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#ifndef __ASM_SYSTEM_H
#define __ASM_SYSTEM_H
#include <linux/kernel.h>
#include <asm/segment.h>
#ifdef __KERNEL__
struct task_struct; /* one of the stranger aspects of C forward declarations.. */
extern void FASTCALL(__switch_to(struct task_struct *prev, struct task_struct *next));
/*
* We do most of the task switching in C, but we need
* to do the EIP/ESP switch in assembly..
*/
#define switch_to(prev,next) do { \
unsigned long eax, edx, ecx; \
asm volatile("pushl %%ebx\n\t" \
"pushl %%esi\n\t" \
"pushl %%edi\n\t" \
"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" \
"popl %%edi\n\t" \
"popl %%esi\n\t" \
"popl %%ebx" \
:"=m" (prev->tss.esp),"=m" (prev->tss.eip), \
"=a" (eax), "=d" (edx), "=c" (ecx) \
:"m" (next->tss.esp),"m" (next->tss.eip), \
"a" (prev), "d" (next)); \
} while (0)
#define _set_base(addr,base) do { unsigned long __pr; \
__asm__ __volatile__ ("movw %%dx,%1\n\t" \
"rorl $16,%%edx\n\t" \
"movb %%dl,%2\n\t" \
"movb %%dh,%3" \
:"=&d" (__pr) \
:"m" (*((addr)+2)), \
"m" (*((addr)+4)), \
"m" (*((addr)+7)), \
"0" (base) \
); } while(0)
#define _set_limit(addr,limit) do { unsigned long __lr; \
__asm__ __volatile__ ("movw %%dx,%1\n\t" \
"rorl $16,%%edx\n\t" \
"movb %2,%%dh\n\t" \
"andb $0xf0,%%dh\n\t" \
"orb %%dh,%%dl\n\t" \
"movb %%dl,%2" \
:"=&d" (__lr) \
:"m" (*(addr)), \
"m" (*((addr)+6)), \
"0" (limit) \
); } while(0)
#define set_base(ldt,base) _set_base( ((char *)&(ldt)) , (base) )
#define set_limit(ldt,limit) _set_limit( ((char *)&(ldt)) , ((limit)-1)>>12 )
static inline unsigned long _get_base(char * addr)
{
unsigned long __base;
__asm__("movb %3,%%dh\n\t"
"movb %2,%%dl\n\t"
"shll $16,%%edx\n\t"
"movw %1,%%dx"
:"=&d" (__base)
:"m" (*((addr)+2)),
"m" (*((addr)+4)),
"m" (*((addr)+7)));
return __base;
}
#define get_base(ldt) _get_base( ((char *)&(ldt)) )
/*
* Load a segment. Fall back on loading the zero
* segment if something goes wrong..
*/
#define loadsegment(seg,value) \
asm volatile("\n" \
"1:\t" \
"movl %0,%%" #seg "\n" \
"2:\n" \
".section .fixup,\"ax\"\n" \
"3:\t" \
"pushl $0\n\t" \
"popl %%" #seg "\n\t" \
"jmp 2b\n" \
".previous\n" \
".section __ex_table,\"a\"\n\t" \
".align 4\n\t" \
".long 1b,3b\n" \
".previous" \
: :"m" (*(unsigned int *)&(value)))
/*
* Clear and set 'TS' bit respectively
*/
#define clts() __asm__ __volatile__ ("clts")
#define read_cr0() ({ \
unsigned int __dummy; \
__asm__( \
"movl %%cr0,%0\n\t" \
:"=r" (__dummy)); \
__dummy; \
})
#define write_cr0(x) \
__asm__("movl %0,%%cr0": :"r" (x));
#define stts() write_cr0(8 | read_cr0())
#endif /* __KERNEL__ */
static inline unsigned long get_limit(unsigned long segment)
{
unsigned long __limit;
__asm__("lsll %1,%0"
:"=r" (__limit):"r" (segment));
return __limit+1;
}
#define nop() __asm__ __volatile__ ("nop")
#define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
#define tas(ptr) (xchg((ptr),1))
struct __xchg_dummy { unsigned long a[100]; };
#define __xg(x) ((struct __xchg_dummy *)(x))
/*
* Note: no "lock" prefix even on SMP: xchg always implies lock anyway
*/
static inline unsigned long __xchg(unsigned long x, void * ptr, int size)
{
switch (size) {
case 1:
__asm__("xchgb %b0,%1"
:"=q" (x)
:"m" (*__xg(ptr)), "0" (x)
:"memory");
break;
case 2:
__asm__("xchgw %w0,%1"
:"=r" (x)
:"m" (*__xg(ptr)), "0" (x)
:"memory");
break;
case 4:
__asm__("xchgl %0,%1"
:"=r" (x)
:"m" (*__xg(ptr)), "0" (x)
:"memory");
break;
}
return x;
}
/*
* Force strict CPU ordering.
* And yes, this is required on UP too when we're talking
* to devices.
*
* For now, "wmb()" doesn't actually do anything, as all
* Intel CPU's follow what Intel calls a *Processor Order*,
* in which all writes are seen in the program order even
* outside the CPU.
*
* I expect future Intel CPU's to have a weaker ordering,
* but I'd also expect them to finally get their act together
* and add some real memory barriers if so.
*/
#define mb() __asm__ __volatile__ ("lock; addl $0,0(%%esp)": : :"memory")
#define rmb() mb()
#define wmb() __asm__ __volatile__ ("": : :"memory")
/* interrupt control.. */
#define __sti() __asm__ __volatile__ ("sti": : :"memory")
#define __cli() __asm__ __volatile__ ("cli": : :"memory")
#define __save_flags(x) \
__asm__ __volatile__("pushfl ; popl %0":"=g" (x): /* no input */ :"memory")
#define __restore_flags(x) \
__asm__ __volatile__("pushl %0 ; popfl": /* no output */ :"g" (x):"memory")
#ifdef __SMP__
extern void __global_cli(void);
extern void __global_sti(void);
extern unsigned long __global_save_flags(void);
extern void __global_restore_flags(unsigned long);
#define cli() __global_cli()
#define sti() __global_sti()
#define save_flags(x) ((x)=__global_save_flags())
#define restore_flags(x) __global_restore_flags(x)
#else
#define cli() __cli()
#define sti() __sti()
#define save_flags(x) __save_flags(x)
#define restore_flags(x) __restore_flags(x)
#endif
/*
* disable hlt during certain critical i/o operations
*/
#define HAVE_DISABLE_HLT
void disable_hlt(void);
void enable_hlt(void);
#endif
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