From: johnmc@sidsa.es
To: binutils@sources.redhat.com
Subject: Re: plt for arm gnu thumb
Date: Thu, 20 Apr 2006 14:32:00 -0000 [thread overview]
Message-ID: <1322.195.53.86.158.1145523785.squirrel@webmail> (raw)
In-Reply-To: <20060419150716.GA13655@nevyn.them.org>
> On Wed, Apr 19, 2006 at 05:00:15PM +0200, johnmc@sidsa.es wrote:
>> Hi Daniel
>
> Please, if you have further questions, send them to the list and not to
> me personally. That's more useful for everyone.
>
> Also, if you want help, I recommend more precise reports: command lines
> used, test cases, objdump output for what appears to be wrong.
>
> --
> Daniel Jacobowitz
> CodeSourcery
>
hello
A couple of days ago I found out that the "procedure linkage table" - plt
produced when transitioning
on an ARM V4t chip does not function.
So the suggestion was that I design my code so that the transition from
the plt is to an ARM compiled
function that then can call a THUMB compiled function.
I have been trying to do this and it does not seem to work either - or
maybe I am not doing it properly as
I have no previous experience using interworking.
In order to test this I have built a small test shared library .
Here are the commands I used to build this SHARED LIBRARY.
The 2 modules used are
dyn_load_module.c - THUMB
dynamic_arm.c - ARM
compile:
arm-elf-gcc -c -fpic -mthumb -mthumb-interwork dyn_load_module.c -o
dyn_load_module.o
arm-elf-gcc -c -fpic -mthumb-interwork dynamic_arm.c -o
dynamic_arm.o
shared link:
arm-elf-ld -shared dyn_load_module.o dynamic_arm.o -o prog.out
=================================
here is the code:
dynamic_arm.c
void func_shared_arm(void)
{
func_shared();
}
dyn_load_module.c
extern void func_shared(void);
static void func_shared_static(void);
int global_var = 0x3333;
int global_var1 = 0xaaaa;
int global_var2 = 0xbbbb;
int global_var3 = 0xeeee;
int global_var4 = 0xffff;
int global_var5 = 0xaaaa;
int global_var6 = 0xaaaa;
int global_var7 = 0xaaaa;
int global_var8 = 0xaaaa;
int global_var9 = 0xaaaa;
static int static_global_var = 0x4444;
static int static_global_var2 = 0x1111;
void func_shared(void)
{
global_var = 0xff;
static_global_var = 200;
func_shared_static();
int x =1;
}
static void func_shared_static(void)
{
int x =1;
}
======================================
very simple stuff - ARM function func_shared_arm() - calls - THUMB funtion
func_shared()
but the assembler produced below just looks like RUBBISH!!
ANYONE GOT ANY IDEA WHAT I AM DOING WRONG -
dyn_load_module.s: file format elf32-littlearm
SYMBOL TABLE:
00000094 l d .hash 00000000 .hash
00000150 l d .dynsym 00000000 .dynsym
00000310 l d .dynstr 00000000 .dynstr
00000410 l d .rel.dyn 00000000 .rel.dyn
00000420 l d .rel.plt 00000000 .rel.plt
00000428 l d .plt 00000000 .plt
00000448 l d .text 00000000 .text
000005c8 l d .dynamic 00000000 .dynamic
00000658 l d .got 00000000 .got
00000670 l d .data 00000000 .data
000006a0 l d .bss 00000000 .bss
00000000 l d .comment 00000000 .comment
00080000 l d .stack 00000000 .stack
00000000 l d *ABS* 00000000 .shstrtab
00000000 l d *ABS* 00000000 .symtab
00000000 l d *ABS* 00000000 .strtab
00000000 l df *ABS* 00000000 dyn_load_module.c
00000698 l O .data 00000004 static_global_var
0000069c l O .data 00000004 static_global_var2
00000490 l F .text 0000001c func_shared_static
00000000 l df *ABS* 00000000 dynamic_arm.c
00000658 l O *ABS* 00000000 .hidden _GLOBAL_OFFSET_TABLE_
00000670 g O .data 00000004 global_var
000004c8 g *ABS* 00000000 __exidx_end
000005c8 g O *ABS* 00000000 _DYNAMIC
000006a0 g *ABS* 00000000 _bss_end__
00000684 g O .data 00000004 global_var5
000006a0 g *ABS* 00000000 __bss_start__
000004c8 g *ABS* 00000000 __exidx_start
0000068c g O .data 00000004 global_var7
000006a0 g *ABS* 00000000 __bss_end__
00000448 g F .text 00000048 func_shared
00000694 g O .data 00000004 global_var9
00000690 g O .data 00000004 global_var8
000006a0 g *ABS* 00000000 __bss_start
00000680 g O .data 00000004 global_var4
000004ac g F .text 0000001c func_shared_arm
000006a0 g *ABS* 00000000 __end__
00000674 g O .data 00000004 global_var1
00000678 g O .data 00000004 global_var2
000006a0 g *ABS* 00000000 _edata
000006a0 g *ABS* 00000000 _end
00080000 g .stack 00000000 _stack
00000670 g .data 00000000 __data_start
00000688 g O .data 00000004 global_var6
0000067c g O .data 00000004 global_var3
Disassembly of section .plt:
00000428 <.plt>:
428: e52de004 str lr, [sp, #-4]!
