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-rw-r--r--arch/x86/include/asm/current.h19
-rw-r--r--arch/x86/kernel/cpu/common.c14
-rw-r--r--arch/x86/kernel/process_32.c2
-rw-r--r--arch/x86/kernel/process_64.c2
-rw-r--r--arch/x86/kernel/smpboot.c2
5 files changed, 24 insertions, 15 deletions
diff --git a/arch/x86/include/asm/current.h b/arch/x86/include/asm/current.h
index 3e204e6140b5..63c42ac3cd86 100644
--- a/arch/x86/include/asm/current.h
+++ b/arch/x86/include/asm/current.h
@@ -3,16 +3,29 @@
#define _ASM_X86_CURRENT_H
#include <linux/compiler.h>
-#include <asm/percpu.h>
#ifndef __ASSEMBLY__
+
+#include <linux/cache.h>
+#include <asm/percpu.h>
+
struct task_struct;
-DECLARE_PER_CPU(struct task_struct *, current_task);
+struct pcpu_hot {
+ union {
+ struct {
+ struct task_struct *current_task;
+ };
+ u8 pad[64];
+ };
+};
+static_assert(sizeof(struct pcpu_hot) == 64);
+
+DECLARE_PER_CPU_ALIGNED(struct pcpu_hot, pcpu_hot);
static __always_inline struct task_struct *get_current(void)
{
- return this_cpu_read_stable(current_task);
+ return this_cpu_read_stable(pcpu_hot.current_task);
}
#define current get_current()
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 8e873181759a..52071539a14c 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -2012,18 +2012,16 @@ static __init int setup_clearcpuid(char *arg)
}
__setup("clearcpuid=", setup_clearcpuid);
+DEFINE_PER_CPU_ALIGNED(struct pcpu_hot, pcpu_hot) = {
+ .current_task = &init_task,
+};
+EXPORT_PER_CPU_SYMBOL(pcpu_hot);
+
#ifdef CONFIG_X86_64
DEFINE_PER_CPU_FIRST(struct fixed_percpu_data,
fixed_percpu_data) __aligned(PAGE_SIZE) __visible;
EXPORT_PER_CPU_SYMBOL_GPL(fixed_percpu_data);
-/*
- * The following percpu variables are hot. Align current_task to
- * cacheline size such that they fall in the same cacheline.
- */
-DEFINE_PER_CPU(struct task_struct *, current_task) ____cacheline_aligned =
- &init_task;
-EXPORT_PER_CPU_SYMBOL(current_task);
DEFINE_PER_CPU(void *, hardirq_stack_ptr);
DEFINE_PER_CPU(bool, hardirq_stack_inuse);
@@ -2083,8 +2081,6 @@ void syscall_init(void)
#else /* CONFIG_X86_64 */
-DEFINE_PER_CPU(struct task_struct *, current_task) = &init_task;
-EXPORT_PER_CPU_SYMBOL(current_task);
DEFINE_PER_CPU(int, __preempt_count) = INIT_PREEMPT_COUNT;
EXPORT_PER_CPU_SYMBOL(__preempt_count);
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 2f314b170c9f..807da45d84c7 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -207,7 +207,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
if (prev->gs | next->gs)
loadsegment(gs, next->gs);
- this_cpu_write(current_task, next_p);
+ raw_cpu_write(pcpu_hot.current_task, next_p);
switch_fpu_finish();
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 6b3418bff326..c4f6cacf6599 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -617,7 +617,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
/*
* Switch the PDA and FPU contexts.
*/
- this_cpu_write(current_task, next_p);
+ raw_cpu_write(pcpu_hot.current_task, next_p);
this_cpu_write(cpu_current_top_of_stack, task_top_of_stack(next_p));
switch_fpu_finish();
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index ce8728d2e5ef..05f315777691 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1046,7 +1046,7 @@ int common_cpu_up(unsigned int cpu, struct task_struct *idle)
/* Just in case we booted with a single CPU. */
alternatives_enable_smp();
- per_cpu(current_task, cpu) = idle;
+ per_cpu(pcpu_hot.current_task, cpu) = idle;
cpu_init_stack_canary(cpu, idle);
/* Initialize the interrupt stack(s) */