提交 c6f5e0ac 编写于 作者: B Brian Gerst 提交者: Tejun Heo

x86-64: Move current task from PDA to per-cpu and consolidate with 32-bit.

Signed-off-by: NBrian Gerst <brgerst@gmail.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
上级 ea927906
#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 */
......@@ -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 */
......
......@@ -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
......
......@@ -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();
......
......@@ -903,10 +903,7 @@ 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);
}
......
......@@ -242,7 +242,7 @@ 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);
......
......@@ -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) +
......
......@@ -790,13 +790,12 @@ 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
......
......@@ -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);
......
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