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/* $Id$
*
* balo.c: BAget LOader
*
* Copyright (C) 1998 Gleb Raiko & Vladimir Roganov
*
*/
#include <linux/kernel.h>
#include <asm/system.h>
#include <asm/ptrace.h>
#include <asm/addrspace.h>
#include <asm/baget/baget.h>
#include "balo.h" /* Includes some kernel symbol values */
static char *banner = "\nBaget Linux Loader v0.2\n";
static void mem_move (long *to, long *from, long size)
{
while (size > 0) {
*to++ = *from++;
size -= sizeof(long);
}
}
static volatile int *mem_limit = (volatile int*)KSEG1;
static volatile int *mem_limit_dbe = (volatile int*)KSEG1;
static int can_write (volatile int* p) {
return p < (int*)(KSEG1+BALO_OFFSET) ||
p >= (int*)(KSEG1+BALO_OFFSET+BALO_SIZE);
}
static volatile enum balo_state_enum {
BALO_INIT,
MEM_INIT,
MEM_PROBE,
START_KERNEL
} balo_state = BALO_INIT;
static __inline__ void reset_and_jump(int start, int mem_upper)
{
__asm__ __volatile__(
".set\tnoreorder\n\t"
".set\tnoat\n\t"
"mfc0\t$1,$12\n\t"
"nop\n\t"
"nop\n\t"
"nop\n\t"
"ori\t$1,$1,0xff00\n\t"
"xori\t$1,$1,0xff00\n\t"
"mtc0\t$1,$12\n\t"
"nop\n\t"
"nop\n\t"
"nop\n\t"
"move\t$4,%1\n\t"
"jr\t%0\n\t"
"nop\n\t"
".set\tat\n\t"
".set\treorder"
: /* no outputs */
:"Ir" (start), "Ir" (mem_upper)
:"$1", "$4", "memory");
}
static void start_kernel(void)
{
extern char _vmlinux_start, _vmlinux_end;
extern char _ramdisk_start, _ramdisk_end;
outs( "Relocating Linux... " );
mem_move((long*)KSEG0, (long*)&_vmlinux_start,
&_vmlinux_end-&_vmlinux_start);
outs("done.\n");
if (&_ramdisk_start != &_ramdisk_end) {
outs("Setting up RAMDISK... ");
if (*(unsigned long*)RAMDISK_BASE != 0xBA) {
outs("Bad RAMDISK_BASE signature in system image.\n");
balo_hungup();
}
*(unsigned long*)RAMDISK_BASE = (unsigned long)&_ramdisk_start;
*(unsigned long*)RAMDISK_SIZE = &_ramdisk_end -&_ramdisk_start;
outs("done.\n");
}
{
extern void flush_cache_low(int isize, int dsize);
flush_cache_low(256*1024,256*1024);
}
balo_printf( "Kernel entry: %x\n\n", START);
balo_state = START_KERNEL;
reset_and_jump(START, (int)mem_limit-KSEG1+KSEG0);
}
static void mem_probe(void)
{
balo_state = MEM_PROBE;
outs("RAM: <");
while(mem_limit < mem_limit_dbe) {
if (can_write(mem_limit) && *mem_limit != 0)
break; /* cycle found */
outc('.');
if (can_write(mem_limit))
*mem_limit = -1; /* mark */
mem_limit += 0x40000;
}
outs(">\n");
start_kernel();
}
volatile unsigned int int_cause;
volatile unsigned int epc;
volatile unsigned int badvaddr;
static void print_regs(void)
{
balo_printf("CAUSE=%x EPC=%x BADVADDR=%x\n",
int_cause, epc, badvaddr);
}
void int_handler(struct pt_regs *regs)
{
switch (balo_state) {
case BALO_INIT:
balo_printf("\nBALO: trap in balo itself.\n");
print_regs();
balo_hungup();
break;
case MEM_INIT:
if ((int_cause & CAUSE_MASK) != CAUSE_DBE) {
balo_printf("\nBALO: unexpected trap during memory init.\n");
print_regs();
balo_hungup();
} else {
mem_probe();
}
break;
case MEM_PROBE:
balo_printf("\nBALO: unexpected trap during memory probe.\n");
print_regs();
balo_hungup();
break;
case START_KERNEL:
balo_printf("\nBALO: unexpected kernel trap.\n");
print_regs();
balo_hungup();
break;
}
balo_printf("\nBALO: unexpected return from handler.\n");
print_regs();
balo_hungup();
}
static void mem_init(void)
{
balo_state = MEM_INIT;
while(1) {
*mem_limit_dbe;
if (can_write(mem_limit_dbe))
*mem_limit_dbe = 0;
mem_limit_dbe += 0x40000; /* +1M */
}
/* no return: must go to int_handler */
}
void balo_entry(void)
{
extern void except_vec3_generic(void);
cli();
outs(banner);
memcpy((void *)(KSEG0 + 0x80), &except_vec3_generic, 0x80);
mem_init();
}
/* Needed for linking */
int vsprintf(char *buf, const char *fmt, va_list arg)
{
outs("BALO: vsprintf called.\n");
balo_hungup();
return 0;
}
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