1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright IBM Corp. 2005, 2011 4 * 5 * Author(s): Rolf Adelsberger, 6 * Michael Holzheu <holzheu@linux.vnet.ibm.com> 7 */ 8 9 #include <linux/device.h> 10 #include <linux/mm.h> 11 #include <linux/kexec.h> 12 #include <linux/delay.h> 13 #include <linux/reboot.h> 14 #include <linux/ftrace.h> 15 #include <linux/debug_locks.h> 16 #include <linux/cpufeature.h> 17 #include <asm/guarded_storage.h> 18 #include <asm/machine.h> 19 #include <asm/pfault.h> 20 #include <asm/cio.h> 21 #include <asm/fpu.h> 22 #include <asm/setup.h> 23 #include <asm/smp.h> 24 #include <asm/ipl.h> 25 #include <asm/diag.h> 26 #include <asm/elf.h> 27 #include <asm/asm-offsets.h> 28 #include <asm/cacheflush.h> 29 #include <asm/abs_lowcore.h> 30 #include <asm/os_info.h> 31 #include <asm/set_memory.h> 32 #include <asm/stacktrace.h> 33 #include <asm/nmi.h> 34 #include <asm/sclp.h> 35 36 typedef void (*relocate_kernel_t)(unsigned long, unsigned long, unsigned long); 37 typedef int (*purgatory_t)(int); 38 39 extern const unsigned char relocate_kernel[]; 40 extern const unsigned long long relocate_kernel_len; 41 42 #ifdef CONFIG_CRASH_DUMP 43 44 /* 45 * Reset the system, copy boot CPU registers to absolute zero, 46 * and jump to the kdump image 47 */ 48 static void __do_machine_kdump(void *data) 49 { 50 struct kimage *image = data; 51 purgatory_t purgatory; 52 unsigned long prefix; 53 54 purgatory = (purgatory_t)image->start; 55 56 /* store_status() saved the prefix register to lowcore */ 57 prefix = (unsigned long)get_lowcore()->prefixreg_save_area; 58 59 /* Now do the reset */ 60 s390_reset_system(); 61 62 /* 63 * Copy dump CPU store status info to absolute zero. 64 * This need to be done *after* s390_reset_system set the 65 * prefix register of this CPU to zero 66 */ 67 memcpy(absolute_pointer(get_lowcore()->floating_pt_save_area), 68 phys_to_virt(prefix + __LC_FPREGS_SAVE_AREA), 512); 69 70 call_nodat(1, int, purgatory, int, 1); 71 72 /* Die if kdump returns */ 73 disabled_wait(); 74 } 75 76 /* 77 * Start kdump: create a LGR log entry, store status of all CPUs and 78 * branch to __do_machine_kdump. 79 */ 80 static noinline void __machine_kdump(void *image) 81 { 82 struct mcesa *mcesa; 83 union ctlreg2 cr2_old, cr2_new; 84 int this_cpu, cpu; 85 86 lgr_info_log(); 87 /* Get status of the other CPUs */ 88 this_cpu = smp_find_processor_id(stap()); 89 for_each_online_cpu(cpu) { 90 if (cpu == this_cpu) 91 continue; 92 if (smp_store_status(cpu)) 93 continue; 94 } 95 /* Store status of the boot CPU */ 96 mcesa = __va(get_lowcore()->mcesad & MCESA_ORIGIN_MASK); 97 if (cpu_has_vx()) 98 save_vx_regs((__vector128 *) mcesa->vector_save_area); 99 if (cpu_has_gs()) { 100 local_ctl_store(2, &cr2_old.reg); 101 cr2_new = cr2_old; 102 cr2_new.gse = 1; 103 local_ctl_load(2, &cr2_new.reg); 104 save_gs_cb((struct gs_cb *) mcesa->guarded_storage_save_area); 105 local_ctl_load(2, &cr2_old.reg); 106 } 107 /* 108 * To create a good backchain for this CPU in the dump store_status 109 * is passed the address of a function. The address is saved into 110 * the PSW save area of the boot CPU and the function is invoked as 111 * a tail call of store_status. The backchain in the dump will look 112 * like this: 113 * restart_int_handler -> __machine_kexec -> __do_machine_kdump 114 * The call to store_status() will not return. 