453 lines
14 KiB
C
453 lines
14 KiB
C
/* This file contains code for initialization of protected mode, to initialize
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* code and data segment descriptors, and to initialize global descriptors
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* for local descriptors in the process table.
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*/
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#include "kernel/kernel.h"
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#include "kernel/proc.h"
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#include "archconst.h"
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#include "proto.h"
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#define INT_GATE_TYPE (INT_286_GATE | DESC_386_BIT)
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#define TSS_TYPE (AVL_286_TSS | DESC_386_BIT)
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struct desctableptr_s {
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char limit[sizeof(u16_t)];
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char base[sizeof(u32_t)]; /* really u24_t + pad for 286 */
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};
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struct gatedesc_s {
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u16_t offset_low;
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u16_t selector;
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u8_t pad; /* |000|XXXXX| ig & trpg, |XXXXXXXX| task g */
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u8_t p_dpl_type; /* |P|DL|0|TYPE| */
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u16_t offset_high;
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};
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PUBLIC struct segdesc_s gdt[GDT_SIZE]; /* used in klib.s and mpx.s */
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PRIVATE struct gatedesc_s idt[IDT_SIZE]; /* zero-init so none present */
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PUBLIC struct tss_s tss; /* zero init */
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FORWARD _PROTOTYPE( void sdesc, (struct segdesc_s *segdp, phys_bytes base,
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vir_bytes size) );
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/*===========================================================================*
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* enable_iop *
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*===========================================================================*/
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PUBLIC void enable_iop(struct proc *pp)
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{
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/* Allow a user process to use I/O instructions. Change the I/O Permission
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* Level bits in the psw. These specify least-privileged Current Permission
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* Level allowed to execute I/O instructions. Users and servers have CPL 3.
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* You can't have less privilege than that. Kernel has CPL 0, tasks CPL 1.
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*/
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pp->p_reg.psw |= 0x3000;
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}
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/*===========================================================================*
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* seg2phys *
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*===========================================================================*/
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PUBLIC phys_bytes seg2phys(const u16_t seg)
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{
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/* Return the base address of a segment, with seg being a
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* register, or a 286/386 segment selector.
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*/
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phys_bytes base;
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struct segdesc_s *segdp;
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segdp = &gdt[seg >> 3];
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base = ((u32_t) segdp->base_low << 0)
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| ((u32_t) segdp->base_middle << 16)
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| ((u32_t) segdp->base_high << 24);
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return base;
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}
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/*===========================================================================*
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* phys2seg *
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*===========================================================================*/
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PRIVATE void phys2seg(u16_t *seg, vir_bytes *off, phys_bytes phys)
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{
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/* Return a segment selector and offset that can be used to reach a physical
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* address, for use by a driver doing memory I/O in the A0000 - DFFFF range.
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*/
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*seg = FLAT_DS_SELECTOR;
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*off = (vir_bytes) phys;
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}
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/*===========================================================================*
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* init_dataseg *
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*===========================================================================*/
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PUBLIC void init_dataseg(register struct segdesc_s *segdp,
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phys_bytes base, vir_bytes size, const int privilege)
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{
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/* Build descriptor for a data segment. */
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sdesc(segdp, base, size);
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segdp->access = (privilege << DPL_SHIFT) | (PRESENT | SEGMENT |
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WRITEABLE);
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/* EXECUTABLE = 0, EXPAND_DOWN = 0, ACCESSED = 0 */
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}
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/*===========================================================================*
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* init_codeseg *
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*===========================================================================*/
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PRIVATE void init_codeseg(register struct segdesc_s *segdp, phys_bytes base,
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vir_bytes size, int privilege)
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{
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/* Build descriptor for a code segment. */
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sdesc(segdp, base, size);
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segdp->access = (privilege << DPL_SHIFT)
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| (PRESENT | SEGMENT | EXECUTABLE | READABLE);
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/* CONFORMING = 0, ACCESSED = 0 */
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}
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PUBLIC struct gate_table_s gate_table_pic[] = {
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{ hwint00, VECTOR( 0), INTR_PRIVILEGE },
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{ hwint01, VECTOR( 1), INTR_PRIVILEGE },
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{ hwint02, VECTOR( 2), INTR_PRIVILEGE },
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{ hwint03, VECTOR( 3), INTR_PRIVILEGE },
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{ hwint04, VECTOR( 4), INTR_PRIVILEGE },
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{ hwint05, VECTOR( 5), INTR_PRIVILEGE },
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{ hwint06, VECTOR( 6), INTR_PRIVILEGE },
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{ hwint07, VECTOR( 7), INTR_PRIVILEGE },
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{ hwint08, VECTOR( 8), INTR_PRIVILEGE },
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{ hwint09, VECTOR( 9), INTR_PRIVILEGE },
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{ hwint10, VECTOR(10), INTR_PRIVILEGE },
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{ hwint11, VECTOR(11), INTR_PRIVILEGE },
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{ hwint12, VECTOR(12), INTR_PRIVILEGE },
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{ hwint13, VECTOR(13), INTR_PRIVILEGE },
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{ hwint14, VECTOR(14), INTR_PRIVILEGE },
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{ hwint15, VECTOR(15), INTR_PRIVILEGE },
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{ NULL, 0, 0}
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};
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/*===========================================================================*
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* prot_init *
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*===========================================================================*/
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PUBLIC void prot_init(void)
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{
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/* Set up tables for protected mode.
