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5033cba0 EB |
1 | /* |
2 | * machine_kexec.c - 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> | |
1a3f239d | 12 | #include <linux/init.h> |
5033cba0 EB |
13 | #include <asm/pgtable.h> |
14 | #include <asm/pgalloc.h> | |
15 | #include <asm/tlbflush.h> | |
16 | #include <asm/mmu_context.h> | |
17 | #include <asm/io.h> | |
18 | #include <asm/apic.h> | |
19 | #include <asm/cpufeature.h> | |
e7b47cca | 20 | #include <asm/desc.h> |
4bb0d3ec | 21 | #include <asm/system.h> |
5033cba0 EB |
22 | |
23 | #define PAGE_ALIGNED __attribute__ ((__aligned__(PAGE_SIZE))) | |
3566561b MD |
24 | static u32 kexec_pgd[1024] PAGE_ALIGNED; |
25 | #ifdef CONFIG_X86_PAE | |
26 | static u32 kexec_pmd0[1024] PAGE_ALIGNED; | |
27 | static u32 kexec_pmd1[1024] PAGE_ALIGNED; | |
5033cba0 | 28 | #endif |
3566561b MD |
29 | static u32 kexec_pte0[1024] PAGE_ALIGNED; |
30 | static u32 kexec_pte1[1024] PAGE_ALIGNED; | |
5033cba0 | 31 | |
5033cba0 EB |
32 | static void set_idt(void *newidt, __u16 limit) |
33 | { | |
e7b47cca | 34 | struct Xgt_desc_struct curidt; |
5033cba0 EB |
35 | |
36 | /* ia32 supports unaliged loads & stores */ | |
e7b47cca EB |
37 | curidt.size = limit; |
38 | curidt.address = (unsigned long)newidt; | |
5033cba0 | 39 | |
f2ab4461 | 40 | load_idt(&curidt); |
5033cba0 EB |
41 | }; |
42 | ||
43 | ||
44 | static void set_gdt(void *newgdt, __u16 limit) | |
45 | { | |
e7b47cca | 46 | struct Xgt_desc_struct curgdt; |
5033cba0 EB |
47 | |
48 | /* ia32 supports unaligned loads & stores */ | |
e7b47cca EB |
49 | curgdt.size = limit; |
50 | curgdt.address = (unsigned long)newgdt; | |
5033cba0 | 51 | |
f2ab4461 | 52 | load_gdt(&curgdt); |
5033cba0 EB |
53 | }; |
54 | ||
55 | static void load_segments(void) | |
56 | { | |
57 | #define __STR(X) #X | |
58 | #define STR(X) __STR(X) | |
59 | ||
60 | __asm__ __volatile__ ( | |
61 | "\tljmp $"STR(__KERNEL_CS)",$1f\n" | |
62 | "\t1:\n" | |
2ec5e3a8 MM |
63 | "\tmovl $"STR(__KERNEL_DS)",%%eax\n" |
64 | "\tmovl %%eax,%%ds\n" | |
65 | "\tmovl %%eax,%%es\n" | |
66 | "\tmovl %%eax,%%fs\n" | |
67 | "\tmovl %%eax,%%gs\n" | |
68 | "\tmovl %%eax,%%ss\n" | |
69 | ::: "eax", "memory"); | |
5033cba0 EB |
70 | #undef STR |
71 | #undef __STR | |
72 | } | |
73 | ||
5033cba0 EB |
74 | /* |
75 | * A architecture hook called to validate the | |
76 | * proposed image and prepare the control pages | |
77 | * as needed. The pages for KEXEC_CONTROL_CODE_SIZE | |
78 | * have been allocated, but the segments have yet | |
79 | * been copied into the kernel. | |
80 | * | |
81 | * Do what every setup is needed on image and the | |
82 | * reboot code buffer to allow us to avoid allocations | |
83 | * later. | |
84 | * | |
85 | * Currently nothing. | |
86 | */ | |
87 | int machine_kexec_prepare(struct kimage *image) | |
88 | { | |
89 | return 0; | |
90 | } | |
91 | ||
92 | /* | |
93 | * Undo anything leftover by machine_kexec_prepare | |
94 | * when an image is freed. | |
95 | */ | |
96 | void machine_kexec_cleanup(struct kimage *image) | |
97 | { | |
98 | } | |
99 | ||
