Hi!
> >Is there a safe way to add debug information like simple string prints in
> >arch/i386/boot/compressed/head.s and in arch/i386/kernel/head.S
> >so that I can see at the console where the boot process hangs?
>
> Time for another version of my VIDEO_CHAR patch.]
What abourt early_printk? Works well on x86-64... And you can easily
redirect printk to early_printk.
#include <asm/io.h>
#ifndef MINIKERNEL
#define VGABASE 0xffffffff800b8000ul /* This is "wrong" address to access it, we should access it using 0xffff8000000b8000ul; but 0xffff8000000b8000ul is not available early at boot. */
#else
#define VGABASE 0xb8000ul
#endif
#define MAX_YPOS 25
#define MAX_XPOS 80
static int current_ypos = 1, current_xpos = 0; /* We want to print before clearing BSS */
int printk_ready = 0;
#ifndef MINIKERNEL
void
early_clear (void)
{
int k, i;
for(k = 0; k < MAX_YPOS; k++)
for(i = 0; i < MAX_XPOS; i++)
writew(0, VGABASE + 2*(MAX_XPOS*k + i));
current_ypos = 0;
}
void
early_puts (const char *str)
{
char c;
int i, k, j;
while ((c = *str++) != '\0') {
if (current_ypos >= MAX_YPOS) {
#ifndef CONFIG_SIMNOW
/* scroll 1 line up */
for(k = 1, j = 0; k < MAX_YPOS; k++, j++) {
for(i = 0; i < MAX_XPOS; i++) {
writew(readw(VGABASE + 2*(MAX_XPOS*k + i)),
VGABASE + 2*(MAX_XPOS*j + i));
}
}
for(i = 0; i < MAX_XPOS; i++) {
writew(0x720, VGABASE + 2*(MAX_XPOS*j + i));
}
current_ypos = MAX_YPOS-1;
#else
/* MUCH faster */
early_clear();
current_ypos = 0;
#endif
}
if (c == '\n') {
current_xpos = 0;
current_ypos++;
} else if (c != '\r') {
writew(((0x7 << 8) | (unsigned short) c),
VGABASE + 2*(MAX_XPOS*current_ypos + current_xpos++));
if (current_xpos >= MAX_XPOS) {
current_xpos = 0;
current_ypos++;
}
}
}
}
#else
#define putc(c, x) writew(((0x7 << 8) | (unsigned short) (c)), \
VGABASE + (x) * 2);
void
early_puts (const char *str)
{
char c;
int i, rest;
while ((c = *str++) != '\0') {
if (c == '\n' || c == '\r') {
/* blank rest of the line */
rest = MAX_XPOS - (current_xpos % MAX_XPOS);
for (i=0; i < rest; i++) {
putc(' ', current_xpos++);
}
} else {
putc(c, current_xpos);
current_xpos++;
}
current_xpos %= MAX_XPOS * MAX_YPOS;
}
}
#endif /* MINIKERNEL */
static char buf[1024];
int early_printk(const char *fmt, ...)
{
va_list args;
int i;
va_start(args, fmt);
i = vsprintf(buf, fmt, args); /* hopefully i < sizeof(buf)-4 */
va_end(args);
if (!printk_ready)
early_puts(buf);
else
printk("%s", buf);
return i;
}
-- I'm pavel@ucw.cz. "In my country we have almost anarchy and I don't care." Panos Katsaloulis describing me w.r.t. patents at discuss@linmodems.org - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Tue Jan 23 2001 - 21:00:13 EST