| #!/usr/bin/env python |
| # Script to analyze code and arrange ld sections. |
| # |
| # Copyright (C) 2008 Kevin O'Connor <kevin@koconnor.net> |
| # |
| # This file may be distributed under the terms of the GNU GPLv3 license. |
| |
| import sys |
| |
| # LD script headers/trailers |
| COMMONHEADER = """ |
| /* DO NOT EDIT! This is an autogenerated file. See tools/layoutrom.py. */ |
| OUTPUT_FORMAT("elf32-i386") |
| OUTPUT_ARCH("i386") |
| SECTIONS |
| { |
| """ |
| COMMONTRAILER = """ |
| |
| /* Discard regular data sections to force a link error if |
| * code attempts to access data not marked with VAR16 (or other |
| * appropriate macro) |
| */ |
| /DISCARD/ : { |
| *(.text*) *(.data*) *(.bss*) *(.rodata*) |
| *(COMMON) *(.discard*) *(.eh_frame) |
| } |
| } |
| """ |
| |
| |
| ###################################################################### |
| # Determine section locations |
| ###################################################################### |
| |
| # Align 'pos' to 'alignbytes' offset |
| def alignpos(pos, alignbytes): |
| mask = alignbytes - 1 |
| return (pos + mask) & ~mask |
| |
| # Determine the final addresses for a list of sections that end at an |
| # address. |
| def getSectionsStart(sections, endaddr, minalign=1): |
| totspace = 0 |
| for size, align, name in sections: |
| if align > minalign: |
| minalign = align |
| totspace = alignpos(totspace, align) + size |
| startaddr = (endaddr - totspace) / minalign * minalign |
| curaddr = startaddr |
| # out = [(addr, sectioninfo), ...] |
| out = [] |
| for sectioninfo in sections: |
| size, align, name = sectioninfo |
| curaddr = alignpos(curaddr, align) |
| out.append((curaddr, sectioninfo)) |
| curaddr += size |
| return out, startaddr |
| |
| # Return the subset of sections with a given name prefix |
| def getSectionsPrefix(sections, prefix): |
| lp = len(prefix) |
| out = [] |
| for size, align, name in sections: |
| if name[:lp] == prefix: |
| out.append((size, align, name)) |
| return out |
| |
| # The 16bit code can't exceed 64K of space. |
| BUILD_BIOS_ADDR = 0xf0000 |
| BUILD_BIOS_SIZE = 0x10000 |
| |
| # Layout the 16bit code. This ensures sections with fixed offset |
| # requirements are placed in the correct location. It also places the |
| # 16bit code as high as possible in the f-segment. |
| def fitSections(sections, fillsections): |
| canrelocate = list(fillsections) |
| # fixedsections = [(addr, sectioninfo), ...] |
| fixedsections = [] |
| for sectioninfo in sections: |
| size, align, name = sectioninfo |
| if name[:11] == '.fixedaddr.': |
| addr = int(name[11:], 16) |
| fixedsections.append((addr, sectioninfo)) |
| if align != 1: |
| print "Error: Fixed section %s has non-zero alignment (%d)" % ( |
| name, align) |
| sys.exit(1) |
| |
| # Find freespace in fixed address area |
| fixedsections.sort() |
| # fixedAddr = [(freespace, sectioninfo), ...] |
| fixedAddr = [] |
| for i in range(len(fixedsections)): |
| fixedsectioninfo = fixedsections[i] |
| addr, section = fixedsectioninfo |
| if i == len(fixedsections) - 1: |
| nextaddr = BUILD_BIOS_SIZE |
| else: |
| nextaddr = fixedsections[i+1][0] |
| avail = nextaddr - addr - section[0] |
| fixedAddr.append((avail, fixedsectioninfo)) |
| |
| # Attempt to fit other sections into fixed area |
| extrasections = [] |
| fixedAddr.sort() |
| canrelocate.sort() |
| totalused = 0 |
| for freespace, fixedsectioninfo in fixedAddr: |
| fixedaddr, fixedsection = fixedsectioninfo |
| addpos = fixedaddr + fixedsection[0] |
| totalused += fixedsection[0] |
| nextfixedaddr = addpos + freespace |
| # print "Filling section %x uses %d, next=%x, available=%d" % ( |
