#!/usr/bin/env python # Script to analyze code and arrange ld sections. # # Copyright (C) 2008-2010 Kevin O'Connor # # This file may be distributed under the terms of the GNU GPLv3 license. import operator 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) *(.note*) } } """ ###################################################################### # 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 setSectionsStart(sections, endaddr, minalign=1, segoffset=0): totspace = 0 for section in sections: if section.align > minalign: minalign = section.align totspace = alignpos(totspace, section.align) + section.size startaddr = int((endaddr - totspace) / minalign) * minalign curaddr = startaddr for section in sections: curaddr = alignpos(curaddr, section.align) section.finalloc = curaddr section.finalsegloc = curaddr - segoffset curaddr += section.size return startaddr, minalign # The 16bit code can't exceed 64K of space. BUILD_BIOS_ADDR = 0xf0000 BUILD_BIOS_SIZE = 0x10000 BUILD_ROM_START = 0xc0000 BUILD_LOWRAM_END = 0xa0000 # Space to reserve in f-segment for dynamic allocations BUILD_MIN_BIOSTABLE = 2048 # 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): # fixedsections = [(addr, section), ...] fixedsections = [] for section in sections: if section.name.startswith('.fixedaddr.'): addr = int(section.name[11:], 16) section.finalloc = addr + BUILD_BIOS_ADDR section.finalsegloc = addr fixedsections.append((addr, section)) if section.align != 1: print("Error: Fixed section %s has non-zero alignment (%d)" % ( section.name, section.align)) sys.exit(1) fixedsections.sort(key=operator.itemgetter(0)) firstfixed = fixedsections[0][0] # Find freespace in fixed address area # fixedAddr = [(freespace, section), ...] 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.size fixedAddr.append((avail, section)) fixedAddr.sort(key=operator.itemgetter(0)) # Attempt to fit other sections into fixed area canrelocate = [(section.size, section.align, section.name, section) for section in fillsections] canrelocate.sort() canrelocate = [section for size, align, name, section in canrelocate] totalused = 0 for freespace, fixedsection in fixedAddr: addpos = fixedsection.finalsegloc + fixedsection.size totalused += fixedsection.size nextfixedaddr = addpos + freespace # print("Filling section %x uses %d, next=%x, available=%d" % ( # fixedsection.finalloc, fixedsection.size, nextfixedaddr, freespace)) while 1: canfit = None for fitsection in canrelocate: if addpos + fitsection.size > nextfixedaddr: # Can't fit and nothing else will fit. break fitnextaddr = alignpos(addpos, fitsection.align) + fitsection.size # print("Test %s - %x vs %x" % ( # fitsection.name, 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) fitsection.finalloc = addpos + BUILD_BIOS_ADDR fitsection.finalsegloc = addpos addpos = fitnextaddr totalused += fitsection.size # print(" Adding %s (size %d align %d) pos=%x avail=%d" % ( # fitsection[2], fitsection[0], fitsection[1] # , fitnextaddr, nextfixedaddr - fitnextaddr)) # 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 firstfixed + BUILD_BIOS_ADDR # Return the subset of sections with a given category def getSectionsCategory(sections, category): return [section for section in sections if section.category == category] # Return the subset of sections with a given name prefix def getSectionsPrefix(sections, prefix): return [section for section in sections if section.name.startswith(prefix)] # The sections (and associated information) to be placed in output rom class LayoutInfo: genreloc = None sections16 = sec16_start = sec16_align = None sections32seg = sec32seg_start = sec32seg_align = None sections32flat = sec32flat_start = sec32flat_align = None sections32init = sec32init_start = sec32init_align = None sections32low = sec32low_start = sec32low_align = None sections32fseg = sec32fseg_start = sec32fseg_align = None zonefseg_start = zonefseg_end = None final_readonly_start = None zonelow_base = final_sec32low_start = None exportsyms = varlowsyms = None # Determine final memory addresses for sections def doLayout(sections, config, genreloc): li = LayoutInfo() li.genreloc = genreloc # Determine 16bit positions li.sections16 = getSectionsCategory(sections, '16') textsections = getSectionsPrefix(li.sections16, '.text.') rodatasections = ( getSectionsPrefix(li.sections16, '.rodata.str1.1') + getSectionsPrefix(li.sections16, '.rodata.