在VDSP中编译uclinux（2）：内存布局

 

1   uclinux的内存布局

在uclinux启动时，有一段空间利用的提示：

Memory map:

 text       = 0x00001000-0x000b0db0

 init       = 0x000b1000-0x000bd23c

 data       = 0x000bf1b8-0x000e5588

 stack      = 0x000c0000-0x000c2000

 bss        = 0x000e5590-0x000f14d8

 available = 0x000f14d8-0x03500000

 rootfs     = 0x03500000-0x03f00000

 DMA Zone = 0x03f00000-0x04000000

其中text代表这段空间中存储的是uclinux内核的代码；init中存放的也是uclinux内核的代码，但是这一段空间在内核启动完成后是可以回收的，即它可以供内核重新分配；DATA段是 uClinux 未被初始化的数据空间；BSS段是 uClinux初始化的数据空间，它的初始化操作将在head.s中完成。此外从0到text开始的这一段空间也会被初始化为0。

2   VDSP中的空间分配

uclinux的空间定位是由链接器完成的，由arch/blackfin/kernel/vmlinux.lds.s控制完成。而VDSP的空间定位则是由ldf文件完成的，而ldf文件的语法与vmlinux.lds.s相似。我们所要做的就是将vmlinux.lds.s中的相关定义转移到ldf文件中。

1、定义一块uclinux使用的内存空间：

MEM_SDRAM_UCLINUX     { TYPE(RAM) START(0x00010000) END(0x001fffff) WIDTH(8) }       在这里，空间的结束使用了一个较大的数值，实际上在uclinux内核中会从代码实际结束的地方开始管理存储空间。

2、将uclinux内核的入口函数写入到0xFFA00000，即a核的启动地址。

       RESOLVE(__start, 0xFFA00000)

       KEEP(__start,_main)

VDSP默认的入口是start，在*_basiccrt.s中实现。经过这样处理后，A核就将从head.s中的__start开始，而B核仍将从*_basiccrt.s中的start开始执行。

3、移植.text段的内容。

              // uclinux的代码部分

              uclinux_text

              {

                     INPUT_SECTION_ALIGN(4)

 

                     __stext__ = .;

                     __stext = .;

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(.text))

                     INPUT_SECTION_ALIGN(8)

                     __sched_text_start = .;               

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(.sched.text))

                     __sched_text_end = .;

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(.text.lock))

 

                     INPUT_SECTION_ALIGN(16)

                     ___start___ex_table = .;

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(__ex_table))

                     ___stop___ex_table = .;

 

                     // 原先放在L1_Code中的内容

                     INPUT_SECTION_ALIGN(4)

                     __CORE = 0;

                     INPUT_SECTIONS($OBJECTS_CORE_A(L1_code) $LIBRARIES_CORE_A(L1_code))

                     INPUT_SECTIONS($OBJECTS_CORE_A(VDK_ISR_code) $LIBRARIES_CORE_A(VDK_ISR_code))

                     INPUT_SECTIONS($OBJECTS_CORE_A(cplb) $LIBRARIES_CORE_A(cplb))

                     INPUT_SECTIONS($OBJECTS_CORE_A(cplb_code) $LIBRARIES_CORE_A(cplb_code))

                     INPUT_SECTIONS($OBJECTS_CORE_A(noncache_code) $LIBRARIES_CORE_A(noncache_code))

                     INPUT_SECTIONS($OBJS_LIBS_INTERNAL_CORE_A(program))

                     INPUT_SECTIONS($OBJS_LIBS_NOT_EXTERNAL_CORE_A(program))

                     INPUT_SECTIONS($OBJECTS_CORE_A(program) $LIBRARIES_CORE_A(program))

 

                     // SDRAM Bank0的内容

                     INPUT_SECTION_ALIGN(4)

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(sdram_data_bank0))

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(sdram_bank0))

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(data1))

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(voldata))

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(constdata))

                    

                     // SDRAM Bank1的内容

                     INPUT_SECTION_ALIGN(4)

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(sdram0))

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(sdram_data_bank1))

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(sdram_bank1))

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(program))

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(noncache_code))

                                         

                     // uclinux代码

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(program))

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(.rodata))

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(.rodata.*))

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(__vermagic))           // Kernel version magic

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(.rodata1))

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(.fixup))

 

                     // Kernel symbol table: Normal symbols

                     INPUT_SECTION_ALIGN(4)

                     ___start___ksymtab = .;

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(__ksymtab))

                     ___stop___ksymtab = .;

 

                     // Kernel symbol table: GPL-only symbols

                     ___start___ksymtab_gpl = .;

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(__ksymtab_gpl))