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* All GDT slots are allocated at compile time.
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*/
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struct desctableptr_s *dtp;
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unsigned ldt_index;
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register struct proc *rp;
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/* Click-round kernel. */
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if(kinfo.data_base % CLICK_SIZE)
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panic("kinfo.data_base not aligned");
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kinfo.data_size = (phys_bytes) (CLICK_CEIL(kinfo.data_size));
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/* Build gdt and idt pointers in GDT where the BIOS expects them. */
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dtp= (struct desctableptr_s *) &gdt[GDT_INDEX];
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* (u16_t *) dtp->limit = (sizeof gdt) - 1;
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* (u32_t *) dtp->base = vir2phys(gdt);
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dtp= (struct desctableptr_s *) &gdt[IDT_INDEX];
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* (u16_t *) dtp->limit = (sizeof idt) - 1;
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* (u32_t *) dtp->base = vir2phys(idt);
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/* Build segment descriptors for tasks and interrupt handlers. */
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init_codeseg(&gdt[CS_INDEX],
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kinfo.code_base, kinfo.code_size, INTR_PRIVILEGE);
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init_dataseg(&gdt[DS_INDEX],
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kinfo.data_base, kinfo.data_size, INTR_PRIVILEGE);
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init_dataseg(&gdt[ES_INDEX], 0L, 0, INTR_PRIVILEGE);
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/* Build local descriptors in GDT for LDT's in process table.
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* The LDT's are allocated at compile time in the process table, and
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* initialized whenever a process' map is initialized or changed.
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*/
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for (rp = BEG_PROC_ADDR, ldt_index = FIRST_LDT_INDEX;
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rp < END_PROC_ADDR; ++rp, ldt_index++) {
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init_dataseg(&gdt[ldt_index], vir2phys(rp->p_seg.p_ldt),
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sizeof(rp->p_seg.p_ldt), INTR_PRIVILEGE);
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gdt[ldt_index].access = PRESENT | LDT;
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rp->p_seg.p_ldt_sel = ldt_index * DESC_SIZE;
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}
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/* Build main TSS */
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tss.ss0 = DS_SELECTOR;
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init_dataseg(&gdt[TSS_INDEX], vir2phys(&tss), sizeof(tss), INTR_PRIVILEGE);
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gdt[TSS_INDEX].access = PRESENT | (INTR_PRIVILEGE << DPL_SHIFT) | TSS_TYPE;
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/* Complete building of main TSS. */
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tss.iobase = sizeof tss; /* empty i/o permissions map */
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}
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PUBLIC void idt_copy_vectors(struct gate_table_s * first)
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{
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struct gate_table_s *gtp;
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for (gtp = first; gtp->gate; gtp++) {
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int_gate(gtp->vec_nr, (vir_bytes) gtp->gate,
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PRESENT | INT_GATE_TYPE |
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(gtp->privilege << DPL_SHIFT));
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}
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}
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/* Build descriptors for interrupt gates in IDT. */
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PUBLIC void idt_init(void)
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{
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struct gate_table_s gate_table[] = {
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{ divide_error, DIVIDE_VECTOR, INTR_PRIVILEGE },
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{ single_step_exception, DEBUG_VECTOR, INTR_PRIVILEGE },
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{ nmi, NMI_VECTOR, INTR_PRIVILEGE },
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{ breakpoint_exception, BREAKPOINT_VECTOR, USER_PRIVILEGE },
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{ overflow, OVERFLOW_VECTOR, USER_PRIVILEGE },
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{ bounds_check, BOUNDS_VECTOR, INTR_PRIVILEGE },
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{ inval_opcode, INVAL_OP_VECTOR, INTR_PRIVILEGE },
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{ copr_not_available, COPROC_NOT_VECTOR, INTR_PRIVILEGE },
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{ double_fault, DOUBLE_FAULT_VECTOR, INTR_PRIVILEGE },
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{ copr_seg_overrun, COPROC_SEG_VECTOR, INTR_PRIVILEGE },
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{ inval_tss, INVAL_TSS_VECTOR, INTR_PRIVILEGE },
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{ segment_not_present, SEG_NOT_VECTOR, INTR_PRIVILEGE },
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{ stack_exception, STACK_FAULT_VECTOR, INTR_PRIVILEGE },
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{ general_protection, PROTECTION_VECTOR, INTR_PRIVILEGE },
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{ page_fault, PAGE_FAULT_VECTOR, INTR_PRIVILEGE },
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{ copr_error, COPROC_ERR_VECTOR, INTR_PRIVILEGE },
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{ alignment_check, ALIGNMENT_CHECK_VECTOR, INTR_PRIVILEGE },
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{ machine_check, MACHINE_CHECK_VECTOR, INTR_PRIVILEGE },
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{ simd_exception, SIMD_EXCEPTION_VECTOR, INTR_PRIVILEGE },
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{ ipc_entry, IPC_VECTOR, USER_PRIVILEGE },
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{ kernel_call_entry, KERN_CALL_VECTOR, USER_PRIVILEGE },
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{ NULL, 0, 0}
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};
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idt_copy_vectors(gate_table);
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idt_copy_vectors(gate_table_pic);
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}
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/*===========================================================================*
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* sdesc *
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*===========================================================================*/
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PRIVATE void sdesc(segdp, base, size)
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register struct segdesc_s *segdp;
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phys_bytes base;
