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/arch/x86/kernel/setup_percpu.c

https://bitbucket.org/ndreys/linux-sunxi
C | 287 lines | 192 code | 26 blank | 69 comment | 18 complexity | 58ee38af1b0520a853b33b51fffd8ab5 MD5 | raw file
Possible License(s): GPL-2.0, LGPL-2.0, AGPL-1.0
  1#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  2
  3#include <linux/kernel.h>
  4#include <linux/module.h>
  5#include <linux/init.h>
  6#include <linux/bootmem.h>
  7#include <linux/percpu.h>
  8#include <linux/kexec.h>
  9#include <linux/crash_dump.h>
 10#include <linux/smp.h>
 11#include <linux/topology.h>
 12#include <linux/pfn.h>
 13#include <asm/sections.h>
 14#include <asm/processor.h>
 15#include <asm/setup.h>
 16#include <asm/mpspec.h>
 17#include <asm/apicdef.h>
 18#include <asm/highmem.h>
 19#include <asm/proto.h>
 20#include <asm/cpumask.h>
 21#include <asm/cpu.h>
 22#include <asm/stackprotector.h>
 23
 24DEFINE_PER_CPU(int, cpu_number);
 25EXPORT_PER_CPU_SYMBOL(cpu_number);
 26
 27#ifdef CONFIG_X86_64
 28#define BOOT_PERCPU_OFFSET ((unsigned long)__per_cpu_load)
 29#else
 30#define BOOT_PERCPU_OFFSET 0
 31#endif
 32
 33DEFINE_PER_CPU(unsigned long, this_cpu_off) = BOOT_PERCPU_OFFSET;
 34EXPORT_PER_CPU_SYMBOL(this_cpu_off);
 35
 36unsigned long __per_cpu_offset[NR_CPUS] __read_mostly = {
 37	[0 ... NR_CPUS-1] = BOOT_PERCPU_OFFSET,
 38};
 39EXPORT_SYMBOL(__per_cpu_offset);
 40
 41/*
 42 * On x86_64 symbols referenced from code should be reachable using
 43 * 32bit relocations.  Reserve space for static percpu variables in
 44 * modules so that they are always served from the first chunk which
 45 * is located at the percpu segment base.  On x86_32, anything can
 46 * address anywhere.  No need to reserve space in the first chunk.
 47 */
 48#ifdef CONFIG_X86_64
 49#define PERCPU_FIRST_CHUNK_RESERVE	PERCPU_MODULE_RESERVE
 50#else
 51#define PERCPU_FIRST_CHUNK_RESERVE	0
 52#endif
 53
 54#ifdef CONFIG_X86_32
 55/**
 56 * pcpu_need_numa - determine percpu allocation needs to consider NUMA
 57 *
 58 * If NUMA is not configured or there is only one NUMA node available,
 59 * there is no reason to consider NUMA.  This function determines
 60 * whether percpu allocation should consider NUMA or not.
 61 *
 62 * RETURNS:
 63 * true if NUMA should be considered; otherwise, false.
 64 */
 65static bool __init pcpu_need_numa(void)
 66{
 67#ifdef CONFIG_NEED_MULTIPLE_NODES
 68	pg_data_t *last = NULL;
 69	unsigned int cpu;
 70
 71	for_each_possible_cpu(cpu) {
 72		int node = early_cpu_to_node(cpu);
 73
 74		if (node_online(node) && NODE_DATA(node) &&
 75		    last && last != NODE_DATA(node))
 76			return true;
 77
 78		last = NODE_DATA(node);
 79	}
 80#endif
 81	return false;
 82}
 83#endif
 84
 85/**
 86 * pcpu_alloc_bootmem - NUMA friendly alloc_bootmem wrapper for percpu
 87 * @cpu: cpu to allocate for
 88 * @size: size allocation in bytes
 89 * @align: alignment
 90 *
 91 * Allocate @size bytes aligned at @align for cpu @cpu.  This wrapper
 92 * does the right thing for NUMA regardless of the current
 93 * configuration.
 94 *
 95 * RETURNS:
 96 * Pointer to the allocated area on success, NULL on failure.