                     ___stop___ksymtab_gpl = .;

 

                     // Kernel symbol table: Normal unused symbols

                     ___start___ksymtab_unused = .;

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(__ksymtab_unused))

                     ___stop___ksymtab_unused = .;

 

                     // Kernel symbol table: GPL-only unused symbols

                     ___start___ksymtab_unused_gpl = .;

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(__ksymtab_unused_gpl))

                     ___stop___ksymtab_unused_gpl = .;

 

 

                     // Kernel symbol table: GPL-future symbols

                     ___start___ksymtab_gpl_future = .;

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(__ksymtab_gpl_future))

                     ___stop___ksymtab_gpl_future = .;

 

                     // Kernel symbol table: Normal symbols

                     ___start___kcrctab = .;

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(__kcrctab))

                     ___stop___kcrctab = .;

 

                     // Kernel symbol table: GPL-only symbols

                     ___start___kcrctab_gpl = .;

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(__kcrctab_gpl))

                     ___stop___kcrctab_gpl = .;

 

                     // Kernel symbol table: GPL-future symbols

                     ___start___kcrctab_gpl_future = .;

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(__kcrctab_gpl_future))

                     ___stop___kcrctab_gpl_future = .;

 

                     // Kernel symbol table: strings

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(__ksymtab_strings))

 

              INPUT_SECTION_ALIGN(4)

                     __etext = .;

              } > MEM_SDRAM_UCLINUX

在这里，除了uclinux的代码外，还插入了VDSP库的代码，因为我们希望尽可能使用VDSP提供的库函数。中间还有一部分代码和数据段混合在一起了，以后再进行细调。

还有一个特殊的符号__stext__，这个符号原来是放在head.s中的，表示uclinux内核第一行代码的起始位置，因为我们将第一行代码写到了0xffa00000，因此在head.s中的符号取消，转而在ldf文件中进行定义。

4、移植.init段定义。

              // 初始化代码部分，可回收

              uclinux_init

              {

                     INPUT_SECTION_ALIGN(4096)

 

                     ___init_begin = .;

                     __sinittext = .;

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(.init.text))

                     __einittext = .;

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(.init.data))

                    

                     INPUT_SECTION_ALIGN(16)

                     ___setup_start = .;

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(.init.setup))

                     ___setup_end = .;

                     ___start___param = .;

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(__param))

                     ___stop___param = .;

                     ___initcall_start = .;

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(.initcall1.init))

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(.initcall2.init))

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(.initcall3.init))

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(.initcall4.init))

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(.initcall5.init))

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(.initcall6.init))

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(.initcall7.init))

                     ___initcall_end = .;

                     ___con_initcall_start = .;

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(.con_initcall.init))

                     ___con_initcall_end = .;

                     ___security_initcall_start = .;

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(.security_initcall.init))

                     ___security_initcall_end = .;

                    

              INPUT_SECTION_ALIGN(4)

                     ___initramfs_start = .;

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(.init.ramfs))

                     ___initramfs_end = .;

                    

               INPUT_SECTION_ALIGN(4)

                     ___init_end = .;

              } > MEM_SDRAM_UCLINUX

5、移植的.text.l1，即需要放在L1中的部分。

              uclinux_text_l1

              {

                     INPUT_SECTION_ALIGN(4)

                     __l1_lma_start = .;

                     __stext_l1 = .;

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(.l1.text))

 

                     INPUT_SECTION_ALIGN(4)

                     __etext_l1 = .;

              } > MEM_A_L1_CODE

6、移植.data.l1数据段。

              uclinux_data_l1

              {

                     INPUT_SECTION_ALIGN(4)

                     __sdata_l1 = .;

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(.l1.data))

              INPUT_SECTIONS(corea.dlb(data1))

                     __edata_l1 = .;

 

                     INPUT_SECTION_ALIGN(4)

                     __sbss_l1 = .;

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(.l1.bss))

 

                     INPUT_SECTION_ALIGN(4)

                     __ebss_l1 = .;

              } > MEM_A_L1_DATA_A

7、移植.data.b.l1。

              uclinux_data_b_l1

              {

                     INPUT_SECTION_ALIGN(4)

                     __sdata_b_l1 = .;

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(.l1.data.B))

                     __edata_b_l1 = .;

 

                     INPUT_SECTION_ALIGN(4)

                     __sbss_b_l1 = .;

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(.l1.bss.B))

 

                     INPUT_SECTION_ALIGN(4)

                     __ebss_b_l1 = .;

              } > MEM_A_L1_DATA_B

8、移植数据段。

              // 数据段

              uclinux_data

              {

                     INPUT_SECTION_ALIGN(0x2000)

