/[pkg-src]/trunk/kernel26-xen/patches-2.6.25-r1/1002-2.6.25-xen-linux-2.6.19-rc1-kexec-move_segment_code-x86_64.patch |
Contents of /trunk/kernel26-xen/patches-2.6.25-r1/1002-2.6.25-xen-linux-2.6.19-rc1-kexec-move_segment_code-x86_64.patch
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Fri May 23 17:35:37 2008 UTC (16 years, 4 months ago) by niro
File size: 4831 byte(s)
Fri May 23 17:35:37 2008 UTC (16 years, 4 months ago) by niro
File size: 4831 byte(s)
-using opensuse xen patchset, updated kernel configs
1 | Subject: kexec: Move asm segment handling code to the assembly file (x86_64) |
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 | 58 ----------------------------------------------------- |
21 | relocate_kernel.S | 50 +++++++++++++++++++++++++++++++++++++++++---- |
22 | 2 files changed, 45 insertions(+), 63 deletions(-) |
23 | |
24 | Index: head-2007-11-30/arch/x86/kernel/machine_kexec_64.c |
25 | =================================================================== |
26 | --- head-2007-11-30.orig/arch/x86/kernel/machine_kexec_64.c 2007-11-30 13:39:59.000000000 +0100 |
27 | +++ head-2007-11-30/arch/x86/kernel/machine_kexec_64.c 2007-11-30 13:41:59.000000000 +0100 |
28 | @@ -113,47 +113,6 @@ static int init_pgtable(struct kimage *i |
29 | return init_level4_page(image, level4p, 0, end_pfn << PAGE_SHIFT); |
30 | } |
31 | |
32 | -static void set_idt(void *newidt, u16 limit) |
33 | -{ |
34 | - struct desc_ptr curidt; |
35 | - |
36 | - /* x86-64 supports unaliged loads & stores */ |
37 | - curidt.size = limit; |
38 | - curidt.address = (unsigned long)newidt; |
39 | - |
40 | - __asm__ __volatile__ ( |
41 | - "lidtq %0\n" |
42 | - : : "m" (curidt) |
43 | - ); |
44 | -}; |
45 | - |
46 | - |
47 | -static void set_gdt(void *newgdt, u16 limit) |
48 | -{ |
49 | - struct desc_ptr curgdt; |
50 | - |
51 | - /* x86-64 supports unaligned loads & stores */ |
52 | - curgdt.size = limit; |
53 | - curgdt.address = (unsigned long)newgdt; |
54 | - |
55 | - __asm__ __volatile__ ( |
56 | - "lgdtq %0\n" |
57 | - : : "m" (curgdt) |
58 | - ); |
59 | -}; |
60 | - |
61 | -static void load_segments(void) |
62 | -{ |
63 | - __asm__ __volatile__ ( |
64 | - "\tmovl %0,%%ds\n" |
65 | - "\tmovl %0,%%es\n" |
66 | - "\tmovl %0,%%ss\n" |
67 | - "\tmovl %0,%%fs\n" |
68 | - "\tmovl %0,%%gs\n" |
69 | - : : "a" (__KERNEL_DS) : "memory" |
70 | - ); |
71 | -} |
72 | - |
73 | int machine_kexec_prepare(struct kimage *image) |
74 | { |
75 | unsigned long start_pgtable; |
76 | @@ -210,23 +169,6 @@ NORET_TYPE void machine_kexec(struct kim |
77 | page_list[PA_TABLE_PAGE] = |
78 | (unsigned long)__pa(page_address(image->control_code_page)); |
79 | |
80 | - /* The segment registers are funny things, they have both a |
81 | - * visible and an invisible part. Whenever the visible part is |
82 | - * set to a specific selector, the invisible part is loaded |
83 | - * with from a table in memory. At no other time is the |
84 | - * descriptor table in memory accessed. |
85 | - * |
86 | - * I take advantage of this here by force loading the |
87 | - * segments, before I zap the gdt with an invalid value. |
88 | - */ |
89 | - load_segments(); |
90 | - /* The gdt & idt are now invalid. |
91 | - * If you want to load them you must set up your own idt & gdt. |
92 | - */ |
93 | - set_gdt(phys_to_virt(0),0); |
94 | - set_idt(phys_to_virt(0),0); |
95 | - |
96 | - /* now call it */ |
97 | relocate_kernel((unsigned long)image->head, (unsigned long)page_list, |
98 | image->start); |
99 | } |
100 | Index: head-2007-11-30/arch/x86/kernel/relocate_kernel_64.S |
101 | =================================================================== |
102 | --- head-2007-11-30.orig/arch/x86/kernel/relocate_kernel_64.S 2007-11-30 13:39:59.000000000 +0100 |
103 | +++ head-2007-11-30/arch/x86/kernel/relocate_kernel_64.S 2007-11-30 13:42:10.000000000 +0100 |
104 | @@ -159,13 +159,39 @@ relocate_new_kernel: |
105 | movq PTR(PA_PGD)(%rsi), %r9 |
106 | movq %r9, %cr3 |
107 | |
108 | + /* setup idt */ |
109 | + movq %r8, %rax |
110 | + addq $(idt_80 - relocate_kernel), %rax |
111 | + lidtq (%rax) |
112 | + |
113 | + /* setup gdt */ |
114 | + movq %r8, %rax |
115 | + addq $(gdt - relocate_kernel), %rax |
116 | + movq %r8, %r9 |
117 | + addq $((gdt_80 - relocate_kernel) + 2), %r9 |
118 | + movq %rax, (%r9) |
119 | + |
120 | + movq %r8, %rax |
121 | + addq $(gdt_80 - relocate_kernel), %rax |
122 | + lgdtq (%rax) |
123 | + |
124 | + /* setup data segment registers */ |
125 | + xorl %eax, %eax |
126 | + movl %eax, %ds |
127 | + movl %eax, %es |
128 | + movl %eax, %fs |
129 | + movl %eax, %gs |
130 | + movl %eax, %ss |
131 | + |
132 | /* setup a new stack at the end of the physical control page */ |
133 | lea 4096(%r8), %rsp |
134 | |
135 | - /* jump to identity mapped page */ |
136 | - addq $(identity_mapped - relocate_kernel), %r8 |
137 | - pushq %r8 |
138 | - ret |
139 | + /* load new code segment and jump to identity mapped page */ |
140 | + movq %r8, %rax |
141 | + addq $(identity_mapped - relocate_kernel), %rax |
142 | + pushq $(gdt_cs - gdt) |
143 | + pushq %rax |
144 | + lretq |
145 | |
146 | identity_mapped: |
147 | /* store the start address on the stack */ |
148 | @@ -272,5 +298,19 @@ identity_mapped: |
149 | xorq %r13, %r13 |
150 | xorq %r14, %r14 |
151 | xorq %r15, %r15 |
152 | - |
153 | ret |
154 | + |
155 | + .align 16 |
156 | +gdt: |
157 | + .quad 0x0000000000000000 /* NULL descriptor */ |
158 | +gdt_cs: |
159 | + .quad 0x00af9a000000ffff |
160 | +gdt_end: |
161 | + |
162 | +gdt_80: |
163 | + .word gdt_end - gdt - 1 /* limit */ |
164 | + .quad 0 /* base - filled in by code above */ |
165 | + |
166 | +idt_80: |
167 | + .word 0 /* limit */ |
168 | + .quad 0 /* base */ |