path: root/include/asm-x86/system.h

#ifndef _ASM_X86_SYSTEM_H_
#define _ASM_X86_SYSTEM_H_

#include <asm/asm.h>
#include <asm/segment.h>
#include <asm/cpufeature.h>
#include <asm/cmpxchg.h>
#include <asm/nops.h>

#include <linux/kernel.h>
#include <linux/irqflags.h>

/* entries in ARCH_DLINFO: */
#ifdef CONFIG_IA32_EMULATION
# define AT_VECTOR_SIZE_ARCH 2
#else
# define AT_VECTOR_SIZE_ARCH 1
#endif

#ifdef CONFIG_X86_32

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)

/*
 * disable hlt during certain critical i/o operations
 */
#define HAVE_DISABLE_HLT
#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						    \