81 lines
2.6 KiB
C
81 lines
2.6 KiB
C
/* The system call implemented in this file:
|
|
* m_type: SYS_SEGCTL
|
|
*
|
|
* The parameters for this system call are:
|
|
* m4_l3: SEG_PHYS (physical base address)
|
|
* m4_l4: SEG_SIZE (size of segment)
|
|
* m4_l1: SEG_SELECT (return segment selector here)
|
|
* m4_l2: SEG_OFFSET (return offset within segment here)
|
|
* m4_l5: SEG_INDEX (return index into remote memory map here)
|
|
*/
|
|
#include "../system.h"
|
|
#include "../protect.h"
|
|
|
|
#if USE_SEGCTL
|
|
|
|
/*===========================================================================*
|
|
* do_segctl *
|
|
*===========================================================================*/
|
|
PUBLIC int do_segctl(m_ptr)
|
|
register message *m_ptr; /* pointer to request message */
|
|
{
|
|
/* Return a segment selector and offset that can be used to reach a physical
|
|
* address, for use by a driver doing memory I/O in the A0000 - DFFFF range.
|
|
*/
|
|
u16_t selector;
|
|
vir_bytes offset;
|
|
int i, index;
|
|
register struct proc *rp;
|
|
phys_bytes phys = (phys_bytes) m_ptr->SEG_PHYS;
|
|
vir_bytes size = (vir_bytes) m_ptr->SEG_SIZE;
|
|
int result;
|
|
|
|
/* First check if there is a slot available for this segment. */
|
|
rp = proc_addr(m_ptr->m_source);
|
|
index = -1;
|
|
for (i=0; i < NR_REMOTE_SEGS; i++) {
|
|
if (! rp->p_priv->s_farmem[i].in_use) {
|
|
index = i;
|
|
rp->p_priv->s_farmem[i].in_use = TRUE;
|
|
rp->p_priv->s_farmem[i].mem_phys = phys;
|
|
rp->p_priv->s_farmem[i].mem_len = size;
|
|
break;
|
|
}
|
|
}
|
|
if (index < 0) return(ENOSPC);
|
|
|
|
if (! machine.protected) {
|
|
selector = phys / HCLICK_SIZE;
|
|
offset = phys % HCLICK_SIZE;
|
|
result = OK;
|
|
} else {
|
|
/* Check if the segment size can be recorded in bytes, that is, check
|
|
* if descriptor's limit field can delimited the allowed memory region
|
|
* precisely. This works up to 1MB. If the size is larger, 4K pages
|
|
* instead of bytes are used.
|
|
*/
|
|
if (size < BYTE_GRAN_MAX) {
|
|
init_dataseg(&rp->p_ldt[EXTRA_LDT_INDEX+i], phys, size,
|
|
USER_PRIVILEGE);
|
|
selector = ((EXTRA_LDT_INDEX+i)*0x08) | (1*0x04) | USER_PRIVILEGE;
|
|
offset = 0;
|
|
result = OK;
|
|
} else {
|
|
init_dataseg(&rp->p_ldt[EXTRA_LDT_INDEX+i], phys & ~0xFFFF, 0,
|
|
USER_PRIVILEGE);
|
|
selector = ((EXTRA_LDT_INDEX+i)*0x08) | (1*0x04) | USER_PRIVILEGE;
|
|
offset = phys & 0xFFFF;
|
|
result = OK;
|
|
}
|
|
}
|
|
|
|
/* Request successfully done. Now return the result. */
|
|
m_ptr->SEG_INDEX = index | REMOTE_SEG;
|
|
m_ptr->SEG_SELECT = selector;
|
|
m_ptr->SEG_OFFSET = offset;
|
|
return(result);
|
|
}
|
|
|
|
#endif /* USE_SEGCTL */
|
|
|