1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright IBM Corp. 2005, 2011 4 * 5 * Author(s): Rolf Adelsberger, 6 * Heiko Carstens <heiko.carstens@de.ibm.com> 7 * Michael Holzheu <holzheu@linux.vnet.ibm.com> 8 */ 9 10 #include <linux/device.h> 11 #include <linux/mm.h> 12 #include <linux/kexec.h> 13 #include <linux/delay.h> 14 #include <linux/reboot.h> 15 #include <linux/ftrace.h> 16 #include <linux/debug_locks.h> 17 #include <linux/suspend.h> 18 #include <asm/cio.h> 19 #include <asm/setup.h> 20 #include <asm/pgtable.h> 21 #include <asm/pgalloc.h> 22 #include <asm/smp.h> 23 #include <asm/ipl.h> 24 #include <asm/diag.h> 25 #include <asm/elf.h> 26 #include <asm/asm-offsets.h> 27 #include <asm/cacheflush.h> 28 #include <asm/os_info.h> 29 #include <asm/set_memory.h> 30 #include <asm/stacktrace.h> 31 #include <asm/switch_to.h> 32 #include <asm/nmi.h> 33 34 typedef void (*relocate_kernel_t)(kimage_entry_t *, unsigned long); 35 36 extern const unsigned char relocate_kernel[]; 37 extern const unsigned long long relocate_kernel_len; 38 39 #ifdef CONFIG_CRASH_DUMP 40 41 /* 42 * PM notifier callback for kdump 43 */ 44 static int machine_kdump_pm_cb(struct notifier_block *nb, unsigned long action, 45 void *ptr) 46 { 47 switch (action) { 48 case PM_SUSPEND_PREPARE: 49 case PM_HIBERNATION_PREPARE: 50 if (kexec_crash_image) 51 arch_kexec_unprotect_crashkres(); 52 break; 53 case PM_POST_SUSPEND: 54 case PM_POST_HIBERNATION: 55 if (kexec_crash_image) 56 arch_kexec_protect_crashkres(); 57 break; 58 default: 59 return NOTIFY_DONE; 60 } 61 return NOTIFY_OK; 62 } 63 64 static int __init machine_kdump_pm_init(void) 65 { 66 pm_notifier(machine_kdump_pm_cb, 0); 67 return 0; 68 } 69 arch_initcall(machine_kdump_pm_init); 70 71 /* 72 * Reset the system, copy boot CPU registers to absolute zero, 73 * and jump to the kdump image 74 */ 75 static void __do_machine_kdump(void *image) 76 { 77 int (*start_kdump)(int); 78 unsigned long prefix; 79 80 /* store_status() saved the prefix register to lowcore */ 81 prefix = (unsigned long) S390_lowcore.prefixreg_save_area; 82 83 /* Now do the reset */ 84 s390_reset_system(); 85 86 /* 87 * Copy dump CPU store status info to absolute zero. 88 * This need to be done *after* s390_reset_system set the 89 * prefix register of this CPU to zero 90 */ 91 memcpy((void *) __LC_FPREGS_SAVE_AREA, 92 (void *)(prefix + __LC_FPREGS_SAVE_AREA), 512); 93 94 __load_psw_mask(PSW_MASK_BASE | PSW_DEFAULT_KEY | PSW_MASK_EA | PSW_MASK_BA); 95 start_kdump = (void *)((struct kimage *) image)->start; 96 start_kdump(1); 97 98 /* Die if start_kdump returns */ 99 disabled_wait(); 100 } 101 102 /* 103 * Start kdump: create a LGR log entry, store status of all CPUs and 104 * branch to __do_machine_kdump. 105 */ 106 static noinline void __machine_kdump(void *image) 107 { 108 struct mcesa *mcesa; 109 union ctlreg2 cr2_old, cr2_new; 110 int this_cpu, cpu; 111 112 lgr_info_log(); 113 /* Get status of the other CPUs */ 114 this_cpu = smp_find_processor_id(stap()); 115 for_each_online_cpu(cpu) { 116 if (cpu == this_cpu) 117 continue; 118 if (smp_store_status(cpu)) 119 continue; 120 } 121 /* Store status of the boot CPU */ 122 mcesa = (struct mcesa *)(S390_lowcore.mcesad & MCESA_ORIGIN_MASK); 123 if (MACHINE_HAS_VX) 124 save_vx_regs((__vector128 *) mcesa->vector_save_area); 125 if (MACHINE_HAS_GS) { 126 __ctl_store(cr2_old.val, 2, 2); 127 cr2_new = cr2_old; 128 cr2_new.gse = 1; 129 __ctl_load(cr2_new.val, 2, 2); 130 save_gs_cb((struct gs_cb *) mcesa->guarded_storage_save_area); 131 __ctl_load(cr2_old.val, 2, 2); 132 } 133 /* 134 * To create a good backchain for this CPU in the dump store_status 135 * is passed the address of a function. The address is saved into 136 * the PSW save area of the boot CPU and the function is invoked as 137 * a tail call of store_status. The backchain in the dump will look 138 * like this: 139 * restart_int_handler -> __machine_kexec -> __do_machine_kdump 140 * The call to store_status() will not return. 