| 1 | /* The kernel call implemented in this file:
|
|---|
| 2 | * m_type: SYS_SEGCTL
|
|---|
| 3 | *
|
|---|
| 4 | * The parameters for this kernel call are:
|
|---|
| 5 | * m4_l3: SEG_PHYS (physical base address)
|
|---|
| 6 | * m4_l4: SEG_SIZE (size of segment)
|
|---|
| 7 | * m4_l1: SEG_SELECT (return segment selector here)
|
|---|
| 8 | * m4_l2: SEG_OFFSET (return offset within segment here)
|
|---|
| 9 | * m4_l5: SEG_INDEX (return index into remote memory map here)
|
|---|
| 10 | */
|
|---|
| 11 | #include "../system.h"
|
|---|
| 12 | #include "../protect.h"
|
|---|
| 13 |
|
|---|
| 14 | #if USE_SEGCTL
|
|---|
| 15 |
|
|---|
| 16 | /*===========================================================================*
|
|---|
| 17 | * do_segctl *
|
|---|
| 18 | *===========================================================================*/
|
|---|
| 19 | PUBLIC int do_segctl(m_ptr)
|
|---|
| 20 | register message *m_ptr; /* pointer to request message */
|
|---|
| 21 | {
|
|---|
| 22 | /* Return a segment selector and offset that can be used to reach a physical
|
|---|
| 23 | * address, for use by a driver doing memory I/O in the A0000 - DFFFF range.
|
|---|
| 24 | */
|
|---|
| 25 | u16_t selector;
|
|---|
| 26 | vir_bytes offset;
|
|---|
| 27 | int i, index;
|
|---|
| 28 | register struct proc *rp;
|
|---|
| 29 | phys_bytes phys = (phys_bytes) m_ptr->SEG_PHYS;
|
|---|
| 30 | vir_bytes size = (vir_bytes) m_ptr->SEG_SIZE;
|
|---|
| 31 | int result;
|
|---|
| 32 |
|
|---|
| 33 | /* First check if there is a slot available for this segment. */
|
|---|
| 34 | rp = proc_addr(who_p);
|
|---|
| 35 | index = -1;
|
|---|
| 36 | for (i=0; i < NR_REMOTE_SEGS; i++) {
|
|---|
| 37 | if (! rp->p_priv->s_farmem[i].in_use) {
|
|---|
| 38 | index = i;
|
|---|
| 39 | rp->p_priv->s_farmem[i].in_use = TRUE;
|
|---|
| 40 | rp->p_priv->s_farmem[i].mem_phys = phys;
|
|---|
| 41 | rp->p_priv->s_farmem[i].mem_len = size;
|
|---|
| 42 | break;
|
|---|
| 43 | }
|
|---|
| 44 | }
|
|---|
| 45 | if (index < 0) return(ENOSPC);
|
|---|
| 46 |
|
|---|
| 47 | if (! machine.prot) {
|
|---|
| 48 | selector = phys / HCLICK_SIZE;
|
|---|
| 49 | offset = phys % HCLICK_SIZE;
|
|---|
| 50 | result = OK;
|
|---|
| 51 | } else {
|
|---|
| 52 | /* Check if the segment size can be recorded in bytes, that is, check
|
|---|
| 53 | * if descriptor's limit field can delimited the allowed memory region
|
|---|
| 54 | * precisely. This works up to 1MB. If the size is larger, 4K pages
|
|---|
| 55 | * instead of bytes are used.
|
|---|
| 56 | */
|
|---|
| 57 | if (size < BYTE_GRAN_MAX) {
|
|---|
| 58 | init_dataseg(&rp->p_ldt[EXTRA_LDT_INDEX+i], phys, size,
|
|---|
| 59 | USER_PRIVILEGE);
|
|---|
| 60 | selector = ((EXTRA_LDT_INDEX+i)*0x08) | (1*0x04) | USER_PRIVILEGE;
|
|---|
| 61 | offset = 0;
|
|---|
| 62 | result = OK;
|
|---|
| 63 | } else {
|
|---|
| 64 | init_dataseg(&rp->p_ldt[EXTRA_LDT_INDEX+i], phys & ~0xFFFF, 0,
|
|---|
| 65 | USER_PRIVILEGE);
|
|---|
| 66 | selector = ((EXTRA_LDT_INDEX+i)*0x08) | (1*0x04) | USER_PRIVILEGE;
|
|---|
| 67 | offset = phys & 0xFFFF;
|
|---|
| 68 | result = OK;
|
|---|
| 69 | }
|
|---|
| 70 | }
|
|---|
| 71 |
|
|---|
| 72 | /* Request successfully done. Now return the result. */
|
|---|
| 73 | m_ptr->SEG_INDEX = index | REMOTE_SEG;
|
|---|
| 74 | m_ptr->SEG_SELECT = selector;
|
|---|
| 75 | m_ptr->SEG_OFFSET = offset;
|
|---|
| 76 | return(result);
|
|---|
| 77 | }
|
|---|
| 78 |
|
|---|
| 79 | #endif /* USE_SEGCTL */
|
|---|
| 80 |
|
|---|
