#ifndef __ASM_SYSTEM_H
#define __ASM_SYSTEM_H
#include <asm/segment.h>
/*
* Entry into gdt where to find first TSS. GDT layout:
* 0 - null
* 1 - not used
* 2 - kernel code segment
* 3 - kernel data segment
* 4 - user code segment
* 5 - user data segment
* ...
* 8 - TSS #0
* 9 - LDT #0
* 10 - TSS #1
* 11 - LDT #1
*/
#define FIRST_TSS_ENTRY 8
#define FIRST_LDT_ENTRY (FIRST_TSS_ENTRY+1)
#define _TSS(n) ((((unsigned long) n)<<4)+(FIRST_TSS_ENTRY<<3))
#define _LDT(n) ((((unsigned long) n)<<4)+(FIRST_LDT_ENTRY<<3))
#define load_TR(n) __asm__("ltr %%ax": /* no output */ :"a" (_TSS(n)))
#define load_ldt(n) __asm__("lldt %%ax": /* no output */ :"a" (_LDT(n)))
#define store_TR(n) \
__asm__("str %%ax\n\t" \
"subl %2,%%eax\n\t" \
"shrl $4,%%eax" \
:"=a" (n) \
:"0" (0),"i" (FIRST_TSS_ENTRY<<3))
/* This special macro can be used to load a debugging register */
#define loaddebug(tsk,register) \
__asm__("movl %0,%%edx\n\t" \
"movl %%edx,%%db" #register "\n\t" \
: /* no output */ \
:"m" (tsk->debugreg[register]) \
:"dx");
Makrodefinicja przełączająca kontekst. W wersji SMP dba o uaktualnienie licznika kernel_counter, służącego do implementacji blokady jądra. Szczegóły w oryginalnym komentarzu
(gc)
/*
* switch_to(n) should switch tasks to task nr n, first
* checking that n isn't the current task, in which case it does nothing.
* This also clears the TS-flag if the task we switched to has used
* the math co-processor latest.
*
* It also reloads the debug regs if necessary..
*/
#ifdef __SMP__
/*
* Keep the lock depth straight. If we switch on an interrupt from
* kernel->user task we need to lose a depth, and if we switch the
* other way we need to gain a depth. Same layer switches come out
* the same.
*
* We spot a switch in user mode because the kernel counter is the
* same as the interrupt counter depth. (We never switch during the
* message/invalidate IPI).
*
* We fsave/fwait so that an exception goes off at the right time
* (as a call from the fsave or fwait in effect) rather than to
* the wrong process.
*/
#define switch_to(prev,next) do { \
cli();\
if(prev->flags&PF_USEDFPU) \
{ \
__asm__ __volatile__("fnsave %0":"=m" (prev->tss.i387.hard)); \
__asm__ __volatile__("fwait"); \
prev->flags&=~PF_USEDFPU; \
} \
prev->lock_depth=syscall_count; \
kernel_counter+=next->lock_depth-prev->lock_depth; \
syscall_count=next->lock_depth; \
__asm__("pushl %%edx\n\t" \
"movl "SYMBOL_NAME_STR(apic_reg)",%%edx\n\t" \
"movl 0x20(%%edx), %%edx\n\t" \
"shrl $22,%%edx\n\t" \
"and $0x3C,%%edx\n\t" \
"movl %%ecx,"SYMBOL_NAME_STR(current_set)"(,%%edx)\n\t" \
"popl %%edx\n\t" \
"ljmp %0\n\t" \
"sti\n\t" \
: /* no output */ \
:"m" (*(((char *)&next->tss.tr)-4)), \
"c" (next)); \
/* Now maybe reload the debug registers */ \
if(prev->debugreg[7]){ \
loaddebug(prev,0); \
loaddebug(prev,1); \
loaddebug(prev,2); \
loaddebug(prev,3); \
loaddebug(prev,6); \
} \
} while (0)
#else
#define switch_to(prev,next) do { \
__asm__("movl %2,"SYMBOL_NAME_STR(current_set)"\n\t" \
"ljmp %0\n\t" \
"cmpl %1,"SYMBOL_NAME_STR(last_task_used_math)"\n\t" \
"jne 1f\n\t" \
"clts\n" \
"1:" \
