Linux 2.6.31.6
[linux/fpc-iii.git] / arch / x86 / kernel / setup_percpu.c
blob07d81916f2120f5a55ad0116620630288682bd74
1 #include <linux/kernel.h>
2 #include <linux/module.h>
3 #include <linux/init.h>
4 #include <linux/bootmem.h>
5 #include <linux/percpu.h>
6 #include <linux/kexec.h>
7 #include <linux/crash_dump.h>
8 #include <linux/smp.h>
9 #include <linux/topology.h>
10 #include <linux/pfn.h>
11 #include <asm/sections.h>
12 #include <asm/processor.h>
13 #include <asm/setup.h>
14 #include <asm/mpspec.h>
15 #include <asm/apicdef.h>
16 #include <asm/highmem.h>
17 #include <asm/proto.h>
18 #include <asm/cpumask.h>
19 #include <asm/cpu.h>
20 #include <asm/stackprotector.h>
22 #ifdef CONFIG_DEBUG_PER_CPU_MAPS
23 # define DBG(x...) printk(KERN_DEBUG x)
24 #else
25 # define DBG(x...)
26 #endif
28 DEFINE_PER_CPU(int, cpu_number);
29 EXPORT_PER_CPU_SYMBOL(cpu_number);
31 #ifdef CONFIG_X86_64
32 #define BOOT_PERCPU_OFFSET ((unsigned long)__per_cpu_load)
33 #else
34 #define BOOT_PERCPU_OFFSET 0
35 #endif
37 DEFINE_PER_CPU(unsigned long, this_cpu_off) = BOOT_PERCPU_OFFSET;
38 EXPORT_PER_CPU_SYMBOL(this_cpu_off);
40 unsigned long __per_cpu_offset[NR_CPUS] __read_mostly = {
41 [0 ... NR_CPUS-1] = BOOT_PERCPU_OFFSET,
43 EXPORT_SYMBOL(__per_cpu_offset);
46 * On x86_64 symbols referenced from code should be reachable using
47 * 32bit relocations. Reserve space for static percpu variables in
48 * modules so that they are always served from the first chunk which
49 * is located at the percpu segment base. On x86_32, anything can
50 * address anywhere. No need to reserve space in the first chunk.
52 #ifdef CONFIG_X86_64
53 #define PERCPU_FIRST_CHUNK_RESERVE PERCPU_MODULE_RESERVE
54 #else
55 #define PERCPU_FIRST_CHUNK_RESERVE 0
56 #endif
58 /**
59 * pcpu_need_numa - determine percpu allocation needs to consider NUMA
61 * If NUMA is not configured or there is only one NUMA node available,
62 * there is no reason to consider NUMA. This function determines
63 * whether percpu allocation should consider NUMA or not.
65 * RETURNS:
66 * true if NUMA should be considered; otherwise, false.
68 static bool __init pcpu_need_numa(void)
70 #ifdef CONFIG_NEED_MULTIPLE_NODES
71 pg_data_t *last = NULL;
72 unsigned int cpu;
74 for_each_possible_cpu(cpu) {
75 int node = early_cpu_to_node(cpu);
77 if (node_online(node) && NODE_DATA(node) &&
78 last && last != NODE_DATA(node))
79 return true;
81 last = NODE_DATA(node);
83 #endif
84 return false;
87 /**
88 * pcpu_alloc_bootmem - NUMA friendly alloc_bootmem wrapper for percpu
89 * @cpu: cpu to allocate for
90 * @size: size allocation in bytes
91 * @align: alignment
93 * Allocate @size bytes aligned at @align for cpu @cpu. This wrapper
94 * does the right thing for NUMA regardless of the current
95 * configuration.
97 * RETURNS:
98 * Pointer to the allocated area on success, NULL on failure.
