machine_kexec.c revision 56b700fd6f1e49149880fb1b6ffee0dca5be45fb 
1/*
2 * machine_kexec.c - handle transition of Linux booting another kernel
3 */
4
5#include <linux/mm.h>
6#include <linux/kexec.h>
7#include <linux/delay.h>
8#include <linux/reboot.h>
9#include <linux/io.h>
10#include <linux/irq.h>
11#include <linux/memblock.h>
12#include <asm/pgtable.h>
13#include <linux/of_fdt.h>
14#include <asm/pgalloc.h>
15#include <asm/mmu_context.h>
16#include <asm/cacheflush.h>
17#include <asm/fncpy.h>
18#include <asm/mach-types.h>
19#include <asm/smp_plat.h>
20#include <asm/system_misc.h>
21
22extern void relocate_new_kernel(void);
23extern const unsigned int relocate_new_kernel_size;
24
25extern unsigned long kexec_start_address;
26extern unsigned long kexec_indirection_page;
27extern unsigned long kexec_mach_type;
28extern unsigned long kexec_boot_atags;
29
30static atomic_t waiting_for_crash_ipi;
31
32/*
33 * Provide a dummy crash_notes definition while crash dump arrives to arm.
34 * This prevents breakage of crash_notes attribute in kernel/ksysfs.c.
35 */
36
37int machine_kexec_prepare(struct kimage *image)
38{
39	struct kexec_segment *current_segment;
40	__be32 header;
41	int i, err;
42
43	/*
44	 * Validate that if the current HW supports SMP, then the SW supports
45	 * and implements CPU hotplug for the current HW. If not, we won't be
46	 * able to kexec reliably, so fail the prepare operation.
47	 */
48	if (num_possible_cpus() > 1 && !platform_can_cpu_hotplug())
49		return -EINVAL;
50
51	/*
52	 * No segment at default ATAGs address. try to locate
53	 * a dtb using magic.
54	 */
55	for (i = 0; i < image->nr_segments; i++) {
56		current_segment = &image->segment[i];
57
58		if (!memblock_is_region_memory(current_segment->mem,
59					       current_segment->memsz))
60			return -EINVAL;
61
62		err = get_user(header, (__be32*)current_segment->buf);
63		if (err)
64			return err;
65
66		if (be32_to_cpu(header) == OF_DT_HEADER)
67			kexec_boot_atags = current_segment->mem;
68	}
69	return 0;
70}
71
72void machine_kexec_cleanup(struct kimage *image)
73{
74}
75
76void machine_crash_nonpanic_core(void *unused)
77{
78	struct pt_regs regs;
79
80	crash_setup_regs(&regs, NULL);
81	printk(KERN_DEBUG "CPU %u will stop doing anything useful since another CPU has crashed\n",
82	       smp_processor_id());
83	crash_save_cpu(&regs, smp_processor_id());
84	flush_cache_all();
85
86	set_cpu_online(smp_processor_id(), false);
87	atomic_dec(&waiting_for_crash_ipi);
88	while (1)
89		cpu_relax();
90}
91
92static void machine_kexec_mask_interrupts(void)
93{
94	unsigned int i;
95	struct irq_desc *desc;
96
97	for_each_irq_desc(i, desc) {
98		struct irq_chip *chip;
99
100		chip = irq_desc_get_chip(desc);
101		if (!chip)
102			continue;
103
104		if (chip->irq_eoi && irqd_irq_inprogress(&desc->irq_data))
105			chip->irq_eoi(&desc->irq_data);
106
107		if (chip->irq_mask)
108			chip->irq_mask(&desc->irq_data);
109
110		if (chip->irq_disable && !irqd_irq_disabled(&desc->irq_data))
111			chip->irq_disable(&desc->irq_data);
112	}
113}
114
115void machine_crash_shutdown(struct pt_regs *regs)
116{
117	unsigned long msecs;
118
119	local_irq_disable();
120
121	atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
122	smp_call_function(machine_crash_nonpanic_core, NULL, false);
123	msecs = 1000; /* Wait at most a second for the other cpus to stop */
124	while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
125		mdelay(1);
126		msecs--;
127	}
128	if (atomic_read(&waiting_for_crash_ipi) > 0)
129		printk(KERN_WARNING "Non-crashing CPUs did not react to IPI\n");
130
131	crash_save_cpu(regs, smp_processor_id());
132	machine_kexec_mask_interrupts();
133
134	printk(KERN_INFO "Loading crashdump kernel...\n");
135}
136
137/*
138 * Function pointer to optional machine-specific reinitialization
139 */
140void (*kexec_reinit)(void);
141
142void machine_kexec(struct kimage *image)
143{
144	unsigned long page_list;
145	unsigned long reboot_code_buffer_phys;
146	unsigned long reboot_entry = (unsigned long)relocate_new_kernel;
147	unsigned long reboot_entry_phys;
148	void *reboot_code_buffer;
149
150	/*
151	 * This can only happen if machine_shutdown() failed to disable some
152	 * CPU, and that can only happen if the checks in
153	 * machine_kexec_prepare() were not correct. If this fails, we can't
154	 * reliably kexec anyway, so BUG_ON is appropriate.
155	 */
156	BUG_ON(num_online_cpus() > 1);
157
158	page_list = image->head & PAGE_MASK;
159
160	/* we need both effective and real address here */
161	reboot_code_buffer_phys =
162	    page_to_pfn(image->control_code_page) << PAGE_SHIFT;
163	reboot_code_buffer = page_address(image->control_code_page);
164
165	/* Prepare parameters for reboot_code_buffer*/
166	kexec_start_address = image->start;
167	kexec_indirection_page = page_list;
168	kexec_mach_type = machine_arch_type;
169	if (!kexec_boot_atags)
170		kexec_boot_atags = image->start - KEXEC_ARM_ZIMAGE_OFFSET + KEXEC_ARM_ATAGS_OFFSET;
171
172
173	/* copy our kernel relocation code to the control code page */
174	reboot_entry = fncpy(reboot_code_buffer,
175			     reboot_entry,
176			     relocate_new_kernel_size);
177	reboot_entry_phys = (unsigned long)reboot_entry +
178		(reboot_code_buffer_phys - (unsigned long)reboot_code_buffer);
179
180	printk(KERN_INFO "Bye!\n");
181
182	if (kexec_reinit)
183		kexec_reinit();
184
185	soft_restart(reboot_entry_phys);
186}
187
188void arch_crash_save_vmcoreinfo(void)
189{
190#ifdef CONFIG_ARM_LPAE
191	VMCOREINFO_CONFIG(ARM_LPAE);
192#endif
193}
194