This commit is contained in:
rsc 2007-08-24 20:28:08 +00:00
parent ffa58d3616
commit 97ac612fb1
5 changed files with 51 additions and 52 deletions

View file

@ -31,31 +31,35 @@
#include "x86.h"
#define SECTSIZE 512
#define ELFHDR ((struct elfhdr*) 0x10000) // scratch space
void readseg(uint, uint, uint);
void
cmain(void)
{
struct elfhdr *elf;
struct proghdr *ph, *eph;
void (*entry)(void);
// read 1st page off disk
readseg((uint) ELFHDR, SECTSIZE*8, 0);
elf = (struct elfhdr*)0x10000; // scratch space
// is this a valid ELF?
if(ELFHDR->magic != ELF_MAGIC)
// Read 1st page off disk
readseg((uint)elf, SECTSIZE*8, 0);
// Is this an ELF executable?
if(elf->magic != ELF_MAGIC)
goto bad;
// load each program segment (ignores ph flags)
ph = (struct proghdr*) ((uchar*) ELFHDR + ELFHDR->phoff);
eph = ph + ELFHDR->phnum;
// Load each program segment (ignores ph flags).
ph = (struct proghdr*)((uchar*)elf + elf->phoff);
eph = ph + elf->phnum;
for(; ph < eph; ph++)
readseg(ph->va, ph->memsz, ph->offset);
// call the entry point from the ELF header
// note: does not return!
((void(*)(void)) (ELFHDR->entry & 0xFFFFFF))();
// Call the entry point from the ELF header.
// Does not return!
entry = (void(*)(void))(elf->entry & 0xFFFFFF);
entry();
bad:
outw(0x8A00, 0x8A00);
@ -67,7 +71,7 @@ bad:
void
waitdisk(void)
{
// wait for disk reaady
// Wait for disk ready.
while((inb(0x1F7) & 0xC0) != 0x40)
;
}
@ -76,9 +80,8 @@ waitdisk(void)
void
readsect(void *dst, uint offset)
{
// wait for disk to be ready
// Issue command.
waitdisk();
outb(0x1F2, 1); // count = 1
outb(0x1F3, offset);
outb(0x1F4, offset >> 8);
@ -86,10 +89,8 @@ readsect(void *dst, uint offset)
outb(0x1F6, (offset >> 24) | 0xE0);
outb(0x1F7, 0x20); // cmd 0x20 - read sectors
// wait for disk to be ready
// Read data.
waitdisk();
// read a sector
insl(0x1F0, dst, SECTSIZE/4);
}
@ -98,24 +99,20 @@ readsect(void *dst, uint offset)
void
readseg(uint va, uint count, uint offset)
{
uint end_va;
uint eva;
va &= 0xFFFFFF;
end_va = va + count;
eva = va + count;
// round down to sector boundary
// Round down to sector boundary.
va &= ~(SECTSIZE - 1);
// translate from bytes to sectors, and kernel starts at sector 1
// Translate from bytes to sectors; kernel starts at sector 1.
offset = (offset / SECTSIZE) + 1;
// If this is too slow, we could read lots of sectors at a time.
// We'd write more to memory than asked, but it doesn't matter --
// we load in increasing order.
while(va < end_va) {
readsect((uchar*) va, offset);
va += SECTSIZE;
offset++;
}
for(; va < eva; va += SECTSIZE, offset++)
readsect((uchar*)va, offset);
}

View file

@ -9,7 +9,11 @@
#include "proc.h"
#include "kbd.h"
struct spinlock console_lock;
#define CRTPORT 0x3d4
#define LPTPORT 0x378
static ushort *crt = (ushort*)0xb8000; // CGA memory
static struct spinlock console_lock;
int panicked = 0;
int use_console_lock = 0;
@ -21,18 +25,16 @@ lpt_putc(int c)
{
int i;
for(i = 0; !(inb(0x378+1) & 0x80) && i < 12800; i++)
for(i = 0; !(inb(LPTPORT+1) & 0x80) && i < 12800; i++)
;
outb(0x378+0, c);
outb(0x378+2, 0x08|0x04|0x01);
outb(0x378+2, 0x08);
outb(LPTPORT+0, c);
outb(LPTPORT+2, 0x08|0x04|0x01);
outb(LPTPORT+2, 0x08);
}
static void
cons_putc(int c)
{
int crtport = 0x3d4; // io port of CGA
ushort *crt = (ushort*) 0xB8000; // base of CGA memory
int ind;
if(panicked){
@ -44,10 +46,10 @@ cons_putc(int c)
lpt_putc(c);
// cursor position, 16 bits, col + 80*row
outb(crtport, 14);
ind = inb(crtport + 1) << 8;
outb(crtport, 15);
ind |= inb(crtport + 1);
outb(CRTPORT, 14);
ind = inb(CRTPORT + 1) << 8;
outb(CRTPORT, 15);
ind |= inb(CRTPORT + 1);
c &= 0xff;
if(c == '\n'){
@ -66,17 +68,17 @@ cons_putc(int c)
memset(crt + ind, 0, sizeof(crt[0]) * ((24 * 80) - ind));
}
outb(crtport, 14);
outb(crtport + 1, ind >> 8);
outb(crtport, 15);
outb(crtport + 1, ind);
outb(CRTPORT, 14);
outb(CRTPORT + 1, ind >> 8);
outb(CRTPORT, 15);
outb(CRTPORT + 1, ind);
}
void
printint(int xx, int base, int sgn)
{
static char digits[] = "0123456789ABCDEF";
char buf[16];
char digits[] = "0123456789ABCDEF";
int i = 0, neg = 0;
uint x;

11
proc.c
View file

@ -65,15 +65,14 @@ growproc(int n)
return cp->sz - n;
}
// Set up CPU's segment descriptors and task state for a
// given process.
// If p==0, set up for "idle" state for when scheduler()
// is idling, not running any process.
// Set up CPU's segment descriptors and task state for a given process.
// If p==0, set up for "idle" state for when scheduler() is running.
void
setupsegs(struct proc *p)
{
struct cpu *c = &cpus[cpu()];
struct cpu *c;
c = &cpus[cpu()];
c->ts.ss0 = SEG_KDATA << 3;
if(p)
c->ts.esp0 = (uint)(p->kstack + KSTACKSIZE);

2
proc.h
View file

@ -12,7 +12,7 @@
// Save all the regular registers so we don't need to care
// which are caller save.
// Don't save %eax, because that's the return register.
// The layout of jmpbuf is known to setjmp.S.
// The layout of jmpbuf must match code in setjmp.S.
struct jmpbuf {
int ebx;
int ecx;

View file

@ -133,8 +133,9 @@ static int (*syscalls[])(void) = {
void
syscall(void)
{
int num = cp->tf->eax;
int num;
num = cp->tf->eax;
if(num >= 0 && num < NELEM(syscalls) && syscalls[num])
cp->tf->eax = syscalls[num]();
else {