100 static void * __init pcpu_alloc_bootmem(unsigned int cpu, unsigned long size,
101 unsigned long align)
103 const unsigned long goal = __pa(MAX_DMA_ADDRESS);
104 #ifdef CONFIG_NEED_MULTIPLE_NODES
105 int node = early_cpu_to_node(cpu);
106 void *ptr;
108 if (!node_online(node) || !NODE_DATA(node)) {
109 ptr = __alloc_bootmem_nopanic(size, align, goal);
110 pr_info("cpu %d has no node %d or node-local memory\n",
111 cpu, node);
112 pr_debug("per cpu data for cpu%d %lu bytes at %016lx\n",
113 cpu, size, __pa(ptr));
114 } else {
115 ptr = __alloc_bootmem_node_nopanic(NODE_DATA(node),
116 size, align, goal);
117 pr_debug("per cpu data for cpu%d %lu bytes on node%d at "
118 "%016lx\n", cpu, size, node, __pa(ptr));
120 return ptr;
121 #else
122 return __alloc_bootmem_nopanic(size, align, goal);
123 #endif
127 * Large page remap allocator
129 * This allocator uses PMD page as unit. A PMD page is allocated for
130 * each cpu and each is remapped into vmalloc area using PMD mapping.
131 * As PMD page is quite large, only part of it is used for the first
132 * chunk. Unused part is returned to the bootmem allocator.
134 * So, the PMD pages are mapped twice - once to the physical mapping
135 * and to the vmalloc area for the first percpu chunk. The double
136 * mapping does add one more PMD TLB entry pressure but still is much
137 * better than only using 4k mappings while still being NUMA friendly.
139 #ifdef CONFIG_NEED_MULTIPLE_NODES
140 struct pcpul_ent {
141 unsigned int cpu;
142 void *ptr;
145 static size_t pcpul_size;
146 static struct pcpul_ent *pcpul_map;
147 static struct vm_struct pcpul_vm;
149 static struct page * __init pcpul_get_page(unsigned int cpu, int pageno)
151 size_t off = (size_t)pageno << PAGE_SHIFT;
153 if (off >= pcpul_size)
154 return NULL;
156 return virt_to_page(pcpul_map[cpu].ptr + off);
159 static ssize_t __init setup_pcpu_lpage(size_t static_size, bool chosen)
161 size_t map_size, dyn_size;
162 unsigned int cpu;
163 int i, j;
164 ssize_t ret;
166 if (!chosen) {
167 size_t vm_size = VMALLOC_END - VMALLOC_START;
168 size_t tot_size = nr_cpu_ids * PMD_SIZE;
170 /* on non-NUMA, embedding is better */
171 if (!pcpu_need_numa())
172 return -EINVAL;
174 /* don't consume more than 20% of vmalloc area */
175 if (tot_size > vm_size / 5) {
176 pr_info("PERCPU: too large chunk size %zuMB for "
177 "large page remap\n", tot_size >> 20);
178 return -EINVAL;
182 /* need PSE */
183 if (!cpu_has_pse) {
184 pr_warning("PERCPU: lpage allocator requires PSE\n");
185 return -EINVAL;
189 * Currently supports only single page. Supporting multiple
190 * pages won't be too difficult if it ever becomes necessary.
192 pcpul_size = PFN_ALIGN(static_size + PERCPU_MODULE_RESERVE +
193 PERCPU_DYNAMIC_RESERVE);
194 if (pcpul_size > PMD_SIZE) {
195 pr_warning("PERCPU: static data is larger than large page, "
196 "can't use large page\n");
197 return -EINVAL;
199 dyn_size = pcpul_size - static_size - PERCPU_FIRST_CHUNK_RESERVE;
201 /* allocate pointer array and alloc large pages */
202 map_size = PFN_ALIGN(nr_cpu_ids * sizeof(pcpul_map[0]));
203 pcpul_map = alloc_bootmem(map_size);
205 for_each_possible_cpu(cpu) {
206 pcpul_map[cpu].cpu = cpu;
207 pcpul_map[cpu].ptr = pcpu_alloc_bootmem(cpu, PMD_SIZE,
208 PMD_SIZE);
209 if (!pcpul_map[cpu].ptr) {
210 pr_warning("PERCPU: failed to allocate large page "
211 "for cpu%u\n", cpu);
212 goto enomem;
216 * Only use pcpul_size bytes and give back the rest.
218 * Ingo: The 2MB up-rounding bootmem is needed to make
219 * sure the partial 2MB page is still fully RAM - it's
220 * not well-specified to have a PAT-incompatible area
221 * (unmapped RAM, device memory, etc.) in that hole.