42c: e59fe004 ldr lr, [pc, #4] ; 438 <func_shared-0x10>
430: e08fe00e add lr, pc, lr
434: e5bef008 ldr pc, [lr, #8]!
438: 00000220 andeq r0, r0, r0, lsr #4
43c: e28fc600 add ip, pc, #0 ; 0x0
440: e28cca00 add ip, ip, #0 ; 0x0
444: e5bcf220 ldr pc, [ip, #544]!
Disassembly of section .text:
00000448 <func_shared>:
448: b580 push {r7, lr}
44a: 4657 mov r7, sl
44c: b480 push {r7}
44e: 4f0d ldr r7, [pc, #52] (484 <.text+0x3c>)
450: 46ba mov sl, r7
452: 44fa add sl, pc
454: 466f mov r7, sp
456: b081 sub sp, #4
458: 4b0b ldr r3, [pc, #44] (488 <.text+0x40>)
45a: 4453 add r3, sl
45c: 681a ldr r2, [r3, #0]
45e: 23ff mov r3, #255
460: 6013 str r3, [r2, #0]
462: 4b0a ldr r3, [pc, #40] (48c <.text+0x44>)
464: 4453 add r3, sl
466: 681a ldr r2, [r3, #0]
468: 23c8 mov r3, #200
46a: 6013 str r3, [r2, #0]
46c: f810f000 bl 490 <func_shared_static>
470: 1f3a sub r2, r7, #4
472: 2301 mov r3, #1
474: 6013 str r3, [r2, #0]
476: 46bd mov sp, r7
478: bc04 pop {r2}
47a: 4692 mov sl, r2
47c: bc80 pop {r7}
47e: bc01 pop {r0}
480: 4700 bx r0
482: 0000 lsl r0, r0, #0
484: 0202 lsl r2, r0, #8
486: 0000 lsl r0, r0, #0
488: 0014 lsl r4, r2, #0
48a: 0000 lsl r0, r0, #0
48c: 0010 lsl r0, r2, #0
...
00000490 <func_shared_static>:
490: b580 push {r7, lr}
492: 4657 mov r7, sl
494: b480 push {r7}
496: 466f mov r7, sp
498: b081 sub sp, #4
49a: 1f3a sub r2, r7, #4
49c: 2301 mov r3, #1
49e: 6013 str r3, [r2, #0]
4a0: 46bd mov sp, r7
4a2: bc04 pop {r2}
4a4: 4692 mov sl, r2
4a6: bc80 pop {r7}
4a8: bc01 pop {r0}
4aa: 4700 bx r0
000004ac <func_shared_arm>:
4ac: e1a0c00d mov ip, sp
4b0: e92dd800 stmdb sp!, {fp, ip, lr, pc}
4b4: e24cb004 sub fp, ip, #4 ; 0x4
4b8: ebffffdf bl 43c <func_shared-0xc>
4bc: e24bd00c sub sp, fp, #12 ; 0xc
4c0: e89d6800 ldmia sp, {fp, sp, lr}
4c4: e12fff1e bx lr
next prev parent reply other threads:[~2006-04-20 9:03 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-04-18 13:06 johnmc
2006-04-18 13:10 ` Daniel Jacobowitz
2006-04-18 15:14 ` johnmc
2006-04-18 15:45 ` Richard Earnshaw
2006-04-18 15:49 ` Daniel Jacobowitz
2006-04-18 16:01 ` Richard Earnshaw
2006-04-18 16:49 ` Daniel Jacobowitz
[not found] ` <4596.195.53.86.158.1145376723.squirrel@webmail>
[not found] ` <20060418203900.GA23304@nevyn.them.org>
[not found] ` <1178.195.53.86.158.1145458815.squirrel@webmail>
[not found] ` <20060419150716.GA13655@nevyn.them.org>
2006-04-20 14:32 ` johnmc [this message]
2006-04-20 14:38 ` Richard Earnshaw
[not found] ` <1507.195.53.86.158.1145536917.squirrel@webmail>
[not found] ` <1145538390.16122.39.camel@pc960.cambridge.arm.com>
[not found] ` <1576.195.53.86.158.1145540607.squirrel@webmail>
[not found] ` <1145541382.16122.62.camel@pc960.cambridge.arm.com>
2006-04-24 18:23 ` johnmc
2006-04-25 17:19 ` Nick Clifton
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