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/fncpy.h> 17 #include <asm/mach-types.h> 18 #include <asm/smp_plat.h> 19 #include <asm/system_misc.h> 20 #include <asm/set_memory.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 image->arch.kernel_r2 = image->start - KEXEC_ARM_ZIMAGE_OFFSET 44 + KEXEC_ARM_ATAGS_OFFSET; 45 46 /* 47 * Validate that if the current HW supports SMP, then the SW supports 48 * and implements CPU hotplug for the current HW. If not, we won't be 49 * able to kexec reliably, so fail the prepare operation. 50 */ 51 if (num_possible_cpus() > 1 && platform_can_secondary_boot() && 52 !platform_can_cpu_hotplug()) 53 return -EINVAL; 54 55 /* 56 * No segment at default ATAGs address. try to locate 57 * a dtb using magic. 58 */ 59 for (i = 0; i < image->nr_segments; i++) { 60 current_segment = &image->segment[i]; 61 62 if (!memblock_is_region_memory(idmap_to_phys(current_segment->mem), 63 current_segment->memsz)) 64 return -EINVAL; 65 66 err = get_user(header, (__be32*)current_segment->buf); 67 if (err) 68 return err; 69 70 if (header == cpu_to_be32(OF_DT_HEADER)) 71 image->arch.kernel_r2 = current_segment->mem; 72 } 73 return 0; 74 } 75 76 void machine_kexec_cleanup(struct kimage *image) 77 { 78 } 79 80 void machine_crash_nonpanic_core(void *unused) 81 { 82 struct pt_regs regs; 83 84 crash_setup_regs(®s, get_irq_regs()); 85 printk(KERN_DEBUG "CPU %u will stop doing anything useful since another CPU has crashed\n", 86 smp_processor_id()); 87 crash_save_cpu(®s, smp_processor_id()); 88 flush_cache_all(); 89 90 set_cpu_online(smp_processor_id(), false); 91 atomic_dec(&waiting_for_crash_ipi); 92 93 while (1) { 94 cpu_relax(); 95 wfe(); 96 } 97 } 98 99 void crash_smp_send_stop(void) 100 { 101 static int cpus_stopped; 102 unsigned long msecs; 103 104 if (cpus_stopped) 105 return; 106 107 atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1); 108 smp_call_function(machine_crash_nonpanic_core, NULL, false); 109 msecs = 1000; /* Wait at most a second for the other cpus to stop */ 110 while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) { 111 mdelay(1); 112 msecs--; 113 } 114 if (atomic_read(&waiting_for_crash_ipi) > 0) 115 pr_warn("Non-crashing CPUs did not react to IPI\n"); 116 117 cpus_stopped = 1; 118 } 119 120 static void machine_kexec_mask_interrupts(void) 121 { 122 unsigned int i; 123 struct irq_desc *desc; 124 125 for_each_irq_desc(i, desc) { 126 struct irq_chip *chip; 127 128 chip = irq_desc_get_chip(desc); 129 if (!chip) 130 continue; 131 132 if (chip->irq_eoi && irqd_irq_inprogress(&desc->irq_data)) 133 chip->irq_eoi(&desc->irq_data); 134 135 if (chip->irq_mask) 136 chip->irq_mask(&desc->irq_data); 137 138 if (chip->irq_disable && !irqd_irq_disabled(&desc->irq_data)) 139 chip->irq_disable(&desc->irq_data); 140 } 141 } 142 143 void machine_crash_shutdown(struct pt_regs *regs) 144 { 145 local_irq_disable(); 146 crash_smp_send_stop(); 147 148 crash_save_cpu(regs, smp_processor_id()); 149 machine_kexec_mask_interrupts(); 150 151 pr_info("Loading crashdump kernel...\n"); 152 } 153 154 /* 155 * Function pointer to optional machine-specific reinitialization 156 */ 157 void (*kexec_reinit)(void); 158 159 void machine_kexec(struct kimage *image) 160 { 161 unsigned long page_list, reboot_entry_phys; 162 void (*reboot_entry)(void); 163 void *reboot_code_buffer; 164 165 /* 166 * This can only happen if machine_shutdown() failed to disable some 167 * CPU, and that can only happen if the checks in 168 * machine_kexec_prepare() were not correct. If this fails, we can't 169 * reliably kexec anyway, so BUG_ON is appropriate. 170 */ 171 BUG_ON(num_online_cpus() > 1); 172 173 page_list = image->head & PAGE_MASK; 174 175 reboot_code_buffer = page_address(image->control_code_page); 176 177 /* Prepare parameters for reboot_code_buffer*/ 178 set_kernel_text_rw(); 179 kexec_start_address = image->start; 180 kexec_indirection_page = page_list; 181 kexec_mach_type = machine_arch_type; 182 kexec_boot_atags = image->arch.kernel_r2; 183 184 /* copy our kernel relocation code to the control code page */ 185 reboot_entry = fncpy(reboot_code_buffer, 186 &relocate_new_kernel, 187 relocate_new_kernel_size); 188 189 /* get the identity mapping physical address for the reboot code */ 190 reboot_entry_phys = virt_to_idmap(reboot_entry); 191 192 pr_info("Bye!\n"); 193 194 if (kexec_reinit) 195 kexec_reinit(); 196 197 soft_restart(reboot_entry_phys); 198 } 199 200 void arch_crash_save_vmcoreinfo(void) 201 { 202 #ifdef CONFIG_ARM_LPAE 203 VMCOREINFO_CONFIG(ARM_LPAE); 204 #endif 205 } 206