x86, ptrace: overflow signal API
[sfrench/cifs-2.6.git] / arch / x86 / 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     2007 - x86_64 support added by Glauber de Oliveira Costa, Red Hat Inc
19 */
20
21 #include <linux/errno.h>
22 #include <linux/module.h>
23 #include <linux/efi.h>
24 #include <linux/bcd.h>
25 #include <linux/highmem.h>
26
27 #include <asm/bug.h>
28 #include <asm/paravirt.h>
29 #include <asm/desc.h>
30 #include <asm/setup.h>
31 #include <asm/arch_hooks.h>
32 #include <asm/time.h>
33 #include <asm/irq.h>
34 #include <asm/delay.h>
35 #include <asm/fixmap.h>
36 #include <asm/apic.h>
37 #include <asm/tlbflush.h>
38 #include <asm/timer.h>
39
40 /* nop stub */
41 void _paravirt_nop(void)
42 {
43 }
44
45 static void __init default_banner(void)
46 {
47         printk(KERN_INFO "Booting paravirtualized kernel on %s\n",
48                pv_info.name);
49 }
50
51 char *memory_setup(void)
52 {
53         return pv_init_ops.memory_setup();
54 }
55
56 /* Simple instruction patching code. */
57 #define DEF_NATIVE(ops, name, code)                                     \
58         extern const char start_##ops##_##name[], end_##ops##_##name[]; \
59         asm("start_" #ops "_" #name ": " code "; end_" #ops "_" #name ":")
60
61 DEF_NATIVE(pv_irq_ops, irq_disable, "cli");
62 DEF_NATIVE(pv_irq_ops, irq_enable, "sti");
63 DEF_NATIVE(pv_irq_ops, restore_fl, "push %eax; popf");
64 DEF_NATIVE(pv_irq_ops, save_fl, "pushf; pop %eax");
65 DEF_NATIVE(pv_cpu_ops, iret, "iret");
66 DEF_NATIVE(pv_cpu_ops, irq_enable_syscall_ret, "sti; sysexit");
67 DEF_NATIVE(pv_mmu_ops, read_cr2, "mov %cr2, %eax");
68 DEF_NATIVE(pv_mmu_ops, write_cr3, "mov %eax, %cr3");
69 DEF_NATIVE(pv_mmu_ops, read_cr3, "mov %cr3, %eax");
70 DEF_NATIVE(pv_cpu_ops, clts, "clts");
71 DEF_NATIVE(pv_cpu_ops, read_tsc, "rdtsc");
72
73 /* Undefined instruction for dealing with missing ops pointers. */
74 static const unsigned char ud2a[] = { 0x0f, 0x0b };
75
76 static unsigned native_patch(u8 type, u16 clobbers, void *ibuf,
77                              unsigned long addr, unsigned len)
78 {
79         const unsigned char *start, *end;
80         unsigned ret;
81
82         switch(type) {
83 #define SITE(ops, x)                                            \
84         case PARAVIRT_PATCH(ops.x):                             \
85                 start = start_##ops##_##x;                      \
86                 end = end_##ops##_##x;                          \
87                 goto patch_site
88
89         SITE(pv_irq_ops, irq_disable);
90         SITE(pv_irq_ops, irq_enable);
91         SITE(pv_irq_ops, restore_fl);
92         SITE(pv_irq_ops, save_fl);
93         SITE(pv_cpu_ops, iret);
94         SITE(pv_cpu_ops, irq_enable_syscall_ret);
95         SITE(pv_mmu_ops, read_cr2);
96         SITE(pv_mmu_ops, read_cr3);
97         SITE(pv_mmu_ops, write_cr3);
98         SITE(pv_cpu_ops, clts);
99         SITE(pv_cpu_ops, read_tsc);
100 #undef SITE
101
102         patch_site:
103                 ret = paravirt_patch_insns(ibuf, len, start, end);
104                 break;
105
106         default:
107                 ret = paravirt_patch_default(type, clobbers, ibuf, addr, len);
108                 break;
109         }
110
111         return ret;
112 }
113
114 unsigned paravirt_patch_nop(void)
115 {
116         return 0;
117 }
118
119 unsigned paravirt_patch_ignore(unsigned len)
120 {
121         return len;
122 }
123
124 struct branch {
125         unsigned char opcode;
126         u32 delta;
127 } __attribute__((packed));
128
129 unsigned paravirt_patch_call(void *insnbuf,
