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linux-next/arch/x86/kernel/setup.c
Mike Travis 23ca4bba3e x86: cleanup early per cpu variables/accesses v4
* Introduce a new PER_CPU macro called "EARLY_PER_CPU".  This is
    used by some per_cpu variables that are initialized and accessed
    before there are per_cpu areas allocated.

    ["Early" in respect to per_cpu variables is "earlier than the per_cpu
    areas have been setup".]

    This patchset adds these new macros:

	DEFINE_EARLY_PER_CPU(_type, _name, _initvalue)
	EXPORT_EARLY_PER_CPU_SYMBOL(_name)
	DECLARE_EARLY_PER_CPU(_type, _name)

	early_per_cpu_ptr(_name)
	early_per_cpu_map(_name, _idx)
	early_per_cpu(_name, _cpu)

    The DEFINE macro defines the per_cpu variable as well as the early
    map and pointer.  It also initializes the per_cpu variable and map
    elements to "_initvalue".  The early_* macros provide access to
    the initial map (usually setup during system init) and the early
    pointer.  This pointer is initialized to point to the early map
    but is then NULL'ed when the actual per_cpu areas are setup.  After
    that the per_cpu variable is the correct access to the variable.

    The early_per_cpu() macro is not very efficient but does show how to
    access the variable if you have a function that can be called both
    "early" and "late".  It tests the early ptr to be NULL, and if not
    then it's still valid.  Otherwise, the per_cpu variable is used
    instead:

	#define early_per_cpu(_name, _cpu) 			\
		(early_per_cpu_ptr(_name) ?			\
			early_per_cpu_ptr(_name)[_cpu] :	\
			per_cpu(_name, _cpu))

    A better method is to actually check the pointer manually.  In the
    case below, numa_set_node can be called both "early" and "late":

	void __cpuinit numa_set_node(int cpu, int node)
	{
	    int *cpu_to_node_map = early_per_cpu_ptr(x86_cpu_to_node_map);

	    if (cpu_to_node_map)
		    cpu_to_node_map[cpu] = node;
	    else
		    per_cpu(x86_cpu_to_node_map, cpu) = node;
	}

  * Add a flag "arch_provides_topology_pointers" that indicates pointers
    to topology cpumask_t maps are available.  Otherwise, use the function
    returning the cpumask_t value.  This is useful if cpumask_t set size
    is very large to avoid copying data on to/off of the stack.

  * The coverage of CONFIG_DEBUG_PER_CPU_MAPS has been increased while
    the non-debug case has been optimized a bit.

  * Remove an unreferenced compiler warning in drivers/base/topology.c

  * Clean up #ifdef in setup.c

For inclusion into sched-devel/latest tree.

Based on:
	git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
    +   sched-devel/latest  .../mingo/linux-2.6-sched-devel.git

Signed-off-by: Mike Travis <travis@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-07-08 11:31:20 +02:00

