#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/percpu.h>
#include <linux/kexec.h>
#include <linux/crash_dump.h>
#include <linux/smp.h>
#include <linux/topology.h>
#include <linux/pfn.h>
#include <asm/sections.h>
#include <asm/processor.h>
#include <asm/setup.h>
#include <asm/mpspec.h>
#include <asm/apicdef.h>
#include <asm/highmem.h>
#include <asm/proto.h>
#include <asm/cpumask.h>
#include <asm/cpu.h>
#include <asm/stackprotector.h>
#ifdef CONFIG_DEBUG_PER_CPU_MAPS
# define DBG(x...) printk(KERN_DEBUG x)
#else
# define DBG(x...)
#endif
DEFINE_PER_CPU(int, cpu_number);
EXPORT_PER_CPU_SYMBOL(cpu_number);
#ifdef CONFIG_X86_64
#define BOOT_PERCPU_OFFSET ((unsigned long)__per_cpu_load)
#else
#define BOOT_PERCPU_OFFSET 0
#endif
DEFINE_PER_CPU(unsigned long, this_cpu_off) = BOOT_PERCPU_OFFSET;
EXPORT_PER_CPU_SYMBOL(this_cpu_off);
unsigned long __per_cpu_offset[NR_CPUS] __read_mostly = {
[0 ... NR_CPUS-1] = BOOT_PERCPU_OFFSET,
};
EXPORT_SYMBOL(__per_cpu_offset);
/*
* On x86_64 symbols referenced from code should be reachable using
* 32bit relocations. Reserve space for static percpu variables in
* modules so that they are always served from the first chunk which
* is located at the percpu segment base. On x86_32, anything can
* address anywhere. No need to reserve space in the first chunk.
*/
#ifdef CONFIG_X86_64
#define PERCPU_FIRST_CHUNK_RESERVE PERCPU_MODULE_RESERVE
#else
#define PERCPU_FIRST_CHUNK_RESERVE 0
#endif
/**
* pcpu_need_numa - determine percpu allocation needs to consider NUMA
*
* If NUMA is not configured or there is only one NUMA node available,
* there is no reason to consider NUMA. This function determines
* whether percpu allocation should consider NUMA or not.
*
* RETURNS:
* true if NUMA should be considered; otherwise, false.
*/
static bool __init pcpu_need_numa(void)
{
#ifdef CONFIG_NEED_MULTIPLE_NODES
pg_data_t *last = NULL;
unsigned int cpu;
for_each_possible_cpu(cpu) {
int node = early_cpu_to_node(cpu);
if (node_online(node) && NODE_DATA(node) &&
last && last != NODE_DATA(node))
return true;
last = NODE_DATA(node);
}
#endif
return false;
}
/**
* pcpu_alloc_bootmem - NUMA friendly alloc_bootmem wrapper for percpu
* @cpu: cpu to allocate for
* @size: size allocation in bytes
* @align: alignment
*
* Allocate @size bytes aligned at @align for cpu @cpu. This wrapper
* does the right thing for NUMA regardless of the current
* configuration.
*
* RETURNS:
* Pointer to the allocated area on success, NULL on failure.
*/
static void * __init pcpu_alloc_bootmem(unsigned int cpu, unsigned long size,
unsigned long align)
{
const unsigned long goal = __pa(MAX_DMA_ADDRESS);
#ifdef CONFIG_NEED_MULTIPLE_NODES
int node = early_cpu_to_node(cpu);
void *ptr;
if (!node_online(node) || !NODE_DATA(node)) {
ptr = __alloc_bootmem_nopanic(size, align, goal);
pr_info("cpu %d has no node %d or node-local memory\n",
cpu, node);
pr_debug("per cpu data for cpu%d %lu bytes at %016lx\n",
cpu, size, __pa(ptr));
} else {
ptr = __alloc_bootmem_node_nopanic(NODE_DATA(node),
size, align, goal);
pr_debug("per cpu data for cpu%d %lu bytes on node%d at "
"%016lx\n", cpu, size, node, __pa(ptr));
}
return ptr;
#else
return __alloc_bootmem_nopanic(size, align, goal);
