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 <asm/guarded_storage.h> 17 #include <asm/pfault.h> 18 #include <asm/cio.h> 19 #include <asm/fpu.h> 20 #include <asm/setup.h> 21 #include <asm/smp.h> 22 #include <asm/ipl.h> 23 #include <asm/diag.h> 24 #include <asm/elf.h> 25 #include <asm/asm-offsets.h> 26 #include <asm/cacheflush.h> 27 #include <asm/abs_lowcore.h> 28 #include <asm/os_info.h> 29 #include <asm/set_memory.h> 30 #include <asm/stacktrace.h> 31 #include <asm/nmi.h> 32 #include <asm/sclp.h> 33 34 typedef void (*relocate_kernel_t)(unsigned long, unsigned long, unsigned long); 35 typedef int (*purgatory_t)(int); 36 37 extern const unsigned char relocate_kernel[]; 38 extern const unsigned long long relocate_kernel_len; 39 40 #ifdef CONFIG_CRASH_DUMP 41 42 /* 43 * Reset the system, copy boot CPU registers to absolute zero, 44 * and jump to the kdump image 45 */ 46 static void __do_machine_kdump(void *data) 47 { 48 struct kimage *image = data; 49 purgatory_t purgatory; 50 unsigned long prefix; 51 52 purgatory = (purgatory_t)image->start; 53 54 /* store_status() saved the prefix register to lowcore */ 55 prefix = (unsigned long) S390_lowcore.prefixreg_save_area; 56 57 /* Now do the reset */ 58 s390_reset_system(); 59 60 /* 61 * Copy dump CPU store status info to absolute zero. 62 * This need to be done *after* s390_reset_system set the 63 * prefix register of this CPU to zero 64 */ 65 memcpy(absolute_pointer(__LC_FPREGS_SAVE_AREA), 66 phys_to_virt(prefix + __LC_FPREGS_SAVE_AREA), 512); 67 68 call_nodat(1, int, purgatory, int, 1); 69 70 /* Die if kdump returns */ 71 disabled_wait(); 72 } 73 74 /* 75 * Start kdump: create a LGR log entry, store status of all CPUs and 76 * branch to __do_machine_kdump. 77 */ 78 static noinline void __machine_kdump(void *image) 79 { 80 struct mcesa *mcesa; 81 union ctlreg2 cr2_old, cr2_new; 82 int this_cpu, cpu; 83 84 lgr_info_log(); 85 /* Get status of the other CPUs */ 86 this_cpu = smp_find_processor_id(stap()); 87 for_each_online_cpu(cpu) { 88 if (cpu == this_cpu) 89 continue; 90 if (smp_store_status(cpu)) 91 continue; 92 } 93 /* Store status of the boot CPU */ 94 mcesa = __va(S390_lowcore.mcesad & MCESA_ORIGIN_MASK); 95 if (cpu_has_vx()) 96 save_vx_regs((__vector128 *) mcesa->vector_save_area); 97 if (MACHINE_HAS_GS) { 98 local_ctl_store(2, &cr2_old.reg); 99 cr2_new = cr2_old; 100 cr2_new.gse = 1; 101 local_ctl_load(2, &cr2_new.reg); 102 save_gs_cb((struct gs_cb *) mcesa->guarded_storage_save_area); 103 local_ctl_load(2, &cr2_old.reg); 104 } 105 /* 106 * To create a good backchain for this CPU in the dump store_status 107 * is passed the address of a function. The address is saved into 108 * the PSW save area of the boot CPU and the function is invoked as 109 * a tail call of store_status. The backchain in the dump will look 110 * like this: 111 * restart_int_handler -> __machine_kexec -> __do_machine_kdump 112 * The call to store_status() will not return. 113 */ 114 store_status(__do_machine_kdump, image); 115 } 116 117 #endif /* CONFIG_CRASH_DUMP */ 118 119 /* 120 * Check if kdump checksums are valid: We call purgatory with parameter "0" 121 */ 122 static bool kdump_csum_valid(struct kimage *image) 123 { 124 #ifdef CONFIG_CRASH_DUMP 125 purgatory_t purgatory = (purgatory_t)image->start; 126 int rc; 127 128 rc = call_nodat(1, int, purgatory, int, 0); 129 return rc == 0; 130 #else 131 return false; 132 #endif 133 } 134 135 #ifdef CONFIG_CRASH_DUMP 136 137 void crash_free_reserved_phys_range(unsigned long begin, unsigned long end) 138 { 139 unsigned long addr, size; 140 141 for (addr = begin; addr < end; addr += PAGE_SIZE) 142 free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT)); 