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)get_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(get_lowcore()->floating_pt_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(get_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 ""
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 machine_shutdown(void)
214 {
215 }
216
217 void machine_crash_shutdown(struct pt_regs *regs)
218 {
219 set_os_info_reipl_block();
220 }
221
222 /*
223 * Do normal kexec
224 */
225 static void __do_machine_kexec(void *data)
226 {
227 unsigned long data_mover, entry, diag308_subcode;
228 struct kimage *image = data;
229
230 data_mover = page_to_phys(image->control_code_page);
231 entry = virt_to_phys(&image->head);
232 diag308_subcode = DIAG308_CLEAR_RESET;
233 if (sclp.has_iplcc)
234 diag308_subcode |= DIAG308_FLAG_EI;
235 s390_reset_system();
236
237 call_nodat(3, void, (relocate_kernel_t)data_mover,
238 unsigned long, entry,
239 unsigned long, image->start,
240 unsigned long, diag308_subcode);
241
242 /* Die if kexec returns */
243 disabled_wait();
244 }
245
246 /*
247 * Reset system and call either kdump or normal kexec
248 */
249 static void __machine_kexec(void *data)
250 {
251 pfault_fini();
252 tracing_off();
253 debug_locks_off();
254 #ifdef CONFIG_CRASH_DUMP
255 if (((struct kimage *) data)->type == KEXEC_TYPE_CRASH)
256 __machine_kdump(data);
257 #endif
258 __do_machine_kexec(data);
259 }
260
261 /*
262 * Do either kdump or normal kexec. In case of kdump we first ask
263 * purgatory, if kdump checksums are valid.
264 */
265 void machine_kexec(struct kimage *image)
266 {
267 if (image->type == KEXEC_TYPE_CRASH && !kdump_csum_valid(image))
268 return;
269 tracer_disable();
270 smp_send_stop();
271 smp_call_ipl_cpu(__machine_kexec, image);
272 }
273
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