ld capping section/segment address at 1<<32

[Roland McGrath]

I've just filed http://sourceware.org/bugzilla/show_bug.cgi?id=13400
for this.

I'm posting here too in hopes of slightly quicker response and because I'm
interested in any discussion.  Is anyone aware of a problem like this already?

What's especially notable is that the truncated section/segment size makes
it so the section/segment ends at exactly 1<<32.  That makes it seem
suspiciously like there is some 32-bit arithmetic going on somewhere.

Thanks,
Roland


$ cat toobig.s
	.text
	.globl _start
_start:	hlt
$ cat toobig.x
ENTRY(_start)
PHDRS {
  text PT_LOAD FILEHDR PHDRS;
  data PT_LOAD;
  reserve PT_LOAD FLAGS(0);
  note PT_NOTE;
  stack PT_GNU_STACK FLAGS(6);
}

RESERVE_TOP = 0x1500000000;

SECTIONS {
  . = 0x10000 + SIZEOF_HEADERS;

  .note.gnu.build-id : {
    *(.note.gnu.build-id)
  } :text :note

  .text : {
    *(.text*)
  } :text
  .rodata : {
    *(.rodata*)
    *(.eh_frame*)
  }

  etext = .;

  . = (ALIGN(CONSTANT(MAXPAGESIZE)) -
       ((CONSTANT(MAXPAGESIZE) - .) & (CONSTANT(MAXPAGESIZE) - 1)));
  . = DATA_SEGMENT_ALIGN(CONSTANT(MAXPAGESIZE), CONSTANT(COMMONPAGESIZE));

  .data : {
    *(.data*)
  } :data
  .bss : {
    *(.bss*)
  }

  . = ALIGN(CONSTANT(COMMONPAGESIZE));
  RESERVE_START = .;
  .reserve : {
    . = RESERVE_TOP - RESERVE_START;
  } :reserve
}
$ ./ld/ld-new  -m elf_x86_64 --build-id -static -z
max-page-size=0x1000 --script=toobig.x -o toobig toobig.o
$ readelf -lSs toobig
There are 7 section headers, starting at offset 0x1c0:

Section Headers:
  [Nr] Name              Type             Address           Offset
       Size              EntSize          Flags  Link  Info  Align
  [ 0]                   NULL             0000000000000000  00000000
       0000000000000000  0000000000000000           0     0     0
  [ 1] .note.gnu.build-i NOTE             0000000000010158  00000158
       0000000000000024  0000000000000000   A       0     0     4
  [ 2] .text             PROGBITS         000000000001017c  0000017c
       0000000000000001  0000000000000000  AX       0     0     4
  [ 3] .reserve          NOBITS           0000000000012000  00001000
       00000000fffee000  0000000000000000  WA       0     0     1
  [ 4] .shstrtab         STRTAB           0000000000000000  0000017d
       000000000000003d  0000000000000000           0     0     1
  [ 5] .symtab           SYMTAB           0000000000000000  00000380
       00000000000000c0  0000000000000018           6     4     8
  [ 6] .strtab           STRTAB           0000000000000000  00000440
       0000000000000028  0000000000000000           0     0     1
Key to Flags:
  W (write), A (alloc), X (execute), M (merge), S (strings)
  I (info), L (link order), G (group), x (unknown)
  O (extra OS processing required) o (OS specific), p (processor specific)

Elf file type is EXEC (Executable file)
Entry point 0x1017c
There are 5 program headers, starting at offset 64

Program Headers:
  Type           Offset             VirtAddr           PhysAddr
                 FileSiz            MemSiz              Flags  Align
  LOAD           0x0000000000000000 0x0000000000010000 0x0000000000010000
                 0x000000000000017d 0x000000000000017d  R E    1000
  LOAD           0x000000000000017d 0x0000000000000000 0x0000000000000000
                 0x0000000000000000 0x0000000000000000         1000
  LOAD           0x0000000000001000 0x0000000000012000 0x0000000000012000
                 0x0000000000000000 0x00000000fffee000         1000
  NOTE           0x0000000000000158 0x0000000000010158 0x0000000000010158
                 0x0000000000000024 0x0000000000000024  R      4
  GNU_STACK      0x0000000000000000 0x0000000000000000 0x0000000000000000
                 0x0000000000000000 0x0000000000000000  RW     8

 Section to Segment mapping:
  Segment Sections...
   00     .note.gnu.build-id .text
   01
   02     .reserve
   03     .note.gnu.build-id
   04

Symbol table '.symtab' contains 8 entries:
   Num:    Value          Size Type    Bind   Vis      Ndx Name
     0: 0000000000000000     0 NOTYPE  LOCAL  DEFAULT  UND
     1: 0000000000010158     0 SECTION LOCAL  DEFAULT    1
     2: 000000000001017c     0 SECTION LOCAL  DEFAULT    2
     3: 0000000000012000     0 SECTION LOCAL  DEFAULT    3
     4: 0000001500000000     0 NOTYPE  GLOBAL DEFAULT  ABS RESERVE_TOP
     5: 000000000001017d     0 NOTYPE  GLOBAL DEFAULT  ABS etext
     6: 000000000001017c     0 NOTYPE  GLOBAL DEFAULT    2 _start
     7: 0000000000012000     0 NOTYPE  GLOBAL DEFAULT  ABS RESERVE_START
$