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, get_irq_regs()); 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 95 while (1) { 96 cpu_relax(); 97 wfe(); 98 } 99 } 100 101 void crash_smp_send_stop(void) 102 { 103 static int cpus_stopped; 104 unsigned long msecs; 105 106 if (cpus_stopped) 107 return; 108 109 atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1); 110 smp_call_function(machine_crash_nonpanic_core, NULL, false); 111 msecs = 1000; /* Wait at most a second for the other cpus to stop */ 112 while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) { 113 mdelay(1); 114 msecs--; 115 } 116 if (atomic_read(&waiting_for_crash_ipi) > 0) 117 pr_warn("Non-crashing CPUs did not react to IPI\n"); 118 119 cpus_stopped = 1; 120 } 121 122 static void machine_kexec_mask_interrupts(void) 123 { 124 unsigned int i; 125 struct irq_desc *desc; 126 127 for_each_irq_desc(i, desc) { 128 struct irq_chip *chip; 129 130 chip = irq_desc_get_chip(desc); 131 if (!chip) 132 continue; 133 134 if (chip->irq_eoi && irqd_irq_inprogress(&desc->irq_data)) 135 chip->irq_eoi(&desc->irq_data); 136 137 if (chip->irq_mask) 138 chip->irq_mask(&desc->irq_data); 139 140 if (chip->irq_disable && !irqd_irq_disabled(&desc->irq_data)) 141 chip->irq_disable(&desc->irq_data); 142 } 143 } 144 145 void machine_crash_shutdown(struct pt_regs *regs) 146 { 147 local_irq_disable(); 148 crash_smp_send_stop(); 149 150 crash_save_cpu(regs, smp_processor_id()); 151 machine_kexec_mask_interrupts(); 152 153 pr_info("Loading crashdump kernel...\n"); 154 } 155 156 /* 157 * Function pointer to optional machine-specific reinitialization 158 */ 159 void (*kexec_reinit)(void); 160 161 void machine_kexec(struct kimage *image) 162 { 163 unsigned long page_list, reboot_entry_phys; 164 void (*reboot_entry)(void); 165 void *reboot_code_buffer; 166 167 /* 168 * This can only happen if machine_shutdown() failed to disable some 169 * CPU, and that can only happen if the checks in 170 * machine_kexec_prepare() were not correct. If this fails, we can't 171 * reliably kexec anyway, so BUG_ON is appropriate. 172 */ 173 BUG_ON(num_online_cpus() > 1); 174 175 page_list = image->head & PAGE_MASK; 176 177 reboot_code_buffer = page_address(image->control_code_page); 178 179 /* Prepare parameters for reboot_code_buffer*/ 180 set_kernel_text_rw(); 181 kexec_start_address = image->start; 182 kexec_indirection_page = page_list; 183 kexec_mach_type = machine_arch_type; 184 kexec_boot_atags = image->arch.kernel_r2; 185 186 /* copy our kernel relocation code to the control code page */ 187 reboot_entry = fncpy(reboot_code_buffer, 188 &relocate_new_kernel, 189 relocate_new_kernel_size); 190 191 /* get the identity mapping physical address for the reboot code */ 192 reboot_entry_phys = virt_to_idmap(reboot_entry); 193 194 pr_info("Bye!\n"); 195 196 if (kexec_reinit) 197 kexec_reinit(); 198 199 soft_restart(reboot_entry_phys); 200 } 201 202 void arch_crash_save_vmcoreinfo(void) 203 { 204 #ifdef CONFIG_ARM_LPAE 205 VMCOREINFO_CONFIG(ARM_LPAE); 206 #endif 207 } 208