223 free_bootmem(__pa(pcpul_map[cpu].ptr + pcpul_size),
224 PMD_SIZE - pcpul_size);
226 memcpy(pcpul_map[cpu].ptr, __per_cpu_load, static_size);
229 /* allocate address and map */
230 pcpul_vm.flags = VM_ALLOC;
231 pcpul_vm.size = nr_cpu_ids * PMD_SIZE;
232 vm_area_register_early(&pcpul_vm, PMD_SIZE);
234 for_each_possible_cpu(cpu) {
235 pmd_t *pmd, pmd_v;
237 pmd = populate_extra_pmd((unsigned long)pcpul_vm.addr +
238 cpu * PMD_SIZE);
239 pmd_v = pfn_pmd(page_to_pfn(virt_to_page(pcpul_map[cpu].ptr)),
240 PAGE_KERNEL_LARGE);
241 set_pmd(pmd, pmd_v);
244 /* we're ready, commit */
245 pr_info("PERCPU: Remapped at %p with large pages, static data "
246 "%zu bytes\n", pcpul_vm.addr, static_size);
248 ret = pcpu_setup_first_chunk(pcpul_get_page, static_size,
249 PERCPU_FIRST_CHUNK_RESERVE, dyn_size,
250 PMD_SIZE, pcpul_vm.addr, NULL);
252 /* sort pcpul_map array for pcpu_lpage_remapped() */
253 for (i = 0; i < nr_cpu_ids - 1; i++)
254 for (j = i + 1; j < nr_cpu_ids; j++)
255 if (pcpul_map[i].ptr > pcpul_map[j].ptr) {
256 struct pcpul_ent tmp = pcpul_map[i];
257 pcpul_map[i] = pcpul_map[j];
258 pcpul_map[j] = tmp;
261 return ret;
263 enomem:
264 for_each_possible_cpu(cpu)
265 if (pcpul_map[cpu].ptr)
266 free_bootmem(__pa(pcpul_map[cpu].ptr), pcpul_size);
267 free_bootmem(__pa(pcpul_map), map_size);
268 return -ENOMEM;
272 * pcpu_lpage_remapped - determine whether a kaddr is in pcpul recycled area
273 * @kaddr: the kernel address in question
275 * Determine whether @kaddr falls in the pcpul recycled area. This is
276 * used by pageattr to detect VM aliases and break up the pcpu PMD
277 * mapping such that the same physical page is not mapped under
278 * different attributes.
280 * The recycled area is always at the tail of a partially used PMD
281 * page.
283 * RETURNS:
284 * Address of corresponding remapped pcpu address if match is found;
285 * otherwise, NULL.
287 void *pcpu_lpage_remapped(void *kaddr)
289 void *pmd_addr = (void *)((unsigned long)kaddr & PMD_MASK);
290 unsigned long offset = (unsigned long)kaddr & ~PMD_MASK;
291 int left = 0, right = nr_cpu_ids - 1;
292 int pos;
294 /* pcpul in use at all? */
295 if (!pcpul_map)
296 return NULL;
298 /* okay, perform binary search */
299 while (left <= right) {
300 pos = (left + right) / 2;
302 if (pcpul_map[pos].ptr < pmd_addr)
303 left = pos + 1;
304 else if (pcpul_map[pos].ptr > pmd_addr)
305 right = pos - 1;
306 else {
307 /* it shouldn't be in the area for the first chunk */
308 WARN_ON(offset < pcpul_size);
310 return pcpul_vm.addr +
311 pcpul_map[pos].cpu * PMD_SIZE + offset;
315 return NULL;
317 #else
318 static ssize_t __init setup_pcpu_lpage(size_t static_size, bool chosen)
320 return -EINVAL;
322 #endif
325 * Embedding allocator
327 * The first chunk is sized to just contain the static area plus
328 * module and dynamic reserves and embedded into linear physical
329 * mapping so that it can use PMD mapping without additional TLB
330 * pressure.
