105 lines
2.8 KiB
C
105 lines
2.8 KiB
C
#ifndef NORELOCATE
|
|
|
|
#include "etherboot.h"
|
|
#include "memsizes.h"
|
|
|
|
/* by Eric Biederman */
|
|
|
|
/* On some platforms etherboot is compiled as a shared library, and we use
|
|
* the ELF pic support to make it relocateable. This works very nicely
|
|
* for code, but since no one has implemented PIC data yet pointer
|
|
* values in variables are a a problem. Global variables are a
|
|
* pain but the return addresses on the stack are the worst. On these
|
|
* platforms relocate_to will restart etherboot, to ensure the stack
|
|
* is reinitialize and hopefully get the global variables
|
|
* appropriately reinitialized as well.
|
|
*
|
|
*/
|
|
|
|
void relocate(void)
|
|
{
|
|
unsigned long addr, eaddr, size;
|
|
unsigned i;
|
|
/* Walk through the memory map and find the highest address
|
|
* below 4GB that etherboot will fit into. Ensure etherboot
|
|
* lies entirely within a range with A20=0. This means that
|
|
* even if something screws up the state of the A20 line, the
|
|
* etherboot code is still visible and we have a chance to
|
|
* diagnose the problem.
|
|
*/
|
|
/* First find the size of etherboot */
|
|
addr = virt_to_phys(_text);
|
|
eaddr = virt_to_phys(_end);
|
|
size = (eaddr - addr + 0xf) & ~0xf;
|
|
|
|
/* If the current etherboot is beyond MAX_ADDR pretend it is
|
|
* at the lowest possible address.
|
|
*/
|
|
if (eaddr > MAX_ADDR) {
|
|
eaddr = 0;
|
|
}
|
|
|
|
for(i = 0; i < meminfo.map_count; i++) {
|
|
unsigned long r_start, r_end;
|
|
if (meminfo.map[i].type != E820_RAM) {
|
|
continue;
|
|
}
|
|
if (meminfo.map[i].addr > MAX_ADDR) {
|
|
continue;
|
|
}
|
|
if (meminfo.map[i].size > MAX_ADDR) {
|
|
continue;
|
|
}
|
|
r_start = meminfo.map[i].addr;
|
|
r_end = r_start + meminfo.map[i].size;
|
|
/* Make the addresses 16 byte (128 bit) aligned */
|
|
r_start = (r_start + 15) & ~15;
|
|
r_end = r_end & ~15;
|
|
if (r_end < r_start) {
|
|
r_end = MAX_ADDR;
|
|
}
|
|
if (r_end < size) {
|
|
/* Avoid overflow weirdness when r_end - size < 0 */
|
|
continue;
|
|
}
|
|
/* Shrink the range down to use only even megabytes
|
|
* (i.e. A20=0).
|
|
*/
|
|
if ( r_end & 0x100000 ) {
|
|
/* If r_end is in an odd megabyte, round down
|
|
* r_end to the top of the next even megabyte.
|
|
*/
|
|
r_end = r_end & ~0xfffff;
|
|
} else if ( ( r_end - size ) & 0x100000 ) {
|
|
/* If r_end is in an even megabyte, but the
|
|
* start of Etherboot would be in an odd
|
|
* megabyte, round down to the top of the next
|
|
* even megabyte.
|
|
*/
|
|
r_end = ( r_end - 0x100000 ) & ~0xfffff;
|
|
}
|
|
/* If we have rounded down r_end below r_ start, skip
|
|
* this block.
|
|
*/
|
|
if ( r_end < r_start ) {
|
|
continue;
|
|
}
|
|
if (eaddr < r_end - size) {
|
|
addr = r_end - size;
|
|
eaddr = r_end;
|
|
}
|
|
}
|
|
if (addr != virt_to_phys(_text)) {
|
|
unsigned long old_addr = virt_to_phys(_text);
|
|
printf("Relocating _text from: [%lx,%lx) to [%lx,%lx)\n",
|
|
old_addr, virt_to_phys(_end),
|
|
addr, eaddr);
|
|
/* arch_relocate_to ( addr ) */
|
|
cleanup();
|
|
relocate_to(addr);
|
|
/* arch_relocated_from ( addr ) */
|
|
}
|
|
}
|
|
|
|
#endif /* NORELOCATE */
|