115 */ 116 store_status(__do_machine_kdump, image); 117 } 118 119 #endif /* CONFIG_CRASH_DUMP */ 120 121 /* 122 * Check if kdump checksums are valid: We call purgatory with parameter "0" 123 */ 124 static bool kdump_csum_valid(struct kimage *image) 125 { 126 #ifdef CONFIG_CRASH_DUMP 127 purgatory_t purgatory = (purgatory_t)image->start; 128 int rc; 129 130 rc = call_nodat(1, int, purgatory, int, 0); 131 return rc == 0; 132 #else 133 return false; 134 #endif 135 } 136 137 #ifdef CONFIG_CRASH_DUMP 138 139 void crash_free_reserved_phys_range(unsigned long begin, unsigned long end) 140 { 141 unsigned long addr, size; 142 143 for (addr = begin; addr < end; addr += PAGE_SIZE) 144 free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT)); 145 size = begin - crashk_res.start; 146 if (size) 147 os_info_crashkernel_add(crashk_res.start, size); 148 else 149 os_info_crashkernel_add(0, 0); 150 } 151 152 static void crash_protect_pages(int protect) 153 { 154 unsigned long size; 155 156 if (!crashk_res.end) 157 return; 158 size = resource_size(&crashk_res); 159 if (protect) 160 set_memory_ro(crashk_res.start, size >> PAGE_SHIFT); 161 else 162 set_memory_rw(crashk_res.start, size >> PAGE_SHIFT); 163 } 164 165 void arch_kexec_protect_crashkres(void) 166 { 167 crash_protect_pages(1); 168 } 169 170 void arch_kexec_unprotect_crashkres(void) 171 { 172 crash_protect_pages(0); 173 } 174 175 #endif 176 177 /* 178 * Give back memory to hypervisor before new kdump is loaded 179 */ 180 static int machine_kexec_prepare_kdump(void) 181 { 182 #ifdef CONFIG_CRASH_DUMP 183 if (machine_is_vm()) 184 diag10_range(PFN_DOWN(crashk_res.start), 185 PFN_DOWN(crashk_res.end - crashk_res.start + 1)); 186 return 0; 187 #else 188 return -EINVAL; 189 #endif 190 } 191 192 int machine_kexec_prepare(struct kimage *image) 193 { 194 void *reboot_code_buffer; 195 196 if (image->type == KEXEC_TYPE_CRASH) 197 return machine_kexec_prepare_kdump(); 198 199 /* We don't support anything but the default image type for now. */ 200 if (image->type != KEXEC_TYPE_DEFAULT) 201 return -EINVAL; 202 203 /* Get the destination where the assembler code should be copied to.*/ 204 reboot_code_buffer = page_to_virt(image->control_code_page); 205 206 /* Then copy it */ 207 memcpy(reboot_code_buffer, relocate_kernel, relocate_kernel_len); 208 return 0; 209 } 210 211 void machine_kexec_cleanup(struct kimage *image) 212 { 213 } 214 215 void machine_shutdown(void) 216 { 217 } 218 219 void machine_crash_shutdown(struct pt_regs *regs) 220 { 221 set_os_info_reipl_block(); 222 } 223 224 /* 225 * Do normal kexec 226 */ 227 static void __do_machine_kexec(void *data) 228 { 229 unsigned long data_mover, entry, diag308_subcode; 230 struct kimage *image = data; 231 232 data_mover = page_to_phys(image->control_code_page); 233 entry = virt_to_phys(&image->head); 234 diag308_subcode = DIAG308_CLEAR_RESET; 235 if (sclp.has_iplcc) 236 diag308_subcode |= DIAG308_FLAG_EI; 237 s390_reset_system(); 238 239 call_nodat(3, void, (relocate_kernel_t)data_mover, 240 unsigned long, entry, 241 unsigned long, image->start, 242 unsigned long, diag308_subcode); 243 244 /* Die if kexec returns */ 245 disabled_wait(); 246 } 247 248 /* 249 * Reset system and call either kdump or normal kexec 250 */ 251 static void __machine_kexec(void *data) 252 { 253 pfault_fini(); 254 tracing_off(); 255 debug_locks_off(); 256 #ifdef CONFIG_CRASH_DUMP 257 if (((struct kimage *) data)->type == KEXEC_TYPE_CRASH) 258 __machine_kdump(data); 259 #endif 260 __do_machine_kexec(data); 261 } 262 263 /* 264 * Do either kdump or normal kexec. In case of kdump we first ask 265 * purgatory, if kdump checksums are valid. 266 */ 267 void machine_kexec(struct kimage *image) 268 { 269 if (image->type == KEXEC_TYPE_CRASH && !kdump_csum_valid(image)) 270 return; 271 tracer_disable(); 272 smp_send_stop(); 273 smp_call_ipl_cpu(__machine_kexec, image); 274 } 275