[PATCH] i386: PARAVIRT: Allow paravirt backend to choose kernel PMD sharing
[linux-2.6] / arch / i386 / kernel / paravirt.c
1 /*  Paravirtualization interfaces
2     Copyright (C) 2006 Rusty Russell IBM Corporation
3
4     This program is free software; you can redistribute it and/or modify
5     it under the terms of the GNU General Public License as published by
6     the Free Software Foundation; either version 2 of the License, or
7     (at your option) any later version.
8
9     This program is distributed in the hope that it will be useful,
10     but WITHOUT ANY WARRANTY; without even the implied warranty of
11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12     GNU General Public License for more details.
13
14     You should have received a copy of the GNU General Public License
15     along with this program; if not, write to the Free Software
16     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
17 */
18 #include <linux/errno.h>
19 #include <linux/module.h>
20 #include <linux/efi.h>
21 #include <linux/bcd.h>
22 #include <linux/start_kernel.h>
23
24 #include <asm/bug.h>
25 #include <asm/paravirt.h>
26 #include <asm/desc.h>
27 #include <asm/setup.h>
28 #include <asm/arch_hooks.h>
29 #include <asm/time.h>
30 #include <asm/irq.h>
31 #include <asm/delay.h>
32 #include <asm/fixmap.h>
33 #include <asm/apic.h>
34 #include <asm/tlbflush.h>
35 #include <asm/timer.h>
36
37 /* nop stub */
38 void _paravirt_nop(void)
39 {
40 }
41
42 static void __init default_banner(void)
43 {
44         printk(KERN_INFO "Booting paravirtualized kernel on %s\n",
45                paravirt_ops.name);
46 }
47
48 char *memory_setup(void)
49 {
50         return paravirt_ops.memory_setup();
51 }
52
53 /* Simple instruction patching code. */
54 #define DEF_NATIVE(name, code)                                  \
55         extern const char start_##name[], end_##name[];         \
56         asm("start_" #name ": " code "; end_" #name ":")
57 DEF_NATIVE(cli, "cli");
58 DEF_NATIVE(sti, "sti");
59 DEF_NATIVE(popf, "push %eax; popf");
60 DEF_NATIVE(pushf, "pushf; pop %eax");
61 DEF_NATIVE(pushf_cli, "pushf; pop %eax; cli");
62 DEF_NATIVE(iret, "iret");
63 DEF_NATIVE(sti_sysexit, "sti; sysexit");
64
65 static const struct native_insns
66 {
67         const char *start, *end;
68 } native_insns[] = {
69         [PARAVIRT_IRQ_DISABLE] = { start_cli, end_cli },
70         [PARAVIRT_IRQ_ENABLE] = { start_sti, end_sti },
71         [PARAVIRT_RESTORE_FLAGS] = { start_popf, end_popf },
72         [PARAVIRT_SAVE_FLAGS] = { start_pushf, end_pushf },
73         [PARAVIRT_SAVE_FLAGS_IRQ_DISABLE] = { start_pushf_cli, end_pushf_cli },
74         [PARAVIRT_INTERRUPT_RETURN] = { start_iret, end_iret },
75         [PARAVIRT_STI_SYSEXIT] = { start_sti_sysexit, end_sti_sysexit },
76 };
77
78 static unsigned native_patch(u8 type, u16 clobbers, void *insns, unsigned len)
79 {
80         unsigned int insn_len;
81
82         /* Don't touch it if we don't have a replacement */
83         if (type >= ARRAY_SIZE(native_insns) || !native_insns[type].start)
84                 return len;
85
86         insn_len = native_insns[type].end - native_insns[type].start;
87
88         /* Similarly if we can't fit replacement. */
89         if (len < insn_len)
90                 return len;
91
92         memcpy(insns, native_insns[type].start, insn_len);
93         return insn_len;
94 }
95
96 void init_IRQ(void)
97 {
98         paravirt_ops.init_IRQ();
99 }
100
101 static void native_flush_tlb(void)
102 {
103         __native_flush_tlb();
104 }
105
106 /*
107  * Global pages have to be flushed a bit differently. Not a real
108  * performance problem because this does not happen often.
