arch/xtensa/cpu/u-boot.lds

   1 /*
   2  * (C) Copyright 2008 - 2013 Tensilica, Inc.
   3  * (C) Copyright 2014 - 2016 Cadence Design Systems Inc.
   4  *
   5  * SPDX-License-Identifier:     GPL-2.0+
   6  */
   7
   8 #include <config.h>
   9 #include <asm/ldscript.h>
  10 #include <asm/arch/core.h>
  11 #include <asm/addrspace.h>
  12 #include <asm-offsets.h>
  13
  14 OUTPUT_ARCH(xtensa)
  15 ENTRY(_start)
  16
  17 /*
  18  * U-Boot resets from SYSROM and unpacks itself from a ROM store to RAM.
  19  * The reset vector is usually near the base of SYSROM and has room
  20  * above it for the ROM store into which the rest of U-Boot is packed.
  21  * The ROM store also needs to be above any other vectors that are in ROM.
  22  * If a core has its vectors near the top of ROM, this must be edited.
  23  *
  24  * Note that to run C code out of ROM, the processor would have to support
  25  * 'relocatable' exception vectors and provide a scratch memory for the
  26  * initial stack. Not all Xtensa processor configurations support that, so
  27  * we can simplify the boot process and unpack U-Boot to RAM immediately.
  28  * This, however, requires that memory have been initialized throug some
  29  * other means (serial ROM, for example) or are initialized early (requiring
  30  * an assembler function. See start.S for more details)
  31  */
  32
  33 SECTIONS
  34 {
  35   . = + SIZEOF_HEADERS;
  36   SECTION_ResetVector(XCHAL_RESET_VECTOR_VADDR, LMA_EQ_VMA)
  37
  38   .reloc_table ALIGN(4) : FOLLOWING(.ResetVector.text)
  39   {
  40     __reloc_table_start = ABSOLUTE(.);
  41 #if XCHAL_HAVE_WINDOWED
  42     RELOCATE2(WindowVectors,text);
  43 #endif
  44     RELOCATE2(KernelExceptionVector,literal);
  45     RELOCATE2(KernelExceptionVector,text);
  46     RELOCATE2(UserExceptionVector,literal);
  47     RELOCATE2(UserExceptionVector,text);
  48     RELOCATE2(DoubleExceptionVector,literal);
  49     RELOCATE2(DoubleExceptionVector,text);
  50     RELOCATE1(text);
  51     RELOCATE1(rodata);
  52     RELOCATE1(data);
  53     RELOCATE1(u_boot_list);
  54     __reloc_table_end = ABSOLUTE(.);
  55   }
  56
  57 #if XCHAL_HAVE_WINDOWED
  58   SECTION_VECTOR(WindowVectors,text,XCHAL_WINDOW_VECTORS_VADDR,
  59                  FOLLOWING(.reloc_table))
  60   SECTION_VECTOR(KernelExceptionVector,literal,XCHAL_KERNEL_VECTOR_VADDR-8,
  61                  FOLLOWING(.WindowVectors.text))
  62 #else
  63   SECTION_VECTOR(KernelExceptionVector,literal,XCHAL_KERNEL_VECTOR_VADDR-8,
  64                  FOLLOWING(.reloc_table))
  65 #endif
  66   SECTION_VECTOR(KernelExceptionVector,text,XCHAL_KERNEL_VECTOR_VADDR,
  67                  FOLLOWING(.KernelExceptionVector.literal))
  68   SECTION_VECTOR(UserExceptionVector,literal,XCHAL_USER_VECTOR_VADDR-8,
  69                  FOLLOWING(.KernelExceptionVector.text))
  70   SECTION_VECTOR(UserExceptionVector,text,XCHAL_USER_VECTOR_VADDR,
  71                  FOLLOWING(.UserExceptionVector.literal))
  72   SECTION_VECTOR(DoubleExceptionVector,literal,XCHAL_DOUBLEEXC_VECTOR_VADDR-8,
  73                  FOLLOWING(.UserExceptionVector.text))
  74   SECTION_VECTOR(DoubleExceptionVector,text,XCHAL_DOUBLEEXC_VECTOR_VADDR,
  75                  FOLLOWING(.DoubleExceptionVector.literal))
  76
  77   __monitor_start = XTENSA_SYS_TEXT_ADDR;
  78
  79   SECTION_text(XTENSA_SYS_TEXT_ADDR, FOLLOWING(.DoubleExceptionVector.text))
  80   SECTION_rodata(ALIGN(16), FOLLOWING(.text))
  81   SECTION_u_boot_list(ALIGN(16), FOLLOWING(.rodata))
  82   SECTION_data(ALIGN(16), FOLLOWING(.u_boot_list))
  83
  84   __reloc_end = .;
  85   __init_end = .;
  86
  87   SECTION_bss(__init_end (OVERLAY),)
  88
  89   __monitor_end = .;
  90
  91   /*
  92    * On many Xtensa boards a region of RAM may be mapped to the ROM address
  93    * space to facilitate on-chip-debug, and U-Boot must fit with that region.
  94    * The config variables CONFIG_SYS_MONITOR_* define the region.
  95    * If U-Boot extends beyond this region it will appear discontiguous in the
  96    * address space and is in danger of overwriting itself during unpacking
  97    * ("relocation").
  98    * This causes U-Boot to crash in a way that is difficult to debug. On some
  99    * boards (such as xtav60) the region is small enough that U-Boot will not
 100    * fit if compiled entirely with -O0 (a common scenario). To avoid a lengthy
 101    * debugging session when this happens, ensure a link-time error occurs.
 102    *
 103    */
 104
 105    ASSERT(__monitor_end - __monitor_start <= CONFIG_SYS_MONITOR_LEN,
 106           "U-Boot ROM image is too large. Check optimization level.")
 107
 108   SECTION_xtensa
 109   SECTION_debug
 110
 111   /DISCARD/ : { *(.dynstr*) }
 112   /DISCARD/ : { *(.hash*) }
 113   /DISCARD/ : { *(.interp) }
 114   /DISCARD/ : { *(.got*) }
 115   /DISCARD/ : { *(.dynsym) }
 116 }