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vir_bytes size;
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{
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/* Fill in the size fields (base, limit and granularity) of a descriptor. */
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segdp->base_low = base;
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segdp->base_middle = base >> BASE_MIDDLE_SHIFT;
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segdp->base_high = base >> BASE_HIGH_SHIFT;
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--size; /* convert to a limit, 0 size means 4G */
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if (size > BYTE_GRAN_MAX) {
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segdp->limit_low = size >> PAGE_GRAN_SHIFT;
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segdp->granularity = GRANULAR | (size >>
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(PAGE_GRAN_SHIFT + GRANULARITY_SHIFT));
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} else {
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segdp->limit_low = size;
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segdp->granularity = size >> GRANULARITY_SHIFT;
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}
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segdp->granularity |= DEFAULT; /* means BIG for data seg */
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}
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/*===========================================================================*
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* int_gate *
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*===========================================================================*/
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PUBLIC void int_gate(unsigned vec_nr, vir_bytes offset, unsigned dpl_type)
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{
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/* Build descriptor for an interrupt gate. */
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register struct gatedesc_s *idp;
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idp = &idt[vec_nr];
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idp->offset_low = offset;
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idp->selector = CS_SELECTOR;
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idp->p_dpl_type = dpl_type;
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idp->offset_high = offset >> OFFSET_HIGH_SHIFT;
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}
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/*===========================================================================*
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* alloc_segments *
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*===========================================================================*/
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PUBLIC void alloc_segments(register struct proc *rp)
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{
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/* This is called at system initialization from main() and by do_newmap().
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* The code has a separate function because of all hardware-dependencies.
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*/
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phys_bytes code_bytes;
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phys_bytes data_bytes;
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int privilege;
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data_bytes = (phys_bytes) (rp->p_memmap[S].mem_vir +
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rp->p_memmap[S].mem_len) << CLICK_SHIFT;
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if (rp->p_memmap[T].mem_len == 0)
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code_bytes = data_bytes; /* common I&D, poor protect */
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else
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code_bytes = (phys_bytes) rp->p_memmap[T].mem_len << CLICK_SHIFT;
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privilege = USER_PRIVILEGE;
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init_codeseg(&rp->p_seg.p_ldt[CS_LDT_INDEX],
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(phys_bytes) rp->p_memmap[T].mem_phys << CLICK_SHIFT,
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code_bytes, privilege);
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init_dataseg(&rp->p_seg.p_ldt[DS_LDT_INDEX],
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(phys_bytes) rp->p_memmap[D].mem_phys << CLICK_SHIFT,
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data_bytes, privilege);
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rp->p_reg.cs = (CS_LDT_INDEX * DESC_SIZE) | TI | privilege;
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rp->p_reg.gs =
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rp->p_reg.fs =
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rp->p_reg.ss =
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rp->p_reg.es =
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rp->p_reg.ds = (DS_LDT_INDEX*DESC_SIZE) | TI | privilege;
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}
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/*===========================================================================*
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* check_segments *
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*===========================================================================*/
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PRIVATE void check_segments(char *File, int line)
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{
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int checked = 0;
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int fail = 0;
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struct proc *rp;
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for (rp = BEG_PROC_ADDR; rp < END_PROC_ADDR; ++rp) {
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int privilege;
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int cs, ds;
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if (isemptyp(rp))
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continue;
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privilege = USER_PRIVILEGE;
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cs = (CS_LDT_INDEX*DESC_SIZE) | TI | privilege;
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ds = (DS_LDT_INDEX*DESC_SIZE) | TI | privilege;
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#define CHECK(s1, s2) if(s1 != s2) { \
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printf("%s:%d: " #s1 " != " #s2 " for ep %d\n", \
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File, line, rp->p_endpoint); fail++; } checked++;
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CHECK(rp->p_reg.cs, cs);
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CHECK(rp->p_reg.gs, ds);
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CHECK(rp->p_reg.fs, ds);
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CHECK(rp->p_reg.ss, ds);
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if(rp->p_endpoint != SYSTEM) {
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CHECK(rp->p_reg.es, ds);
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}
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CHECK(rp->p_reg.ds, ds);
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}
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if(fail) {
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printf("%d/%d checks failed\n", fail, checked);
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panic("wrong: %d", fail);
