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Date: Fri, 16 Jan 2009 09:16:25 -0500
From: Brian Gerst <brgerst@...il.com>
To: Tejun Heo <tj@...nel.org>
Cc: Ingo Molnar <mingo@...e.hu>, linux-kernel@...r.kernel.org,
Brian Gerst <brgerst@...il.com>
Subject: [PATCH 06/17] x86-64: Move current task from PDA to per-cpu and consolidate with 32-bit.
Signed-off-by: Brian Gerst <brgerst@...il.com>
---
arch/x86/include/asm/current.h | 24 +++---------------------
arch/x86/include/asm/pda.h | 4 ++--
arch/x86/include/asm/system.h | 4 ++--
arch/x86/kernel/asm-offsets_64.c | 1 -
arch/x86/kernel/cpu/common.c | 5 +----
arch/x86/kernel/dumpstack_64.c | 2 +-
arch/x86/kernel/process_64.c | 5 ++++-
arch/x86/kernel/smpboot.c | 3 +--
arch/x86/xen/smp.c | 3 +--
9 files changed, 15 insertions(+), 36 deletions(-)
diff --git a/arch/x86/include/asm/current.h b/arch/x86/include/asm/current.h
index 0728480..c68c361 100644
--- a/arch/x86/include/asm/current.h
+++ b/arch/x86/include/asm/current.h
@@ -1,39 +1,21 @@
#ifndef _ASM_X86_CURRENT_H
#define _ASM_X86_CURRENT_H
-#ifdef CONFIG_X86_32
#include <linux/compiler.h>
#include <asm/percpu.h>
+#ifndef __ASSEMBLY__
struct task_struct;
DECLARE_PER_CPU(struct task_struct *, current_task);
-static __always_inline struct task_struct *get_current(void)
-{
- return percpu_read(current_task);
-}
-
-#else /* X86_32 */
-
-#ifndef __ASSEMBLY__
-#include <asm/pda.h>
-
-struct task_struct;
static __always_inline struct task_struct *get_current(void)
{
- return read_pda(pcurrent);
+ return percpu_read(current_task);
}
-#else /* __ASSEMBLY__ */
-
-#include <asm/asm-offsets.h>
-#define GET_CURRENT(reg) movq %gs:(pda_pcurrent),reg
+#define current get_current()
#endif /* __ASSEMBLY__ */
-#endif /* X86_32 */
-
-#define current get_current()
-
#endif /* _ASM_X86_CURRENT_H */
diff --git a/arch/x86/include/asm/pda.h b/arch/x86/include/asm/pda.h
index 668d5a5..7209302 100644
--- a/arch/x86/include/asm/pda.h
+++ b/arch/x86/include/asm/pda.h
@@ -11,8 +11,8 @@
/* Per processor datastructure. %gs points to it while the kernel runs */
struct x8664_pda {
- struct task_struct *pcurrent; /* 0 Current process */
- unsigned long dummy;
+ unsigned long unused1;
+ unsigned long unused2;
unsigned long kernelstack; /* 16 top of kernel stack for current */
unsigned long oldrsp; /* 24 user rsp for system call */
int irqcount; /* 32 Irq nesting counter. Starts -1 */
diff --git a/arch/x86/include/asm/system.h b/arch/x86/include/asm/system.h
index 8e626ea..4399aac 100644
--- a/arch/x86/include/asm/system.h
+++ b/arch/x86/include/asm/system.h
@@ -94,7 +94,7 @@ do { \
"call __switch_to\n\t" \
".globl thread_return\n" \
"thread_return:\n\t" \
- "movq %%gs:%P[pda_pcurrent],%%rsi\n\t" \
+ "movq "__percpu_seg_str"%P[current_task],%%rsi\n\t" \
"movq %P[thread_info](%%rsi),%%r8\n\t" \
LOCK_PREFIX "btr %[tif_fork],%P[ti_flags](%%r8)\n\t" \
"movq %%rax,%%rdi\n\t" \
@@ -106,7 +106,7 @@ do { \
[ti_flags] "i" (offsetof(struct thread_info, flags)), \
[tif_fork] "i" (TIF_FORK), \
[thread_info] "i" (offsetof(struct task_struct, stack)), \
- [pda_pcurrent] "i" (offsetof(struct x8664_pda, pcurrent)) \
+ [current_task] "m" (per_cpu_var(current_task)) \
