xref: /openbmc/linux/arch/s390/kernel/machine_kexec.c (revision c819e2cf)
1 /*
2  * Copyright IBM Corp. 2005, 2011
3  *
4  * Author(s): Rolf Adelsberger,
5  *	      Heiko Carstens <heiko.carstens@de.ibm.com>
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 <linux/suspend.h>
17 #include <asm/cio.h>
18 #include <asm/setup.h>
19 #include <asm/pgtable.h>
20 #include <asm/pgalloc.h>
21 #include <asm/smp.h>
22 #include <asm/reset.h>
23 #include <asm/ipl.h>
24 #include <asm/diag.h>
25 #include <asm/elf.h>
26 #include <asm/asm-offsets.h>
27 #include <asm/os_info.h>
28 #include <asm/switch_to.h>
29 
30 typedef void (*relocate_kernel_t)(kimage_entry_t *, unsigned long);
31 
32 extern const unsigned char relocate_kernel[];
33 extern const unsigned long long relocate_kernel_len;
34 
35 #ifdef CONFIG_CRASH_DUMP
36 
37 /*
38  * Create ELF notes for one CPU
39  */
40 static void add_elf_notes(int cpu)
41 {
42 	struct save_area *sa = (void *) 4608 + store_prefix();
43 	void *ptr;
44 
45 	memcpy((void *) (4608UL + sa->pref_reg), sa, sizeof(*sa));
46 	ptr = (u64 *) per_cpu_ptr(crash_notes, cpu);
47 	ptr = fill_cpu_elf_notes(ptr, sa, NULL);
48 	memset(ptr, 0, sizeof(struct elf_note));
49 }
50 
51 /*
52  * Initialize CPU ELF notes
53  */
54 static void setup_regs(void)
55 {
56 	unsigned long sa = S390_lowcore.prefixreg_save_area + SAVE_AREA_BASE;
57 	struct _lowcore *lc;
58 	int cpu, this_cpu;
59 
60 	/* Get lowcore pointer from store status of this CPU (absolute zero) */
61 	lc = (struct _lowcore *)(unsigned long)S390_lowcore.prefixreg_save_area;
62 	this_cpu = smp_find_processor_id(stap());
63 	add_elf_notes(this_cpu);
64 	for_each_online_cpu(cpu) {
65 		if (cpu == this_cpu)
66 			continue;
67 		if (smp_store_status(cpu))
68 			continue;
69 		add_elf_notes(cpu);
70 	}
71 	if (MACHINE_HAS_VX)
72 		save_vx_regs_safe((void *) lc->vector_save_area_addr);
73 	/* Copy dump CPU store status info to absolute zero */
74 	memcpy((void *) SAVE_AREA_BASE, (void *) sa, sizeof(struct save_area));
75 }
76 
77 /*
78  * PM notifier callback for kdump
79  */
80 static int machine_kdump_pm_cb(struct notifier_block *nb, unsigned long action,
81 			       void *ptr)
82 {
83 	switch (action) {
84 	case PM_SUSPEND_PREPARE:
85 	case PM_HIBERNATION_PREPARE:
86 		if (crashk_res.start)
87 			crash_map_reserved_pages();
88 		break;
89 	case PM_POST_SUSPEND:
90 	case PM_POST_HIBERNATION:
91 		if (crashk_res.start)
92 			crash_unmap_reserved_pages();
93 		break;
94 	default:
95 		return NOTIFY_DONE;
96 	}
97 	return NOTIFY_OK;
98 }
99 
100 static int __init machine_kdump_pm_init(void)
101 {
102 	pm_notifier(machine_kdump_pm_cb, 0);
103 	return 0;
104 }
105 arch_initcall(machine_kdump_pm_init);
106 #endif
107 
108 /*
109  * Start kdump: We expect here that a store status has been done on our CPU
110  */
111 static void __do_machine_kdump(void *image)
112 {
113 #ifdef CONFIG_CRASH_DUMP
114 	int (*start_kdump)(int) = (void *)((struct kimage *) image)->start;
115 
116 	setup_regs();
117 	__load_psw_mask(PSW_MASK_BASE | PSW_DEFAULT_KEY | PSW_MASK_EA | PSW_MASK_BA);
118 	start_kdump(1);
119 #endif
120 }
121 
122 /*
123  * Check if kdump checksums are valid: We call purgatory with parameter "0"
124  */
125 static int kdump_csum_valid(struct kimage *image)
126 {
127 #ifdef CONFIG_CRASH_DUMP
128 	int (*start_kdump)(int) = (void *)image->start;
129 	int rc;
130 
131 	__arch_local_irq_stnsm(0xfb); /* disable DAT */
132 	rc = start_kdump(0);
133 	__arch_local_irq_stosm(0x04); /* enable DAT */
134 	return rc ? 0 : -EINVAL;
135 #else