141 */ 142 store_status(__do_machine_kdump, image); 143 } 144 #endif 145 146 static unsigned long do_start_kdump(unsigned long addr) 147 { 148 struct kimage *image = (struct kimage *) addr; 149 int (*start_kdump)(int) = (void *)image->start; 150 int rc; 151 152 __arch_local_irq_stnsm(0xfb); /* disable DAT */ 153 rc = start_kdump(0); 154 __arch_local_irq_stosm(0x04); /* enable DAT */ 155 return rc; 156 } 157 158 /* 159 * Check if kdump checksums are valid: We call purgatory with parameter "0" 160 */ 161 static bool kdump_csum_valid(struct kimage *image) 162 { 163 #ifdef CONFIG_CRASH_DUMP 164 int rc; 165 166 rc = CALL_ON_STACK(do_start_kdump, S390_lowcore.nodat_stack, 1, image); 167 return rc == 0; 168 #else 169 return false; 170 #endif 171 } 172 173 #ifdef CONFIG_CRASH_DUMP 174 175 void crash_free_reserved_phys_range(unsigned long begin, unsigned long end) 176 { 177 unsigned long addr, size; 178 179 for (addr = begin; addr < end; addr += PAGE_SIZE) 180 free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT)); 181 size = begin - crashk_res.start; 182 if (size) 183 os_info_crashkernel_add(crashk_res.start, size); 184 else 185 os_info_crashkernel_add(0, 0); 186 } 187 188 static void crash_protect_pages(int protect) 189 { 190 unsigned long size; 191 192 if (!crashk_res.end) 193 return; 194 size = resource_size(&crashk_res); 195 if (protect) 196 set_memory_ro(crashk_res.start, size >> PAGE_SHIFT); 197 else 198 set_memory_rw(crashk_res.start, size >> PAGE_SHIFT); 199 } 200 201 void arch_kexec_protect_crashkres(void) 202 { 203 crash_protect_pages(1); 204 } 205 206 void arch_kexec_unprotect_crashkres(void) 207 { 208 crash_protect_pages(0); 209 } 210 211 #endif 212 213 /* 214 * Give back memory to hypervisor before new kdump is loaded 215 */ 216 static int machine_kexec_prepare_kdump(void) 217 { 218 #ifdef CONFIG_CRASH_DUMP 219 if (MACHINE_IS_VM) 220 diag10_range(PFN_DOWN(crashk_res.start), 221 PFN_DOWN(crashk_res.end - crashk_res.start + 1)); 222 return 0; 223 #else 224 return -EINVAL; 225 #endif 226 } 227 228 int machine_kexec_prepare(struct kimage *image) 229 { 230 void *reboot_code_buffer; 231 232 if (image->type == KEXEC_TYPE_CRASH) 233 return machine_kexec_prepare_kdump(); 234 235 /* We don't support anything but the default image type for now. */ 236 if (image->type != KEXEC_TYPE_DEFAULT) 237 return -EINVAL; 238 239 /* Get the destination where the assembler code should be copied to.*/ 240 reboot_code_buffer = (void *) page_to_phys(image->control_code_page); 241 242 /* Then copy it */ 243 memcpy(reboot_code_buffer, relocate_kernel, relocate_kernel_len); 244 return 0; 245 } 246 247 void machine_kexec_cleanup(struct kimage *image) 248 { 249 } 250 251 void arch_crash_save_vmcoreinfo(void) 252 { 253 VMCOREINFO_SYMBOL(lowcore_ptr); 254 VMCOREINFO_SYMBOL(high_memory); 255 VMCOREINFO_LENGTH(lowcore_ptr, NR_CPUS); 256 mem_assign_absolute(S390_lowcore.vmcore_info, paddr_vmcoreinfo_note()); 257 vmcoreinfo_append_str("SDMA=%lx\n", __sdma); 258 vmcoreinfo_append_str("EDMA=%lx\n", __edma); 259 vmcoreinfo_append_str("KERNELOFFSET=%lx\n", kaslr_offset()); 260 } 261 262 void machine_shutdown(void) 263 { 264 } 265 266 void machine_crash_shutdown(struct pt_regs *regs) 267 { 268 set_os_info_reipl_block(); 269 } 270 271 /* 272 * Do normal kexec 273 */ 274 static void __do_machine_kexec(void *data) 275 { 276 relocate_kernel_t data_mover; 277 struct kimage *image = data; 278 279 s390_reset_system(); 280 data_mover = (relocate_kernel_t) page_to_phys(image->control_code_page); 281 282 __arch_local_irq_stnsm(0xfb); /* disable DAT - avoid no-execute */ 283 /* Call the moving routine */ 284 (*data_mover)(&image->head, image->start); 285 286 /* Die if kexec returns */ 287 disabled_wait(); 288 } 289 290 /* 291 * Reset system and call either kdump or normal kexec 292 */ 293 static void __machine_kexec(void *data) 294 { 295 __arch_local_irq_stosm(0x04); /* enable DAT */ 296 pfault_fini(); 297 tracing_off(); 298 debug_locks_off(); 299 #ifdef CONFIG_CRASH_DUMP 300 if (((struct kimage *) data)->type == KEXEC_TYPE_CRASH) 301 __machine_kdump(data); 302 #endif 303 __do_machine_kexec(data); 304 } 305 306 /* 307 * Do either kdump or normal kexec. In case of kdump we first ask 308 * purgatory, if kdump checksums are valid. 309 */ 310 void machine_kexec(struct kimage *image) 311 { 312 if (image->type == KEXEC_TYPE_CRASH && !kdump_csum_valid(image)) 313 return; 314 tracer_disable(); 315 smp_send_stop(); 316 smp_call_ipl_cpu(__machine_kexec, image); 317 } 318