#endif
}
/*
* Helpers for first chunk memory allocation
*/
static void * __init pcpu_fc_alloc(unsigned int cpu, size_t size)
{
return pcpu_alloc_bootmem(cpu, size, size);
}
static void __init pcpu_fc_free(void *ptr, size_t size)
{
free_bootmem(__pa(ptr), size);
}
/*
* Large page remapping allocator
*/
#ifdef CONFIG_NEED_MULTIPLE_NODES
static void __init pcpul_map(void *ptr, size_t size, void *addr)
{
pmd_t *pmd, pmd_v;
pmd = populate_extra_pmd((unsigned long)addr);
pmd_v = pfn_pmd(page_to_pfn(virt_to_page(ptr)), PAGE_KERNEL_LARGE);
set_pmd(pmd, pmd_v);
}
static int pcpu_lpage_cpu_distance(unsigned int from, unsigned int to)
{
if (early_cpu_to_node(from) == early_cpu_to_node(to))
return LOCAL_DISTANCE;
else
return REMOTE_DISTANCE;
}
static ssize_t __init setup_pcpu_lpage(size_t static_size, bool chosen)
{
size_t reserve = PERCPU_MODULE_RESERVE + PERCPU_DYNAMIC_RESERVE;
size_t dyn_size = reserve - PERCPU_FIRST_CHUNK_RESERVE;
size_t unit_map_size, unit_size;
int *unit_map;
int nr_units;
ssize_t ret;
/* on non-NUMA, embedding is better */
if (!chosen && !pcpu_need_numa())
return -EINVAL;
/* need PSE */
if (!cpu_has_pse) {
pr_warning("PERCPU: lpage allocator requires PSE\n");
return -EINVAL;
}
/* allocate and build unit_map */
unit_map_size = num_possible_cpus() * sizeof(int);
unit_map = alloc_bootmem_nopanic(unit_map_size);
if (!unit_map) {
pr_warning("PERCPU: failed to allocate unit_map\n");
return -ENOMEM;
}
ret = pcpu_lpage_build_unit_map(static_size,
PERCPU_FIRST_CHUNK_RESERVE,
&dyn_size, &unit_size, PMD_SIZE,
unit_map, pcpu_lpage_cpu_distance);
if (ret < 0) {
pr_warning("PERCPU: failed to build unit_map\n");
goto out_free;
}
nr_units = ret;
/* do the parameters look okay? */
if (!chosen) {
size_t vm_size = VMALLOC_END - VMALLOC_START;
size_t tot_size = nr_units * unit_size;
/* don't consume more than 20% of vmalloc area */
if (tot_size > vm_size / 5) {
pr_info("PERCPU: too large chunk size %zuMB for "
"large page remap\n", tot_size >> 20);
ret = -EINVAL;
goto out_free;
}
}
ret = pcpu_lpage_first_chunk(static_size, PERCPU_FIRST_CHUNK_RESERVE,
dyn_size, unit_size, PMD_SIZE,
unit_map, nr_units,
pcpu_fc_alloc, pcpu_fc_free, pcpul_map);
out_free:
if (ret < 0)
free_bootmem(__pa(unit_map), unit_map_size);
return ret;
}
#else
static ssize_t __init setup_pcpu_lpage(size_t static_size, bool chosen)
{
return -EINVAL;
}
#endif
/*
* Embedding allocator
*
* The first chunk is sized to just contain the static area plus
* module and dynamic reserves and embedded into linear physical
* mapping so that it can use PMD mapping without additional TLB
* pressure.
*/
static ssize_t __init setup_pcpu_embed(size_t static_size, bool chosen)
{
size_t reserve = PERCPU_MODULE_RESERVE + PERCPU_DYNAMIC_RESERVE;
/*
* If large page isn't supported, there's no benefit in doing
* this. Also, embedding allocation doesn't play well with
* NUMA.
*/
if (!chosen && (!cpu_has_pse || pcpu_need_numa()))
return -EINVAL;
return pcpu_embed_first_chunk(static_size, PERCPU_FIRST_CHUNK_RESERVE,
reserve - PERCPU_FIRST_CHUNK_RESERVE);
}
/*
* 4k allocator
*
* Boring fallback 4k allocator. This allocator puts more pressure on
* PTE TLBs but other than that behaves nicely on both UMA and NUMA.
