec_mach_type = machine_arch_type; 178 data->kexec_r2 = image->arch.kernel_r2; 179 180 /* get the identity mapping physical address for the reboot code */ 181 reboot_entry_phys = virt_to_idmap(reboot_entry); 182 183 pr_info("Bye!\n"); 184 185 soft_restart(reboot_entry_phys); 186 } 187 arch_crash_save_vmcoreinfo(void)188 void arch_crash_save_vmcoreinfo(void) 189 { 190 #ifdef CONFIG_ARM_LPAE 191 VMCOREINFO_CONFIG(ARM_LPAE); 192 #endif 193 } 194