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