Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wirel...
[linux-2.6.git] / arch / x86 / xen / setup.c
1 /*
2  * Machine specific setup for xen
3  *
4  * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
5  */
6
7 #include <linux/module.h>
8 #include <linux/sched.h>
9 #include <linux/mm.h>
10 #include <linux/pm.h>
11 #include <linux/memblock.h>
12
13 #include <asm/elf.h>
14 #include <asm/vdso.h>
15 #include <asm/e820.h>
16 #include <asm/setup.h>
17 #include <asm/acpi.h>
18 #include <asm/xen/hypervisor.h>
19 #include <asm/xen/hypercall.h>
20
21 #include <xen/xen.h>
22 #include <xen/page.h>
23 #include <xen/interface/callback.h>
24 #include <xen/interface/memory.h>
25 #include <xen/interface/physdev.h>
26 #include <xen/features.h>
27
28 #include "xen-ops.h"
29 #include "vdso.h"
30
31 /* These are code, but not functions.  Defined in entry.S */
32 extern const char xen_hypervisor_callback[];
33 extern const char xen_failsafe_callback[];
34 extern void xen_sysenter_target(void);
35 extern void xen_syscall_target(void);
36 extern void xen_syscall32_target(void);
37
38 /* Amount of extra memory space we add to the e820 ranges */
39 phys_addr_t xen_extra_mem_start, xen_extra_mem_size;
40
41 /* 
42  * The maximum amount of extra memory compared to the base size.  The
43  * main scaling factor is the size of struct page.  At extreme ratios
44  * of base:extra, all the base memory can be filled with page
45  * structures for the extra memory, leaving no space for anything
46  * else.
47  * 
48  * 10x seems like a reasonable balance between scaling flexibility and
49  * leaving a practically usable system.
50  */
51 #define EXTRA_MEM_RATIO         (10)
52
53 static __init void xen_add_extra_mem(unsigned long pages)
54 {
55         u64 size = (u64)pages * PAGE_SIZE;
56         u64 extra_start = xen_extra_mem_start + xen_extra_mem_size;
57
58         if (!pages)
59                 return;
60
61         e820_add_region(extra_start, size, E820_RAM);
62         sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
63
64         memblock_x86_reserve_range(extra_start, extra_start + size, "XEN EXTRA");
65
66         xen_extra_mem_size += size;
67
68         xen_max_p2m_pfn = PFN_DOWN(extra_start + size);
69 }
70
71 static unsigned long __init xen_release_chunk(phys_addr_t start_addr,
72                                               phys_addr_t end_addr)
73 {
74         struct xen_memory_reservation reservation = {
75                 .address_bits = 0,
76                 .extent_order = 0,
77                 .domid        = DOMID_SELF
78         };
79         unsigned long start, end;
80         unsigned long len = 0;
81         unsigned long pfn;
82         int ret;
83
84         start = PFN_UP(start_addr);
85         end = PFN_DOWN(end_addr);
86
87         if (end <= start)
88                 return 0;
89
90         printk(KERN_INFO "xen_release_chunk: looking at area pfn %lx-%lx: ",
91                start, end);
92         for(pfn = start; pfn < end; pfn++) {
93                 unsigned long mfn = pfn_to_mfn(pfn);
94
95                 /* Make sure pfn exists to start with */
96                 if (mfn == INVALID_P2M_ENTRY || mfn_to_pfn(mfn) != pfn)
97                         continue;
98
99                 set_xen_guest_handle(reservation.extent_start, &mfn);
100                 reservation.nr_extents = 1;
101
102                 ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation,
103                                            &reservation);
104                 WARN(ret != 1, "Failed to release memory %lx-%lx err=%d\n",
105                      start, end, ret);
106                 if (ret == 1) {
107                         set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
108                         len++;
109                 }
110         }
111         printk(KERN_CONT "%ld pages freed\n", len);
112
113         return len;
114 }
115
116 static unsigned long __init xen_return_unused_memory(unsigned long max_pfn,
117                                                      const struct e820map *e820)
118 {
119         phys_addr_t max_addr = PFN_PHYS(max_pfn);
120         phys_addr_t last_end = ISA_END_ADDRESS;
121         unsigned long released = 0;
122         int i;
123
124         /* Free any unused memory above the low 1Mbyte. */
125         for (i = 0; i < e820->nr_map && last_end < max_addr; i++) {
126                 phys_addr_t end = e820->map[i].addr;
127                 end = min(max_addr, end);
128
129                 if (last_end < end)
130                         released += xen_release_chunk(last_end, end);
131                 last_end = max(last_end, e820->map[i].addr + e820->map[i].size);
132         }
133
134         if (last_end < max_addr)
135                 released += xen_release_chunk(last_end, max_addr);
136
137         printk(KERN_INFO "released %ld pages of unused memory\n", released);
138         return released;
139 }
140
141 /**
142  * machine_specific_memory_setup - Hook for machine specific memory setup.