130                              const void *target, u16 tgt_clobbers,
131                              unsigned long addr, u16 site_clobbers,
132                              unsigned len)
133 {
134         struct branch *b = insnbuf;
135         unsigned long delta = (unsigned long)target - (addr+5);
136
137         if (tgt_clobbers & ~site_clobbers)
138                 return len;     /* target would clobber too much for this site */
139         if (len < 5)
140                 return len;     /* call too long for patch site */
141
142         b->opcode = 0xe8; /* call */
143         b->delta = delta;
144         BUILD_BUG_ON(sizeof(*b) != 5);
145
146         return 5;
147 }
148
149 unsigned paravirt_patch_jmp(void *insnbuf, const void *target,
150                             unsigned long addr, unsigned len)
151 {
152         struct branch *b = insnbuf;
153         unsigned long delta = (unsigned long)target - (addr+5);
154
155         if (len < 5)
156                 return len;     /* call too long for patch site */
157
158         b->opcode = 0xe9;       /* jmp */
159         b->delta = delta;
160
161         return 5;
162 }
163
164 /* Neat trick to map patch type back to the call within the
165  * corresponding structure. */
166 static void *get_call_destination(u8 type)
167 {
168         struct paravirt_patch_template tmpl = {
169                 .pv_init_ops = pv_init_ops,
170                 .pv_time_ops = pv_time_ops,
171                 .pv_cpu_ops = pv_cpu_ops,
172                 .pv_irq_ops = pv_irq_ops,
173                 .pv_apic_ops = pv_apic_ops,
174                 .pv_mmu_ops = pv_mmu_ops,
175         };
176         return *((void **)&tmpl + type);
177 }
178
179 unsigned paravirt_patch_default(u8 type, u16 clobbers, void *insnbuf,
180                                 unsigned long addr, unsigned len)
181 {
182         void *opfunc = get_call_destination(type);
183         unsigned ret;
184
185         if (opfunc == NULL)
186                 /* If there's no function, patch it with a ud2a (BUG) */
187                 ret = paravirt_patch_insns(insnbuf, len, ud2a, ud2a+sizeof(ud2a));
188         else if (opfunc == paravirt_nop)
189                 /* If the operation is a nop, then nop the callsite */
190                 ret = paravirt_patch_nop();
191         else if (type == PARAVIRT_PATCH(pv_cpu_ops.iret) ||
192                  type == PARAVIRT_PATCH(pv_cpu_ops.irq_enable_syscall_ret))
193                 /* If operation requires a jmp, then jmp */
194                 ret = paravirt_patch_jmp(insnbuf, opfunc, addr, len);
195         else
196                 /* Otherwise call the function; assume target could
197                    clobber any caller-save reg */
198                 ret = paravirt_patch_call(insnbuf, opfunc, CLBR_ANY,
199                                           addr, clobbers, len);
200
201         return ret;
202 }
203
204 unsigned paravirt_patch_insns(void *insnbuf, unsigned len,
205                               const char *start, const char *end)
206 {
207         unsigned insn_len = end - start;
208
209         if (insn_len > len || start == NULL)
210                 insn_len = len;
211         else
212                 memcpy(insnbuf, start, insn_len);
213
214         return insn_len;
215 }
216
217 void init_IRQ(void)
218 {
219         pv_irq_ops.init_IRQ();
220 }
221
222 static void native_flush_tlb(void)
223 {
224         __native_flush_tlb();
225 }
226
227 /*
228  * Global pages have to be flushed a bit differently. Not a real
229  * performance problem because this does not happen often.
