在__lib_init_array中，CC2538 (Cortex m3)启动时出现硬故障

Question

我试图将mbed-os (RTX RTOS)项目移植到CC2538 (ARM Cortex M3)，它是使用集成了ARM -none-eabi-gcc的mbed-cli工具链编译的。当我尝试启动MCU时，我在启动时陷入硬故障错误。

00202678 <__libc_init_array>:
  202678:       b570            push    {r4, r5, r6, lr}
  20267a:       4e0f            ldr     r6, [pc, #60]   ; (2026b8 <__libc_init_array+0x40>)
  20267c:       4d0f            ldr     r5, [pc, #60]   ; (2026bc <__libc_init_array+0x44>)
  20267e:       1b76            subs    r6, r6, r5
  202680:       10b6            asrs    r6, r6, #2
  202682:       bf18            it      ne
  202684:       2400            movne   r4, #0
  202686:       d005            beq.n   202694 <__libc_init_array+0x1c>
  202688:       3401            adds    r4, #1
  20268a:       f855 3b04       ldr.w   r3, [r5], #4
  20268e:       4798            blx     r3
  202690:       42a6            cmp     r6, r4
  202692:       d1f9            bne.n   202688 <__libc_init_array+0x10>
  202694:       4e0a            ldr     r6, [pc, #40]   ; (2026c0 <__libc_init_array+0x48>)
  202696:       4d0b            ldr     r5, [pc, #44]   ; (2026c4 <__libc_init_array+0x4c>)
  202698:       f004 fec2       bl      207420 <_etext>
  20269c:       1b76            subs    r6, r6, r5
  20269e:       10b6            asrs    r6, r6, #2
  2026a0:       bf18            it      ne
  2026a2:       2400            movne   r4, #0
  2026a4:       d006            beq.n   2026b4 <__libc_init_array+0x3c>
  2026a6:       3401            adds    r4, #1
  2026a8:       f855 3b04       ldr.w   r3, [r5], #4
  2026ac:       4798            blx     r3
  2026ae:       42a6            cmp     r6, r4
  2026b0:       d1f9            bne.n   2026a6 <__libc_init_array+0x2e>
  2026b2:       bd70            pop     {r4, r5, r6, pc}
  2026b4:       bd70            pop     {r4, r5, r6, pc}
  2026b6:       bf00            nop

我跟踪了代码流，最后一步PC正在执行

 2026a4:       d006            beq.n   2026b4 <__libc_init_array+0x3c>

然后

 2026b4:       bd70            pop     {r4, r5, r6, pc}

此时，PC得到值0，然后跳转到地址0x00000000而引起

after CPU execute

 202678:       b570            push    {r4, r5, r6, lr}

---

[register]
R0 =00000000
R1 =00000001
R2 =00000000
R3 =00000002
R4 =00000000
R5 =00000000
R6 =00000000
R7 =00000000
R8 =00000000
R9 =00000000
R10=00000000
R11=00000000
R12=00200F51
SP =200019F0
LR =00200A77
PC =0020267A
[memory]
200019b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
200019c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
200019d0: f0 09 00 20 00 00 00 00 00 00 00 00 04 0a 00 20
200019e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
200019f0: 00 00 00 00 00 00 00 00 00 00 00 00 77 0a 20 00
20001a00: 00 00 00 00 5d 0c 20 00 00 04 00 00 01 01 00 00

---

before CPU execute

2026b4:       bd70            pop     {r4, r5, r6, pc}

调试器转储

[register]
R0 =00000000
R1 =00000001
R2 =00000000
R3 =00000002
R4 =00000000
R5 =00000000
R6 =00000000
R7 =00000000
R8 =00000000
R9 =00000000
R10=00000000
R11=00000000
R12=00200F51
SP =200019C0
LR =0020269D
PC =002026B4
[memory]
200019b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
200019c0: 02 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
200019d0: 00 00 00 00 9d 26 20 00 02 00 00 00 00 00 00 00
200019e0: 00 00 00 00 00 00 00 00 00 00 00 00 9d 26 20 00
200019f0: 00 00 00 00 00 00 00 00 00 00 00 00 77 0a 20 00
20001a00: 00 00 00 00 5d 0c 20 00 00 04 00 00 01 01 00 00