__func__.') + getSectionsPrefix(li.sections16, '.rodata.__PRETTY_FUNCTION__.')) datasections = getSectionsPrefix(li.sections16, '.data16.') fixedsections = getSectionsPrefix(li.sections16, '.fixedaddr.') firstfixed = fitSections(fixedsections, textsections) remsections = [s for s in textsections+rodatasections+datasections if s.finalloc is None] li.sec16_start, li.sec16_align = setSectionsStart( remsections, firstfixed, segoffset=BUILD_BIOS_ADDR) # Determine 32seg positions li.sections32seg = getSectionsCategory(sections, '32seg') textsections = getSectionsPrefix(li.sections32seg, '.text.') rodatasections = ( getSectionsPrefix(li.sections32seg, '.rodata.str1.1') + getSectionsPrefix(li.sections32seg, '.rodata.__func__.') + getSectionsPrefix(li.sections32seg, '.rodata.__PRETTY_FUNCTION__.')) datasections = getSectionsPrefix(li.sections32seg, '.data32seg.') li.sec32seg_start, li.sec32seg_align = setSectionsStart( textsections + rodatasections + datasections, li.sec16_start , segoffset=BUILD_BIOS_ADDR) # Determine "fseg memory" data positions li.sections32fseg = getSectionsCategory(sections, '32fseg') li.sec32fseg_start, li.sec32fseg_align = setSectionsStart( li.sections32fseg, li.sec32seg_start, 16 , segoffset=BUILD_BIOS_ADDR) # Determine 32flat runtime positions li.sections32flat = getSectionsCategory(sections, '32flat') textsections = getSectionsPrefix(li.sections32flat, '.text.') rodatasections = getSectionsPrefix(li.sections32flat, '.rodata') datasections = getSectionsPrefix(li.sections32flat, '.data.') bsssections = getSectionsPrefix(li.sections32flat, '.bss.') li.sec32flat_start, li.sec32flat_align = setSectionsStart( textsections + rodatasections + datasections + bsssections , li.sec32fseg_start, 16) # Determine 32flat init positions li.sections32init = getSectionsCategory(sections, '32init') init32_textsections = getSectionsPrefix(li.sections32init, '.text.') init32_rodatasections = getSectionsPrefix(li.sections32init, '.rodata') init32_datasections = getSectionsPrefix(li.sections32init, '.data.') init32_bsssections = getSectionsPrefix(li.sections32init, '.bss.') li.sec32init_start, li.sec32init_align = setSectionsStart( init32_textsections + init32_rodatasections + init32_datasections + init32_bsssections , li.sec32flat_start, 16) # Determine location of ZoneFSeg memory. li.zonefseg_end = li.sec32flat_start if not genreloc: li.zonefseg_end = li.sec32init_start li.zonefseg_start = BUILD_BIOS_ADDR if li.zonefseg_start + BUILD_MIN_BIOSTABLE > li.zonefseg_end: # Not enough ZoneFSeg space - force a minimum space. li.zonefseg_end = li.sec32fseg_start li.zonefseg_start = li.zonefseg_end - BUILD_MIN_BIOSTABLE li.sec32flat_start, li.sec32flat_align = setSectionsStart( textsections + rodatasections + datasections + bsssections , li.zonefseg_start, 16) li.sec32init_start, li.sec32init_align = setSectionsStart( init32_textsections + init32_rodatasections + init32_datasections + init32_bsssections , li.sec32flat_start, 16) li.final_readonly_start = min(BUILD_BIOS_ADDR, li.sec32flat_start) if not genreloc: li.final_readonly_start = min(BUILD_BIOS_ADDR, li.sec32init_start) # Determine "low memory" data positions li.sections32low = getSectionsCategory(sections, '32low') sec32low_end = li.sec32init_start if config.get('CONFIG_MALLOC_UPPERMEMORY'): final_sec32low_end = li.final_readonly_start zonelow_base = final_sec32low_end - 64*1024 li.zonelow_base = max(BUILD_ROM_START, alignpos(zonelow_base, 2*1024)) else: final_sec32low_end = BUILD_LOWRAM_END li.zonelow_base = final_sec32low_end - 64*1024 relocdelta = final_sec32low_end - sec32low_end li.sec32low_start, li.sec32low_align = setSectionsStart( li.sections32low, sec32low_end, 16 , segoffset=li.zonelow_base - relocdelta) li.final_sec32low_start = li.sec32low_start + relocdelta # Print statistics size16 = BUILD_BIOS_ADDR + BUILD_BIOS_SIZE - li.sec16_start size32seg = li.sec16_start - li.sec32seg_start size32fseg = li.sec32seg_start - li.sec32fseg_start size32flat = li.sec32fseg_start - li.sec32flat_start