*/
static void __init pcpu4k_populate_pte(unsigned long addr)
{
populate_extra_pte(addr);
}
static ssize_t __init setup_pcpu_4k(size_t static_size)
{
return pcpu_4k_first_chunk(static_size, PERCPU_FIRST_CHUNK_RESERVE,
pcpu_fc_alloc, pcpu_fc_free,
pcpu4k_populate_pte);
}
/* for explicit first chunk allocator selection */
static char pcpu_chosen_alloc[16] __initdata;
static int __init percpu_alloc_setup(char *str)
{
strncpy(pcpu_chosen_alloc, str, sizeof(pcpu_chosen_alloc) - 1);
return 0;
}
early_param("percpu_alloc", percpu_alloc_setup);
static inline void setup_percpu_segment(int cpu)
{
#ifdef CONFIG_X86_32
struct desc_struct gdt;
pack_descriptor(&gdt, per_cpu_offset(cpu), 0xFFFFF,
0x2 | DESCTYPE_S, 0x8);
gdt.s = 1;
write_gdt_entry(get_cpu_gdt_table(cpu),
GDT_ENTRY_PERCPU, &gdt, DESCTYPE_S);
#endif
}
void __init setup_per_cpu_areas(void)
{
size_t static_size = __per_cpu_end - __per_cpu_start;
unsigned int cpu;
unsigned long delta;
size_t pcpu_unit_size;
ssize_t ret;
pr_info("NR_CPUS:%d nr_cpumask_bits:%d nr_cpu_ids:%d nr_node_ids:%d\n",
NR_CPUS, nr_cpumask_bits, nr_cpu_ids, nr_node_ids);
/*
* Allocate percpu area. If PSE is supported, try to make use
* of large page mappings. Please read comments on top of
* each allocator for details.
*/
ret = -EINVAL;
if (strlen(pcpu_chosen_alloc)) {
if (strcmp(pcpu_chosen_alloc, "4k")) {
if (!strcmp(pcpu_chosen_alloc, "lpage"))
ret = setup_pcpu_lpage(static_size, true);
else if (!strcmp(pcpu_chosen_alloc, "embed"))
ret = setup_pcpu_embed(static_size, true);
else
pr_warning("PERCPU: unknown allocator %s "
"specified\n", pcpu_chosen_alloc);
if (ret < 0)
pr_warning("PERCPU: %s allocator failed (%zd), "
"falling back to 4k\n",
pcpu_chosen_alloc, ret);
}
} else {
ret = setup_pcpu_lpage(static_size, false);
if (ret < 0)
ret = setup_pcpu_embed(static_size, false);
}
if (ret < 0)
ret = setup_pcpu_4k(static_size);
if (ret < 0)
panic("cannot allocate static percpu area (%zu bytes, err=%zd)",
static_size, ret);
pcpu_unit_size = ret;
/* alrighty, percpu areas up and running */
delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
for_each_possible_cpu(cpu) {
per_cpu_offset(cpu) =
delta + pcpu_unit_map[cpu] * pcpu_unit_size;
per_cpu(this_cpu_off, cpu) = per_cpu_offset(cpu);
per_cpu(cpu_number, cpu) = cpu;
setup_percpu_segment(cpu);
setup_stack_canary_segment(cpu);
/*
* Copy data used in early init routines from the
* initial arrays to the per cpu data areas. These
* arrays then become expendable and the *_early_ptr's
* are zeroed indicating that the static arrays are
* gone.
*/
#ifdef CONFIG_X86_LOCAL_APIC
per_cpu(x86_cpu_to_apicid, cpu) =
early_per_cpu_map(x86_cpu_to_apicid, cpu);
per_cpu(x86_bios_cpu_apicid, cpu) =
early_per_cpu_map(x86_bios_cpu_apicid, cpu);
#endif
#ifdef CONFIG_X86_64
per_cpu(irq_stack_ptr, cpu) =
per_cpu(irq_stack_union.irq_stack, cpu) +
IRQ_STACK_SIZE - 64;
#ifdef CONFIG_NUMA
per_cpu(x86_cpu_to_node_map, cpu) =
early_per_cpu_map(x86_cpu_to_node_map, cpu);
#endif
#endif
/*
* Up to this point, the boot CPU has been using .data.init
* area. Reload any changed state for the boot CPU.
*/
if (cpu == boot_cpu_id)
switch_to_new_gdt(cpu);
}
/* indicate the early static arrays will soon be gone */
#ifdef CONFIG_X86_LOCAL_APIC
early_per_cpu_ptr(x86_cpu_to_apicid) = NULL;
early_per_cpu_ptr(x86_bios_cpu_apicid) = NULL;
#endif
#if defined(CONFIG_X86_64) && defined(CONFIG_NUMA)
early_per_cpu_ptr(x86_cpu_to_node_map) = NULL;
#endif
#if defined(CONFIG_X86_64) && defined(CONFIG_NUMA)
/*
* make sure boot cpu node_number is right, when boot cpu is on the
* node that doesn't have mem installed
*/
per_cpu(node_number, boot_cpu_id) = cpu_to_node(boot_cpu_id);
#endif
/* Setup node to cpumask map */
setup_node_to_cpumask_map();
/* Setup cpu initialized, callin, callout masks */
setup_cpu_local_masks();
}