143 size = begin - crashk_res.start; 144 if (size) 145 os_info_crashkernel_add(crashk_res.start, size); 146 else 147 os_info_crashkernel_add(0, 0); 148 } 149 150 static void crash_protect_pages(int protect) 151 { 152 unsigned long size; 153 154 if (!crashk_res.end) 155 return; 156 size = resource_size(&crashk_res); 157 if (protect) 158 set_memory_ro(crashk_res.start, size >> PAGE_SHIFT); 159 else 160 set_memory_rw(crashk_res.start, size >> PAGE_SHIFT); 161 } 162 163 void arch_kexec_protect_crashkres(void) 164 { 165 crash_protect_pages(1); 166 } 167 168 void arch_kexec_unprotect_crashkres(void) 169 { 170 crash_protect_pages(0); 171 } 172 173 #endif 174 175 /* 176 * Give back memory to hypervisor before new kdump is loaded 177 */ 178 static int machine_kexec_prepare_kdump(void) 179 { 180 #ifdef CONFIG_CRASH_DUMP 181 if (MACHINE_IS_VM) 182 diag10_range(PFN_DOWN(crashk_res.start), 183 PFN_DOWN(crashk_res.end - crashk_res.start + 1)); 184 return 0; 185 #else 186 return -EINVAL; 187 #endif 188 } 189 190 int machine_kexec_prepare(struct kimage *image) 191 { 192 void *reboot_code_buffer; 193 194 if (image->type == KEXEC_TYPE_CRASH) 195 return machine_kexec_prepare_kdump(); 196 197 /* We don't support anything but the default image type for now. */ 198 if (image->type != KEXEC_TYPE_DEFAULT) 199 return -EINVAL; 200 201 /* Get the destination where the assembler code should be copied to.*/ 202 reboot_code_buffer = page_to_virt(image->control_code_page); 203 204 /* Then copy it */ 205 memcpy(reboot_code_buffer, relocate_kernel, relocate_kernel_len); 206 return 0; 207 } 208 209 void machine_kexec_cleanup(struct kimage *image) 210 { 211 } 212 213 void arch_crash_save_vmcoreinfo(void) 214 { 215 struct lowcore *abs_lc; 216 217 VMCOREINFO_SYMBOL(lowcore_ptr); 218 VMCOREINFO_SYMBOL(high_memory); 219 VMCOREINFO_LENGTH(lowcore_ptr, NR_CPUS); 220 vmcoreinfo_append_str("SAMODE31=%lx\n", (unsigned long)__samode31); 221 vmcoreinfo_append_str("EAMODE31=%lx\n", (unsigned long)__eamode31); 222 vmcoreinfo_append_str("KERNELOFFSET=%lx\n", kaslr_offset()); 223 abs_lc = get_abs_lowcore(); 224 abs_lc->vmcore_info = paddr_vmcoreinfo_note(); 225 put_abs_lowcore(abs_lc); 226 } 227 228 void machine_shutdown(void) 229 { 230 } 231 232 void machine_crash_shutdown(struct pt_regs *regs) 233 { 234 set_os_info_reipl_block(); 235 } 236 237 /* 238 * Do normal kexec 239 */ 240 static void __do_machine_kexec(void *data) 241 { 242 unsigned long data_mover, entry, diag308_subcode; 243 struct kimage *image = data; 244 245 data_mover = page_to_phys(image->control_code_page); 246 entry = virt_to_phys(&image->head); 247 diag308_subcode = DIAG308_CLEAR_RESET; 248 if (sclp.has_iplcc) 249 diag308_subcode |= DIAG308_FLAG_EI; 250 s390_reset_system(); 251 252 call_nodat(3, void, (relocate_kernel_t)data_mover, 253 unsigned long, entry, 254 unsigned long, image->start, 255 unsigned long, diag308_subcode); 256 257 /* Die if kexec returns */ 258 disabled_wait(); 259 } 260 261 /* 262 * Reset system and call either kdump or normal kexec 263 */ 264 static void __machine_kexec(void *data) 265 { 266 pfault_fini(); 267 tracing_off(); 268 debug_locks_off(); 269 #ifdef CONFIG_CRASH_DUMP 270 if (((struct kimage *) data)->type == KEXEC_TYPE_CRASH) 271 __machine_kdump(data); 272 #endif 273 __do_machine_kexec(data); 274 } 275 276 /* 277 * Do either kdump or normal kexec. In case of kdump we first ask 278 * purgatory, if kdump checksums are valid. 279 */ 280 void machine_kexec(struct kimage *image) 281 { 282 if (image->type == KEXEC_TYPE_CRASH && !kdump_csum_valid(image)) 283 return; 284 tracer_disable(); 285 smp_send_stop(); 286 smp_call_ipl_cpu(__machine_kexec, image); 287 } 288