uclinux-2008R1.5-RC3(bf561)到VDSP5的移植(18)：_sdata
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快乐虾
http://blog.csdn.net/lights_joy/
本文适用于
ADI bf561 DSP
uclinux-2008r1.5-rc3(smp patch)
Visual DSP++ 5.0(update 5)
欢迎转载，但请保留作者信息
至此，还有几个链接错误：
[Error li1021] The following symbols referenced in processor 'p0' could not be resolved:
'_sdata [__sdata]' referenced from 'corea.dlb[head.doj]'
'_stext [__stext]' referenced from 'corea.dlb[head.doj]'
'bf53x_relocate_l1_mem [_bf53x_relocate_l1_mem]' referenced from 'corea.dlb[head.doj]'
'cmdline_init [_cmdline_init]' referenced from 'corea.dlb[head.doj]'
'init_pda [_init_pda]' referenced from 'corea.dlb[head.doj]'
'init_thread_union [_init_thread_union]' referenced from 'corea.dlb[head.doj]'
'start_kernel [_start_kernel]' referenced from 'corea.dlb[head.doj]'
下面就看看_sdata的问题。
在head.s中，要保存数据段的起始位置，如下所示：
p1.l = __rambase;
p1.h = __rambase;
r0.l = __sdata;
r0.h = __sdata;
[p1] = r0;
在这里，__rambase是在head.s中定义的一个变量：
.data
/*
* Set up the usable of RAM stuff. Size of RAM is determined then
* an initial stack set up at the end.
*/
.align 4
__rambase:
.long 0
__ramstart:
.long 0
__ramend:
.long 0
而_sdata的定义则是在vmlinux.lds.s中，它指向数据段的首地址，如下所示：
.data :
{
/* make sure the init_task is aligned to the
* kernel thread size so we can locate the kernel
* stack properly and quickly.
*/
__sdata = .;
. = ALIGN(THREAD_SIZE);
*(.data.init_task)
. = ALIGN(32);
*(.data.cacheline_aligned)
#if !L1_DATA_A_LENGTH
. = ALIGN(32);
*(.data_l1.cacheline_aligned)
#endif
DATA_DATA
*(.data)
CONSTRUCTORS
. = ALIGN(THREAD_SIZE);
__edata = .;
}
下面就需要修改LDF文件了，先给数据段分一块内存空间：
MEM_UCLINUX_DATA { TYPE(RAM) START(0x00010000) END(0x0001ffff) WIDTH(8) }
MEM_UCLINUX_BSS { TYPE(RAM) START(0x00020000) END(0x0002ffff) WIDTH(8) }
MEM_SDRAM_BANK0 { TYPE(RAM) START(0x00030000) END(0x00ffffff) WIDTH(8) }
MEM_SDRAM_BANK1 { TYPE(RAM) START(0x01000000) END(0x01ffffff) WIDTH(8) }
MEM_SDRAM_BANK2 { TYPE(RAM) START(0x02000000) END(0x02ffffff) WIDTH(8) }
MEM_SDRAM_BANK3 { TYPE(RAM) START(0x03000000) END(0x03ffffff) WIDTH(8) }
因为.data段在bss段之前，内存空间定义也相应地在前面，还是以64K为单位定义空间，真浪费！！
接下来在LDF中添加一个section：
uclinux_data
{
/* make sure the init_task is aligned to the
* kernel thread size so we can locate the kernel
* stack properly and quickly.