143  **/
144 char * __init xen_memory_setup(void)
145 {
146         static struct e820entry map[E820MAX] __initdata;
147
148         unsigned long max_pfn = xen_start_info->nr_pages;
149         unsigned long long mem_end;
150         int rc;
151         struct xen_memory_map memmap;
152         unsigned long extra_pages = 0;
153         unsigned long extra_limit;
154         int i;
155         int op;
156
157         max_pfn = min(MAX_DOMAIN_PAGES, max_pfn);
158         mem_end = PFN_PHYS(max_pfn);
159
160         memmap.nr_entries = E820MAX;
161         set_xen_guest_handle(memmap.buffer, map);
162
163         op = xen_initial_domain() ?
164                 XENMEM_machine_memory_map :
165                 XENMEM_memory_map;
166         rc = HYPERVISOR_memory_op(op, &memmap);
167         if (rc == -ENOSYS) {
168                 BUG_ON(xen_initial_domain());
169                 memmap.nr_entries = 1;
170                 map[0].addr = 0ULL;
171                 map[0].size = mem_end;
172                 /* 8MB slack (to balance backend allocations). */
173                 map[0].size += 8ULL << 20;
174                 map[0].type = E820_RAM;
175                 rc = 0;
176         }
177         BUG_ON(rc);
178
179         e820.nr_map = 0;
180         xen_extra_mem_start = mem_end;
181         for (i = 0; i < memmap.nr_entries; i++) {
182                 unsigned long long end;
183
184                 /* Guard against non-page aligned E820 entries. */
185                 if (map[i].type == E820_RAM)
186                         map[i].size -= (map[i].size + map[i].addr) % PAGE_SIZE;
187
188                 end = map[i].addr + map[i].size;
189                 if (map[i].type == E820_RAM && end > mem_end) {
190                         /* RAM off the end - may be partially included */
191                         u64 delta = min(map[i].size, end - mem_end);
192
193                         map[i].size -= delta;
194                         end -= delta;
195
196                         extra_pages += PFN_DOWN(delta);
197                 }
198
199                 if (map[i].size > 0 && end > xen_extra_mem_start)
200                         xen_extra_mem_start = end;
201
202                 /* Add region if any remains */
203                 if (map[i].size > 0)
204                         e820_add_region(map[i].addr, map[i].size, map[i].type);
205         }
206
207         /*
208          * In domU, the ISA region is normal, usable memory, but we
209          * reserve ISA memory anyway because too many things poke
210          * about in there.
211          *
212          * In Dom0, the host E820 information can leave gaps in the
213          * ISA range, which would cause us to release those pages.  To
214          * avoid this, we unconditionally reserve them here.
215          */
216         e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS,
217                         E820_RESERVED);
218
219         /*
220          * Reserve Xen bits:
221          *  - mfn_list
222          *  - xen_start_info
223          * See comment above "struct start_info" in <xen/interface/xen.h>
224          */
225         memblock_x86_reserve_range(__pa(xen_start_info->mfn_list),
226                       __pa(xen_start_info->pt_base),
227                         "XEN START INFO");
228
229         sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
230
231         extra_pages += xen_return_unused_memory(xen_start_info->nr_pages, &e820);
232
233         /*
234          * Clamp the amount of extra memory to a EXTRA_MEM_RATIO
235          * factor the base size.  On non-highmem systems, the base
236          * size is the full initial memory allocation; on highmem it
237          * is limited to the max size of lowmem, so that it doesn't
238          * get completely filled.
239          *
240          * In principle there could be a problem in lowmem systems if
241          * the initial memory is also very large with respect to
242          * lowmem, but we won't try to deal with that here.
