[relocate] Remove the even megabyte constraint
iPXE is now capable of operating in odd megabytes of memory, so remove the obsolete code enforcing an even-megabyte constraint. Signed-off-by: Michael Brown <mcb30@ipxe.org>
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@ -32,12 +32,12 @@ extern char _etextdata[];
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#define MAX_ADDR (0xfff00000UL)
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#define MAX_ADDR (0xfff00000UL)
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/**
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/**
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* Relocate Etherboot
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* Relocate iPXE
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*
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*
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* @v ix86 x86 register dump from prefix
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* @v ix86 x86 register dump from prefix
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* @ret ix86 x86 registers to return to prefix
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* @ret ix86 x86 registers to return to prefix
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*
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*
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* This finds a suitable location for Etherboot near the top of 32-bit
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* This finds a suitable location for iPXE near the top of 32-bit
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* address space, and returns the physical address of the new location
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* address space, and returns the physical address of the new location
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* to the prefix in %edi.
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* to the prefix in %edi.
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*/
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*/
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@ -59,11 +59,7 @@ __asmcall void relocate ( struct i386_all_regs *ix86 ) {
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start, end, padded_size, max_align );
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start, end, padded_size, max_align );
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/* Walk through the memory map and find the highest address
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/* Walk through the memory map and find the highest address
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* below 4GB that etherboot will fit into. Ensure etherboot
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* below 4GB that iPXE will fit into.
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* lies entirely within a range with A20=0. This means that
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* even if something screws up the state of the A20 line, the
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* etherboot code is still visible and we have a chance to
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* diagnose the problem.
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*/
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*/
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new_end = end;
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new_end = end;
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for ( i = 0 ; i < memmap.count ; i++ ) {
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for ( i = 0 ; i < memmap.count ; i++ ) {
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@ -87,42 +83,6 @@ __asmcall void relocate ( struct i386_all_regs *ix86 ) {
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} else {
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} else {
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r_end = region->end;
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r_end = region->end;
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}
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}
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/* Shrink the range down to use only even megabytes
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* (i.e. A20=0).
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*/
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if ( ( r_end - 1 ) & 0x100000 ) {
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/* If last byte that might be used (r_end-1)
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* is in an odd megabyte, round down r_end to
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* the top of the next even megabyte.
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*
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* Make sure that we don't accidentally wrap
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* r_end below 0.
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*/
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if ( r_end >= 1 ) {
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r_end = ( r_end - 1 ) & ~0xfffff;
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DBG ( "...end truncated to %lx "
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"(avoid ending in odd megabyte)\n",
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r_end );
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}
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} else if ( ( r_end - size ) & 0x100000 ) {
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/* If the last byte that might be used
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* (r_end-1) is in an even megabyte, but the
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* first byte that might be used (r_end-size)
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* is an odd megabyte, round down to the top
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* of the next even megabyte.
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*
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* Make sure that we don't accidentally wrap
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* r_end below 0.
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*/
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if ( r_end >= 0x100000 ) {
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r_end = ( r_end - 0x100000 ) & ~0xfffff;
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DBG ( "...end truncated to %lx "
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"(avoid starting in odd megabyte)\n",
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r_end );
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}
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}
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DBG ( "...usable portion is [%lx,%lx)\n", r_start, r_end );
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DBG ( "...usable portion is [%lx,%lx)\n", r_start, r_end );
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/* If we have rounded down r_end below r_ start, skip
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/* If we have rounded down r_end below r_ start, skip
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@ -133,19 +93,19 @@ __asmcall void relocate ( struct i386_all_regs *ix86 ) {
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continue;
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continue;
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}
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}
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/* Check that there is enough space to fit in Etherboot */
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/* Check that there is enough space to fit in iPXE */
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if ( ( r_end - r_start ) < size ) {
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if ( ( r_end - r_start ) < size ) {
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DBG ( "...too small (need %lx bytes)\n", size );
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DBG ( "...too small (need %lx bytes)\n", size );
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continue;
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continue;
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}
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}
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/* If the start address of the Etherboot we would
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/* If the start address of the iPXE we would
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* place in this block is higher than the end address
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* place in this block is higher than the end address
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* of the current highest block, use this block.
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* of the current highest block, use this block.
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*
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*
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* Note that this avoids overlaps with the current
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* Note that this avoids overlaps with the current
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* Etherboot, as well as choosing the highest of all
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* iPXE, as well as choosing the highest of all viable
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* viable blocks.
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* blocks.
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*/
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*/
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if ( ( r_end - size ) > new_end ) {
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if ( ( r_end - size ) > new_end ) {
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new_end = r_end;
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new_end = r_end;
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@ -153,7 +113,7 @@ __asmcall void relocate ( struct i386_all_regs *ix86 ) {
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}
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}
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}
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}
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/* Calculate new location of Etherboot, and align it to the
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/* Calculate new location of iPXE, and align it to the
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* required alignemnt.
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* required alignemnt.
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*/
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*/
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new_start = new_end - padded_size;
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new_start = new_end - padded_size;
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