136 	return -EINVAL;
137 #endif
138 }
139 
140 /*
141  * Map or unmap crashkernel memory
142  */
143 static void crash_map_pages(int enable)
144 {
145 	unsigned long size = resource_size(&crashk_res);
146 
147 	BUG_ON(crashk_res.start % KEXEC_CRASH_MEM_ALIGN ||
148 	       size % KEXEC_CRASH_MEM_ALIGN);
149 	if (enable)
150 		vmem_add_mapping(crashk_res.start, size);
151 	else {
152 		vmem_remove_mapping(crashk_res.start, size);
153 		if (size)
154 			os_info_crashkernel_add(crashk_res.start, size);
155 		else
156 			os_info_crashkernel_add(0, 0);
157 	}
158 }
159 
160 /*
161  * Map crashkernel memory
162  */
163 void crash_map_reserved_pages(void)
164 {
165 	crash_map_pages(1);
166 }
167 
168 /*
169  * Unmap crashkernel memory
170  */
171 void crash_unmap_reserved_pages(void)
172 {
173 	crash_map_pages(0);
174 }
175 
176 /*
177  * Give back memory to hypervisor before new kdump is loaded
178  */
179 static int machine_kexec_prepare_kdump(void)
180 {
181 #ifdef CONFIG_CRASH_DUMP
182 	if (MACHINE_IS_VM)
183 		diag10_range(PFN_DOWN(crashk_res.start),
184 			     PFN_DOWN(crashk_res.end - crashk_res.start + 1));
185 	return 0;
186 #else
187 	return -EINVAL;
188 #endif
189 }
190 
191 int machine_kexec_prepare(struct kimage *image)
192 {
193 	void *reboot_code_buffer;
194 
195 	/* Can't replace kernel image since it is read-only. */
196 	if (ipl_flags & IPL_NSS_VALID)
197 		return -EOPNOTSUPP;
198 
199 	if (image->type == KEXEC_TYPE_CRASH)
200 		return machine_kexec_prepare_kdump();
201 
202 	/* We don't support anything but the default image type for now. */
203 	if (image->type != KEXEC_TYPE_DEFAULT)
204 		return -EINVAL;
205 
206 	/* Get the destination where the assembler code should be copied to.*/
207 	reboot_code_buffer = (void *) page_to_phys(image->control_code_page);
208 
209 	/* Then copy it */
210 	memcpy(reboot_code_buffer, relocate_kernel, relocate_kernel_len);
211 	return 0;
212 }
213 
214 void machine_kexec_cleanup(struct kimage *image)
215 {
216 }
217 
218 void arch_crash_save_vmcoreinfo(void)
219 {
220 	VMCOREINFO_SYMBOL(lowcore_ptr);
221 	VMCOREINFO_SYMBOL(high_memory);
222 	VMCOREINFO_LENGTH(lowcore_ptr, NR_CPUS);
223 }
224 
225 void machine_shutdown(void)
226 {
227 }
228 
229 void machine_crash_shutdown(struct pt_regs *regs)
230 {
231 }
232 
233 /*
234  * Do normal kexec
235  */
236 static void __do_machine_kexec(void *data)
237 {
238 	relocate_kernel_t data_mover;
239 	struct kimage *image = data;
240 
241 	data_mover = (relocate_kernel_t) page_to_phys(image->control_code_page);
242 
243 	/* Call the moving routine */
244 	(*data_mover)(&image->head, image->start);
245 }
246 
247 /*
248  * Reset system and call either kdump or normal kexec
249  */
250 static void __machine_kexec(void *data)
251 {
252 	struct kimage *image = data;
253 
254 	__arch_local_irq_stosm(0x04); /* enable DAT */
255 	pfault_fini();
256 	tracing_off();
257 	debug_locks_off();
258 	if (image->type == KEXEC_TYPE_CRASH) {
259 		lgr_info_log();
260 		s390_reset_system(__do_machine_kdump, data);
261 	} else {
262 		s390_reset_system(__do_machine_kexec, data);
263 	}
264 	disabled_wait((unsigned long) __builtin_return_address(0));
265 }
266 
267 /*
268  * Do either kdump or normal kexec. In case of kdump we first ask
269  * purgatory, if kdump checksums are valid.
270  */
271 void machine_kexec(struct kimage *image)
272 {
273 	if (image->type == KEXEC_TYPE_CRASH && !kdump_csum_valid(image))
274 		return;
275 	tracer_disable();
276 	smp_send_stop();
277 	smp_call_ipl_cpu(__machine_kexec, image);
278 }
279