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/* Project: OSLib
* Description: The OS Construction Kit
* Date: 1.6.2000
* Idea by: Luca Abeni & Gerardo Lamastra
*
* OSLib is an SO project aimed at developing a common, easy-to-use
* low-level infrastructure for developing OS kernels and Embedded
* Applications; it partially derives from the HARTIK project but it
* currently is independently developed.
*
* OSLib is distributed under GPL License, and some of its code has
* been derived from the Linux kernel source; also some important
* ideas come from studying the DJGPP go32 extender.
*
* We acknowledge the Linux Community, Free Software Foundation,
* D.J. Delorie and all the other developers who believe in the
* freedom of software and ideas.
*
* For legalese, check out the included GPL license.
*/
/* Routines that implements threads (creation, end, dump, and AS
assignment */
#include <ll/i386/stdio.h>
#include <ll/i386/mem.h>
#include <ll/i386/cons.h>
#include <ll/i386/error.h>
#include <ll/i386/tss-ctx.h>
#include <ll/sys/ll/ll-instr.h> /* Only for HW instr... */
#include <ll/sys/ll/ll-func.h>
FILE
(KL
-Context
-Switch
);
extern TSS TSS_table
[TSSMax
];
extern WORD TSS_control
[TSSMax
];
extern BYTE ll_FPU_stdctx
[FPU_CONTEXT_SIZE
];
#ifdef __VIRCSW__
extern unsigned short int currCtx
;
extern int activeInt
;
#endif
extern DWORD entrypoint
;
/* Just a debugging function; it dumps the status of the TSS */
void dump_TSS
(WORD sel
)
{
BYTE acc
,gran
;
DWORD base
,lim
;
message
("TR %x\n", sel
);
sel
= TSSsel2index
(sel
);
message
("SS:SP %x:%lx\n", TSS_table
[sel
].
ss, TSS_table
[sel
].
esp);
message
("Stack0 : %x:%lx\n", TSS_table
[sel
].
ss0, TSS_table
[sel
].
esp0);
message
("Stack1 : %x:%lx\n", TSS_table
[sel
].
ss1, TSS_table
[sel
].
esp1);
message
("Stack2 : %x:%lx\n", TSS_table
[sel
].
ss2, TSS_table
[sel
].
esp2);
message
("CS : %x DS : %x\n", TSS_table
[sel
].
cs, TSS_table
[sel
].
ds);
sel
= TSSindex2sel
(sel
);
message
("Descriptor [%x] Info",sel
);
base
= GDT_read
(sel
,&lim
,&acc
,&gran
);
message
("Base : %lx Lim : %lx Acc : %x Gran %x\n", base
, lim
, (unsigned)(acc
),(unsigned)(gran
));
}
void ll_context_setspace
(CONTEXT c
, WORD as
)
{
int index
= TSSsel2index
(c
);
TSS_table
[index
].
ss0 = as
;
TSS_table
[index
].
cs = as
+ 8;
TSS_table
[index
].
es = as
;
TSS_table
[index
].
ds = as
;
TSS_table
[index
].
ss = as
;
}
/* Initialize context -> TSS in 32 bit */
CONTEXT ll_context_create
(void (*task
)(void *p
),BYTE
*stack
,
void *parm
,void (*killer
)(void),WORD control
)
{
CONTEXT index
= 0;
DWORD
*stack_ptr
= (DWORD
*)stack
;
/* Push onto stack the input parameter */
/* And the entry point to the task killer procedure */
stack_ptr
--;
*stack_ptr
= (DWORD
)(parm
);
stack_ptr
--;
*stack_ptr
= (DWORD
)(killer
);
/* Find a free TSS */
while ((TSS_control
[index
] & TSS_USED
) && (index
< TSSMain
)) index
++;
/* This exception would signal an error */
if (index
>= TSSMain
) {
message
("No more Descriptors...\n");
return 0;
}
TSS_control
[index
] |= (TSS_USED
| control
);
/* Fill the TSS structure */
/* No explicit protection; use only one stack */
TSS_table
[index
].
esp0 = (DWORD
)(stack_ptr
);
TSS_table
[index
].
esp1 = 0;
TSS_table
[index
].
esp2 = 0;
TSS_table
[index
].
ss0 = get_DS
();
TSS_table
[index
].
ss1 = 0;
TSS_table
[index
].
ss2 = 0;
/* No paging activated */
TSS_table
[index
].
cr3 = 0;
/* Task entry point */
TSS_table
[index
].
eip = (DWORD
)(task
);
/* Need only to unmask interrupts */
TSS_table
[index
].
eflags = 0x00000200;
TSS_table
[index
].
eax = 0;
TSS_table
[index
].
ebx = 0;
TSS_table
[index
].
ecx = 0;
TSS_table
[index
].
edx = 0;
TSS_table
[index
].
esi = 0;
TSS_table
[index
].
edi = 0;
TSS_table
[index
].
esp = (DWORD
)(stack_ptr
);
TSS_table
[index
].
ebp = (DWORD
)(stack_ptr
);
TSS_table
[index
].
cs = get_CS
();
TSS_table
[index
].
es = get_DS
();
TSS_table
[index
].
ds = get_DS
();
TSS_table
[index
].
ss = get_DS
();
TSS_table
[index
].
gs = X_FLATDATA_SEL
;
TSS_table
[index
].
fs = X_FLATDATA_SEL
;
/* Use only the GDT */
TSS_table
[index
].
ldt = 0;
TSS_table
[index
].
trap = 0;
TSS_table
[index
].
io_base = 0;
/* Fill in the coprocessor status */
memcpy(TSS_table
[index
].
ctx_FPU,ll_FPU_stdctx
,FPU_CONTEXT_SIZE
);
/* Convert the index into a valid selector */
/* Which really represent CONTEXT */
return(TSSindex2sel
(index
));
}
/* Release the used TSS */
void ll_context_delete
(CONTEXT c
)
{
int index
= TSSsel2index
(c
);
TSS_control
[index
] = 0;
}
#if 0 /* It does not work... Fix it!!! */
DWORD ll_push_func
(void (*func
)(void))
{
DWORD
*p
;
DWORD old
;
p
= (DWORD
*)entrypoint
;
old
= *p
;
*p
= (DWORD
)func
;
return old
;
}
#endif
/* Well this is used for debug purposes mainly; as the context is an */
/* abstract type, we must provide some function to convert in into a */
/* printable form; anyway this depend from the architecture as the context */
char *ll_context_sprintf
(char *str
, CONTEXT c
)
{
ksprintf
(str
, "%x (Hex)", c
);
return(str
);
}