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