board_init_lowlevel_return: Error: symbol ABS is in a different section

[Ivo Clarysse <ivo.clarysse@gmail.com>]

When compiling barebox recently, I get an error:

[..]
  arm-none-linux-gnueabi-gcc -Wp,-MD,arch/arm/cpu/.start.o.d
-nostdinc -isystem
/opt/arm-2009q3/bin/../lib/gcc/arm-none-linux-gnueabi/4.4.1/include
-D__KERNEL__ -D__BAREBOX__ -Iinclude
-I/home/imxbuild/barebox-master/build-mx25pdk/arch/arm/include
-I/home/imxbuild/barebox-master/build-mx25pdk/arch/arm/include
-include include/linux/autoconf.h -fno-builtin -ffreestanding
-D__ARM__ -fno-strict-aliasing -marm -mlittle-endian -mabi=apcs-gnu
-mno-thumb-interwork -D__LINUX_ARM_ARCH__=5 -march=armv5te
-mtune=arm9tdmi -Iarch/arm/mach-imx/include -DTEXT_BASE=0x83F00000 -P
-fdata-sections -ffunction-sections -Wall -Wundef -Wstrict-prototypes
-Wno-trigraphs -fno-strict-aliasing -fno-common -Os -pipe
-fno-stack-protector -Wdeclaration-after-statement -Wno-pointer-sign
 -D"KBUILD_STR(s)=#s" -D"KBUILD_BASENAME=KBUILD_STR(start)"
-D"KBUILD_MODNAME=KBUILD_STR(start)" -c -o arch/arm/cpu/start.o
arch/arm/cpu/start.c
{standard input}: Assembler messages:
{standard input}:37: Error: symbol *ABS* is in a different section
make[1]: *** [arch/arm/cpu/start.o] Error 1
make: *** [arch/arm/cpu] Error 2

This seems to be due to:

[...]
void __naked __bare_init board_init_lowlevel_return(void)
{
        uint32_t r;

        /* Setup the stack */
        r = STACK_BASE + STACK_SIZE - 16;
        __asm__ __volatile__("mov sp, %0" : : "r"(r));

        /* Get runtime address of this function */
        __asm__ __volatile__("adr %0, 0":"=r"(r));
[...]

Which yields the following assembly:

@ 0 "" 2
        .size   exception_vectors, .-exception_vectors
        .section        .text_bare_init.text,"ax",%progbits
        .align  2
        .global board_init_lowlevel_return
        .type   board_init_lowlevel_return, %function
board_init_lowlevel_return:
        @ Naked Function: prologue and epilogue provided by programmer.
        @ args = 0, pretend = 0, frame = 0
        @ frame_needed = 0, uses_anonymous_args = 0
        ldr     r3, .L7
#APP
@ 900 "start.i" 1
        mov sp, r3
@ 0 "" 2
@ 901 "start.i" 1
        adr r1, 0
@ 0 "" 2
[...]


My toolchain (CodeSourcery G++ Lite, 2009Q3 - also tested with the
2010Q1 release), does not seem to like "adr r1, 0".

I can get it to compile, by changing change board_init_lowlevel to:

void __naked __bare_init board_init_lowlevel_return(void)
{
        uint32_t r;

        __asm__ __volatile__("1:");

        /* Setup the stack */
        r = STACK_BASE + STACK_SIZE - 16;
        __asm__ __volatile__("mov sp, %0" : : "r"(r));

        /* Get runtime address of this function */
        __asm__ __volatile__("adr %0, 1b":"=r"(r));
[...]


Is this a problem with the toolchain I use, or should barebox be patched ?


Ivo.

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