109  */
110 static void native_flush_tlb_global(void)
111 {
112         __native_flush_tlb_global();
113 }
114
115 static void native_flush_tlb_single(u32 addr)
116 {
117         __native_flush_tlb_single(addr);
118 }
119
120 /* These are in entry.S */
121 extern void native_iret(void);
122 extern void native_irq_enable_sysexit(void);
123
124 static int __init print_banner(void)
125 {
126         paravirt_ops.banner();
127         return 0;
128 }
129 core_initcall(print_banner);
130
131 struct paravirt_ops paravirt_ops = {
132         .name = "bare hardware",
133         .paravirt_enabled = 0,
134         .kernel_rpl = 0,
135         .shared_kernel_pmd = 1, /* Only used when CONFIG_X86_PAE is set */
136
137         .patch = native_patch,
138         .banner = default_banner,
139         .arch_setup = paravirt_nop,
140         .memory_setup = machine_specific_memory_setup,
141         .get_wallclock = native_get_wallclock,
142         .set_wallclock = native_set_wallclock,
143         .time_init = hpet_time_init,
144         .init_IRQ = native_init_IRQ,
145
146         .cpuid = native_cpuid,
147         .get_debugreg = native_get_debugreg,
148         .set_debugreg = native_set_debugreg,
149         .clts = native_clts,
150         .read_cr0 = native_read_cr0,
151         .write_cr0 = native_write_cr0,
152         .read_cr2 = native_read_cr2,
153         .write_cr2 = native_write_cr2,
154         .read_cr3 = native_read_cr3,
155         .write_cr3 = native_write_cr3,
156         .read_cr4 = native_read_cr4,
157         .read_cr4_safe = native_read_cr4_safe,
158         .write_cr4 = native_write_cr4,
159         .save_fl = native_save_fl,
160         .restore_fl = native_restore_fl,
161         .irq_disable = native_irq_disable,
162         .irq_enable = native_irq_enable,
163         .safe_halt = native_safe_halt,
164         .halt = native_halt,
165         .wbinvd = native_wbinvd,
166         .read_msr = native_read_msr_safe,
167         .write_msr = native_write_msr_safe,
168         .read_tsc = native_read_tsc,
169         .read_pmc = native_read_pmc,
170         .get_scheduled_cycles = native_read_tsc,
171         .get_cpu_khz = native_calculate_cpu_khz,
172         .load_tr_desc = native_load_tr_desc,
173         .set_ldt = native_set_ldt,
174         .load_gdt = native_load_gdt,
175         .load_idt = native_load_idt,
176         .store_gdt = native_store_gdt,
177         .store_idt = native_store_idt,
178         .store_tr = native_store_tr,
179         .load_tls = native_load_tls,
180         .write_ldt_entry = write_dt_entry,
181         .write_gdt_entry = write_dt_entry,
182         .write_idt_entry = write_dt_entry,
183         .load_esp0 = native_load_esp0,
184
185         .set_iopl_mask = native_set_iopl_mask,
186         .io_delay = native_io_delay,
187
188 #ifdef CONFIG_X86_LOCAL_APIC
189         .apic_write = native_apic_write,
190         .apic_write_atomic = native_apic_write_atomic,
191         .apic_read = native_apic_read,
192         .setup_boot_clock = setup_boot_APIC_clock,
193         .setup_secondary_clock = setup_secondary_APIC_clock,
194 #endif
195         .set_lazy_mode = paravirt_nop,
196
197         .pagetable_setup_start = native_pagetable_setup_start,
198         .pagetable_setup_done = native_pagetable_setup_done,
199
200         .flush_tlb_user = native_flush_tlb,
201         .flush_tlb_kernel = native_flush_tlb_global,
202         .flush_tlb_single = native_flush_tlb_single,
203
204         .map_pt_hook = paravirt_nop,
205
206         .alloc_pt = paravirt_nop,
207         .alloc_pd = paravirt_nop,
208         .alloc_pd_clone = paravirt_nop,
209         .release_pt = paravirt_nop,
210         .release_pd = paravirt_nop,
211
212         .set_pte = native_set_pte,
213         .set_pte_at = native_set_pte_at,
214         .set_pmd = native_set_pmd,
215         .pte_update = paravirt_nop,
216         .pte_update_defer = paravirt_nop,
217
218         .ptep_get_and_clear = native_ptep_get_and_clear,
219
220 #ifdef CONFIG_X86_PAE
221         .set_pte_atomic = native_set_pte_atomic,
222         .set_pte_present = native_set_pte_present,
223         .set_pud = native_set_pud,
224         .pte_clear = native_pte_clear,
225         .pmd_clear = native_pmd_clear,
226
227         .pmd_val = native_pmd_val,
228         .make_pmd = native_make_pmd,
229 #endif
230
231         .pte_val = native_pte_val,
232         .pgd_val = native_pgd_val,
233
234         .make_pte = native_make_pte,
235         .make_pgd = native_make_pgd,
236
237         .irq_enable_sysexit = native_irq_enable_sysexit,
238         .iret = native_iret,
239
240         .startup_ipi_hook = paravirt_nop,
241 };
242
243 /*
244  * NOTE: CONFIG_PARAVIRT is experimental and the paravirt_ops
245  * semantics are subject to change. Hence we only do this
246  * internal-only export of this, until it gets sorted out and
247  * all lowlevel CPU ops used by modules are separately exported.
248  */
249 EXPORT_SYMBOL_GPL(paravirt_ops);