---

如果我在__libc_init_array中执行pop寄存器指令时手动修改StackPointer为0x200019f0。我发现它将成功跳转到main()在最后。似乎问题解决了。我的问题是为什么堆栈控制在__libc_init_array()中出错??我甚至在mbed-os的整个项目下都找不到__libc_init_array()函数的实现源代码。

---

附加了。ld文件

MEMORY
{
    FLASH_FW (rx) : ORIGIN = 0x00200000 + 0,
                    LENGTH = (0x00200000 + (((((0) << 0 | (512) << 4 | (32) << 16 | ((1) ? 0x01000000 : 0) | ((1) ? 0x02000000 : 0)) & 0x0000FFF0) >> 4) << 10) - 0x0000002C) - (0x00200000 + 0)
    FLASH_CCA (RX) : ORIGIN = (0x00200000 + (((((0) << 0 | (512) << 4 | (32) << 16 | ((1) ? 0x01000000 : 0) | ((1) ? 0x02000000 : 0)) & 0x0000FFF0) >> 4) << 10) - 0x0000002C), LENGTH = 0x0000002C
    NRSRAM (RWX) : ORIGIN = 0x20000000, LENGTH = 0
    FRSRAM (RWX) : ORIGIN = (((((((0) << 0 | (512) << 4 | (32) << 16 | ((1) ? 0x01000000 : 0) | ((1) ? 0x02000000 : 0)) & 0x00FF0000) >> 16) << 10) - ((((((((0) << 0 | (512) << 4 | (32) << 16 | ((1) ? 0x01000000 : 0) | ((1) ? 0x02000000 : 0)) & 0x00FF0000) >> 16) << 10)) < (16384)) ? ((((((0) << 0 | (512) << 4 | (32) << 16 | ((1) ? 0x01000000 : 0) | ((1) ? 0x02000000 : 0)) & 0x00FF0000) >> 16) << 10)) : (16384))) ? 0x20000000 : 0x20004000), LENGTH = (((((0) << 0 | (512) << 4 | (32) << 16 | ((1) ? 0x01000000 : 0) | ((1) ? 0x02000000 : 0)) & 0x00FF0000) >> 16) << 10)
}
/* Linker script to place sections and symbol values. Should be used together
 * with other linker script that defines memory regions FLASH and RAM.
 * It references following symbols, which must be defined in code:
 *   Reset_Handler : Entry of reset handler
 *
 * It defines following symbols, which code can use without definition:
 *   __exidx_start
 *   __exidx_end
 *   __etext
 *   __data_start__
 *   __preinit_array_start
 *   __preinit_array_end
 *   __init_array_start
 *   __init_array_end
 *   __fini_array_start
 *   __fini_array_end
 *   __data_end__
 *   __bss_start__
 *   __bss_end__
 *   __end__
 *   end
 *   __HeapLimit
 *   __StackLimit
 *   __StackTop
 *   __stack
 */
ENTRY(flash_cca_lock_page)
SECTIONS
{
    .text :
    {
        _text = .;
        *(.vectors)
        *(.text*)
        *(.rodata*)
        _etext = .;
    } > FLASH_FW= 0
    .socdata (NOLOAD) :
    {
        *(.udma_channel_control_table)
    } > FRSRAM
    .data : ALIGN(4)
    {
        _data = .;
        *(.data*)
        _edata = .;
    } > FRSRAM AT > FLASH_FW
    _ldata = LOADADDR(.data);
    .ARM.exidx :
    {
        *(.ARM.exidx*)
    } > FLASH_FW
    .bss :
    {
        _bss = .;
        *(.bss*)
        *(COMMON)
        _ebss = .;
    } > FRSRAM
    .heap :
    {
        __end__ = .;
        end = __end__;
        *(.heap*)
        __HeapLimit = .;
    } > RAM
    .stack (NOLOAD) :
    {
        *(.stack)
    } > FRSRAM
    _heap = .;
    _eheap = ORIGIN(FRSRAM) + LENGTH(FRSRAM);
    .nrdata (NOLOAD) :
    {
        _nrdata = .;
        *(.nrdata*)
        _enrdata = .;
    } > NRSRAM
    .flashcca :
    {
        *(.flashcca)
    } > FLASH_CCA
}

