ARM: move signal handlers into a vdso-like page
[linux-3.10.git] / arch / arm / kernel / machine_kexec.c
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/mach-types.h>
18 #include <asm/system_misc.h>
19
20 extern const unsigned char relocate_new_kernel[];
21 extern const unsigned int relocate_new_kernel_size;
22
23 extern unsigned long kexec_start_address;
24 extern unsigned long kexec_indirection_page;
25 extern unsigned long kexec_mach_type;
26 extern unsigned long kexec_boot_atags;
27
28 static atomic_t waiting_for_crash_ipi;
29
30 /*
31  * Provide a dummy crash_notes definition while crash dump arrives to arm.
32  * This prevents breakage of crash_notes attribute in kernel/ksysfs.c.
33  */
34
35 int machine_kexec_prepare(struct kimage *image)
36 {
37         struct kexec_segment *current_segment;
38         __be32 header;
39         int i, err;
40
41         /*
42          * No segment at default ATAGs address. try to locate
43          * a dtb using magic.
44          */
45         for (i = 0; i < image->nr_segments; i++) {
46                 current_segment = &image->segment[i];
47
48                 if (!memblock_is_region_memory(current_segment->mem,
49                                                current_segment->memsz))
50                         return -EINVAL;
51
52                 err = get_user(header, (__be32*)current_segment->buf);
53                 if (err)
54                         return err;
55
56                 if (be32_to_cpu(header) == OF_DT_HEADER)
57                         kexec_boot_atags = current_segment->mem;
58         }
59         return 0;
60 }
61
62 void machine_kexec_cleanup(struct kimage *image)
63 {
64 }
65
66 void machine_crash_nonpanic_core(void *unused)
67 {
68         struct pt_regs regs;
69
70         crash_setup_regs(&regs, NULL);
71         printk(KERN_DEBUG "CPU %u will stop doing anything useful since another CPU has crashed\n",
72                smp_processor_id());
73         crash_save_cpu(&regs, smp_processor_id());
74         flush_cache_all();
75
76         atomic_dec(&waiting_for_crash_ipi);
77         while (1)
78                 cpu_relax();
79 }
80
81 static void machine_kexec_mask_interrupts(void)
82 {
83         unsigned int i;
84         struct irq_desc *desc;
85
86         for_each_irq_desc(i, desc) {
87                 struct irq_chip *chip;
88
89                 chip = irq_desc_get_chip(desc);
90                 if (!chip)
91                         continue;
92
93                 if (chip->irq_eoi && irqd_irq_inprogress(&desc->irq_data))
94                         chip->irq_eoi(&desc->irq_data);
95
96                 if (chip->irq_mask)
97                         chip->irq_mask(&desc->irq_data);
98
99                 if (chip->irq_disable && !irqd_irq_disabled(&desc->irq_data))
100                         chip->irq_disable(&desc->irq_data);
101         }
102 }
103
104 void machine_crash_shutdown(struct pt_regs *regs)
105 {
106         unsigned long msecs;
107
108         local_irq_disable();
109
110         atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
111         smp_call_function(machine_crash_nonpanic_core, NULL, false);
112         msecs = 1000; /* Wait at most a second for the other cpus to stop */
113         while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
114                 mdelay(1);
115                 msecs--;
116         }
117         if (atomic_read(&waiting_for_crash_ipi) > 0)
118                 printk(KERN_WARNING "Non-crashing CPUs did not react to IPI\n");
119
120         crash_save_cpu(regs, smp_processor_id());
121         machine_kexec_mask_interrupts();
122
123         printk(KERN_INFO "Loading crashdump kernel...\n");
124 }
125
126 /*
127  * Function pointer to optional machine-specific reinitialization
128  */
129 void (*kexec_reinit)(void);
130
131 void machine_kexec(struct kimage *image)
132 {
133         unsigned long page_list;
134         unsigned long reboot_code_buffer_phys;
135         void *reboot_code_buffer;
136
137         if (num_online_cpus() > 1) {
138                 pr_err("kexec: error: multiple CPUs still online\n");
139                 return;
140         }
141
142         page_list = image->head & PAGE_MASK;
143
144         /* we need both effective and real address here */
145         reboot_code_buffer_phys =
146             page_to_pfn(image->control_code_page) << PAGE_SHIFT;
147         reboot_code_buffer = page_address(image->control_code_page);
148
149         /* Prepare parameters for reboot_code_buffer*/
150         kexec_start_address = image->start;
151         kexec_indirection_page = page_list;
152         kexec_mach_type = machine_arch_type;
153         if (!kexec_boot_atags)
154                 kexec_boot_atags = image->start - KEXEC_ARM_ZIMAGE_OFFSET + KEXEC_ARM_ATAGS_OFFSET;
155
156
157         /* copy our kernel relocation code to the control code page */
158         memcpy(reboot_code_buffer,
159                relocate_new_kernel, relocate_new_kernel_size);
160
161
162         flush_icache_range((unsigned long) reboot_code_buffer,
163                            (unsigned long) reboot_code_buffer + KEXEC_CONTROL_PAGE_SIZE);
164         printk(KERN_INFO "Bye!\n");
165
166         if (kexec_reinit)
167                 kexec_reinit();
168
169         soft_restart(reboot_code_buffer_phys);
170 }