| # fixedaddr, fixedsection[0], nextfixedaddr, freespace) |
| while 1: |
| canfit = None |
| for fitsection in canrelocate: |
| fitsize, fitalign, fitname = fitsection |
| if addpos + fitsize > nextfixedaddr: |
| # Can't fit and nothing else will fit. |
| break |
| fitnextaddr = alignpos(addpos, fitalign) + fitsize |
| # print "Test %s - %x vs %x" % ( |
| # fitname, fitnextaddr, nextfixedaddr) |
| if fitnextaddr > nextfixedaddr: |
| # This item can't fit. |
| continue |
| canfit = (fitnextaddr, fitsection) |
| if canfit is None: |
| break |
| # Found a section that can fit. |
| fitnextaddr, fitsection = canfit |
| canrelocate.remove(fitsection) |
| extrasections.append((addpos, fitsection)) |
| addpos = fitnextaddr |
| totalused += fitsection[0] |
| # print " Adding %s (size %d align %d) pos=%x avail=%d" % ( |
| # fitsection[2], fitsection[0], fitsection[1] |
| # , fitnextaddr, nextfixedaddr - fitnextaddr) |
| firstfixed = fixedsections[0][0] |
| |
| # Report stats |
| total = BUILD_BIOS_SIZE-firstfixed |
| slack = total - totalused |
| print ("Fixed space: 0x%x-0x%x total: %d slack: %d" |
| " Percent slack: %.1f%%" % ( |
| firstfixed, BUILD_BIOS_SIZE, total, slack, |
| (float(slack) / total) * 100.0)) |
| |
| return fixedsections + extrasections, firstfixed |
| |
| def doLayout(sections16, sections32seg, sections32flat): |
| # Determine 16bit positions |
| textsections = getSectionsPrefix(sections16, '.text.') |
| rodatasections = (getSectionsPrefix(sections16, '.rodata.str1.1') |
| + getSectionsPrefix(sections16, '.rodata.__func__.')) |
| datasections = getSectionsPrefix(sections16, '.data16.') |
| fixedsections = getSectionsPrefix(sections16, '.fixedaddr.') |
| |
| locs16fixed, firstfixed = fitSections(fixedsections, textsections) |
| prunesections = [i[1] for i in locs16fixed] |
| remsections = [i for i in textsections+rodatasections+datasections |
| if i not in prunesections] |
| locs16, code16_start = getSectionsStart(remsections, firstfixed) |
| locs16 = locs16 + locs16fixed |
| locs16.sort() |
| |
| # Determine 32seg positions |
| textsections = getSectionsPrefix(sections32seg, '.text.') |
| rodatasections = (getSectionsPrefix(sections32seg, '.rodata.str1.1') |
| + getSectionsPrefix(sections32seg, '.rodata.__func__.')) |
| datasections = getSectionsPrefix(sections32seg, '.data32seg.') |
| |
| locs32seg, code32seg_start = getSectionsStart( |
| textsections + rodatasections + datasections, code16_start) |
| |
| # Determine 32flat positions |
| textsections = getSectionsPrefix(sections32flat, '.text.') |
| rodatasections = getSectionsPrefix(sections32flat, '.rodata') |
| datasections = getSectionsPrefix(sections32flat, '.data.') |
| bsssections = getSectionsPrefix(sections32flat, '.bss.') |
| |
| locs32flat, code32flat_start = getSectionsStart( |
| textsections + rodatasections + datasections + bsssections |
| , code32seg_start + BUILD_BIOS_ADDR, 16) |
| |
| # Print statistics |
| size16 = BUILD_BIOS_SIZE - code16_start |
| size32seg = code16_start - code32seg_start |
| size32flat = code32seg_start + BUILD_BIOS_ADDR - code32flat_start |
| print "16bit size: %d" % size16 |
| print "32bit segmented size: %d" % size32seg |
| print "32bit flat size: %d" % size32flat |
| |
| return locs16, locs32seg, locs32flat |
| |
| |
| ###################################################################### |
| # Linker script output |
| ###################################################################### |
| |
| # Write LD script includes for the given cross references |
| def outXRefs(xrefs, finallocs, delta=0): |
| out = "" |
| for symbol, (fileid, section, addr) in xrefs.items(): |
| if fileid < 2: |
