x86-64: Move current task from PDA to per-cpu and consolidate with 32-bit. (c6f5e0ac) · Commits · 戴 / test

arch/x86/include/asm/current.h

+3 −21

Original line number	Diff line number	Diff line
		#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 */

+2 −2

Original line number	Diff line number	Diff line
		@@ -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 */

+2 −2

Original line number	Diff line number	Diff line
		@@ -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

+0 −1

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		@@ -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();

+1 −4

Original line number	Diff line number	Diff line
		@@ -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);
		}