100 | /* | |
101 | * Do not allocate memory (or fail in any way) in machine_kexec(). | |
102 | * We are past the point of no return, committed to rebooting now. | |
103 | */ | |
104 | NORET_TYPE void machine_kexec(struct kimage *image) | |
105 | { | |
3566561b MD |
106 | unsigned long page_list[PAGES_NR]; |
107 | void *control_page; | |
5033cba0 EB |
108 | |
109 | /* Interrupts aren't acceptable while we reboot */ | |
110 | local_irq_disable(); | |
111 | ||
3566561b MD |
112 | control_page = page_address(image->control_code_page); |
113 | memcpy(control_page, relocate_kernel, PAGE_SIZE); | |
114 | ||
115 | page_list[PA_CONTROL_PAGE] = __pa(control_page); | |
116 | page_list[VA_CONTROL_PAGE] = (unsigned long)relocate_kernel; | |
117 | page_list[PA_PGD] = __pa(kexec_pgd); | |
118 | page_list[VA_PGD] = (unsigned long)kexec_pgd; | |
119 | #ifdef CONFIG_X86_PAE | |
120 | page_list[PA_PMD_0] = __pa(kexec_pmd0); | |
121 | page_list[VA_PMD_0] = (unsigned long)kexec_pmd0; | |
122 | page_list[PA_PMD_1] = __pa(kexec_pmd1); | |
123 | page_list[VA_PMD_1] = (unsigned long)kexec_pmd1; | |
124 | #endif | |
125 | page_list[PA_PTE_0] = __pa(kexec_pte0); | |
126 | page_list[VA_PTE_0] = (unsigned long)kexec_pte0; | |
127 | page_list[PA_PTE_1] = __pa(kexec_pte1); | |
128 | page_list[VA_PTE_1] = (unsigned long)kexec_pte1; | |
5033cba0 | 129 | |
2a8a3d5b EB |
130 | /* The segment registers are funny things, they have both a |
131 | * visible and an invisible part. Whenever the visible part is | |
132 | * set to a specific selector, the invisible part is loaded | |
133 | * with from a table in memory. At no other time is the | |
134 | * descriptor table in memory accessed. | |
5033cba0 EB |
135 | * |
136 | * I take advantage of this here by force loading the | |
137 | * segments, before I zap the gdt with an invalid value. | |
138 | */ | |
139 | load_segments(); | |
140 | /* The gdt & idt are now invalid. | |
141 | * If you want to load them you must set up your own idt & gdt. | |
142 | */ | |
143 | set_gdt(phys_to_virt(0),0); | |
144 | set_idt(phys_to_virt(0),0); | |
145 | ||
146 | /* now call it */ | |
3566561b MD |
147 | relocate_kernel((unsigned long)image->head, (unsigned long)page_list, |
148 | image->start, cpu_has_pae); | |
5033cba0 | 149 | } |
1a3f239d RR |
150 | |
151 | /* crashkernel=size@addr specifies the location to reserve for | |
152 | * a crash kernel. By reserving this memory we guarantee | |
153 | * that linux never sets it up as a DMA target. | |
154 | * Useful for holding code to do something appropriate | |
155 | * after a kernel panic. | |
156 | */ | |
157 | static int __init parse_crashkernel(char *arg) | |
158 | { | |
159 | unsigned long size, base; | |
160 | size = memparse(arg, &arg); | |
161 | if (*arg == '@') { | |
162 | base = memparse(arg+1, &arg); | |
163 | /* FIXME: Do I want a sanity check | |
164 | * to validate the memory range? | |
165 | */ | |
166 | crashk_res.start = base; | |
167 | crashk_res.end = base + size - 1; | |
168 | } | |
169 | return 0; | |
170 | } | |
171 | early_param("crashkernel", parse_crashkernel); |