This is the mail archive of the
binutils@sources.redhat.com
mailing list for the binutils project.
RE: How do I prevent ld from merging PT_LOAD segments?
- From: Jeff Baker <jbaker at qnx dot com>
- To: Jeff Baker <jbaker at qnx dot com>, "'binutils at sources dot redhat dot com'" <binutils at sources dot redhat dot com>
- Date: Tue, 8 Jul 2003 15:41:02 -0400
- Subject: RE: How do I prevent ld from merging PT_LOAD segments?
In case it helps, here are two objdumps. The first is of a correct binary
linked with the 2.10.1 linker. The second is a bad binary linked with the
2.12.1 linker. Both were linked from the same object files and using the
same linker script. I left off the symbol tables to keep this as short as
possible.
portmap-good: file format elf32-littlearm
portmap-good
architecture: arm, flags 0x00000112:
EXEC_P, HAS_SYMS, D_PAGED
start address 0x00100bcc
Program Header:
PHDR off 0x00000034 vaddr 0x00100034 paddr 0x00000000 align 2**2
filesz 0x000000c0 memsz 0x000000c0 flags r-x
INTERP off 0x000000f4 vaddr 0x001000f4 paddr 0x00000000 align 2**0
filesz 0x00000014 memsz 0x00000014 flags r--
LOAD off 0x00000000 vaddr 0x00100000 paddr 0x00100000 align 2**12
filesz 0x00001cb0 memsz 0x00001cb0 flags r-x
LOAD off 0x00001cb0 vaddr 0x00102cb0 paddr 0x00102cb0 align 2**12
filesz 0x00000164 memsz 0x00000204 flags rw-
DYNAMIC off 0x00001d7c vaddr 0x00102d7c paddr 0x00000000 align 2**2
filesz 0x00000098 memsz 0x00000098 flags rw-
NOTE off 0x00001e14 vaddr 0x00000000 paddr 0x00000000 align 2**2
filesz 0x00000050 memsz 0x00000000 flags ---
Dynamic Section:
NEEDED librpc.so.2
NEEDED libsocket.so.2
NEEDED libc.so.2
INIT 0x100950
FINI 0x101ca4
HASH 0x100108
STRTAB 0x1005f0
SYMTAB 0x100280
STRSZ 0x21f
SYMENT 0x10
DEBUG 0x0
PLTGOT 0x102cd0
PLTRELSZ 0x130
PLTREL 0x11
JMPREL 0x100820
REL 0x100810
RELSZ 0x10
RELENT 0x8
private flags = 0: [interworking not enabled] [APCS-32] [floats passed in
integer registers] [absolute position]
Sections:
Idx Name Size VMA LMA File off Algn
0 .interp 00000014 001000f4 001000f4 000000f4 2**0
CONTENTS, ALLOC, LOAD, READONLY, DATA
1 .note 00000000 00100108 00100108 00000108 2**0
CONTENTS, ALLOC, LOAD, READONLY, DATA
2 .hash 00000178 00100108 00100108 00000108 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
3 .dynsym 00000370 00100280 00100280 00000280 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
4 .dynstr 0000021f 001005f0 001005f0 000005f0 2**0
CONTENTS, ALLOC, LOAD, READONLY, DATA
5 .rel.bss 00000010 00100810 00100810 00000810 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
6 .rel.plt 00000130 00100820 00100820 00000820 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
7 .init 0000000c 00100950 00100950 00000950 2**2
CONTENTS, ALLOC, LOAD, READONLY, CODE
8 .plt 00000270 0010095c 0010095c 0000095c 2**2
CONTENTS, ALLOC, LOAD, READONLY, CODE
9 .text 000010d8 00100bcc 00100bcc 00000bcc 2**2
CONTENTS, ALLOC, LOAD, READONLY, CODE
10 .fini 0000000c 00101ca4 00101ca4 00001ca4 2**2
CONTENTS, ALLOC, LOAD, READONLY, CODE
11 .data 00000010 00102cb0 00102cb0 00001cb0 2**2
CONTENTS, ALLOC, LOAD, DATA
12 .ctors 00000008 00102cc0 00102cc0 00001cc0 2**2
CONTENTS, ALLOC, LOAD, DATA
13 .dtors 00000008 00102cc8 00102cc8 00001cc8 2**2
CONTENTS, ALLOC, LOAD, DATA
14 .got 000000ac 00102cd0 00102cd0 00001cd0 2**2
CONTENTS, ALLOC, LOAD, DATA
15 .dynamic 00000098 00102d7c 00102d7c 00001d7c 2**2
CONTENTS, ALLOC, LOAD, DATA
16 .bss 000000a0 00102e14 00102e14 00001e14 2**3
ALLOC
17 QNX_usage 00000003 00000000 00000000 00002a6c 2**0
CONTENTS, READONLY
18 QNX_info 000000a4 00000000 00000000 00002a6f 2**0
CONTENTS, READONLY