332 static ssize_t __init setup_pcpu_embed(size_t static_size, bool chosen)
334 size_t reserve = PERCPU_MODULE_RESERVE + PERCPU_DYNAMIC_RESERVE;
337 * If large page isn't supported, there's no benefit in doing
338 * this. Also, embedding allocation doesn't play well with
339 * NUMA.
341 if (!chosen && (!cpu_has_pse || pcpu_need_numa()))
342 return -EINVAL;
344 return pcpu_embed_first_chunk(static_size, PERCPU_FIRST_CHUNK_RESERVE,
345 reserve - PERCPU_FIRST_CHUNK_RESERVE, -1);
349 * 4k page allocator
351 * This is the basic allocator. Static percpu area is allocated
352 * page-by-page and most of initialization is done by the generic
353 * setup function.
355 static struct page **pcpu4k_pages __initdata;
356 static int pcpu4k_nr_static_pages __initdata;
358 static struct page * __init pcpu4k_get_page(unsigned int cpu, int pageno)
360 if (pageno < pcpu4k_nr_static_pages)
361 return pcpu4k_pages[cpu * pcpu4k_nr_static_pages + pageno];
362 return NULL;
365 static void __init pcpu4k_populate_pte(unsigned long addr)
367 populate_extra_pte(addr);
370 static ssize_t __init setup_pcpu_4k(size_t static_size)
372 size_t pages_size;
373 unsigned int cpu;
374 int i, j;
375 ssize_t ret;
377 pcpu4k_nr_static_pages = PFN_UP(static_size);
379 /* unaligned allocations can't be freed, round up to page size */
380 pages_size = PFN_ALIGN(pcpu4k_nr_static_pages * nr_cpu_ids
381 * sizeof(pcpu4k_pages[0]));
382 pcpu4k_pages = alloc_bootmem(pages_size);
384 /* allocate and copy */
385 j = 0;
386 for_each_possible_cpu(cpu)
387 for (i = 0; i < pcpu4k_nr_static_pages; i++) {
388 void *ptr;
390 ptr = pcpu_alloc_bootmem(cpu, PAGE_SIZE, PAGE_SIZE);
391 if (!ptr) {
392 pr_warning("PERCPU: failed to allocate "
393 "4k page for cpu%u\n", cpu);
394 goto enomem;
397 memcpy(ptr, __per_cpu_load + i * PAGE_SIZE, PAGE_SIZE);
398 pcpu4k_pages[j++] = virt_to_page(ptr);
401 /* we're ready, commit */
402 pr_info("PERCPU: Allocated %d 4k pages, static data %zu bytes\n",
403 pcpu4k_nr_static_pages, static_size);
405 ret = pcpu_setup_first_chunk(pcpu4k_get_page, static_size,
406 PERCPU_FIRST_CHUNK_RESERVE, -1,
407 -1, NULL, pcpu4k_populate_pte);
408 goto out_free_ar;
410 enomem:
411 while (--j >= 0)
412 free_bootmem(__pa(page_address(pcpu4k_pages[j])), PAGE_SIZE);
413 ret = -ENOMEM;
414 out_free_ar:
415 free_bootmem(__pa(pcpu4k_pages), pages_size);
416 return ret;
419 /* for explicit first chunk allocator selection */
420 static char pcpu_chosen_alloc[16] __initdata;
422 static int __init percpu_alloc_setup(char *str)
424 strncpy(pcpu_chosen_alloc, str, sizeof(pcpu_chosen_alloc) - 1);
425 return 0;
427 early_param("percpu_alloc", percpu_alloc_setup);
429 static inline void setup_percpu_segment(int cpu)
431 #ifdef CONFIG_X86_32
432 struct desc_struct gdt;
434 pack_descriptor(&gdt, per_cpu_offset(cpu), 0xFFFFF,
435 0x2 | DESCTYPE_S, 0x8);
436 gdt.s = 1;
437 write_gdt_entry(get_cpu_gdt_table(cpu),
438 GDT_ENTRY_PERCPU, &gdt, DESCTYPE_S);
439 #endif
442 void __init setup_per_cpu_areas(void)
444 size_t static_size = __per_cpu_end - __per_cpu_start;
445 unsigned int cpu;
446 unsigned long delta;
447 size_t pcpu_unit_size;
448 ssize_t ret;
450 pr_info("NR_CPUS:%d nr_cpumask_bits:%d nr_cpu_ids:%d nr_node_ids:%d\n",
451 NR_CPUS, nr_cpumask_bits, nr_cpu_ids, nr_node_ids);
454 * Allocate percpu area. If PSE is supported, try to make use
455 * of large page mappings. Please read comments on top of
456 * each allocator for details.
