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 <asm/pgtable.h> 14 #include <linux/of_fdt.h> 15 #include <asm/pgalloc.h> 16 #include <asm/mmu_context.h> 17 #include <asm/cacheflush.h> 18 #include <asm/fncpy.h> 19 #include <asm/mach-types.h> 20 #include <asm/smp_plat.h> 21 #include <asm/system_misc.h> 22 #include <asm/set_memory.h> 23 24 extern void relocate_new_kernel(void); 25 extern const unsigned int relocate_new_kernel_size; 26 27 extern unsigned long kexec_start_address; 28 extern unsigned long kexec_indirection_page; 29 extern unsigned long kexec_mach_type; 30 extern unsigned long kexec_boot_atags; 31 32 static atomic_t waiting_for_crash_ipi; 33 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 image->arch.kernel_r2 = image->start - KEXEC_ARM_ZIMAGE_OFFSET 46 + KEXEC_ARM_ATAGS_OFFSET; 47 48 /* 49 * Validate that if the current HW supports SMP, then the SW supports 50 * and implements CPU hotplug for the current HW. If not, we won't be 51 * able to kexec reliably, so fail the prepare operation. 52 */ 53 if (num_possible_cpus() > 1 && platform_can_secondary_boot() && 54 !platform_can_cpu_hotplug()) 55 return -EINVAL; 56 57 /* 58 * No segment at default ATAGs address. try to locate 59 * a dtb using magic. 60 */ 61 for (i = 0; i < image->nr_segments; i++) { 62 current_segment = &image->segment[i]; 63 64 if (!memblock_is_region_memory(idmap_to_phys(current_segment->mem), 65 current_segment->memsz)) 66 return -EINVAL; 67 68 err = get_user(header, (__be32*)current_segment->buf); 69 if (err) 70 return err; 71 72 if (header == cpu_to_be32(OF_DT_HEADER)) 73 image->arch.kernel_r2 = current_segment->mem; 74 } 75 return 0; 76 } 77 78 void machine_kexec_cleanup(struct kimage *image) 79 { 80 } 81 82 void machine_crash_nonpanic_core(void *unused) 83 { 84 struct pt_regs regs; 85 86 crash_setup_regs(®s, NULL); 87 printk(KERN_DEBUG "CPU %u will stop doing anything useful since another CPU has crashed\n", 88 smp_processor_id()); 89 crash_save_cpu(®s, smp_processor_id()); 90 flush_cache_all(); 91 92 set_cpu_online(smp_processor_id(), false); 93 atomic_dec(&waiting_for_crash_ipi); 94 while (1) 95 cpu_relax(); 96 } 97 98 static void machine_kexec_mask_interrupts(void) 99 { 100 unsigned int i; 101 struct irq_desc *desc; 102 103 for_each_irq_desc(i, desc) { 104 struct irq_chip *chip; 105 106 chip = irq_desc_get_chip(desc); 107 if (!chip) 108 continue; 109 110 if (chip->irq_eoi && irqd_irq_inprogress(&desc->irq_data)) 111 chip->irq_eoi(&desc->irq_data); 112 113 if (chip->irq_mask) 114 chip->irq_mask(&desc->irq_data); 115 116 if (chip->irq_disable && !irqd_irq_disabled(&desc->irq_data)) 117 chip->irq_disable(&desc->irq_data); 118 } 119 } 120 121 void machine_crash_shutdown(struct pt_regs *regs) 122 { 123 unsigned long msecs; 124 125 local_irq_disable(); 126 127 atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1); 128 smp_call_function(machine_crash_nonpanic_core, NULL, false); 129 msecs = 1000; /* Wait at most a second for the other cpus to stop */ 130 while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) { 131 mdelay(1); 132 msecs--; 133 } 134 if (atomic_read(&waiting_for_crash_ipi) > 0) 135 pr_warn("Non-crashing CPUs did not react to IPI\n"); 136 137 crash_save_cpu(regs, smp_processor_id()); 138 machine_kexec_mask_interrupts(); 139 140 pr_info("Loading crashdump kernel...\n"); 141 } 142 143 /* 144 * Function pointer to optional machine-specific reinitialization 145 */ 146 void (*kexec_reinit)(void); 147 148 void machine_kexec(struct kimage *image) 149 { 150 unsigned long page_list, reboot_entry_phys; 151 void (*reboot_entry)(void); 152 void *reboot_code_buffer; 153 154 /* 155 * This can only happen if machine_shutdown() failed to disable some 156 * CPU, and that can only happen if the checks in 157 * machine_kexec_prepare() were not correct. If this fails, we can't 158 * reliably kexec anyway, so BUG_ON is appropriate. 159 */ 160 BUG_ON(num_online_cpus() > 1); 161 162 page_list = image->head & PAGE_MASK; 163 164 reboot_code_buffer = page_address(image->control_code_page); 165 166 /* Prepare parameters for reboot_code_buffer*/ 167 set_kernel_text_rw(); 168 kexec_start_address = image->start; 169 kexec_indirection_page = page_list; 170 kexec_mach_type = machine_arch_type; 171 kexec_boot_atags = image->arch.kernel_r2; 172 173 /* copy our kernel relocation code to the control code page */ 174 reboot_entry = fncpy(reboot_code_buffer, 175 &relocate_new_kernel, 176 relocate_new_kernel_size); 177 178 /* get the identity mapping physical address for the reboot code */ 179 reboot_entry_phys = virt_to_idmap(reboot_entry); 180 181 pr_info("Bye!\n"); 182 183 if (kexec_reinit) 184 kexec_reinit(); 185 186 soft_restart(reboot_entry_phys); 187 } 188 189 void arch_crash_save_vmcoreinfo(void) 190 { 191 #ifdef CONFIG_ARM_LPAE 192 VMCOREINFO_CONFIG(ARM_LPAE); 193 #endif 194 } 195