*/
__sdata = .;
INPUT_SECTION_ALIGN(8192)
/*
*(.data.init_task)
. = ALIGN(32);
*(.data.cacheline_aligned)
#if !L1_DATA_A_LENGTH
. = ALIGN(32);
*(.data_l1.cacheline_aligned)
#endif
DATA_DATA
*(.data)
CONSTRUCTORS
*/
INPUT_SECTION_ALIGN(8192)
__edata = .;
} > MEM_UCLINUX_DATA
在这里，直接将THREAD_SIZE替换为8192，避免在LDF中包含头文件。此外注释了section里面的所有内容，因为我们的原则是：按需添加。
看看还有几个error：
[Error li1021] The following symbols referenced in processor 'p0' could not be resolved:
'_stext [__stext]' referenced from 'corea.dlb[head.doj]'
'bf53x_relocate_l1_mem [_bf53x_relocate_l1_mem]' referenced from 'corea.dlb[head.doj]'
'cmdline_init [_cmdline_init]' referenced from 'corea.dlb[head.doj]'
'init_pda [_init_pda]' referenced from 'corea.dlb[head.doj]'
'init_thread_union [_init_thread_union]' referenced from 'corea.dlb[head.doj]'
'start_kernel [_start_kernel]' referenced from 'corea.dlb[head.doj]'
1 参考资料
uclinux-2008R1.5-RC3(bf561)到VDSP5的移植(1)：前言(<?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" /><chsdate w:st="on" isrocdate="False" islunardate="False" day="12" month="1" year="2009">2009-1-12</chsdate>)
uclinux-2008R1.5-RC3(bf561)到VDSP5的移植(2)：代码注释(<chsdate w:st="on" isrocdate="False" islunardate="False" day="12" month="1" year="2009">2009-1-12</chsdate>)
uclinux-2008R1.5-RC3(bf561)到VDSP5的移植(3)：vdsp项目创建(<chsdate w:st="on" isrocdate="False" islunardate="False" day="12" month="1" year="2009">2009-1-12</chsdate>)
uclinux-2008R1.5-RC3(bf561)到VDSP5的移植(4)：目录差异(<chsdate w:st="on" isrocdate="False" islunardate="False" day="12" month="1" year="2009">2009-1-12</chsdate>)
uclinux-2008R1.5-RC3(bf561)到VDSP5的移植(5)：'bf561.h'的问题(<chsdate w:st="on" isrocdate="False" islunardate="False" day="12" month="1" year="2009">2009-1-12</chsdate>)
uclinux-2008R1.5-RC3(bf561)到VDSP5的移植(6)：CONFIG_BFIN_KERNEL_CLOCK(<chsdate w:st="on" isrocdate="False" islunardate="False" day="12" month="1" year="2009">2009-1-12</chsdate>)
uclinux-2008R1.5-RC3(bf561)到VDSP5的移植(7)：CONFIG_MEM_MT48LC16M16A2TG_75(<chsdate w:st="on" isrocdate="False" islunardate="False" day="12" month="1" year="2009">2009-1-12</chsdate>)
uclinux-2008R1.5-RC3(bf561)到VDSP5的移植(8)：CONFIG_CLKIN_HZ(<chsdate w:st="on" isrocdate="False" islunardate="False" day="12" month="1" year="2009">2009-1-12</chsdate>)
uclinux-2008R1.5-RC3(bf561)到VDSP5的移植(9)：CONFIG_MEM_SIZE(<chsdate w:st="on" isrocdate="False" islunardate="False" day="12" month="1" year="2009">2009-1-12</chsdate>)
uclinux-2008R1.5-RC3(bf561)到VDSP5的移植(10)：CONFIG_FLASH_SPEED_BTT(<chsdate w:st="on" isrocdate="False" islunardate="False" day="13" month="1" year="2009">2009-1-13</chsdate>)
uclinux-2008R1.5-RC3(bf561)到VDSP5的移植(11)：__INIT(<chsdate w:st="on" isrocdate="False" islunardate="False" day="13" month="1" year="2009">2009-1-13</chsdate>)
uclinux-2008R1.5-RC3(bf561)到VDSP5的移植(12)：trace_buffer_init(<chsdate w:st="on" isrocdate="False" islunardate="False" day="13" month="1" year="2009">2009-1-13</chsdate>)
uclinux-2008R1.5-RC3(bf561)到VDSP5的移植(13)：ENDPROC(<chsdate w:st="on" isrocdate="False" islunardate="False" day="13" month="1" year="2009">2009-1-13</chsdate>)
uclinux-2008R1.5-RC3(bf561)到VDSP5的移植(14)：__FINIT(<chsdate w:st="on" isrocdate="False" islunardate="False" day="13" month="1" year="2009">2009-1-13</chsdate>)
uclinux-2008R1.5-RC3(bf561)到VDSP5的移植(15)：CONFIG_BANK_x(<chsdate w:st="on" isrocdate="False" islunardate="False" day="13" month="1" year="2009">2009-1-13</chsdate>)
uclinux-2008R1.5-RC3(bf561)到VDSP5的移植(16)：使用head.s做为入口点(<chsdate w:st="on" isrocdate="False" islunardate="False" day="13" month="1" year="2009">2009-1-13</chsdate>)
uclinux-2008R1.5-RC3(bf561)到VDSP5的移植(17)：__bss_start(<chsdate w:st="on" isrocdate="False" islunardate="False" day="13" month="1" year="2009">2009-1-13</chsdate>)