230  */
231 static void native_flush_tlb_global(void)
232 {
233         __native_flush_tlb_global();
234 }
235
236 static void native_flush_tlb_single(unsigned long addr)
237 {
238         __native_flush_tlb_single(addr);
239 }
240
241 /* These are in entry.S */
242 extern void native_iret(void);
243 extern void native_irq_enable_syscall_ret(void);
244
245 static int __init print_banner(void)
246 {
247         pv_init_ops.banner();
248         return 0;
249 }
250 core_initcall(print_banner);
251
252 static struct resource reserve_ioports = {
253         .start = 0,
254         .end = IO_SPACE_LIMIT,
255         .name = "paravirt-ioport",
256         .flags = IORESOURCE_IO | IORESOURCE_BUSY,
257 };
258
259 static struct resource reserve_iomem = {
260         .start = 0,
261         .end = -1,
262         .name = "paravirt-iomem",
263         .flags = IORESOURCE_MEM | IORESOURCE_BUSY,
264 };
265
266 /*
267  * Reserve the whole legacy IO space to prevent any legacy drivers
268  * from wasting time probing for their hardware.  This is a fairly
269  * brute-force approach to disabling all non-virtual drivers.
270  *
271  * Note that this must be called very early to have any effect.
272  */
273 int paravirt_disable_iospace(void)
274 {
275         int ret;
276
277         ret = request_resource(&ioport_resource, &reserve_ioports);
278         if (ret == 0) {
279                 ret = request_resource(&iomem_resource, &reserve_iomem);
280                 if (ret)
281                         release_resource(&reserve_ioports);
282         }
283
284         return ret;
285 }
286
287 static DEFINE_PER_CPU(enum paravirt_lazy_mode, paravirt_lazy_mode) = PARAVIRT_LAZY_NONE;
288
289 static inline void enter_lazy(enum paravirt_lazy_mode mode)
290 {
291         BUG_ON(x86_read_percpu(paravirt_lazy_mode) != PARAVIRT_LAZY_NONE);
292         BUG_ON(preemptible());
293
294         x86_write_percpu(paravirt_lazy_mode, mode);
295 }
296
297 void paravirt_leave_lazy(enum paravirt_lazy_mode mode)
298 {
299         BUG_ON(x86_read_percpu(paravirt_lazy_mode) != mode);
300         BUG_ON(preemptible());
301
302         x86_write_percpu(paravirt_lazy_mode, PARAVIRT_LAZY_NONE);
303 }
304
305 void paravirt_enter_lazy_mmu(void)
306 {
307         enter_lazy(PARAVIRT_LAZY_MMU);
308 }
309
310 void paravirt_leave_lazy_mmu(void)
311 {
312         paravirt_leave_lazy(PARAVIRT_LAZY_MMU);
313 }
314
315 void paravirt_enter_lazy_cpu(void)
316 {
317         enter_lazy(PARAVIRT_LAZY_CPU);
318 }
319
320 void paravirt_leave_lazy_cpu(void)
321 {
322         paravirt_leave_lazy(PARAVIRT_LAZY_CPU);
323 }
324
325 enum paravirt_lazy_mode paravirt_get_lazy_mode(void)
326 {
327         return x86_read_percpu(paravirt_lazy_mode);
328 }
329
330 struct pv_info pv_info = {
331         .name = "bare hardware",
332         .paravirt_enabled = 0,
333         .kernel_rpl = 0,
334         .shared_kernel_pmd = 1, /* Only used when CONFIG_X86_PAE is set */
335 };
336
337 struct pv_init_ops pv_init_ops = {
338         .patch = native_patch,
339         .banner = default_banner,
340         .arch_setup = paravirt_nop,
341         .memory_setup = machine_specific_memory_setup,
342 };
343
344 struct pv_time_ops pv_time_ops = {
345         .time_init = hpet_time_init,
346         .get_wallclock = native_get_wallclock,
347         .set_wallclock = native_set_wallclock,
348         .sched_clock = native_sched_clock,
349         .get_cpu_khz = native_calculate_cpu_khz,
350 };
351
352 struct pv_irq_ops pv_irq_ops = {
353         .init_IRQ = native_init_IRQ,
354         .save_fl = native_save_fl,
355         .restore_fl = native_restore_fl,
356         .irq_disable = native_irq_disable,
357         .irq_enable = native_irq_enable,
358         .safe_halt = native_safe_halt,
359         .halt = native_halt,
360 };
361
362 struct pv_cpu_ops pv_cpu_ops = {
363         .cpuid = native_cpuid,
