/[pkg-src]/trunk/kernel26-xen/patches-2.6.25-r1/1001-2.6.25-xen-linux-2.6.19-rc1-kexec-move_segment_code-i386.patch |
Contents of /trunk/kernel26-xen/patches-2.6.25-r1/1001-2.6.25-xen-linux-2.6.19-rc1-kexec-move_segment_code-i386.patch
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Fri May 23 17:35:37 2008 UTC (16 years, 4 months ago) by niro
File size: 5122 byte(s)
Fri May 23 17:35:37 2008 UTC (16 years, 4 months ago) by niro
File size: 5122 byte(s)
-using opensuse xen patchset, updated kernel configs
1 | Subject: kexec: Move asm segment handling code to the assembly file (i386) |
2 | From: http://xenbits.xensource.com/xen-unstable.hg (tip 13816) |
3 | Patch-mainline: obsolete |
4 | |
5 | This patch moves the idt, gdt, and segment handling code from machine_kexec.c |
6 | to relocate_kernel.S. The main reason behind this move is to avoid code |
7 | duplication in the Xen hypervisor. With this patch all code required to kexec |
8 | is put on the control page. |
9 | |
10 | On top of that this patch also counts as a cleanup - I think it is much |
11 | nicer to write assembly directly in assembly files than wrap inline assembly |
12 | in C functions for no apparent reason. |
13 | |
14 | Signed-off-by: Magnus Damm <magnus@valinux.co.jp> |
15 | Acked-by: jbeulich@novell.com |
16 | --- |
17 | |
18 | Applies to 2.6.19-rc1. |
19 | |
20 | machine_kexec.c | 59 ----------------------------------------------------- |
21 | relocate_kernel.S | 58 +++++++++++++++++++++++++++++++++++++++++++++++----- |
22 | 2 files changed, 53 insertions(+), 64 deletions(-) |
23 | |
24 | Index: head-2008-02-26/arch/x86/kernel/machine_kexec_32.c |
25 | =================================================================== |
26 | --- head-2008-02-26.orig/arch/x86/kernel/machine_kexec_32.c 2008-02-26 11:43:15.000000000 +0100 |
27 | +++ head-2008-02-26/arch/x86/kernel/machine_kexec_32.c 2008-02-26 11:45:10.000000000 +0100 |
28 | @@ -30,48 +30,6 @@ static u32 kexec_pmd1[1024] PAGE_ALIGNED |
29 | static u32 kexec_pte0[1024] PAGE_ALIGNED; |
30 | static u32 kexec_pte1[1024] PAGE_ALIGNED; |
31 | |
32 | -static void set_idt(void *newidt, __u16 limit) |
33 | -{ |
34 | - struct desc_ptr curidt; |
35 | - |
36 | - /* ia32 supports unaliged loads & stores */ |
37 | - curidt.size = limit; |
38 | - curidt.address = (unsigned long)newidt; |
39 | - |
40 | - load_idt(&curidt); |
41 | -}; |
42 | - |
43 | - |
44 | -static void set_gdt(void *newgdt, __u16 limit) |
45 | -{ |
46 | - struct desc_ptr curgdt; |
47 | - |
48 | - /* ia32 supports unaligned loads & stores */ |
49 | - curgdt.size = limit; |
50 | - curgdt.address = (unsigned long)newgdt; |
51 | - |
52 | - load_gdt(&curgdt); |
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" |
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"); |
70 | -#undef STR |
71 | -#undef __STR |
72 | -} |
73 | - |
74 | /* |
75 | * A architecture hook called to validate the |
76 | * proposed image and prepare the control pages |
77 | @@ -128,23 +86,6 @@ NORET_TYPE void machine_kexec(struct kim |
78 | page_list[PA_PTE_1] = __pa(kexec_pte1); |
79 | page_list[VA_PTE_1] = (unsigned long)kexec_pte1; |
80 | |
81 | - /* The segment registers are funny things, they have both a |