=================================================================
portmap: file format elf32-littlearm
portmap
architecture: arm, flags 0x00000112:
EXEC_P, HAS_SYMS, D_PAGED
start address 0x00100b9c
Program Header:
PHDR off 0x00000034 vaddr 0x00100034 paddr 0x00100034 align 2**2
filesz 0x000000c0 memsz 0x000000c0 flags r-x
INTERP off 0x000000f4 vaddr 0x001000f4 paddr 0x001000f4 align 2**0
filesz 0x00000014 memsz 0x00000014 flags r--
LOAD off 0x00000000 vaddr 0x00100000 paddr 0x00100000 align 2**15
filesz 0x00002e0c memsz 0x00002eac flags rwx
DYNAMIC off 0x00002c90 vaddr 0x00102c90 paddr 0x00102c90 align 2**2
filesz 0x000000c0 memsz 0x000000c0 flags rw-
NOTE off 0x00000108 vaddr 0x00100108 paddr 0x00100108 align 2**0
filesz 0x00000000 memsz 0x00000000 flags r--
Dynamic Section:
NEEDED librpc.so.2
NEEDED libsocket.so.2
NEEDED libc.so.2
INIT 0x100920
FINI 0x101c74
HASH 0x100108
STRTAB 0x1005dc
SYMTAB 0x10027c
STRSZ 0x202
SYMENT 0x10
DEBUG 0x0
PLTGOT 0x102d60
PLTRELSZ 0x130
PLTREL 0x11
JMPREL 0x1007f0
REL 0x1007e0
RELSZ 0x10
RELENT 0x8
private flags = 2: [interworking not enabled] [APCS-32] [floats passed in
integer registers] [absolute position]
Sections:
Idx Name Size VMA LMA File off Algn
0 .interp 00000014 001000f4 001000f4 000000f4 2**0
CONTENTS, ALLOC, LOAD, READONLY, DATA
1 .note 00000000 00100108 00100108 00000108 2**0
CONTENTS, ALLOC, LOAD, READONLY, DATA
2 .hash 00000174 00100108 00100108 00000108 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
3 .dynsym 00000360 0010027c 0010027c 0000027c 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
4 .dynstr 00000202 001005dc 001005dc 000005dc 2**0
CONTENTS, ALLOC, LOAD, READONLY, DATA
5 .rel.bss 00000010 001007e0 001007e0 000007e0 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
6 .rel.plt 00000130 001007f0 001007f0 000007f0 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
7 .init 0000000c 00100920 00100920 00000920 2**2
CONTENTS, ALLOC, LOAD, READONLY, CODE
8 .plt 00000270 0010092c 0010092c 0000092c 2**2
CONTENTS, ALLOC, LOAD, READONLY, CODE
9 .text 000010d8 00100b9c 00100b9c 00000b9c 2**2
CONTENTS, ALLOC, LOAD, READONLY, CODE
10 .fini 0000000c 00101c74 00101c74 00001c74 2**2
CONTENTS, ALLOC, LOAD, READONLY, CODE
11 .data 00000010 00102c80 00102c80 00002c80 2**2
CONTENTS, ALLOC, LOAD, DATA
12 .dynamic 000000c0 00102c90 00102c90 00002c90 2**2
CONTENTS, ALLOC, LOAD, DATA
13 .ctors 00000008 00102d50 00102d50 00002d50 2**2
CONTENTS, ALLOC, LOAD, DATA
14 .dtors 00000008 00102d58 00102d58 00002d58 2**2
CONTENTS, ALLOC, LOAD, DATA
15 .got 000000ac 00102d60 00102d60 00002d60 2**2
CONTENTS, ALLOC, LOAD, DATA
16 .bss 000000a0 00102e0c 00102e0c 00002e0c 2**3
ALLOC
> -----Original Message-----
> From: Jeff Baker [mailto:jbaker@qnx.com]
> Sent: July 7, 2003 4:08 PM
> To: 'binutils@sources.redhat.com'
> Subject: How do I prevent ld from merging PT_LOAD segments?
>
> We're currently in the process of moving from binutils-2.10.1 (Wow, that's
> old) to binutils-2.12.1 (Wow, that's... not quite so old). I've observed
> a
> new behaviour that I've confirmed is also in the current head branch.
>
> The newer binutils (arm, ppc and sh4) seem to be merging two PT_LOAD
> segments into one (x86 and mips don't). For various reasons we need to
> have
> both of these segments separate.
>
> My wild, uninformed theory is that this is the result of a new feature
> added
> after 2.10.1 that can be overridden somewhere in the linker scripts.
> Whether I'm correct or not, I don't know how to deal with this. I would
> appreciate an explanation of this behaviour if someone is feeling
> benevolent
> enough to give me one.
>
> Thanks,
> Jeff