364         .get_debugreg = native_get_debugreg,
365         .set_debugreg = native_set_debugreg,
366         .clts = native_clts,
367         .read_cr0 = native_read_cr0,
368         .write_cr0 = native_write_cr0,
369         .read_cr4 = native_read_cr4,
370         .read_cr4_safe = native_read_cr4_safe,
371         .write_cr4 = native_write_cr4,
372         .wbinvd = native_wbinvd,
373         .read_msr = native_read_msr_safe,
374         .write_msr = native_write_msr_safe,
375         .read_tsc = native_read_tsc,
376         .read_pmc = native_read_pmc,
377         .load_tr_desc = native_load_tr_desc,
378         .set_ldt = native_set_ldt,
379         .load_gdt = native_load_gdt,
380         .load_idt = native_load_idt,
381         .store_gdt = native_store_gdt,
382         .store_idt = native_store_idt,
383         .store_tr = native_store_tr,
384         .load_tls = native_load_tls,
385         .write_ldt_entry = native_write_ldt_entry,
386         .write_gdt_entry = native_write_gdt_entry,
387         .write_idt_entry = native_write_idt_entry,
388         .load_sp0 = native_load_sp0,
389
390         .irq_enable_syscall_ret = native_irq_enable_syscall_ret,
391         .iret = native_iret,
392
393         .set_iopl_mask = native_set_iopl_mask,
394         .io_delay = native_io_delay,
395
396         .lazy_mode = {
397                 .enter = paravirt_nop,
398                 .leave = paravirt_nop,
399         },
400 };
401
402 struct pv_apic_ops pv_apic_ops = {
403 #ifdef CONFIG_X86_LOCAL_APIC
404         .apic_write = native_apic_write,
405         .apic_write_atomic = native_apic_write_atomic,
406         .apic_read = native_apic_read,
407         .setup_boot_clock = setup_boot_APIC_clock,
408         .setup_secondary_clock = setup_secondary_APIC_clock,
409         .startup_ipi_hook = paravirt_nop,
410 #endif
411 };
412
413 struct pv_mmu_ops pv_mmu_ops = {
414         .pagetable_setup_start = native_pagetable_setup_start,
415         .pagetable_setup_done = native_pagetable_setup_done,
416
417         .read_cr2 = native_read_cr2,
418         .write_cr2 = native_write_cr2,
419         .read_cr3 = native_read_cr3,
420         .write_cr3 = native_write_cr3,
421
422         .flush_tlb_user = native_flush_tlb,
423         .flush_tlb_kernel = native_flush_tlb_global,
424         .flush_tlb_single = native_flush_tlb_single,
425         .flush_tlb_others = native_flush_tlb_others,
426
427         .alloc_pt = paravirt_nop,
428         .alloc_pd = paravirt_nop,
429         .alloc_pd_clone = paravirt_nop,
430         .release_pt = paravirt_nop,
431         .release_pd = paravirt_nop,
432
433         .set_pte = native_set_pte,
434         .set_pte_at = native_set_pte_at,
435         .set_pmd = native_set_pmd,
436         .pte_update = paravirt_nop,
437         .pte_update_defer = paravirt_nop,
438
439 #ifdef CONFIG_HIGHPTE
440         .kmap_atomic_pte = kmap_atomic,
441 #endif
442
443 #ifdef CONFIG_X86_PAE
444         .set_pte_atomic = native_set_pte_atomic,
445         .set_pte_present = native_set_pte_present,
446         .set_pud = native_set_pud,
447         .pte_clear = native_pte_clear,
448         .pmd_clear = native_pmd_clear,
449
450         .pmd_val = native_pmd_val,
451         .make_pmd = native_make_pmd,
452 #endif
453
454         .pte_val = native_pte_val,
455         .pgd_val = native_pgd_val,
456
457         .make_pte = native_make_pte,
458         .make_pgd = native_make_pgd,
459
460         .dup_mmap = paravirt_nop,
461         .exit_mmap = paravirt_nop,
462         .activate_mm = paravirt_nop,
463
464         .lazy_mode = {
465                 .enter = paravirt_nop,
466                 .leave = paravirt_nop,
467         },
468 };
469
470 EXPORT_SYMBOL_GPL(pv_time_ops);
471 EXPORT_SYMBOL    (pv_cpu_ops);
472 EXPORT_SYMBOL    (pv_mmu_ops);
473 EXPORT_SYMBOL_GPL(pv_apic_ops);
474 EXPORT_SYMBOL_GPL(pv_info);
475 EXPORT_SYMBOL    (pv_irq_ops);