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
34typedef void (*relocate_kernel_t)(unsigned long, unsigned long, unsigned long);
35typedef int (*purgatory_t)(int);
36
37extern const unsigned char relocate_kernel[];
38extern 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 */
46static 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) S390_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(__LC_FPREGS_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 */
78static 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(S390_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 "0"
121 */
122static 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
137void 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
150static 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
163void arch_kexec_protect_crashkres(void)
164{
165	crash_protect_pages(1);
166}
167
168void 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 */
178static 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
190int 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
209void machine_kexec_cleanup(struct kimage *image)
210{
211}
212
213void machine_shutdown(void)
214{
215}
216
217void machine_crash_shutdown(struct pt_regs *regs)
218{
219	set_os_info_reipl_block();
220}
221
222/*
223 * Do normal kexec
224 */
225static 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 */
249static 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 */
265void 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