: "memory", "cc" __EXTRA_CLOBBER)
#endif
diff --git a/arch/x86/kernel/asm-offsets_64.c b/arch/x86/kernel/asm-offsets_64.c
index cae6697..4f7a210 100644
--- a/arch/x86/kernel/asm-offsets_64.c
+++ b/arch/x86/kernel/asm-offsets_64.c
@@ -51,7 +51,6 @@ int main(void)
#define ENTRY(entry) DEFINE(pda_ ## entry, offsetof(struct x8664_pda, entry))
ENTRY(kernelstack);
ENTRY(oldrsp);
- ENTRY(pcurrent);
ENTRY(irqcount);
DEFINE(pda_size, sizeof(struct x8664_pda));
BLANK();
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 1cf466f..fbc8468 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -898,10 +898,7 @@ void __cpuinit pda_init(int cpu)
pda->kernelstack = (unsigned long)stack_thread_info() -
PDA_STACKOFFSET + THREAD_SIZE;
- if (cpu == 0) {
- /* others are initialized in smpboot.c */
- pda->pcurrent = &init_task;
- } else {
+ if (cpu != 0) {
if (pda->nodenumber == 0 && cpu_to_node(cpu) != NUMA_NO_NODE)
pda->nodenumber = cpu_to_node(cpu);
}
diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c
index 46c6bf0..0c01ad2 100644
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -241,7 +241,7 @@ void show_registers(struct pt_regs *regs)
int i;
unsigned long sp;
const int cpu = smp_processor_id();
- struct task_struct *cur = cpu_pda(cpu)->pcurrent;
+ struct task_struct *cur = current;
sp = regs->sp;
printk("CPU %d ", cpu);
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 416fb92..e00c31a 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -57,6 +57,9 @@
asmlinkage extern void ret_from_fork(void);
+DEFINE_PER_CPU(struct task_struct *, current_task) = &init_task;
+EXPORT_PER_CPU_SYMBOL(current_task);
+
unsigned long kernel_thread_flags = CLONE_VM | CLONE_UNTRACED;
static ATOMIC_NOTIFIER_HEAD(idle_notifier);
@@ -615,7 +618,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
*/
prev->usersp = read_pda(oldrsp);
write_pda(oldrsp, next->usersp);
- write_pda(pcurrent, next_p);
+ percpu_write(current_task, next_p);
write_pda(kernelstack,
(unsigned long)task_stack_page(next_p) +
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index a33da98..ecc2fc5 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -792,13 +792,12 @@ static int __cpuinit do_boot_cpu(int apicid, int cpu)
set_idle_for_cpu(cpu, c_idle.idle);
do_rest:
-#ifdef CONFIG_X86_32
per_cpu(current_task, cpu) = c_idle.idle;
+#ifdef CONFIG_X86_32
init_gdt(cpu);
/* Stack for startup_32 can be just as for start_secondary onwards */
irq_ctx_init(cpu);
#else
- cpu_pda(cpu)->pcurrent = c_idle.idle;
clear_tsk_thread_flag(c_idle.idle, TIF_FORK);
initial_gs = per_cpu_offset(cpu);
#endif
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index 9ff3b09..72c2eb9 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -279,12 +279,11 @@ static int __cpuinit xen_cpu_up(unsigned int cpu)
struct task_struct *idle = idle_task(cpu);
int rc;
+ per_cpu(current_task, cpu) = idle;
#ifdef CONFIG_X86_32
init_gdt(cpu);
- per_cpu(current_task, cpu) = idle;
irq_ctx_init(cpu);
#else
- cpu_pda(cpu)->pcurrent = idle;
clear_tsk_thread_flag(idle, TIF_FORK);
#endif
xen_setup_timer(cpu);
--
1.6.1.rc1
--
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