458 ret = -EINVAL;
459 if (strlen(pcpu_chosen_alloc)) {
460 if (strcmp(pcpu_chosen_alloc, "4k")) {
461 if (!strcmp(pcpu_chosen_alloc, "lpage"))
462 ret = setup_pcpu_lpage(static_size, true);
463 else if (!strcmp(pcpu_chosen_alloc, "embed"))
464 ret = setup_pcpu_embed(static_size, true);
465 else
466 pr_warning("PERCPU: unknown allocator %s "
467 "specified\n", pcpu_chosen_alloc);
468 if (ret < 0)
469 pr_warning("PERCPU: %s allocator failed (%zd), "
470 "falling back to 4k\n",
471 pcpu_chosen_alloc, ret);
473 } else {
474 ret = setup_pcpu_lpage(static_size, false);
475 if (ret < 0)
476 ret = setup_pcpu_embed(static_size, false);
478 if (ret < 0)
479 ret = setup_pcpu_4k(static_size);
480 if (ret < 0)
481 panic("cannot allocate static percpu area (%zu bytes, err=%zd)",
482 static_size, ret);
484 pcpu_unit_size = ret;
486 /* alrighty, percpu areas up and running */
487 delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
488 for_each_possible_cpu(cpu) {
489 per_cpu_offset(cpu) = delta + cpu * pcpu_unit_size;
490 per_cpu(this_cpu_off, cpu) = per_cpu_offset(cpu);
491 per_cpu(cpu_number, cpu) = cpu;
492 setup_percpu_segment(cpu);
493 setup_stack_canary_segment(cpu);
495 * Copy data used in early init routines from the
496 * initial arrays to the per cpu data areas. These
497 * arrays then become expendable and the *_early_ptr's
498 * are zeroed indicating that the static arrays are
499 * gone.
501 #ifdef CONFIG_X86_LOCAL_APIC
502 per_cpu(x86_cpu_to_apicid, cpu) =
503 early_per_cpu_map(x86_cpu_to_apicid, cpu);
504 per_cpu(x86_bios_cpu_apicid, cpu) =
505 early_per_cpu_map(x86_bios_cpu_apicid, cpu);
506 #endif
507 #ifdef CONFIG_X86_64
508 per_cpu(irq_stack_ptr, cpu) =
509 per_cpu(irq_stack_union.irq_stack, cpu) +
510 IRQ_STACK_SIZE - 64;
511 #ifdef CONFIG_NUMA
512 per_cpu(x86_cpu_to_node_map, cpu) =
513 early_per_cpu_map(x86_cpu_to_node_map, cpu);
514 #endif
515 #endif
517 * Up to this point, the boot CPU has been using .data.init
518 * area. Reload any changed state for the boot CPU.
520 if (cpu == boot_cpu_id)
521 switch_to_new_gdt(cpu);
524 /* indicate the early static arrays will soon be gone */
525 #ifdef CONFIG_X86_LOCAL_APIC
526 early_per_cpu_ptr(x86_cpu_to_apicid) = NULL;
527 early_per_cpu_ptr(x86_bios_cpu_apicid) = NULL;
528 #endif
529 #if defined(CONFIG_X86_64) && defined(CONFIG_NUMA)
530 early_per_cpu_ptr(x86_cpu_to_node_map) = NULL;
531 #endif
533 #if defined(CONFIG_X86_64) && defined(CONFIG_NUMA)
535 * make sure boot cpu node_number is right, when boot cpu is on the
536 * node that doesn't have mem installed
538 per_cpu(node_number, boot_cpu_id) = cpu_to_node(boot_cpu_id);
539 #endif
541 /* Setup node to cpumask map */
542 setup_node_to_cpumask_map();
544 /* Setup cpu initialized, callin, callout masks */
545 setup_cpu_local_masks();