2b67609d0a1c0af2214c77f0a616acc742b84268
[linux-2.6.git] / arch / x86 / kernel / machine_kexec_32.c
1 /*
2  * handle transition of Linux booting another kernel
3  * Copyright (C) 2002-2005 Eric Biederman  <ebiederm@xmission.com>
4  *
5  * This source code is licensed under the GNU General Public License,
6  * Version 2.  See the file COPYING for more details.
7  */
8
9 #include <linux/mm.h>
10 #include <linux/kexec.h>
11 #include <linux/delay.h>
12 #include <linux/init.h>
13 #include <linux/numa.h>
14 #include <linux/ftrace.h>
15
16 #include <asm/pgtable.h>
17 #include <asm/pgalloc.h>
18 #include <asm/tlbflush.h>
19 #include <asm/mmu_context.h>
20 #include <asm/io.h>
21 #include <asm/apic.h>
22 #include <asm/cpufeature.h>
23 #include <asm/desc.h>
24 #include <asm/system.h>
25 #include <asm/cacheflush.h>
26
27 #define PAGE_ALIGNED __attribute__ ((__aligned__(PAGE_SIZE)))
28 static u32 kexec_pgd[1024] PAGE_ALIGNED;
29 #ifdef CONFIG_X86_PAE
30 static u32 kexec_pmd0[1024] PAGE_ALIGNED;
31 static u32 kexec_pmd1[1024] PAGE_ALIGNED;
32 #endif
33 static u32 kexec_pte0[1024] PAGE_ALIGNED;
34 static u32 kexec_pte1[1024] PAGE_ALIGNED;
35
36 static void set_idt(void *newidt, __u16 limit)
37 {
38         struct desc_ptr curidt;
39
40         /* ia32 supports unaliged loads & stores */
41         curidt.size    = limit;
42         curidt.address = (unsigned long)newidt;
43
44         load_idt(&curidt);
45 }
46
47
48 static void set_gdt(void *newgdt, __u16 limit)
49 {
50         struct desc_ptr curgdt;
51
52         /* ia32 supports unaligned loads & stores */
53         curgdt.size    = limit;
54         curgdt.address = (unsigned long)newgdt;
55
56         load_gdt(&curgdt);
57 }
58
59 static void load_segments(void)
60 {
61 #define __STR(X) #X
62 #define STR(X) __STR(X)
63
64         __asm__ __volatile__ (
65                 "\tljmp $"STR(__KERNEL_CS)",$1f\n"
66                 "\t1:\n"
67                 "\tmovl $"STR(__KERNEL_DS)",%%eax\n"
68                 "\tmovl %%eax,%%ds\n"
69                 "\tmovl %%eax,%%es\n"
70                 "\tmovl %%eax,%%fs\n"
71                 "\tmovl %%eax,%%gs\n"
72                 "\tmovl %%eax,%%ss\n"
73                 ::: "eax", "memory");
74 #undef STR
75 #undef __STR
76 }
77
78 /*
79  * A architecture hook called to validate the
80  * proposed image and prepare the control pages
81  * as needed.  The pages for KEXEC_CONTROL_CODE_SIZE
82  * have been allocated, but the segments have yet
83  * been copied into the kernel.
84  *
85  * Do what every setup is needed on image and the
86  * reboot code buffer to allow us to avoid allocations
87  * later.
88  *
89  * Make control page executable.
90  */
91 int machine_kexec_prepare(struct kimage *image)
92 {
93         if (nx_enabled)
94                 set_pages_x(image->control_code_page, 1);
95         return 0;
96 }
97
98 /*
99  * Undo anything leftover by machine_kexec_prepare
100  * when an image is freed.
101  */
102 void machine_kexec_cleanup(struct kimage *image)
103 {
104         if (nx_enabled)
105                 set_pages_nx(image->control_code_page, 1);
106 }
107
108 /*
109  * Do not allocate memory (or fail in any way) in machine_kexec().
110  * We are past the point of no return, committed to rebooting now.
111  */
112 void machine_kexec(struct kimage *image)
113 {
114         unsigned long page_list[PAGES_NR];
115         void *control_page;
116         asmlinkage unsigned long
117                 (*relocate_kernel_ptr)(unsigned long indirection_page,
118                                        unsigned long control_page,
119                                        unsigned long start_address,
120                                        unsigned int has_pae,
121                                        unsigned int preserve_context);
122
123         tracer_disable();
124
125         /* Interrupts aren't acceptable while we reboot */
126         local_irq_disable();
127
128         control_page = page_address(image->control_code_page);
129         memcpy(control_page, relocate_kernel, PAGE_SIZE/2);
130
131         relocate_kernel_ptr = control_page;
132         page_list[PA_CONTROL_PAGE] = __pa(control_page);
133         page_list[VA_CONTROL_PAGE] = (unsigned long)control_page;
134         page_list[PA_PGD] = __pa(kexec_pgd);
135         page_list[VA_PGD] = (unsigned long)kexec_pgd;
136 #ifdef CONFIG_X86_PAE
137         page_list[PA_PMD_0] = __pa(kexec_pmd0);
138         page_list[VA_PMD_0] = (unsigned long)kexec_pmd0;
139         page_list[PA_PMD_1] = __pa(kexec_pmd1);
140         page_list[VA_PMD_1] = (unsigned long)kexec_pmd1;
141 #endif
142         page_list[PA_PTE_0] = __pa(kexec_pte0);
143         page_list[VA_PTE_0] = (unsigned long)kexec_pte0;
144         page_list[PA_PTE_1] = __pa(kexec_pte1);
145         page_list[VA_PTE_1] = (unsigned long)kexec_pte1;
146         page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page) << PAGE_SHIFT);
147
148         /* The segment registers are funny things, they have both a
149          * visible and an invisible part.  Whenever the visible part is
150          * set to a specific selector, the invisible part is loaded
151          * with from a table in memory.  At no other time is the
152          * descriptor table in memory accessed.
153          *
154          * I take advantage of this here by force loading the
155          * segments, before I zap the gdt with an invalid value.
156          */
157         load_segments();
158         /* The gdt & idt are now invalid.
159          * If you want to load them you must set up your own idt & gdt.
160          */
161         set_gdt(phys_to_virt(0),0);
162         set_idt(phys_to_virt(0),0);
163
164         /* now call it */
165         image->start = relocate_kernel_ptr((unsigned long)image->head,
166                                            (unsigned long)page_list,
167                                            image->start, cpu_has_pae,
168                                            image->preserve_context);
169 }
170
171 void arch_crash_save_vmcoreinfo(void)
172 {
173 #ifdef CONFIG_NUMA
174         VMCOREINFO_SYMBOL(node_data);
175         VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
176 #endif
177 #ifdef CONFIG_X86_PAE
178         VMCOREINFO_CONFIG(X86_PAE);
179 #endif
180 }
181