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Commit 0a3b4d15 authored by Glauber de Oliveira Costa's avatar Glauber de Oliveira Costa Committed by Ingo Molnar
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x86: move switch_to macro to system.h 



This patch moves the switch_to() macro to system.h

As those macros are fundamentally different between i386 and x86_64,
they are enclosed around an ifdef.

Signed-off-by: default avatarGlauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 833d8469

include/asm-x86/system.h

+61 −0
Original line number Diff line number Diff line
@@ -6,8 +6,69 @@ 
#include <linux/kernel.h>



#ifdef CONFIG_X86_32

#define AT_VECTOR_SIZE_ARCH 2 /* entries in ARCH_DLINFO */



struct task_struct; /* one of the stranger aspects of C forward declarations */

extern struct task_struct *FASTCALL(__switch_to(struct task_struct *prev,

						struct task_struct *next));



/*

 * Saving eflags is important. It switches not only IOPL between tasks,

 * it also protects other tasks from NT leaking through sysenter etc.

 */

#define switch_to(prev, next, last) do {				\

	unsigned long esi, edi;						\

	asm volatile("pushfl\n\t"		/* Save flags */	\

		     "pushl %%ebp\n\t"					\

		     "movl %%esp,%0\n\t"	/* save ESP */		\

		     "movl %5,%%esp\n\t"	/* restore ESP */	\

		     "movl $1f,%1\n\t"		/* save EIP */		\

		     "pushl %6\n\t"		/* restore EIP */	\

		     "jmp __switch_to\n"				\

		     "1:\t"						\

		     "popl %%ebp\n\t"					\

		     "popfl"						\

		     :"=m" (prev->thread.sp), "=m" (prev->thread.ip),	\

		      "=a" (last), "=S" (esi), "=D" (edi)		\

		     :"m" (next->thread.sp), "m" (next->thread.ip),	\

		      "2" (prev), "d" (next));				\

} while (0)



# include "system_32.h"

#else

#define __SAVE(reg, offset) "movq %%" #reg ",(14-" #offset ")*8(%%rsp)\n\t"

#define __RESTORE(reg, offset) "movq (14-" #offset ")*8(%%rsp),%%" #reg "\n\t"



/* frame pointer must be last for get_wchan */

#define SAVE_CONTEXT    "pushf ; pushq %%rbp ; movq %%rsi,%%rbp\n\t"

#define RESTORE_CONTEXT "movq %%rbp,%%rsi ; popq %%rbp ; popf\t"



#define __EXTRA_CLOBBER  \

	, "rcx", "rbx", "rdx", "r8", "r9", "r10", "r11", \

	  "r12", "r13", "r14", "r15"



/* Save restore flags to clear handle leaking NT */

#define switch_to(prev, next, last) \

	asm volatile(SAVE_CONTEXT					  \

	     "movq %%rsp,%P[threadrsp](%[prev])\n\t" /* save RSP */	  \

	     "movq %P[threadrsp](%[next]),%%rsp\n\t" /* restore RSP */	  \

	     "call __switch_to\n\t"					  \

	     ".globl thread_return\n"					  \

	     "thread_return:\n\t"					  \

	     "movq %%gs:%P[pda_pcurrent],%%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" 					  \

	     "jc   ret_from_fork\n\t"					  \

	     RESTORE_CONTEXT						  \

	     : "=a" (last)					  	  \

	     : [next] "S" (next), [prev] "D" (prev),			  \

	       [threadrsp] "i" (offsetof(struct task_struct, thread.sp)), \

	       [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))  \

	     : "memory", "cc" __EXTRA_CLOBBER)

# include "system_64.h"

#endif

include/asm-x86/system_32.h

+0 −31
Original line number Diff line number Diff line
@@ -5,37 +5,6 @@ 
#include <asm/cpufeature.h>

#include <asm/cmpxchg.h>



#ifdef __KERNEL__

#define AT_VECTOR_SIZE_ARCH 2 /* entries in ARCH_DLINFO */



struct task_struct;	/* one of the stranger aspects of C forward declarations.. */

extern struct task_struct * FASTCALL(__switch_to(struct task_struct *prev, struct task_struct *next));



/*

 * Saving eflags is important. It switches not only IOPL between tasks,

 * it also protects other tasks from NT leaking through sysenter etc.

 */

#define switch_to(prev,next,last) do {					\

	unsigned long esi,edi;						\

	asm volatile("pushfl\n\t"		/* Save flags */	\

		     "pushl %%ebp\n\t"					\

		     "movl %%esp,%0\n\t"	/* save ESP */		\

		     "movl %5,%%esp\n\t"	/* restore ESP */	\

		     "movl $1f,%1\n\t"		/* save EIP */		\

		     "pushl %6\n\t"		/* restore EIP */	\

		     "jmp __switch_to\n"				\

		     "1:\t"						\

		     "popl %%ebp\n\t"					\

		     "popfl"						\

		     :"=m" (prev->thread.sp),"=m" (prev->thread.ip),	\

		      "=a" (last),"=S" (esi),"=D" (edi)			\

		     :"m" (next->thread.sp),"m" (next->thread.ip),	\

		      "2" (prev), "d" (next));				\

} while (0)



#endif	/* __KERNEL__ */





#include <linux/irqflags.h>



/*

include/asm-x86/system_64.h

+0 −43
Original line number Diff line number Diff line
@@ -4,49 +4,6 @@ 
#include <asm/segment.h>

#include <asm/cmpxchg.h>



#ifdef __KERNEL__



/* entries in ARCH_DLINFO: */

#ifdef CONFIG_IA32_EMULATION

# define AT_VECTOR_SIZE_ARCH 2

#else

# define AT_VECTOR_SIZE_ARCH 1

#endif



#define __SAVE(reg,offset) "movq %%" #reg ",(14-" #offset ")*8(%%rsp)\n\t"

#define __RESTORE(reg,offset) "movq (14-" #offset ")*8(%%rsp),%%" #reg "\n\t"



/* frame pointer must be last for get_wchan */

#define SAVE_CONTEXT    "pushf ; pushq %%rbp ; movq %%rsi,%%rbp\n\t"

#define RESTORE_CONTEXT "movq %%rbp,%%rsi ; popq %%rbp ; popf\t"



#define __EXTRA_CLOBBER  \

	,"rcx","rbx","rdx","r8","r9","r10","r11","r12","r13","r14","r15"



/* Save restore flags to clear handle leaking NT */

#define switch_to(prev,next,last) \

	asm volatile(SAVE_CONTEXT						    \

		     "movq %%rsp,%P[threadrsp](%[prev])\n\t" /* save RSP */	  \

		     "movq %P[threadrsp](%[next]),%%rsp\n\t" /* restore RSP */	  \

		     "call __switch_to\n\t"					  \

		     ".globl thread_return\n"					\

		     "thread_return:\n\t"					    \

		     "movq %%gs:%P[pda_pcurrent],%%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" 					  \

		     "jc   ret_from_fork\n\t"					  \

		     RESTORE_CONTEXT						    \

		     : "=a" (last)					  	  \

		     : [next] "S" (next), [prev] "D" (prev),			  \

		       [threadrsp] "i" (offsetof(struct task_struct, thread.sp)), \

		       [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))   \

		     : "memory", "cc" __EXTRA_CLOBBER)

    

#endif	/* __KERNEL__ */



static inline unsigned long read_cr8(void)

{