STM32 Semihosting: se recibió SIGTRAP cuando se llamó a printf

He seguido esta guía aquí ( http://www.wolinlabs.com/blog/stm32f4.semihosting.html ) para que funcione el semihosting en el STM32F103. Básicamente, mi objetivo es hacer que printf funcione sobre JTAG (ST-Link/v2).

El único cambio de la guía fue que _sbrk buscaba 'final' en lugar de '__final__'. Aquí está mi archivo de enlace.

ENTRY(Reset_Handler)

MEMORY {
/*Adust LENGTH to RAMsize of target MCU:*/
/*STM32F103RBT --> 20K*/
RAM (RWX) : ORIGIN = 0x20000000 , LENGTH = 20K
/*STM32F103RET --> 64K*/
/*RAM (RWX) : ORIGIN = 0x20000000 , LENGTH = 64K*/

EXTSRAM (RWX) : ORIGIN = 0x68000000 , LENGTH = 0

/*Adust LENGTH to (FLASHsize - FeePROMsize) of target MCU:*/
/*STM32F103RBT --> 126K*/
FLASH (RX) : ORIGIN = 0x08000000 , LENGTH = 126K
/*STM32F103RET --> 508K*/
/*FLASH (RX) : ORIGIN = 0x08000000 , LENGTH = 508K*/

/*Adust ORIGIN to (0x08000000 + (FLASHsize-FeePROMsize)) of target MCU*/
/*and adust LENGTH to FeePROMsize allocated:*/
/*STM32F103RBT --> 0x08000000+126K, 2K*/
EEMUL (RWX) : ORIGIN = 0x08000000+126K, LENGTH = 2K
/*STM32F103RET --> 0x08000000+508K, 4K*/
/*EEMUL (RWX) : ORIGIN = 0x08000000+508K, LENGTH = 4K*/
}

_estack = ORIGIN(RAM)+LENGTH(RAM); /* end of the stack */
_seemul = ORIGIN(EEMUL); /* start of the eeprom emulation area */
_min_stack = 0x100; /* minimum stack space to reserve for the user app */

/* check valid alignment for the vector table */
ASSERT(ORIGIN(FLASH) == ALIGN(ORIGIN(FLASH), 0x80), "Start of memory region     flash not aligned for startup vector table");

SECTIONS {
/* vector table and program code goes into FLASH */
.text : {
    . = ALIGN(0x80);
    _isr_vectors_offs = . - 0x08000000;
    KEEP(*(.isr_vectors))
    . = ALIGN(4);
    CREATE_OBJECT_SYMBOLS
    *(.text .text.*)
} >FLASH

.rodata : ALIGN (4) {
    *(.rodata .rodata.*)

    . = ALIGN(4);
    KEEP(*(.init))

    . = ALIGN(4);
    __preinit_array_start = .;
    KEEP (*(.preinit_array))
    __preinit_array_end = .;

    . = ALIGN(4);
    __init_array_start = .;
    KEEP (*(SORT(.init_array.*)))
    KEEP (*(.init_array))
    __init_array_end = .;

    . = ALIGN(4);
    KEEP(*(.fini))

    . = ALIGN(4);
    __fini_array_start = .;
    KEEP (*(.fini_array))
    KEEP (*(SORT(.fini_array.*)))
    __fini_array_end = .;

    *(.init .init.*)
    *(.fini .fini.*)

    PROVIDE_HIDDEN (__preinit_array_start = .);
    KEEP (*(.preinit_array))
    PROVIDE_HIDDEN (__preinit_array_end = .);
    PROVIDE_HIDDEN (__init_array_start = .);
    KEEP (*(SORT(.init_array.*)))
    KEEP (*(.init_array))
    PROVIDE_HIDDEN (__init_array_end = .);
    PROVIDE_HIDDEN (__fini_array_start = .);
    KEEP (*(.fini_array))
    KEEP (*(SORT(.fini_array.*)))
    PROVIDE_HIDDEN (__fini_array_end = .);

    . = ALIGN (8);
    *(.rom)
    *(.rom.b)
    _etext = .;
    _sidata = _etext; /* exported for the startup function */
} >FLASH