 97 */
 98static void * __init pcpu_alloc_bootmem(unsigned int cpu, unsigned long size,
 99					unsigned long align)
100{
101	const unsigned long goal = __pa(MAX_DMA_ADDRESS);
102#ifdef CONFIG_NEED_MULTIPLE_NODES
103	int node = early_cpu_to_node(cpu);
104	void *ptr;
105
106	if (!node_online(node) || !NODE_DATA(node)) {
107		ptr = __alloc_bootmem_nopanic(size, align, goal);
108		pr_info("cpu %d has no node %d or node-local memory\n",
109			cpu, node);
110		pr_debug("per cpu data for cpu%d %lu bytes at %016lx\n",
111			 cpu, size, __pa(ptr));
112	} else {
113		ptr = __alloc_bootmem_node_nopanic(NODE_DATA(node),
114						   size, align, goal);
115		pr_debug("per cpu data for cpu%d %lu bytes on node%d at %016lx\n",
116			 cpu, size, node, __pa(ptr));
117	}
118	return ptr;
119#else
120	return __alloc_bootmem_nopanic(size, align, goal);
121#endif
122}
123
124/*
125 * Helpers for first chunk memory allocation
126 */
127static void * __init pcpu_fc_alloc(unsigned int cpu, size_t size, size_t align)
128{
129	return pcpu_alloc_bootmem(cpu, size, align);
130}
131
132static void __init pcpu_fc_free(void *ptr, size_t size)
133{
134	free_bootmem(__pa(ptr), size);
135}
136
137static int __init pcpu_cpu_distance(unsigned int from, unsigned int to)
138{
139#ifdef CONFIG_NEED_MULTIPLE_NODES
140	if (early_cpu_to_node(from) == early_cpu_to_node(to))
141		return LOCAL_DISTANCE;
142	else
143		return REMOTE_DISTANCE;
144#else
145	return LOCAL_DISTANCE;
146#endif
147}
148
149static void __init pcpup_populate_pte(unsigned long addr)
150{
151	populate_extra_pte(addr);
152}
153
154static inline void setup_percpu_segment(int cpu)
155{
156#ifdef CONFIG_X86_32
157	struct desc_struct gdt;
158
159	pack_descriptor(&gdt, per_cpu_offset(cpu), 0xFFFFF,
160			0x2 | DESCTYPE_S, 0x8);
161	gdt.s = 1;
162	write_gdt_entry(get_cpu_gdt_table(cpu),
163			GDT_ENTRY_PERCPU, &gdt, DESCTYPE_S);
164#endif
165}
166
167void __init setup_per_cpu_areas(void)
168{
169	unsigned int cpu;
170	unsigned long delta;
171	int rc;
172
173	pr_info("NR_CPUS:%d nr_cpumask_bits:%d nr_cpu_ids:%d nr_node_ids:%d\n",
174		NR_CPUS, nr_cpumask_bits, nr_cpu_ids, nr_node_ids);
175
176	/*
177	 * Allocate percpu area.  Embedding allocator is our favorite;
178	 * however, on NUMA configurations, it can result in very
179	 * sparse unit mapping and vmalloc area isn't spacious enough
180	 * on 32bit.  Use page in that case.
181	 */
182#ifdef CONFIG_X86_32
183	if (pcpu_chosen_fc == PCPU_FC_AUTO && pcpu_need_numa())
184		pcpu_chosen_fc = PCPU_FC_PAGE;
185#endif
186	rc = -EINVAL;
187	if (pcpu_chosen_fc != PCPU_FC_PAGE) {
188		const size_t dyn_size = PERCPU_MODULE_RESERVE +
189			PERCPU_DYNAMIC_RESERVE - PERCPU_FIRST_CHUNK_RESERVE;
190		size_t atom_size;
191
192		/*
193		 * On 64bit, use PMD_SIZE for atom_size so that embedded
194		 * percpu areas are aligned to PMD.  This, in the future,
195		 * can also allow using PMD mappings in vmalloc area.  Use
196		 * PAGE_SIZE on 32bit as vmalloc space is highly contended
197		 * and large vmalloc area allocs can easily fail.
