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[PATCH] x86-64: Fix vgetcpu when CONFIG_HOTPLUG_CPU is disabled

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The vgetcpu per CPU initialization previously relied on CPU hotplug
events for all CPUs to initialize the per CPU state. That only
worked only on kernels with CONFIG_HOTPLUG_CPU enabled.  On the
others some CPUs didn't get their state initialized properly
and vgetcpu wouldn't work.

Change the initialization sequence to instead run in a normal
initcall (which runs after the normal CPU bootup) and initialize
all running CPUs there. Later hotplug CPUs are still handled
with an hotplug notifier.

This actually simplifies the code somewhat.

Signed-off-by: Andi Kleen <ak@suse.de>
This commit is contained in:
Andi Kleen 2006-11-14 16:57:46 +01:00 committed by Andi Kleen
parent fa18f477d0
commit 8c131af1db
4 changed files with 26 additions and 35 deletions
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3
arch/x86_64/kernel/smp.c
View file

@ -376,9 +376,8 @@ int smp_call_function_single (int cpu, void (*func) (void *info), void *info,
/* prevent preemption and reschedule on another processor */
int me = get_cpu();
if (cpu == me) {
WARN_ON(1);
put_cpu();
return -EBUSY;
return 0;
}
spin_lock_bh(&call_lock);
__smp_call_function_single(cpu, func, info, nonatomic, wait);

11
arch/x86_64/kernel/time.c
View file

@ -876,15 +876,6 @@ static struct irqaction irq0 = {
timer_interrupt, IRQF_DISABLED, CPU_MASK_NONE, "timer", NULL, NULL
};
static int __cpuinit
time_cpu_notifier(struct notifier_block *nb, unsigned long action, void *hcpu)
{
unsigned cpu = (unsigned long) hcpu;
if (action == CPU_ONLINE)
vsyscall_set_cpu(cpu);
return NOTIFY_DONE;
}
void __init time_init(void)
{
if (nohpet)
@ -925,8 +916,6 @@ void __init time_init(void)
vxtime.last_tsc = get_cycles_sync();
set_cyc2ns_scale(cpu_khz);
setup_irq(0, &irq0);
hotcpu_notifier(time_cpu_notifier, 0);
time_cpu_notifier(NULL, CPU_ONLINE, (void *)(long)smp_processor_id());
#ifndef CONFIG_SMP
time_init_gtod();

45
arch/x86_64/kernel/vsyscall.c
View file

@ -27,6 +27,9 @@
#include <linux/jiffies.h>
#include <linux/sysctl.h>
#include <linux/getcpu.h>
#include <linux/cpu.h>
#include <linux/smp.h>
#include <linux/notifier.h>
#include <asm/vsyscall.h>
#include <asm/pgtable.h>
@ -243,32 +246,17 @@ static ctl_table kernel_root_table2[] = {
#endif
static void __cpuinit write_rdtscp_cb(void *info)
{
write_rdtscp_aux((unsigned long)info);
}
void __cpuinit vsyscall_set_cpu(int cpu)
/* Assume __initcall executes before all user space. Hopefully kmod
doesn't violate that. We'll find out if it does. */
static void __cpuinit vsyscall_set_cpu(int cpu)
{
unsigned long *d;
unsigned long node = 0;
#ifdef CONFIG_NUMA
node = cpu_to_node[cpu];
#endif
if (cpu_has(&cpu_data[cpu], X86_FEATURE_RDTSCP)) {
void *info = (void *)((node << 12) | cpu);
/* Can happen on preemptive kernel */
if (get_cpu() == cpu)
write_rdtscp_cb(info);
#ifdef CONFIG_SMP
else {
/* the notifier is unfortunately not executed on the
target CPU */
smp_call_function_single(cpu,write_rdtscp_cb,info,0,1);
}
#endif
put_cpu();
}
if (cpu_has(&cpu_data[cpu], X86_FEATURE_RDTSCP))
write_rdtscp_aux((node << 12) | cpu);
/* Store cpu number in limit so that it can be loaded quickly
in user space in vgetcpu.
@ -280,6 +268,21 @@ void __cpuinit vsyscall_set_cpu(int cpu)
*d |= (node >> 4) << 48;
}
static void __cpuinit cpu_vsyscall_init(void *arg)
{
/* preemption should be already off */
vsyscall_set_cpu(raw_smp_processor_id());
}
static int __cpuinit
cpu_vsyscall_notifier(struct notifier_block *n, unsigned long action, void *arg)
{
long cpu = (long)arg;
if (action == CPU_ONLINE)
smp_call_function_single(cpu, cpu_vsyscall_init, NULL, 0, 1);
return NOTIFY_DONE;
}
static void __init map_vsyscall(void)
{
extern char __vsyscall_0;
@ -299,6 +302,8 @@ static int __init vsyscall_init(void)
#ifdef CONFIG_SYSCTL
register_sysctl_table(kernel_root_table2, 0);
#endif
on_each_cpu(cpu_vsyscall_init, NULL, 0, 1);
hotcpu_notifier(cpu_vsyscall_notifier, 0);
return 0;
}

2
include/asm-x86_64/vsyscall.h
View file

@ -59,8 +59,6 @@ extern seqlock_t xtime_lock;
extern int sysctl_vsyscall;
extern void vsyscall_set_cpu(int cpu);
#define ARCH_HAVE_XTIME_LOCK 1
#endif /* __KERNEL__ */