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 <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/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
31 typedef void (*relocate_kernel_t)(kimage_entry_t *, unsigned long);
32
33 extern const unsigned char relocate_kernel[];
34 extern const unsigned long long relocate_kernel_len;
35
36 #ifdef CONFIG_CRASH_DUMP
37
38 /*
39 * Reset the system, copy boot CPU registers to absolute zero,
40 * and jump to the kdump image
41 */
__do_machine_kdump(void * image)42 static void __do_machine_kdump(void *image)
43 {
44 int (*start_kdump)(int);
45 unsigned long prefix;
46
47 /* store_status() saved the prefix register to lowcore */
48 prefix = (unsigned long) S390_lowcore.prefixreg_save_area;
49
50 /* Now do the reset */
51 s390_reset_system();
52
53 /*
54 * Copy dump CPU store status info to absolute zero.
55 * This need to be done *after* s390_reset_system set the
56 * prefix register of this CPU to zero
57 */
58 memcpy((void *) __LC_FPREGS_SAVE_AREA,
59 (void *)(prefix + __LC_FPREGS_SAVE_AREA), 512);
60
61 __load_psw_mask(PSW_MASK_BASE | PSW_DEFAULT_KEY | PSW_MASK_EA | PSW_MASK_BA);
62 start_kdump = (void *)((struct kimage *) image)->start;
63 start_kdump(1);
64
65 /* Die if start_kdump returns */
66 disabled_wait();
67 }
68
69 /*
70 * Start kdump: create a LGR log entry, store status of all CPUs and
71 * branch to __do_machine_kdump.
72 */
__machine_kdump(void * image)73 static noinline void __machine_kdump(void *image)
74 {
75 struct mcesa *mcesa;
76 union ctlreg2 cr2_old, cr2_new;
77 int this_cpu, cpu;
78
79 lgr_info_log();
80 /* Get status of the other CPUs */
81 this_cpu = smp_find_processor_id(stap());
82 for_each_online_cpu(cpu) {
83 if (cpu == this_cpu)
84 continue;
85 if (smp_store_status(cpu))
86 continue;
87 }
88 /* Store status of the boot CPU */
89 mcesa = (struct mcesa *)(S390_lowcore.mcesad & MCESA_ORIGIN_MASK);
90 if (MACHINE_HAS_VX)
91 save_vx_regs((__vector128 *) mcesa->vector_save_area);
92 if (MACHINE_HAS_GS) {
93 __ctl_store(cr2_old.val, 2, 2);
94 cr2_new = cr2_old;
95 cr2_new.gse = 1;
96 __ctl_load(cr2_new.val, 2, 2);
97 save_gs_cb((struct gs_cb *) mcesa->guarded_storage_save_area);
98 __ctl_load(cr2_old.val, 2, 2);
99 }
100 /*
101 * To create a good backchain for this CPU in the dump store_status
102 * is passed the address of a function. The address is saved into
103 * the PSW save area of the boot CPU and the function is invoked as
104 * a tail call of store_status. The backchain in the dump will look
105 * like this:
106 * restart_int_handler -> __machine_kexec -> __do_machine_kdump
107 * The call to store_status() will not return.