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}
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}
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/*===========================================================================*
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* printseg *
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*===========================================================================*/
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PUBLIC void printseg(char *banner, const int iscs, struct proc *pr,
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const u32_t selector)
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{
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u32_t base, limit, index, dpl;
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struct segdesc_s *desc;
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if(banner) { printf("%s", banner); }
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index = selector >> 3;
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printf("RPL %d, ind %d of ",
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(selector & RPL_MASK), index);
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if(selector & TI) {
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printf("LDT");
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if(index >= LDT_SIZE) {
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printf("invalid index in ldt\n");
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return;
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}
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if(!pr) {
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printf("local selector but unknown process\n");
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return;
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}
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desc = &pr->p_seg.p_ldt[index];
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} else {
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printf("GDT");
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if(index >= GDT_SIZE) {
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printf("invalid index in gdt\n");
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return;
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}
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desc = &gdt[index];
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}
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limit = desc->limit_low |
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(((u32_t) desc->granularity & LIMIT_HIGH) << GRANULARITY_SHIFT);
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if(desc->granularity & GRANULAR) {
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limit = (limit << PAGE_GRAN_SHIFT) + 0xfff;
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}
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base = desc->base_low |
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((u32_t) desc->base_middle << BASE_MIDDLE_SHIFT) |
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((u32_t) desc->base_high << BASE_HIGH_SHIFT);
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printf(" -> base 0x%08lx size 0x%08lx ", base, limit+1);
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if(iscs) {
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if(!(desc->granularity & BIG))
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printf("16bit ");
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} else {
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if(!(desc->granularity & BIG))
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printf("not big ");
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}
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if(desc->granularity & 0x20) { /* reserved */
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panic("granularity reserved field set");
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}
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if(!(desc->access & PRESENT))
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printf("notpresent ");
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if(!(desc->access & SEGMENT))
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printf("system ");
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if(desc->access & EXECUTABLE) {
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printf(" exec ");
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if(desc->access & CONFORMING) printf("conforming ");
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if(!(desc->access & READABLE)) printf("non-readable ");
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} else {
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printf("nonexec ");
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if(desc->access & EXPAND_DOWN) printf("non-expand-down ");
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if(!(desc->access & WRITEABLE)) printf("non-writable ");
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}
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if(!(desc->access & ACCESSED)) {
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printf("nonacc ");
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}
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dpl = ((u32_t) desc->access & DPL) >> DPL_SHIFT;
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printf("DPL %d\n", dpl);
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return;
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}
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/*===========================================================================*
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* prot_set_kern_seg_limit *
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*===========================================================================*/
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PUBLIC int prot_set_kern_seg_limit(const vir_bytes limit)
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{
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struct proc *rp;
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int orig_click;
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int incr_clicks;
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if(limit <= kinfo.data_base) {
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printf("prot_set_kern_seg_limit: limit bogus\n");
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return EINVAL;
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}
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/* Do actual increase. */
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orig_click = kinfo.data_size / CLICK_SIZE;
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kinfo.data_size = limit - kinfo.data_base;
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incr_clicks = kinfo.data_size / CLICK_SIZE - orig_click;
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prot_init();
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/* Increase kernel processes too. */
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for (rp = BEG_PROC_ADDR; rp < END_PROC_ADDR; ++rp) {
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if (isemptyp(rp) || !iskernelp(rp))
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continue;
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rp->p_memmap[S].mem_len += incr_clicks;
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alloc_segments(rp);
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rp->p_memmap[S].mem_len -= incr_clicks;
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}
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return OK;
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}
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