| addr += delta |
| out += "%s = 0x%x ;\n" % (symbol, finallocs[(fileid, section)] + addr) |
| return out |
| |
| # Write LD script includes for the given sections using relative offsets |
| def outRelSections(locs, startsym): |
| out = "" |
| for addr, sectioninfo in locs: |
| size, align, name = sectioninfo |
| out += ". = ( 0x%x - %s ) ;\n" % (addr, startsym) |
| if name == '.rodata.str1.1': |
| out += "_rodata = . ;\n" |
| out += "*(%s)\n" % (name,) |
| return out |
| |
| # Layout the 32bit segmented code. This places the code as high as possible. |
| def writeLinkerScripts(locs16, locs32seg, locs32flat |
| , xref16, xref32seg, xref32flat |
| , out16, out32seg, out32flat): |
| # Index to final location for each section |
| # finallocs[(fileid, section)] = addr |
| finallocs = {} |
| for fileid, locs in ((0, locs16), (1, locs32seg), (2, locs32flat)): |
| for addr, sectioninfo in locs: |
| finallocs[(fileid, sectioninfo[2])] = addr |
| |
| # Write 16bit linker script |
| code16_start = locs16[0][0] |
| output = open(out16, 'wb') |
| output.write(COMMONHEADER + outXRefs(xref16, finallocs) + """ |
| code16_start = 0x%x ; |
| .text16 code16_start : { |
| """ % (code16_start) |
| + outRelSections(locs16, 'code16_start') |
| + """ |
| } |
| """ |
| + COMMONTRAILER) |
| output.close() |
| |
| # Write 32seg linker script |
| code32seg_start = code16_start |
| if locs32seg: |
| code32seg_start = locs32seg[0][0] |
| output = open(out32seg, 'wb') |
| output.write(COMMONHEADER + outXRefs(xref32seg, finallocs) + """ |
| code32seg_start = 0x%x ; |
| .text32seg code32seg_start : { |
| """ % (code32seg_start) |
| + outRelSections(locs32seg, 'code32seg_start') |
| + """ |
| } |
| """ |
| + COMMONTRAILER) |
| output.close() |
| |
| # Write 32flat linker script |
| output = open(out32flat, 'wb') |
| output.write(COMMONHEADER |
| + outXRefs(xref32flat, finallocs, BUILD_BIOS_ADDR) + """ |
| code32flat_start = 0x%x ; |
| .text code32flat_start : { |
| """ % (locs32flat[0][0]) |
| + outRelSections(locs32flat, 'code32flat_start') |
| + """ |
| . = ( 0x%x - code32flat_start ) ; |
| *(.text32seg) |
| . = ( 0x%x - code32flat_start ) ; |
| *(.text16) |
| code32flat_end = ABSOLUTE(.) ; |
| } :text |
| """ % (code32seg_start + BUILD_BIOS_ADDR, code16_start + BUILD_BIOS_ADDR) |
| + COMMONTRAILER |
| + """ |
| ENTRY(post32) |
| PHDRS |
| { |
| text PT_LOAD AT ( code32flat_start ) ; |
| } |
| """) |
| output.close() |
| |
| |
| ###################################################################### |
| # Section garbage collection |
| ###################################################################### |
| |
| # Find and keep the section associated with a symbol (if available). |
| def keepsymbol(symbol, infos, pos, callerpos=None): |
| addr, section = infos[pos][1].get(symbol, (None, None)) |
| if section is None or '*' in section or section[:9] == '.discard.': |
| return -1 |
| if callerpos is not None and symbol not in infos[callerpos][4]: |
| # This symbol reference is a cross section reference (an xref). |
| # xref[symbol] = (fileid, section, addr) |
| infos[callerpos][4][symbol] = (pos, section, addr) |
| keepsection(section, infos, pos) |
| return 0 |
| |
| # Note required section, and recursively set all referenced sections |
| # as required. |
| def keepsection(name, infos, pos=0): |
| if name in infos[pos][3]: |
| # Already kept - nothing to do. |
| return |
| infos[pos][3].append(name) |
| relocs = infos[pos][2].get(name) |
| if relocs is None: |
| return |
| # Keep all sections that this section points to |
| for symbol in relocs: |
| ret = keepsymbol(symbol, infos, pos) |
| if not ret: |
| continue |