243          */
244         extra_limit = min(EXTRA_MEM_RATIO * min(max_pfn, PFN_DOWN(MAXMEM)),
245                           max_pfn + extra_pages);
246
247         if (extra_limit >= max_pfn)
248                 extra_pages = extra_limit - max_pfn;
249         else
250                 extra_pages = 0;
251
252         xen_add_extra_mem(extra_pages);
253
254         return "Xen";
255 }
256
257 /*
258  * Set the bit indicating "nosegneg" library variants should be used.
259  * We only need to bother in pure 32-bit mode; compat 32-bit processes
260  * can have un-truncated segments, so wrapping around is allowed.
261  */
262 static void __init fiddle_vdso(void)
263 {
264 #ifdef CONFIG_X86_32
265         u32 *mask;
266         mask = VDSO32_SYMBOL(&vdso32_int80_start, NOTE_MASK);
267         *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
268         mask = VDSO32_SYMBOL(&vdso32_sysenter_start, NOTE_MASK);
269         *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
270 #endif
271 }
272
273 static __cpuinit int register_callback(unsigned type, const void *func)
274 {
275         struct callback_register callback = {
276                 .type = type,
277                 .address = XEN_CALLBACK(__KERNEL_CS, func),
278                 .flags = CALLBACKF_mask_events,
279         };
280
281         return HYPERVISOR_callback_op(CALLBACKOP_register, &callback);
282 }
283
284 void __cpuinit xen_enable_sysenter(void)
285 {
286         int ret;
287         unsigned sysenter_feature;
288
289 #ifdef CONFIG_X86_32
290         sysenter_feature = X86_FEATURE_SEP;
291 #else
292         sysenter_feature = X86_FEATURE_SYSENTER32;
293 #endif
294
295         if (!boot_cpu_has(sysenter_feature))
296                 return;
297
298         ret = register_callback(CALLBACKTYPE_sysenter, xen_sysenter_target);
299         if(ret != 0)
300                 setup_clear_cpu_cap(sysenter_feature);
301 }
302
303 void __cpuinit xen_enable_syscall(void)
304 {
305 #ifdef CONFIG_X86_64
306         int ret;
307
308         ret = register_callback(CALLBACKTYPE_syscall, xen_syscall_target);
309         if (ret != 0) {
310                 printk(KERN_ERR "Failed to set syscall callback: %d\n", ret);
311                 /* Pretty fatal; 64-bit userspace has no other
312                    mechanism for syscalls. */
313         }
314
315         if (boot_cpu_has(X86_FEATURE_SYSCALL32)) {
316                 ret = register_callback(CALLBACKTYPE_syscall32,
317                                         xen_syscall32_target);
318                 if (ret != 0)
319                         setup_clear_cpu_cap(X86_FEATURE_SYSCALL32);
320         }
321 #endif /* CONFIG_X86_64 */
322 }
323
324 void __init xen_arch_setup(void)
325 {
326         xen_panic_handler_init();
327
328         HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments);
329         HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_writable_pagetables);
330
331         if (!xen_feature(XENFEAT_auto_translated_physmap))
332                 HYPERVISOR_vm_assist(VMASST_CMD_enable,
333                                      VMASST_TYPE_pae_extended_cr3);
334
335         if (register_callback(CALLBACKTYPE_event, xen_hypervisor_callback) ||
336             register_callback(CALLBACKTYPE_failsafe, xen_failsafe_callback))
337                 BUG();
338
339         xen_enable_sysenter();
340         xen_enable_syscall();
341
342 #ifdef CONFIG_ACPI
343         if (!(xen_start_info->flags & SIF_INITDOMAIN)) {
344                 printk(KERN_INFO "ACPI in unprivileged domain disabled\n");
345                 disable_acpi();
346         }
347 #endif
348
349         memcpy(boot_command_line, xen_start_info->cmd_line,
350                MAX_GUEST_CMDLINE > COMMAND_LINE_SIZE ?
351                COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE);
352
353         /* Set up idle, making sure it calls safe_halt() pvop */
354 #ifdef CONFIG_X86_32
355         boot_cpu_data.hlt_works_ok = 1;
356 #endif
357         pm_idle = default_idle;
358         boot_option_idle_override = IDLE_HALT;
359
360         fiddle_vdso();
361 }