aboutsummaryrefslogtreecommitdiff
path: root/arch/x86_64/kernel/vsyscall.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/x86_64/kernel/vsyscall.c')
-rw-r--r--arch/x86_64/kernel/vsyscall.c47
1 files changed, 27 insertions, 20 deletions
diff --git a/arch/x86_64/kernel/vsyscall.c b/arch/x86_64/kernel/vsyscall.c
index a98b460af6a..92546c1526f 100644
--- a/arch/x86_64/kernel/vsyscall.c
+++ b/arch/x86_64/kernel/vsyscall.c
@@ -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 +268,23 @@ 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());
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+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;
+}
+#endif
+
static void __init map_vsyscall(void)
{
extern char __vsyscall_0;
@@ -299,6 +304,8 @@ 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;
}