| # Not in primary sections - it may be a cross 16/32 reference |
| ret = keepsymbol(symbol, infos, (pos+1)%3, pos) |
| if not ret: |
| continue |
| ret = keepsymbol(symbol, infos, (pos+2)%3, pos) |
| if not ret: |
| continue |
| |
| # Return a list of kept sections. |
| def getSectionsList(sections, names): |
| return [i for i in sections if i[2] in names] |
| |
| # Determine which sections are actually referenced and need to be |
| # placed into the output file. |
| def gc(info16, info32seg, info32flat): |
| # infos = ((sections, symbols, relocs, keep sections, xrefs), ...) |
| infos = ((info16[0], info16[1], info16[2], [], {}), |
| (info32seg[0], info32seg[1], info32seg[2], [], {}), |
| (info32flat[0], info32flat[1], info32flat[2], [], {})) |
| # Start by keeping sections that are globally visible. |
| for size, align, section in info16[0]: |
| if section[:11] == '.fixedaddr.' or '.export.' in section: |
| keepsection(section, infos) |
| keepsymbol('post32', infos, 0, 2) |
| # Return sections found. |
| keep16 = getSectionsList(info16[0], infos[0][3]), infos[0][4] |
| keep32seg = getSectionsList(info32seg[0], infos[1][3]), infos[1][4] |
| keep32flat = getSectionsList(info32flat[0], infos[2][3]), infos[2][4] |
| return keep16, keep32seg, keep32flat |
| |
| |
| ###################################################################### |
| # Startup and input parsing |
| ###################################################################### |
| |
| # Read in output from objdump |
| def parseObjDump(file): |
| # sections = [(size, align, section), ...] |
| sections = [] |
| # symbols[symbol] = (addr, section) |
| symbols = {} |
| # relocs[section] = [symbol, ...] |
| relocs = {} |
| |
| state = None |
| for line in file.readlines(): |
| line = line.rstrip() |
| if line == 'Sections:': |
| state = 'section' |
| continue |
| if line == 'SYMBOL TABLE:': |
| state = 'symbol' |
| continue |
| if line[:24] == 'RELOCATION RECORDS FOR [': |
| state = 'reloc' |
| relocsection = line[24:-2] |
| continue |
| |
| if state == 'section': |
| try: |
| idx, name, size, vma, lma, fileoff, align = line.split() |
| if align[:3] != '2**': |
| continue |
| sections.append((int(size, 16), 2**int(align[3:]), name)) |
| except: |
| pass |
| continue |
| if state == 'symbol': |
| try: |
| section, size, symbol = line[17:].split() |
| size = int(size, 16) |
| addr = int(line[:8], 16) |
| symbols[symbol] = addr, section |
| except: |
| pass |
| continue |
| if state == 'reloc': |
| try: |
| off, type, symbol = line.split() |
| off = int(off, 16) |
| relocs.setdefault(relocsection, []).append(symbol) |
| except: |
| pass |
| return sections, symbols, relocs |
| |
| def main(): |
| # Get output name |
| in16, in32seg, in32flat, out16, out32seg, out32flat = sys.argv[1:] |
| |
| # Read in the objdump information |
| infile16 = open(in16, 'rb') |
| infile32seg = open(in32seg, 'rb') |
| infile32flat = open(in32flat, 'rb') |
| |
| # infoX = (sections, symbols, relocs) |
| info16 = parseObjDump(infile16) |
| info32seg = parseObjDump(infile32seg) |
| info32flat = parseObjDump(infile32flat) |
| |
| # Figure out which sections to keep. |
| # keepX = (sections, xrefs) |
| keep16, keep32seg, keep32flat = gc(info16, info32seg, info32flat) |
| |
| # Determine the final memory locations of each kept section. |
| # locsX = [(addr, sectioninfo), ...] |
| locs16, locs32seg, locs32flat = doLayout( |
| keep16[0], keep32seg[0], keep32flat[0]) |
| |
| # Write out linker script files. |
| writeLinkerScripts(locs16, locs32seg, locs32flat |
| , keep16[1], keep32seg[1], keep32flat[1] |
| , out16, out32seg, out32flat) |
| |
| if __name__ == '__main__': |
| main() |