1 files changed, 138 insertions, 0 deletions

diff --git a/qemu/roms/ipxe/src/arch/i386/core/relocate.c b/qemu/roms/ipxe/src/arch/i386/core/relocate.c
new file mode 100644
index 000000000..5fbf2d2c2
--- /dev/null
+++ b/qemu/roms/ipxe/src/arch/i386/core/relocate.c
@@ -0,0 +1,138 @@
+#include <ipxe/io.h>
+#include <registers.h>
+
+/*
+ * Originally by Eric Biederman
+ *
+ * Heavily modified by Michael Brown 
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+/*
+ * The linker passes in the symbol _max_align, which is the alignment
+ * that we must preserve, in bytes.
+ *
+ */
+extern char _max_align[];
+#define max_align ( ( unsigned int ) _max_align )
+
+/* Linker symbols */
+extern char _textdata[];
+extern char _etextdata[];
+
+/* within 1MB of 4GB is too close. 
+ * MAX_ADDR is the maximum address we can easily do DMA to.
+ *
+ * Not sure where this constraint comes from, but kept it from Eric's
+ * old code - mcb30
+ */
+#define MAX_ADDR (0xfff00000UL)
+
+/**
+ * Relocate iPXE
+ *
+ * @v ebp		Maximum address to use for relocation
+ * @ret esi		Current physical address
+ * @ret edi		New physical address
+ * @ret ecx		Length to copy
+ *
+ * This finds a suitable location for iPXE near the top of 32-bit
+ * address space, and returns the physical address of the new location
+ * to the prefix in %edi.
+ */
+__asmcall void relocate ( struct i386_all_regs *ix86 ) {
+	struct memory_map memmap;
+	unsigned long start, end, size, padded_size, max;
+	unsigned long new_start, new_end;
+	unsigned i;
+
+	/* Get memory map and current location */
+	get_memmap ( &memmap );
+	start = virt_to_phys ( _textdata );
+	end = virt_to_phys ( _etextdata );
+	size = ( end - start );
+	padded_size = ( size + max_align - 1 );
+
+	DBG ( "Relocate: currently at [%lx,%lx)\n"
+	      "...need %lx bytes for %d-byte alignment\n",
+	      start, end, padded_size, max_align );
+
+	/* Determine maximum usable address */
+	max = MAX_ADDR;
+	if ( ix86->regs.ebp < max ) {
+		max = ix86->regs.ebp;
+		DBG ( "Limiting relocation to [0,%lx)\n", max );
+	}
+
+	/* Walk through the memory map and find the highest address
+	 * below 4GB that iPXE will fit into.
+	 */
+	new_end = end;
+	for ( i = 0 ; i < memmap.count ; i++ ) {
+		struct memory_region *region = &memmap.regions[i];
+		unsigned long r_start, r_end;
+
+		DBG ( "Considering [%llx,%llx)\n", region->start, region->end);
+		
+		/* Truncate block to maximum address.  This will be
+		 * less than 4GB, which means that we can get away
+		 * with using just 32-bit arithmetic after this stage.
+		 */
+		if ( region->start > max ) {
+			DBG ( "...starts after max=%lx\n", max );
+			continue;
+		}
+		r_start = region->start;
+		if ( region->end > max ) {
+			DBG ( "...end truncated to max=%lx\n", max );
+			r_end = max;
+		} else {
+			r_end = region->end;
+		}
+		DBG ( "...usable portion is [%lx,%lx)\n", r_start, r_end );
+
+		/* If we have rounded down r_end below r_ start, skip
+		 * this block.
+		 */
+		if ( r_end < r_start ) {
+			DBG ( "...truncated to negative size\n" );
+			continue;
+		}
+
+		/* Check that there is enough space to fit in iPXE */
+		if ( ( r_end - r_start ) < size ) {
+			DBG ( "...too small (need %lx bytes)\n", size );
+			continue;
+		}
+
+		/* If the start address of the iPXE we would
+		 * place in this block is higher than the end address
+		 * of the current highest block, use this block.
+		 *
+		 * Note that this avoids overlaps with the current
+		 * iPXE, as well as choosing the highest of all viable
+		 * blocks.
+		 */
+		if ( ( r_end - size ) > new_end ) {
+			new_end = r_end;
+			DBG ( "...new best block found.\n" );
+		}
+	}
+
+	/* Calculate new location of iPXE, and align it to the
+	 * required alignemnt.
+	 */
+	new_start = new_end - padded_size;
+	new_start += ( start - new_start ) & ( max_align - 1 );
+	new_end = new_start + size;
+
+	DBG ( "Relocating from [%lx,%lx) to [%lx,%lx)\n",
+	      start, end, new_start, new_end );
+	
+	/* Let prefix know what to copy */
+	ix86->regs.esi = start;
+	ix86->regs.edi = new_start;
+	ix86->regs.ecx = size;
+}