212 lines
5.2 KiB
C

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/percpu.h>
#include <asm/smp.h>
#include <asm/percpu.h>
#include <asm/sections.h>
#include <asm/processor.h>
#include <asm/setup.h>
#include <asm/topology.h>
#include <asm/mpspec.h>
#include <asm/apicdef.h>
#ifdef CONFIG_X86_LOCAL_APIC
unsigned int num_processors;
unsigned disabled_cpus __cpuinitdata;
/* Processor that is doing the boot up */
unsigned int boot_cpu_physical_apicid = -1U;
EXPORT_SYMBOL(boot_cpu_physical_apicid);
/* Bitmask of physically existing CPUs */
physid_mask_t phys_cpu_present_map;
#endif
/* map cpu index to physical APIC ID */
DEFINE_EARLY_PER_CPU(u16, x86_cpu_to_apicid, BAD_APICID);
DEFINE_EARLY_PER_CPU(u16, x86_bios_cpu_apicid, BAD_APICID);
EXPORT_EARLY_PER_CPU_SYMBOL(x86_cpu_to_apicid);
EXPORT_EARLY_PER_CPU_SYMBOL(x86_bios_cpu_apicid);
#if defined(CONFIG_NUMA) && defined(CONFIG_X86_64)
#define X86_64_NUMA 1
DEFINE_EARLY_PER_CPU(int, x86_cpu_to_node_map, NUMA_NO_NODE);
EXPORT_EARLY_PER_CPU_SYMBOL(x86_cpu_to_node_map);
#endif
#if defined(CONFIG_HAVE_SETUP_PER_CPU_AREA) && defined(CONFIG_X86_SMP)
/*
* 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.
*/
static void __init setup_per_cpu_maps(void)
{
int cpu;
for_each_possible_cpu(cpu) {
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);
#ifdef X86_64_NUMA
per_cpu(x86_cpu_to_node_map, cpu) =
early_per_cpu_map(x86_cpu_to_node_map, cpu);
#endif
}
/* indicate the early static arrays will soon be gone */
early_per_cpu_ptr(x86_cpu_to_apicid) = NULL;
early_per_cpu_ptr(x86_bios_cpu_apicid) = NULL;
#ifdef X86_64_NUMA
early_per_cpu_ptr(x86_cpu_to_node_map) = NULL;
#endif
}
#ifdef CONFIG_HAVE_CPUMASK_OF_CPU_MAP
cpumask_t *cpumask_of_cpu_map __read_mostly;
EXPORT_SYMBOL(cpumask_of_cpu_map);
/* requires nr_cpu_ids to be initialized */
static void __init setup_cpumask_of_cpu(void)
{
int i;
/* alloc_bootmem zeroes memory */
cpumask_of_cpu_map = alloc_bootmem_low(sizeof(cpumask_t) * nr_cpu_ids);
for (i = 0; i < nr_cpu_ids; i++)
cpu_set(i, cpumask_of_cpu_map[i]);
}
#else
static inline void setup_cpumask_of_cpu(void) { }
#endif
#ifdef CONFIG_X86_32
/*
* Great future not-so-futuristic plan: make i386 and x86_64 do it
* the same way
*/
unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
EXPORT_SYMBOL(__per_cpu_offset);
#endif
/*
* Great future plan:
* Declare PDA itself and support (irqstack,tss,pgd) as per cpu data.
* Always point %gs to its beginning
*/
void __init setup_per_cpu_areas(void)
{
int i, highest_cpu = 0;
unsigned long size;
#ifdef CONFIG_HOTPLUG_CPU
prefill_possible_map();
#endif
/* Copy section for each CPU (we discard the original) */
size = PERCPU_ENOUGH_ROOM;
printk(KERN_INFO "PERCPU: Allocating %lu bytes of per cpu data\n",
size);
for_each_possible_cpu(i) {
char *ptr;
#ifndef CONFIG_NEED_MULTIPLE_NODES
ptr = alloc_bootmem_pages(size);
#else
int node = early_cpu_to_node(i);
if (!node_online(node) || !NODE_DATA(node)) {
ptr = alloc_bootmem_pages(size);
printk(KERN_INFO
"cpu %d has no node %d or node-local memory\n",
i, node);
}
else
ptr = alloc_bootmem_pages_node(NODE_DATA(node), size);
#endif
if (!ptr)
panic("Cannot allocate cpu data for CPU %d\n", i);
#ifdef CONFIG_X86_64
cpu_pda(i)->data_offset = ptr - __per_cpu_start;
#else
__per_cpu_offset[i] = ptr - __per_cpu_start;
#endif
memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start);
highest_cpu = i;
}
nr_cpu_ids = highest_cpu + 1;
printk(KERN_DEBUG "NR_CPUS: %d, nr_cpu_ids: %d\n", NR_CPUS, nr_cpu_ids);
/* Setup percpu data maps */
setup_per_cpu_maps();
/* Setup cpumask_of_cpu map */
setup_cpumask_of_cpu();
}
#endif
#ifdef X86_64_NUMA
void __cpuinit numa_set_node(int cpu, int node)
{
int *cpu_to_node_map = early_per_cpu_ptr(x86_cpu_to_node_map);
if (cpu_to_node_map)
cpu_to_node_map[cpu] = node;
else if (per_cpu_offset(cpu))
per_cpu(x86_cpu_to_node_map, cpu) = node;
else
Dprintk(KERN_INFO "Setting node for non-present cpu %d\n", cpu);
}
void __cpuinit numa_clear_node(int cpu)
{
numa_set_node(cpu, NUMA_NO_NODE);
}
void __cpuinit numa_add_cpu(int cpu)
{
cpu_set(cpu, node_to_cpumask_map[early_cpu_to_node(cpu)]);
}
void __cpuinit numa_remove_cpu(int cpu)
{
cpu_clear(cpu, node_to_cpumask_map[cpu_to_node(cpu)]);
}
#endif /* CONFIG_NUMA */
#if defined(CONFIG_DEBUG_PER_CPU_MAPS) && defined(CONFIG_X86_64)
int cpu_to_node(int cpu)
{
if (early_per_cpu_ptr(x86_cpu_to_node_map)) {
printk(KERN_WARNING
"cpu_to_node(%d): usage too early!\n", cpu);
dump_stack();
return early_per_cpu_ptr(x86_cpu_to_node_map)[cpu];
}
return per_cpu(x86_cpu_to_node_map, cpu);
}
EXPORT_SYMBOL(cpu_to_node);
int early_cpu_to_node(int cpu)
{
if (early_per_cpu_ptr(x86_cpu_to_node_map))
return early_per_cpu_ptr(x86_cpu_to_node_map)[cpu];
if (!per_cpu_offset(cpu)) {
printk(KERN_WARNING
"early_cpu_to_node(%d): no per_cpu area!\n", cpu);
dump_stack();
return NUMA_NO_NODE;
}
return per_cpu(x86_cpu_to_node_map, cpu);
}
#endif