/*
    this data is expected by the program to be in ram
    but we have to store it in the FLASH otherwise it
    will get lost between resets, so the startup code
    has to copy it into RAM before the program starts
*/
.data : ALIGN (8) {
    _sdata = . ; /* exported for the startup function */
    . = ALIGN(4);
    KEEP(*(.jcr))
    *(.got.plt) *(.got)
    *(.shdata)
    *(.data .data.*)
    . = ALIGN (8);
    *(.ram)
    *(.ramfunc*)
     . = ALIGN(4);
    _edata = . ; /* exported for the startup function */
} >RAM AT>FLASH

/* This is the uninitialized data section */
.bss (NOLOAD): {
    . = ALIGN(4);
    _sbss = . ; /* exported for the startup function */
    *(.shbss)
    *(.bss .bss.*)
    *(COMMON)
    . = ALIGN (8);
    *(.ram.b)
    . = ALIGN(4);
     _ebss = . ; /* exported for the startup function */
    _end = .;
    __end = .;
    PROVIDE(end = .);
} >RAM AT>FLASH
/* ensure there is enough room for the user stack */
._usrstack (NOLOAD): {
    . = ALIGN(4);
    _susrstack = . ;
    . = . + _min_stack ;
    . = ALIGN(4);
    _eusrstack = . ;
} >RAM

/* Stabs debugging sections. */
.stab 0 : { *(.stab) }
.stabstr 0 : { *(.stabstr) }
.stab.excl 0 : { *(.stab.excl) }
.stab.exclstr 0 : { *(.stab.exclstr) }
.stab.index 0 : { *(.stab.index) }
.stab.indexstr 0 : { *(.stab.indexstr) }
.comment 0 : { *(.comment) }
/* DWARF debug sections.
    Symbols in the DWARF debugging sections are relative to the beginning
    of the section so we begin them at 0. */
/* DWARF 1 */
.debug 0 : { *(.debug) }
.line 0 : { *(.line) }
/* GNU DWARF 1 extensions */
.debug_srcinfo 0 : { *(.debug_srcinfo) }
.debug_sfnames 0 : { *(.debug_sfnames) }
/* DWARF 1.1 and DWARF 2 */
.debug_aranges 0 : { *(.debug_aranges) }
.debug_pubnames 0 : { *(.debug_pubnames) }
/* DWARF 2 */
.debug_info 0 : { *(.debug_info .gnu.linkonce.wi.*) }
.debug_abbrev 0 : { *(.debug_abbrev) }
.debug_line 0 : { *(.debug_line) }
.debug_frame 0 : { *(.debug_frame) }
.debug_str 0 : { *(.debug_str) }
.debug_loc 0 : { *(.debug_loc) }
.debug_macinfo 0 : { *(.debug_macinfo) }
/* SGI/MIPS DWARF 2 extensions */
.debug_weaknames 0 : { *(.debug_weaknames) }
.debug_funcnames 0 : { *(.debug_funcnames) }
.debug_typenames 0 : { *(.debug_typenames) }
.debug_varnames 0 : { *(.debug_varnames) }
/* DWARF 3 */
.debug_pubtypes 0 : { *(.debug_pubtypes) }
.debug_ranges 0 : { *(.debug_ranges) }

.ARM.attributes 0 : { KEEP (*(.ARM.attributes)) KEEP (*(.gnu.attributes)) }
.note.gnu.arm.ident 0 : { KEEP (*(.note.gnu.arm.ident)) }
/DISCARD/ : { *(.note.GNU-stack) *(.gnu_debuglink) }
}

Cuando depuro mi programa cuando uso la función printf, el seguimiento de la llamada es el siguiente.

1. principal() en principal.c
2. _put_r() en puts.c
3. __sfvwrite_r() en fvwrite.c
4. _write_r() en escritor.c
5. _write() en llamadas al sistema.c
6. _swiwrite() en syscalls.c
7. do_AngelSWI() en swi.h

En esta etapa se recibe la señal 'SIGTRAP'.

¿Alguien tiene una pista de lo que está yendo mal?