198		 */
199#ifdef CONFIG_X86_64
200		atom_size = PMD_SIZE;
201#else
202		atom_size = PAGE_SIZE;
203#endif
204		rc = pcpu_embed_first_chunk(PERCPU_FIRST_CHUNK_RESERVE,
205					    dyn_size, atom_size,
206					    pcpu_cpu_distance,
207					    pcpu_fc_alloc, pcpu_fc_free);
208		if (rc < 0)
209			pr_warning("%s allocator failed (%d), falling back to page size\n",
210				   pcpu_fc_names[pcpu_chosen_fc], rc);
211	}
212	if (rc < 0)
213		rc = pcpu_page_first_chunk(PERCPU_FIRST_CHUNK_RESERVE,
214					   pcpu_fc_alloc, pcpu_fc_free,
215					   pcpup_populate_pte);
216	if (rc < 0)
217		panic("cannot initialize percpu area (err=%d)", rc);
218
219	/* alrighty, percpu areas up and running */
220	delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
221	for_each_possible_cpu(cpu) {
222		per_cpu_offset(cpu) = delta + pcpu_unit_offsets[cpu];
223		per_cpu(this_cpu_off, cpu) = per_cpu_offset(cpu);
224		per_cpu(cpu_number, cpu) = cpu;
225		setup_percpu_segment(cpu);
226		setup_stack_canary_segment(cpu);
227		/*
228		 * Copy data used in early init routines from the
229		 * initial arrays to the per cpu data areas.  These
230		 * arrays then become expendable and the *_early_ptr's
231		 * are zeroed indicating that the static arrays are
232		 * gone.
233		 */
234#ifdef CONFIG_X86_LOCAL_APIC
235		per_cpu(x86_cpu_to_apicid, cpu) =
236			early_per_cpu_map(x86_cpu_to_apicid, cpu);
237		per_cpu(x86_bios_cpu_apicid, cpu) =
238			early_per_cpu_map(x86_bios_cpu_apicid, cpu);
239#endif
240#ifdef CONFIG_X86_32
241		per_cpu(x86_cpu_to_logical_apicid, cpu) =
242			early_per_cpu_map(x86_cpu_to_logical_apicid, cpu);
243#endif
244#ifdef CONFIG_X86_64
245		per_cpu(irq_stack_ptr, cpu) =
246			per_cpu(irq_stack_union.irq_stack, cpu) +
247			IRQ_STACK_SIZE - 64;
248#endif
249#ifdef CONFIG_NUMA
250		per_cpu(x86_cpu_to_node_map, cpu) =
251			early_per_cpu_map(x86_cpu_to_node_map, cpu);
252		/*
253		 * Ensure that the boot cpu numa_node is correct when the boot
254		 * cpu is on a node that doesn't have memory installed.
255		 * Also cpu_up() will call cpu_to_node() for APs when
256		 * MEMORY_HOTPLUG is defined, before per_cpu(numa_node) is set
257		 * up later with c_init aka intel_init/amd_init.
258		 * So set them all (boot cpu and all APs).
259		 */
260		set_cpu_numa_node(cpu, early_cpu_to_node(cpu));
261#endif
262		/*
263		 * Up to this point, the boot CPU has been using .init.data
264		 * area.  Reload any changed state for the boot CPU.
265		 */
266		if (!cpu)
267			switch_to_new_gdt(cpu);
268	}
269
270	/* indicate the early static arrays will soon be gone */
271#ifdef CONFIG_X86_LOCAL_APIC
272	early_per_cpu_ptr(x86_cpu_to_apicid) = NULL;
273	early_per_cpu_ptr(x86_bios_cpu_apicid) = NULL;
274#endif
275#ifdef CONFIG_X86_32
276	early_per_cpu_ptr(x86_cpu_to_logical_apicid) = NULL;
277#endif
278#ifdef CONFIG_NUMA
279	early_per_cpu_ptr(x86_cpu_to_node_map) = NULL;
280#endif
281
282	/* Setup node to cpumask map */
283	setup_node_to_cpumask_map();
284
285	/* Setup cpu initialized, callin, callout masks */
286	setup_cpu_local_masks();
287}