1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2019 FORTH-ICS/CARV 4 * Nick Kossifidis <mick@ics.forth.gr> 5 */ 6 7 #include <linux/kexec.h> 8 #include <asm/kexec.h> /* For riscv_kexec_* symbol defines */ 9 #include <linux/smp.h> /* For smp_send_stop () */ 10 #include <asm/cacheflush.h> /* For local_flush_icache_all() */ 11 #include <asm/barrier.h> /* For smp_wmb() */ 12 #include <asm/page.h> /* For PAGE_MASK */ 13 #include <linux/libfdt.h> /* For fdt_check_header() */ 14 #include <asm/set_memory.h> /* For set_memory_x() */ 15 #include <linux/compiler.h> /* For unreachable() */ 16 #include <linux/cpu.h> /* For cpu_down() */ 17 #include <linux/reboot.h> 18 19 /* 20 * kexec_image_info - Print received image details 21 */ 22 static void 23 kexec_image_info(const struct kimage *image) 24 { 25 unsigned long i; 26 27 pr_debug("Kexec image info:\n"); 28 pr_debug("\ttype: %d\n", image->type); 29 pr_debug("\tstart: %lx\n", image->start); 30 pr_debug("\thead: %lx\n", image->head); 31 pr_debug("\tnr_segments: %lu\n", image->nr_segments); 32 33 for (i = 0; i < image->nr_segments; i++) { 34 pr_debug("\t segment[%lu]: %016lx - %016lx", i, 35 image->segment[i].mem, 36 image->segment[i].mem + image->segment[i].memsz); 37 pr_debug("\t\t0x%lx bytes, %lu pages\n", 38 (unsigned long) image->segment[i].memsz, 39 (unsigned long) image->segment[i].memsz / PAGE_SIZE); 40 } 41 } 42 43 /* 44 * machine_kexec_prepare - Initialize kexec 45 * 46 * This function is called from do_kexec_load, when the user has 47 * provided us with an image to be loaded. Its goal is to validate 48 * the image and prepare the control code buffer as needed. 49 * Note that kimage_alloc_init has already been called and the 50 * control buffer has already been allocated. 51 */ 52 int 53 machine_kexec_prepare(struct kimage *image) 54 { 55 struct kimage_arch *internal = &image->arch; 56 struct fdt_header fdt = {0}; 57 void *control_code_buffer = NULL; 58 unsigned int control_code_buffer_sz = 0; 59 int i = 0; 60 61 kexec_image_info(image); 62 63 /* Find the Flattened Device Tree and save its physical address */ 64 for (i = 0; i < image->nr_segments; i++) { 65 if (image->segment[i].memsz <= sizeof(fdt)) 66 continue; 67 68 if (copy_from_user(&fdt, image->segment[i].buf, sizeof(fdt))) 69 continue; 70 71 if (fdt_check_header(&fdt)) 72 continue; 73 74 internal->fdt_addr = (unsigned long) image->segment[i].mem; 75 break; 76 } 77 78 if (!internal->fdt_addr) { 79 pr_err("Device tree not included in the provided image\n"); 80 return -EINVAL; 81 } 82 83 /* Copy the assembler code for relocation to the control page */ 84 if (image->type != KEXEC_TYPE_CRASH) { 85 control_code_buffer = page_address(image->control_code_page); 86 control_code_buffer_sz = page_size(image->control_code_page); 87 88 if (unlikely(riscv_kexec_relocate_size > control_code_buffer_sz)) { 89 pr_err("Relocation code doesn't fit within a control page\n"); 90 return -EINVAL; 91 } 92 93 memcpy(control_code_buffer, riscv_kexec_relocate, 94 riscv_kexec_relocate_size); 95 96 /* Mark the control page executable */ 97 set_memory_x((unsigned long) control_code_buffer, 1); 98 } 99 100 return 0; 101 } 102 103 104 /* 105 * machine_kexec_cleanup - Cleanup any leftovers from 106 * machine_kexec_prepare 107 * 108 * This function is called by kimage_free to handle any arch-specific 109 * allocations done on machine_kexec_prepare. Since we didn't do any 110 * allocations there, this is just an empty function. Note that the 111 * control buffer is freed by kimage_free. 112 */ 113 void 114 machine_kexec_cleanup(struct kimage *image) 115 { 116 } 117 118 119 /* 120 * machine_shutdown - Prepare for a kexec reboot 121 * 122 * This function is called by kernel_kexec just before machine_kexec 123 * below. Its goal is to prepare the rest of the system (the other 124 * harts and possibly devices etc) for a kexec reboot. 125 */ 126 void machine_shutdown(void) 127 { 128 /* 129 * No more interrupts on this hart 130 * until we are back up. 131 */ 132 local_irq_disable(); 133 134 #if defined(CONFIG_HOTPLUG_CPU) 135 smp_shutdown_nonboot_cpus(smp_processor_id()); 136 #endif 137 } 138 139 /* 140 * machine_crash_shutdown - Prepare to kexec after a kernel crash 141 * 142 * This function is called by crash_kexec just before machine_kexec 143 * below and its goal is similar to machine_shutdown, but in case of 144 * a kernel crash. Since we don't handle such cases yet, this function 145 * is empty. 146 */ 147 void 148 machine_crash_shutdown(struct pt_regs *regs) 149 { 150 crash_save_cpu(regs, smp_processor_id()); 151 machine_shutdown(); 152 pr_info("Starting crashdump kernel...\n"); 153 } 154 155 /* 156 * machine_kexec - Jump to the loaded kimage 157 * 158 * This function is called by kernel_kexec which is called by the 159 * reboot system call when the reboot cmd is LINUX_REBOOT_CMD_KEXEC, 160 * or by crash_kernel which is called by the kernel's arch-specific 161 * trap handler in case of a kernel panic. It's the final stage of 162 * the kexec process where the pre-loaded kimage is ready to be 163 * executed. We assume at this point that all other harts are 164 * suspended and this hart will be the new boot hart. 165 */ 166 void __noreturn 167 machine_kexec(struct kimage *image) 168 { 169 struct kimage_arch *internal = &image->arch; 170 unsigned long jump_addr = (unsigned long) image->start; 171 unsigned long first_ind_entry = (unsigned long) &image->head; 172 unsigned long this_cpu_id = smp_processor_id(); 173 unsigned long this_hart_id = cpuid_to_hartid_map(this_cpu_id); 174 unsigned long fdt_addr = internal->fdt_addr; 175 void *control_code_buffer = page_address(image->control_code_page); 176 riscv_kexec_method kexec_method = NULL; 177 178 if (image->type != KEXEC_TYPE_CRASH) 179 kexec_method = control_code_buffer; 180 else 181 kexec_method = (riscv_kexec_method) &riscv_kexec_norelocate; 182 183 pr_notice("Will call new kernel at %08lx from hart id %lx\n", 184 jump_addr, this_hart_id); 185 pr_notice("FDT image at %08lx\n", fdt_addr); 186 187 /* Make sure the relocation code is visible to the hart */ 188 local_flush_icache_all(); 189 190 /* Jump to the relocation code */ 191 pr_notice("Bye...\n"); 192 kexec_method(first_ind_entry, jump_addr, fdt_addr, 193 this_hart_id, kernel_map.va_pa_offset); 194 unreachable(); 195 } 196