82 | - * visible and an invisible part. Whenever the visible part is |
83 | - * set to a specific selector, the invisible part is loaded |
84 | - * with from a table in memory. At no other time is the |
85 | - * descriptor table in memory accessed. |
86 | - * |
87 | - * I take advantage of this here by force loading the |
88 | - * segments, before I zap the gdt with an invalid value. |
89 | - */ |
90 | - load_segments(); |
91 | - /* The gdt & idt are now invalid. |
92 | - * If you want to load them you must set up your own idt & gdt. |
93 | - */ |
94 | - set_gdt(phys_to_virt(0),0); |
95 | - set_idt(phys_to_virt(0),0); |
96 | - |
97 | - /* now call it */ |
98 | relocate_kernel((unsigned long)image->head, (unsigned long)page_list, |
99 | image->start, cpu_has_pae); |
100 | } |
101 | Index: head-2008-02-26/arch/x86/kernel/relocate_kernel_32.S |
102 | =================================================================== |
103 | --- head-2008-02-26.orig/arch/x86/kernel/relocate_kernel_32.S 2008-01-24 23:58:37.000000000 +0100 |
104 | +++ head-2008-02-26/arch/x86/kernel/relocate_kernel_32.S 2008-02-26 11:45:10.000000000 +0100 |
105 | @@ -154,14 +154,45 @@ relocate_new_kernel: |
106 | movl PTR(PA_PGD)(%ebp), %eax |
107 | movl %eax, %cr3 |
108 | |
109 | + /* setup idt */ |
110 | + movl %edi, %eax |
111 | + addl $(idt_48 - relocate_kernel), %eax |
112 | + lidtl (%eax) |
113 | + |
114 | + /* setup gdt */ |
115 | + movl %edi, %eax |
116 | + addl $(gdt - relocate_kernel), %eax |
117 | + movl %edi, %esi |
118 | + addl $((gdt_48 - relocate_kernel) + 2), %esi |
119 | + movl %eax, (%esi) |
120 | + |
121 | + movl %edi, %eax |
122 | + addl $(gdt_48 - relocate_kernel), %eax |
123 | + lgdtl (%eax) |
124 | + |
125 | + /* setup data segment registers */ |
126 | + mov $(gdt_ds - gdt), %eax |
127 | + mov %eax, %ds |
128 | + mov %eax, %es |
129 | + mov %eax, %fs |
130 | + mov %eax, %gs |
131 | + mov %eax, %ss |
132 | + |
133 | /* setup a new stack at the end of the physical control page */ |
134 | lea 4096(%edi), %esp |
135 | |
136 | - /* jump to identity mapped page */ |
137 | - movl %edi, %eax |
138 | - addl $(identity_mapped - relocate_kernel), %eax |
139 | - pushl %eax |
140 | - ret |
141 | + /* load new code segment and jump to identity mapped page */ |
142 | + movl %edi, %esi |
143 | + xorl %eax, %eax |
144 | + pushl %eax |
145 | + pushl %esi |
146 | + pushl %eax |
147 | + movl $(gdt_cs - gdt), %eax |
148 | + pushl %eax |
149 | + movl %edi, %eax |
150 | + addl $(identity_mapped - relocate_kernel),%eax |
151 | + pushl %eax |
152 | + iretl |
153 | |
154 | identity_mapped: |
155 | /* store the start address on the stack */ |
156 | @@ -250,3 +281,20 @@ identity_mapped: |
157 | xorl %edi, %edi |
158 | xorl %ebp, %ebp |
159 | ret |
160 | + |
161 | + .align 16 |
162 | +gdt: |
163 | + .quad 0x0000000000000000 /* NULL descriptor */ |
164 | +gdt_cs: |
165 | + .quad 0x00cf9a000000ffff /* kernel 4GB code at 0x00000000 */ |
166 | +gdt_ds: |
167 | + .quad 0x00cf92000000ffff /* kernel 4GB data at 0x00000000 */ |
168 | +gdt_end: |
169 | + |
170 | +gdt_48: |
171 | + .word gdt_end - gdt - 1 /* limit */ |
172 | + .long 0 /* base - filled in by code above */ |
173 | + |
174 | +idt_48: |
175 | + .word 0 /* limit */ |
176 | + .long 0 /* base */ |