Answer 1

@notlikethat是对的，问题是链接脚本文件，但根本原因不是节重叠。就像我上面贴的。在__libc_init_array ()

202678:       b570            push    {r4, r5, r6, lr}

此时，堆栈指针指向0x200019F0，但当pop操作时，堆栈指针却指向0x200019C0，这导致了Hardfault错误。我跟踪了代码流，在__libc_init_array()中，它将在

处跳转到<_init>节

 202698:       f004 fec2       bl      207420 <_etext>

在内存中是这样的

00207420 <_init>:
  207420:       b5f8            push    {r3, r4, r5, r6, r7, lr}
  207422:       bf00            nop
00207424 <_fini>:
  207426:       b5f8            push    {r3, r4, r5, r6, r7, lr}
  207428:       bf00            nop

我想知道这个函数会导致堆栈指针超过计数，因为<_init>部分只显示push指令而没有pop指令。我对<_init>部分做了更多的网络搜索，并确认不应该只有2个说明。并受链接器文件的影响。

在之前的链接器文件中，我没有关心.init &.fini部分。然后我做了一些修改，它看起来像

.text :
{
    _text = .;
    *(.vectors)
    *(.text*)
    KEEP(*(.init))
    KEEP(*(.fini))
    /* .ctors */
    *crtbegin.o(.ctors)
    *crtbegin?.o(.ctors)
    *(EXCLUDE_FILE(*crtend?.o *crtend.o) .ctors)
    *(SORT(.ctors.*))
    *(.ctors)
    /* .dtors */
    *crtbegin.o(.dtors)
    *crtbegin?.o(.dtors)
    *(EXCLUDE_FILE(*crtend?.o *crtend.o) .dtors)
    *(SORT(.dtors.*))
    *(.dtors)
    *(.rodata*)
    KEEP(*(.eh_frame*))
    _etext = .;
} > FLASH_FW= 0
.socdata (NOLOAD) :

编译后<_init> &<_fini>部分的修改如下:

00207040 <_init>:
  207040:       b5f8            push    {r3, r4, r5, r6, r7, lr}
  207042:       bf00            nop
  207044:       bcf8            pop     {r3, r4, r5, r6, r7}
  207046:       bc08            pop     {r3}
  207048:       469e            mov     lr, r3
  20704a:       4770            bx      lr
0020704c <_fini>:
  20704c:       b5f8            push    {r3, r4, r5, r6, r7, lr}
  20704e:       bf00            nop
  207050:       bcf8            pop     {r3, r4, r5, r6, r7}
  207052:       bc08            pop     {r3}
  207054:       469e            mov     lr, r3
  207056:       4770            bx      lr
  207058:       6465626d        .word   0x6465626d
  20705c:       73736120        .word   0x73736120
  207060:       61747265        .word   0x61747265
  207064:       6e6f6974        .word   0x6e6f6974
  207068:       69616620        .word   0x69616620
  20706c:       3a64656c        .word   0x3a64656c
  207070:       2c732520        .word   0x2c732520
  207074:       6c696620        .word   0x6c696620
  207078:       25203a65        .word   0x25203a65

，然后成功跳转到main()。