[U-Boot-Users] Why are some global vars part of the image, and some not?

[Timur Tabi <timur@freescale.com>]

Timur Tabi wrote:

> #ifdef CFG_SPD_BUS_NUM
> static volatile unsigned int i2c_bus_num = CFG_SPD_BUS_NUM;
> #else
> static volatile unsigned int i2c_bus_num = 0;
> #endif

Ok, I fixed my problem by changing the above line to:

static volatile unsigned int i2c_bus_num __attribute__ ((section ("data"))) = 0;

Is "data" the right section to use?  Here's my lds file:

OUTPUT_ARCH(powerpc)
SECTIONS
{
   /* Read-only sections, merged into text segment: */
   . = + SIZEOF_HEADERS;
   .interp : { *(.interp) }
   .hash          : { *(.hash)		}
   .dynsym        : { *(.dynsym)		}
   .dynstr        : { *(.dynstr)		}
   .rel.text      : { *(.rel.text)		}
   .rela.text     : { *(.rela.text) 	}
   .rel.data      : { *(.rel.data)		}
   .rela.data     : { *(.rela.data) 	}
   .rel.rodata    : { *(.rel.rodata) 	}
   .rela.rodata   : { *(.rela.rodata) 	}
   .rel.got       : { *(.rel.got)		}
   .rela.got      : { *(.rela.got)		}
   .rel.ctors     : { *(.rel.ctors)	}
   .rela.ctors    : { *(.rela.ctors)	}
   .rel.dtors     : { *(.rel.dtors)	}
   .rela.dtors    : { *(.rela.dtors)	}
   .rel.bss       : { *(.rel.bss)		}
   .rela.bss      : { *(.rela.bss)		}
   .rel.plt       : { *(.rel.plt)		}
   .rela.plt      : { *(.rela.plt)		}
   .init          : { *(.init)	}
   .plt : { *(.plt) }
   .text      :
   {
     cpu/mpc83xx/start.o	(.text)
     *(.text)
     *(.fixup)
     *(.got1)
     . = ALIGN(16);
     *(.rodata)
     *(.rodata1)
     *(.rodata.str1.4)
     *(.eh_frame)
   }
   .fini      : { *(.fini)    } =0
   .ctors     : { *(.ctors)   }
   .dtors     : { *(.dtors)   }

   /* Read-write section, merged into data segment: */
   . = (. + 0x0FFF) & 0xFFFFF000;
   _erotext = .;
   PROVIDE (erotext = .);
   .reloc   :
   {
     *(.got)
     _GOT2_TABLE_ = .;
     *(.got2)
     _FIXUP_TABLE_ = .;
     *(.fixup)
   }
   __got2_entries = (_FIXUP_TABLE_ - _GOT2_TABLE_) >> 2;
   __fixup_entries = (. - _FIXUP_TABLE_) >> 2;

   .data    :
   {
     *(.data)
     *(.data1)
     *(.sdata)
     *(.sdata2)
     *(.dynamic)
     CONSTRUCTORS
   }
   _edata  =  .;
   PROVIDE (edata = .);

   . = .;
   __u_boot_cmd_start = .;
   .u_boot_cmd : { *(.u_boot_cmd) }
   __u_boot_cmd_end = .;


   . = .;
   __start___ex_table = .;
   __ex_table : { *(__ex_table) }
   __stop___ex_table = .;

   . = ALIGN(4096);
   __init_begin = .;
   .text.init : { *(.text.init) }
   .data.init : { *(.data.init) }
   . = ALIGN(4096);
   __init_end = .;

   __bss_start = .;
   .bss       :
   {
    *(.sbss) *(.scommon)
    *(.dynbss)
    *(.bss)
    *(COMMON)
   }
   _end = . ;
   PROVIDE (end = .);
}
ENTRY(_start)

-- 
Timur Tabi
Linux Kernel Developer @ Freescale