108 */
109 store_status(__do_machine_kdump, image);
110 }
111
do_start_kdump(unsigned long addr)112 static unsigned long do_start_kdump(unsigned long addr)
113 {
114 struct kimage *image = (struct kimage *) addr;
115 int (*start_kdump)(int) = (void *)image->start;
116 int rc;
117
118 __arch_local_irq_stnsm(0xfb); /* disable DAT */
119 rc = start_kdump(0);
120 __arch_local_irq_stosm(0x04); /* enable DAT */
121 return rc;
122 }
123
124 #endif /* CONFIG_CRASH_DUMP */
125
126 /*
127 * Check if kdump checksums are valid: We call purgatory with parameter "0"
128 */
kdump_csum_valid(struct kimage * image)129 static bool kdump_csum_valid(struct kimage *image)
130 {
131 #ifdef CONFIG_CRASH_DUMP
132 int rc;
133
134 preempt_disable();
135 rc = call_on_stack(1, S390_lowcore.nodat_stack, unsigned long, do_start_kdump,
136 unsigned long, (unsigned long)image);
137 preempt_enable();
138 return rc == 0;
139 #else
140 return false;
141 #endif
142 }
143
144 #ifdef CONFIG_CRASH_DUMP
145
crash_free_reserved_phys_range(unsigned long begin,unsigned long end)146 void crash_free_reserved_phys_range(unsigned long begin, unsigned long end)
147 {
148 unsigned long addr, size;
149
150 for (addr = begin; addr < end; addr += PAGE_SIZE)
151 free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT));
152 size = begin - crashk_res.start;
153 if (size)
154 os_info_crashkernel_add(crashk_res.start, size);
155 else
156 os_info_crashkernel_add(0, 0);
157 }
158
crash_protect_pages(int protect)159 static void crash_protect_pages(int protect)
160 {
161 unsigned long size;
162
163 if (!crashk_res.end)
164 return;
165 size = resource_size(&crashk_res);
166 if (protect)
167 set_memory_ro(crashk_res.start, size >> PAGE_SHIFT);
168 else
169 set_memory_rw(crashk_res.start, size >> PAGE_SHIFT);
170 }
171
arch_kexec_protect_crashkres(void)172 void arch_kexec_protect_crashkres(void)
173 {
174 crash_protect_pages(1);
175 }
176
arch_kexec_unprotect_crashkres(void)177 void arch_kexec_unprotect_crashkres(void)
178 {
179 crash_protect_pages(0);
180 }
181
182 #endif
183
184 /*
185 * Give back memory to hypervisor before new kdump is loaded
186 */
machine_kexec_prepare_kdump(void)187 static int machine_kexec_prepare_kdump(void)
188 {
189 #ifdef CONFIG_CRASH_DUMP
190 if (MACHINE_IS_VM)
191 diag10_range(PFN_DOWN(crashk_res.start),
192 PFN_DOWN(crashk_res.end - crashk_res.start + 1));
193 return 0;
194 #else
195 return -EINVAL;
196 #endif
197 }
198
machine_kexec_prepare(struct kimage * image)199 int machine_kexec_prepare(struct kimage *image)
200 {
201 void *reboot_code_buffer;
202
203 if (image->type == KEXEC_TYPE_CRASH)
204 return machine_kexec_prepare_kdump();
205
206 /* We don't support anything but the default image type for now. */
207 if (image->type != KEXEC_TYPE_DEFAULT)
208 return -EINVAL;
209
210 /* Get the destination where the assembler code should be copied to.*/
211 reboot_code_buffer = (void *) page_to_phys(image->control_code_page);
212
213 /* Then copy it */
214 memcpy(reboot_code_buffer, relocate_kernel, relocate_kernel_len);
215 return 0;
216 }
217
machine_kexec_cleanup(struct kimage * image)218 void machine_kexec_cleanup(struct kimage *image)
219 {
220 }
221
arch_crash_save_vmcoreinfo(void)222 void arch_crash_save_vmcoreinfo(void)
223 {
224 VMCOREINFO_SYMBOL(lowcore_ptr);
225 VMCOREINFO_SYMBOL(high_memory);
226 VMCOREINFO_LENGTH(lowcore_ptr, NR_CPUS);
227 vmcoreinfo_append_str("SAMODE31=%lx\n", __samode31);
228 vmcoreinfo_append_str("EAMODE31=%lx\n", __eamode31);
229 vmcoreinfo_append_str("KERNELOFFSET=%lx\n", kaslr_offset());
230 put_abs_lowcore(vmcore_info, paddr_vmcoreinfo_note());
231 }
232
machine_shutdown(void)233 void machine_shutdown(void)
234 {
235 }
236
machine_crash_shutdown(struct pt_regs * regs)237 void machine_crash_shutdown(struct pt_regs *regs)
238 {
239 set_os_info_reipl_block();
240 }
241
242 /*
243 * Do normal kexec
244 */
__do_machine_kexec(void * data)245 static void __do_machine_kexec(void *data)
246 {
247 relocate_kernel_t data_mover;
248 struct kimage *image = data;
249
250 s390_reset_system();
251 data_mover = (relocate_kernel_t) page_to_phys(image->control_code_page);
252
253 __arch_local_irq_stnsm(0xfb); /* disable DAT - avoid no-execute */
254 /* Call the moving routine */
255 (*data_mover)(&image->head, image->start);
256
257 /* Die if kexec returns */
258 disabled_wait();
259 }
260
261 /*
262 * Reset system and call either kdump or normal kexec
263 */
__machine_kexec(void * data)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 */
machine_kexec(struct kimage * image)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