                     __sdata = .;

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(.data.init_task))

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(.data))

 

                     // 原先放在DATA_A的内容

                     INPUT_SECTION_ALIGN(4)

                     ___l1_data_cache_a = 0;

                     INPUT_SECTIONS($OBJECTS_CORE_A(L1_data_a) $LIBRARIES_CORE_A(L1_data_a))

                     INPUT_SECTIONS($OBJECTS_CORE_A{DualCoreMem("CoreA")}(cplb_data) $LIBRARIES_CORE_A{DualCoreMem("CoreA")}(cplb_data))

                     INPUT_SECTIONS($OBJECTS_CORE_A(cplb_data) $LIBRARIES_CORE_A(cplb_data))

                     INPUT_SECTIONS($OBJECTS_CORE_A(voldata) $LIBRARIES_CORE_A(voldata))

                     INPUT_SECTIONS($OBJECTS_CORE_A(constdata) $LIBRARIES_CORE_A(constdata))

                     INPUT_SECTIONS($OBJS_LIBS_INTERNAL_CORE_A(data1))

                     INPUT_SECTIONS($OBJS_LIBS_NOT_EXTERNAL_CORE_A(data1))

                     INPUT_SECTIONS($OBJECTS_CORE_A(data1) $LIBRARIES_CORE_A(data1))

                     INPUT_SECTIONS($OBJECTS_CORE_A(.edt) $LIBRARIES_CORE_A(.edt))

                     INPUT_SECTIONS($OBJECTS_CORE_A(.cht) $LIBRARIES_CORE_A(.cht))

 

                     // 原先放在data_b的内容

                     INPUT_SECTION_ALIGN(4)

                     ___l1_data_cache_b = 0;

                     INPUT_SECTIONS($OBJECTS_CORE_A(ctor) $LIBRARIES_CORE_A(ctor))

                     INPUT_SECTIONS($OBJECTS_CORE_A(ctorl) $LIBRARIES_CORE_A(ctorl))

                     INPUT_SECTIONS($OBJECTS_CORE_A(vtbl) $LIBRARIES_CORE_A(vtbl))

                     INPUT_SECTIONS($OBJECTS_CORE_A(.gdt) $LIBRARIES_CORE_A(.gdt))

                     INPUT_SECTIONS($OBJECTS_CORE_A(.gdtl) $LIBRARIES_CORE_A(.gdtl))

                     INPUT_SECTIONS($OBJECTS_CORE_A(.frt) $LIBRARIES_CORE_A(.frt))

                     INPUT_SECTIONS($OBJECTS_CORE_A(.rtti) $LIBRARIES_CORE_A(.rtti))

                     INPUT_SECTIONS($OBJECTS_CORE_A(.edt) $LIBRARIES_CORE_A(.edt))

                     INPUT_SECTIONS($OBJECTS_CORE_A(.cht) $LIBRARIES_CORE_A(.cht))

                     INPUT_SECTIONS($OBJS_LIBS_INTERNAL_CORE_A(data1))

                     INPUT_SECTIONS($OBJS_LIBS_NOT_EXTERNAL_CORE_A(data1))

                     INPUT_SECTIONS($OBJECTS_CORE_A(data1) $LIBRARIES_CORE_A(data1))

                     INPUT_SECTIONS($OBJECTS_CORE_A{DualCoreMem("CoreA")}(cplb_data) $LIBRARIES_CORE_A{DualCoreMem("CoreA")}(cplb_data))

                     INPUT_SECTIONS($OBJECTS_CORE_A(cplb_data) $LIBRARIES_CORE_A(cplb_data))

                     INPUT_SECTIONS($OBJECTS_CORE_A(voldata) $LIBRARIES_CORE_A(voldata))

                     INPUT_SECTIONS($OBJECTS_CORE_A(constdata) $LIBRARIES_CORE_A(constdata))

                                                              

                     _jiffies = _jiffies_64;

                    

                     INPUT_SECTION_ALIGN(4)

                     __edata = .;

              } > MEM_SDRAM_UCLINUX

在这里插入了VDSP库中的数据段。

9、移植bss段。

              // bss段

              uclinux_bss

              {

                     INPUT_SECTION_ALIGN(4)

                     ___bss_start = .;

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(.bss))

                     INPUT_SECTIONS($LIBRARIES_SML3_CM(COMMON))

                     INPUT_SECTION_ALIGN(4)

                     ___bss_stop = .;

                     __end = . ;

              } > MEM_SDRAM_UCLINUX