: /* no outputs */ \
:"m" (*(((char *)&next->tss.tr)-4)), \
"r" (prev), "r" (next)); \
/* Now maybe reload the debug registers */ \
if(prev->debugreg[7]){ \
loaddebug(prev,0); \
loaddebug(prev,1); \
loaddebug(prev,2); \
loaddebug(prev,3); \
loaddebug(prev,6); \
} \
} while (0)
#endif
#define _set_base(addr,base) \
__asm__("movw %%dx,%0\n\t" \
"rorl $16,%%edx\n\t" \
"movb %%dl,%1\n\t" \
"movb %%dh,%2" \
: /* no output */ \
:"m" (*((addr)+2)), \
"m" (*((addr)+4)), \
"m" (*((addr)+7)), \
"d" (base) \
:"dx")
#define _set_limit(addr,limit) \
__asm__("movw %%dx,%0\n\t" \
"rorl $16,%%edx\n\t" \
"movb %1,%%dh\n\t" \
"andb $0xf0,%%dh\n\t" \
"orb %%dh,%%dl\n\t" \
"movb %%dl,%1" \
: /* no output */ \
:"m" (*(addr)), \
"m" (*((addr)+6)), \
"d" (limit) \
:"dx")
#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)) )
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")
/*
* Clear and set 'TS' bit respectively
*/
#define clts() __asm__ __volatile__ ("clts")
#define stts() \
__asm__ __volatile__ ( \
"movl %%cr0,%%eax\n\t" \
"orl $8,%%eax\n\t" \
"movl %%eax,%%cr0" \
: /* no outputs */ \
: /* no inputs */ \
:"ax")
#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))
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;
}
#define mb() __asm__ __volatile__ ("" : : :"memory")
#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")
#define iret() __asm__ __volatile__ ("iret": : :"memory")
#define _set_gate(gate_addr,type,dpl,addr) \
__asm__ __volatile__ ("movw %%dx,%%ax\n\t" \
"movw %2,%%dx\n\t" \
"movl %%eax,%0\n\t" \
"movl %%edx,%1" \
:"=m" (*((long *) (gate_addr))), \
"=m" (*(1+(long *) (gate_addr))) \
:"i" ((short) (0x8000+(dpl<<13)+(type<<8))), \
"d" ((char *) (addr)),"a" (KERNEL_CS << 16) \
:"ax","dx")
#define set_intr_gate(n,addr) \
_set_gate(&idt[n],14,0,addr)
#define set_trap_gate(n,addr) \
_set_gate(&idt[n],15,0,addr)
#define set_system_gate(n,addr) \
_set_gate(&idt[n],15,3,addr)
#define set_call_gate(a,addr) \
_set_gate(a,12,3,addr)
#define _set_seg_desc(gate_addr,type,dpl,base,limit) {\
*((gate_addr)+1) = ((base) & 0xff000000) | \
(((base) & 0x00ff0000)>>16) | \
((limit) & 0xf0000) | \
((dpl)<<13) | \
(0x00408000) | \
((type)<<8); \
*(gate_addr) = (((base) & 0x0000ffff)<<16) | \
((limit) & 0x0ffff); }
#define _set_tssldt_desc(n,addr,limit,type) \
__asm__ __volatile__ ("movw $" #limit ",%1\n\t" \
"movw %%ax,%2\n\t" \
"rorl $16,%%eax\n\t" \
"movb %%al,%3\n\t" \
"movb $" type ",%4\n\t" \
"movb $0x00,%5\n\t" \
"movb %%ah,%6\n\t" \
"rorl $16,%%eax" \
: /* no output */ \
:"a" (addr+0xc0000000), "m" (*(n)), "m" (*(n+2)), "m" (*(n+4)), \
"m" (*(n+5)), "m" (*(n+6)), "m" (*(n+7)) \
)
#define set_tss_desc(n,addr) _set_tssldt_desc(((char *) (n)),((int)(addr)),235,"0x89")
#define set_ldt_desc(n,addr,size) \
_set_tssldt_desc(((char *) (n)),((int)(addr)),((size << 3) - 1),"0x82")
/*
* This is the ldt that every process will get unless we need
* something other than this.
*/
extern struct desc_struct default_ldt;
/*
* disable hlt during certain critical i/o operations
*/
#define HAVE_DISABLE_HLT
void disable_hlt(void);
void enable_hlt(void);
#endif