size32init = li.sec32flat_start - li.sec32init_start sizelow = sec32low_end - li.sec32low_start print("16bit size: %d" % size16) print("32bit segmented size: %d" % size32seg) print("32bit flat size: %d" % size32flat) print("32bit flat init size: %d" % size32init) print("Lowmem size: %d" % sizelow) print("f-segment var size: %d" % size32fseg) return li ###################################################################### # Linker script output ###################################################################### # Write LD script includes for the given cross references def outXRefs(sections, useseg=0, exportsyms=[], forcedelta=0): xrefs = dict([(symbol.name, symbol) for symbol in exportsyms]) out = "" for section in sections: for reloc in section.relocs: symbol = reloc.symbol if (symbol.section is not None and (symbol.section.fileid != section.fileid or symbol.name != reloc.symbolname)): xrefs[reloc.symbolname] = symbol for symbolname, symbol in xrefs.items(): loc = symbol.section.finalloc if useseg: loc = symbol.section.finalsegloc out += "%s = 0x%x ;\n" % (symbolname, loc + forcedelta + symbol.offset) return out # Write LD script includes for the given sections using relative offsets def outRelSections(sections, startsym, useseg=0): sections = [(section.finalloc, section) for section in sections if section.finalloc is not None] sections.sort(key=operator.itemgetter(0)) out = "" for addr, section in sections: loc = section.finalloc if useseg: loc = section.finalsegloc out += ". = ( 0x%x - %s ) ;\n" % (loc, startsym) if section.name == '.rodata.str1.1': out += "_rodata = . ;\n" out += "*(%s)\n" % (section.name,) return out # Build linker script output for a list of relocations. def strRelocs(outname, outrel, relocs): relocs.sort() return (" %s_start = ABSOLUTE(.) ;\n" % (outname,) + "".join(["LONG(0x%x - %s)\n" % (pos, outrel) for pos in relocs]) + " %s_end = ABSOLUTE(.) ;\n" % (outname,)) # Find all relocations in the given sections with the given attributes def getRelocs(sections, type=None, category=None, notcategory=None): out = [] for section in sections: for reloc in section.relocs: if reloc.symbol.section is None: continue destcategory = reloc.symbol.section.category if ((type is None or reloc.type == type) and (category is None or destcategory == category) and (notcategory is None or destcategory != notcategory)): out.append(section.finalloc + reloc.offset) return out # Return the start address and minimum alignment for a set of sections def getSectionsStart(sections, defaddr=0): return min([section.finalloc for section in sections if section.finalloc is not None] or [defaddr]) # Output the linker scripts for all required sections. def writeLinkerScripts(li, out16, out32seg, out32flat): # Write 16bit linker script out = outXRefs(li.sections16, useseg=1) + """ zonelow_base = 0x%x ; _zonelow_seg = 0x%x ; code16_start = 0x%x ; .text16 code16_start : { %s } """ % (li.zonelow_base, int(li.zonelow_base / 16), li.sec16_start - BUILD_BIOS_ADDR, outRelSections(li.sections16, 'code16_start', useseg=1)) outfile = open(out16, 'w') outfile.write(COMMONHEADER + out + COMMONTRAILER) outfile.close() # Write 32seg linker script out = outXRefs(li.sections32seg, useseg=1) + """ code32seg_start = 0x%x ; .text32seg code32seg_start : { %s } """ % (li.sec32seg_start - BUILD_BIOS_ADDR, outRelSections(li.sections32seg, 'code32seg_start', useseg=1)) outfile = open(out32seg, 'w') outfile.write(COMMONHEADER + out + COMMONTRAILER) outfile.close() # Write 32flat linker script sections32all = (li.sections32flat + li.sections32init + li.sections32fseg) sec32all_start = li.sec32low_start relocstr = "" if li.genreloc: # Generate relocations absrelocs = getRelocs( li.sections32init, type='R_386_32', category='32init') relrelocs = getRelocs( li.sections32init, type='R_386_PC32', notcategory='32init') initrelocs = getRelocs( li.sections32flat + li.sections32low + li.sections16 + li.sections32seg + li.sections32fseg, category='32init') relocstr = (strRelocs("_reloc_abs", "code32init_start", absrelocs) + strRelocs("_reloc_rel", "code32init_start", relrelocs) + strRelocs("_reloc_init", "code32flat_start", initrelocs)) numrelocs = len(absrelocs + relrelocs + initrelocs) sec32all_start -= numrelocs * 4 out = outXRefs(li.sections32low, exportsyms=li.varlowsyms , forcedelta=li.final_sec32low_start-li.sec32low_start) out += outXRefs(sections32all, exportsyms=li.exportsyms) + """ _reloc_min_align = 0x%x ; zonefseg_start = 0x%x ; zonefseg_end = 0x%x ; zonelow_base = 0x%x ; final_varlow_start = 0x%x ; final_readonly_start = 0x%x ; code32flat_start = 0x%x ; .text code32flat_start : { %s varlow_start = ABSOLUTE(.) ; %s varlow_end = ABSOLUTE(.) ; code32init_start = ABSOLUTE(.) ; %s code32init_end = ABSOLUTE(.) ; %s %s . = ( 0x%x - code32flat_start ) ; *(.text32seg) . = ( 0x%x - code32flat_start ) ; *(.text16) code32flat_end = ABSOLUTE(.) ; } :text """ % (li.sec32init_align, li.zonefseg_start, li.zonefseg_end, li.zonelow_base, li.final_sec32low_start, li.final_readonly_start, sec32all_start, relocstr, outRelSections(li.sections32low, 'code32flat_start'), outRelSections(li.sections32init, 'code32flat_start'), outRelSections(li.sections32flat, 'code32flat_start'), outRelSections(li.sections32fseg, 'code32flat_start'), li.sec32seg_start, li.sec16_start) out = COMMONHEADER + out + COMMONTRAILER + """ ENTRY(entry_elf) PHDRS { text PT_LOAD AT ( code32flat_start ) ; } """ outfile = open(out32flat, 'w') outfile.write(out) outfile.close() ###################################################################### # Detection of init code ###################################################################### def markRuntime(section, sections, chain=[]): if (section is None or not section.keep or section.category is not None or '.init.' in section.name or section.fileid != '32flat'): return if '.data.varinit.' in section.name: print("ERROR: %s is VARVERIFY32INIT but used from %s" % ( section.name, chain)) sys.exit(1) section.category = '32flat' # Recursively mark all sections this section points to for reloc in section.relocs: markRuntime(reloc.symbol.section, sections, chain + [section.name]) def findInit(sections): # Recursively find and mark all "runtime" sections. for section in sections: if ('.data.varlow.' in section.name or '.data.varfseg.' in section.name or '.runtime.' in section.name or '.export.' in section.name): markRuntime(section, sections) for section in sections: if section.category is not None: continue if section.fileid == '32flat': section.category = '32init' else: section.category = section.fileid ###################################################################### # Section garbage collection ###################################################################### CFUNCPREFIX = [('_cfunc16_', 0), ('_cfunc32seg_', 1), ('_cfunc32flat_', 2)] # Find and keep the section associated with a symbol (if available). def keepsymbol(reloc, infos, pos, isxref): symbolname = reloc.symbolname mustbecfunc = 0 for symprefix, needpos in CFUNCPREFIX: if symbolname.startswith(symprefix): if needpos != pos: return -1 symbolname = symbolname[len(symprefix):] mustbecfunc = 1 break symbol = infos[pos][1].get(symbolname) if (symbol is None or symbol.section is None or symbol.section.name.startswith('.discard.')): return -1 isdestcfunc = (symbol.section.name.startswith('.text.') and not symbol.section.name.startswith('.text.asm.')) if ((mustbecfunc and not isdestcfunc) or (not mustbecfunc and isdestcfunc and isxref)): return -1 reloc.symbol = symbol keepsection(symbol.section, infos, pos) return 0 # Note required section, and recursively set all referenced sections # as required. def keepsection(section, infos, pos=0): if section.keep: # Already kept - nothing to do. return section.keep = 1 # Keep all sections that this section points to for reloc in section.relocs: ret = keepsymbol(reloc, infos, pos, 0) if not ret: continue # Not in primary sections - it may be a cross 16/32 reference ret = keepsymbol(reloc, infos, (pos+1)%3, 1) if not ret: continue ret = keepsymbol(reloc, infos, (pos+2)%3, 1) if not ret: continue # Determine which sections are actually referenced and need to be # placed into the output file. def gc(info16, info32seg, info32flat): # infos = ((sections16, symbols16), (sect32seg, sym32seg) # , (sect32flat, sym32flat)) infos = (info16, info32seg, info32flat) # Start by keeping sections that are globally visible. for