[Bug target/56473] Cross Compile Ubuntu x86_64 to Raspberry Pi Code Seg Faults When Executed

[tomdean at speakeasy dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56473

--- Comment #4 from Thomas Dean <tomdean at speakeasy dot org> 2013-02-28 00:38:56 UTC ---
Looking again at gdb, _start from ubuntu is not the same as _start on
RaspberryPi, although both compiler versions are the same.
###################
## build on ubuntu
## gdb on raspi
tomdean@raspberrypi:~/p9x79/bug$ gdb hello
GNU gdb (GDB) 7.4.1-debian
<snip>
Reading symbols from /home/tomdean/p9x79/bug/hello...done.
(gdb) b main
Breakpoint 1 at 0x8364: file hello.c, line 3.
(gdb) r
Starting program: /home/tomdean/p9x79/bug/hello 

Program received signal SIGSEGV, Segmentation fault.
0x000573a6 in ?? ()
(gdb) bt
#0  0x000573a6 in ?? ()
#1  0x000082ee in _start ()
(gdb) disassemble/r _start
Dump of assembler code for function _start:
   0x000082e4 <+0>:     4f f0 00 0b     mov.w   r11, #0
   0x000082e8 <+4>:     4f f0 00 0e     mov.w   lr, #0
   0x000082ec <+8>:     5d f8 04 1b     ldr.w   r1, [sp], #4
   0x000082f0 <+12>:    6a 46   mov     r2, sp
   0x000082f2 <+14>:    4d f8 04 2d     str.w   r2, [sp, #-4]!
   0x000082f6 <+18>:    4d f8 04 0d     str.w   r0, [sp, #-4]!
   0x000082fa <+22>:    df f8 14 c0     ldr.w   r12, [pc, #20]  ; 0x8310
<_start+44>
   0x000082fe <+26>:    4d f8 04 cd     str.w   r12, [sp, #-4]!
   0x00008302 <+30>:    04 48   ldr     r0, [pc, #16]   ; (0x8314 <_start+48>)
   0x00008304 <+32>:    04 4b   ldr     r3, [pc, #16]   ; (0x8318 <_start+52>)
   0x00008306 <+34>:    ff f7 da ef     blx     0x82bc <__libc_start_main>
   0x0000830a <+38>:    ff f7 e6 ef     blx     0x82d8 <abort>
   0x0000830e <+42>:    00 00 bd 83                     ; <UNDEFINED>
instruction: 0x83bd0000
   0x00008312 <+46>:    00 00 5c 83     cmphi   r12, #0
   0x00008316 <+50>:    00 00 79 83     cmnhi   r9, #0
   0x0000831a <+54>:    00 00 03 4b     blmi    0xc8322
End of assembler dump.

###################
## compile on ubuntu
## link on raspi
## gdb on raspi
ubuntu> arm-linux-gnueabihf-gcc-4.6 -g -mcpu=arm1176jzf-s -mfpu=vfp
-mfloat-abi=hard -marm hello.c -Wl,-t -c -o hello.o
tomdean@raspberrypi:~/p9x79/bug$ arm-linux-gnueabihf-gcc-4.6 -g
-mcpu=arm1176jzf-s -mfpu=vfp -mfloat-abi=hard -marm hello.o -Wl,-t -o
~/work/hello
tomdean@raspberrypi:~/p9x79/bug$ gdb ~/work/hello
GNU gdb (GDB) 7.4.1-debian
<snip>
Reading symbols from /home/tomdean/work/hello...done.
(gdb) b main
Breakpoint 1 at 0x8398: file hello.c, line 3.
(gdb) r
Starting program: /home/tomdean/work/hello 

Breakpoint 1, main () at hello.c:3
3         return 0;
(gdb) disassemble/r _start   
Dump of assembler code for function _start:
   0x000082e4 <+0>:     00 b0 a0 e3     mov     r11, #0
   0x000082e8 <+4>:     00 e0 a0 e3     mov     lr, #0
   0x000082ec <+8>:     04 10 9d e4     pop     {r1}            ; (ldr r1,
[sp], #4)
   0x000082f0 <+12>:    0d 20 a0 e1     mov     r2, sp
   0x000082f4 <+16>:    04 20 2d e5     push    {r2}            ; (str r2, [sp,
#-4]!)
   0x000082f8 <+20>:    04 00 2d e5     push    {r0}            ; (str r0, [sp,
#-4]!)
   0x000082fc <+24>:    10 c0 9f e5     ldr     r12, [pc, #16]  ; 0x8314
<_start+48>
   0x00008300 <+28>:    04 c0 2d e5     push    {r12}           ; (str r12,
[sp, #-4]!)
   0x00008304 <+32>:    0c 00 9f e5     ldr     r0, [pc, #12]   ; 0x8318
<_start+52>
   0x00008308 <+36>:    0c 30 9f e5     ldr     r3, [pc, #12]   ; 0x831c
<_start+56>
   0x0000830c <+40>:    eb ff ff eb     bl      0x82c0 <__libc_start_main>
   0x00008310 <+44>:    f0 ff ff eb     bl      0x82d8 <abort>
   0x00008314 <+48>:    0c 84 00 00     andeq   r8, r0, r12, lsl #8
   0x00008318 <+52>:    90 83 00 00     muleq   r0, r0, r3
   0x0000831c <+56>:    ac 83 00 00     andeq   r8, r0, r12, lsr #7
End of assembler dump.