section in info16[0]: if section.name.startswith('.fixedaddr.') or '.export.' in section.name: keepsection(section, infos) return [section for section in info16[0]+info32seg[0]+info32flat[0] if section.keep] ###################################################################### # Startup and input parsing ###################################################################### class Section: name = size = alignment = fileid = relocs = None finalloc = finalsegloc = category = keep = None class Reloc: offset = type = symbolname = symbol = None class Symbol: name = offset = section = None # Read in output from objdump def parseObjDump(file, fileid): # sections = [section, ...] sections = [] sectionmap = {} # symbols[symbolname] = symbol symbols = {} 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.startswith('RELOCATION RECORDS FOR ['): sectionname = line[24:-2] if sectionname.startswith('.debug_'): # Skip debugging sections (to reduce parsing time) state = None continue state = 'reloc' relocsection = sectionmap[sectionname] continue if state == 'section': try: idx, name, size, vma, lma, fileoff, align = line.split() if align[:3] != '2**': continue section = Section() section.name = name section.size = int(size, 16) section.align = 2**int(align[3:]) section.fileid = fileid section.relocs = [] sections.append(section) sectionmap[name] = section except ValueError: pass continue if state == 'symbol': try: parts = line[17:].split() if len(parts) == 3: sectionname, size, name = parts elif len(parts) == 4 and parts[2] == '.hidden': sectionname, size, hidden, name = parts else: continue symbol = Symbol() symbol.size = int(size, 16) symbol.offset = int(line[:8], 16) symbol.name = name symbol.section = sectionmap.get(sectionname) symbols[name] = symbol except ValueError: pass continue if state == 'reloc': try: off, type, symbolname = line.split() reloc = Reloc() reloc.offset = int(off, 16) reloc.type = type reloc.symbolname = symbolname reloc.symbol = symbols.get(symbolname) if reloc.symbol is None: # Some binutils (2.20.1) give section name instead # of a symbol - create a dummy symbol. reloc.symbol = symbol = Symbol() symbol.size = 0 symbol.offset = 0 symbol.name = symbolname symbol.section = sectionmap.get(symbolname) symbols[symbolname] = symbol relocsection.relocs.append(reloc) except ValueError: pass return sections, symbols # Parser for constants in simple C header files. def scanconfig(file): f = open(file, 'r') opts = {} for l in f.readlines(): parts = l.split() if len(parts) != 3: continue if parts[0] != '#define': continue value = parts[2] if value.isdigit() or (value.startswith('0x') and value[2:].isdigit()): value = int(value, 0) opts[parts[1]] = value return opts def main(): # Get output name in16, in32seg, in32flat, cfgfile, out16, out32seg, out32flat = sys.argv[1:] # Read in the objdump information infile16 = open(in16, 'r') infile32seg = open(in32seg, 'r') infile32flat = open(in32flat, 'r') # infoX = (sections, symbols) info16 = parseObjDump(infile16, '16') info32seg = parseObjDump(infile32seg, '32seg') info32flat = parseObjDump(infile32flat, '32flat') # Read kconfig config file config = scanconfig(cfgfile) # Figure out which sections to keep. sections = gc(info16, info32seg, info32flat) # Separate 32bit flat into runtime and init parts findInit(sections) # Note "low memory" and "fseg memory" parts for section in getSectionsPrefix(sections, '.data.varlow.'): section.category = '32low' for section in getSectionsPrefix(sections, '.data.varfseg.'): section.category = '32fseg' # Determine the final memory locations of each kept section. genreloc = '_reloc_abs_start' in info32flat[1] li = doLayout(sections, config, genreloc) # Exported symbols li.exportsyms = [symbol for symbol in info16[1].values() if (symbol.section is not None and '.export.' in symbol.section.name and symbol.name != symbol.section.name)] li.varlowsyms = [symbol for symbol in info32flat[1].values() if (symbol.section is not None and symbol.section.finalloc is not None and '.data.varlow.' in symbol.section.name and symbol.name != symbol.section.name)] # Write out linker script files. writeLinkerScripts(li, out16, out32seg, out32flat) if __name__ == '__main__': main()