arm linux中一些重要的宏及地址定义

分类： LINUX

转载自http://biancheng.dnbcw.info/linux/352414.html。在此基础上，做一些修改。
 
1）TEXT_OFFSET  内核在RAM中的起始位置相对于RAM起始地址偏移。值为0x00008000


./arch/arm/Makefile

111 textofs-y
:= 0x00008000

112 textofs-$(CONFIG_ARCH_CLPS711X)
:= 0x00028000

113 # We don't want the htc bootloader
to corrupt kernel during resume

114 textofs-$(CONFIG_PM_H1940)
:= 0x00108000

115 # SA1111 DMA bug: we don't want the kernel
to live in precious DMA-able memory

116 ifeq ($(CONFIG_ARCH_SA1100),y)

117 textofs-$(CONFIG_SA1111)
:= 0x00208000

118 endif

212 # The byte offset of the kernel image in RAM from the start of RAM.

213 TEXT_OFFSET
:= $(textofs-y)

2）PAGE_OFFSE   内核镜像起始虚拟地址。值为0xC0000000

arch/arm/Kconfig

1165 config PAGE_OFFSET
----这个就是CONFIG_PAGE_OFFSET宏，默认值为0xC0000000

1166 hex

1167 default 0x40000000 if VMSPLIT_1G

1168 default 0x80000000 if VMSPLIT_2G

1169 default 0xC0000000


./arch/arm/include/asm/memory.h


34 #define PAGE_OFFSET UL(CONFIG_PAGE_OFF
9c9a
SET)

3）PHYS_OFFSET  RAM启始物理地址，对应于DDR的物理地址。需要在mach-xxxx/include/mach/memory.h文件中定义这个宏。
 
对于2410来说值为0x30000000，RAM接在片选6上

arch/arm/mach-s3c2410/include/mach/memory.h

#define PHYS_OFFSET    UL(0x30000000)

4）KERNEL_RAM_VADDR  内核在RAM中的虚拟地址。值为0xC0008000

5）KERNEL_RAM_PADDR  内核在RAM中的物理地址。值为0x30008000
arch/arm/kernel/head.S

 29 #define KERNEL_RAM_VADDR        (PAGE_OFFSET + TEXT_OFFSET)

 30 #define KERNEL_RAM_PADDR        (PHYS_OFFSET + TEXT_OFFSET)

6）swapper_pg_dir 初始页表虚拟地址，值为0xC0004000，
一般分配KERNEL_RAM_VADDR地址下16K作为页表，因此，我们必须确保正确设置KERNEL_RAM_VADDR。

arch/arm/kernel/head.S

 44         .globl 
swapper_pg_dir

 45         .equ   
swapper_pg_dir, KERNEL_RAM_VADDR - 0x4000

7）VMALLOC_START 0xc4800000

8）VMALLOC_END   0xe0000000

9）MODULES_VADDR 0xbf000000

10）MODULES_END   0xc0000000


arch/arm/include/asm/memory.h 47 #ifndef CONFIG_THUMB2_KERNEL

 48 #define MODULES_VADDR           (PAGE_OFFSET - 16*1024*1024)

 49 #else

 50 /* smaller range for Thumb-2 symbols relocation (2^24)*/

 51 #define MODULES_VADDR           (PAGE_OFFSET - 8*1024*1024)

 52 #endif

 53

 54 #if TASK_SIZE > MODULES_VADDR

 55 #error Top of user space clashes with start of module space

 56 #endif

 57

 58 /*

 59  * The highmem pkmap virtual space shares the end of the module area.

 60  */

 61 #ifdef CONFIG_HIGHMEM

 62 #define MODULES_END             (PAGE_OFFSET - PMD_SIZE)
 63 #else

 64 #define MODULES_END             (PAGE_OFFSET)
 65 #endif

11)PKMAP_BASE          
arch/arm/include/asm/highmem.h:
6:#define PKMAP_BASE           (PAGE_OFFSET - PMD_SIZE)
 
12)TASK_SIZE
./arch/arm/include/asm/memory.h

 34 #define PAGE_OFFSET             UL(CONFIG_PAGE_OFFSET)

 35 #define TASK_SIZE               (UL(CONFIG_PAGE_OFFSET) - UL(0x01000000))

 36 #define TASK_UNMAPPED_BASE      (UL(CONFIG_PAGE_OFFSET) / 3)

13）一些不同地址之间转换的宏
./arch/arm/include/asm/memory.h

135 /*

136  * Physical vs virtual RAM address space conversion.  These are

137  * private definitions which should NOT be used outside memory.h

138  * files.  Use virt_to_phys/phys_to_virt/__pa/__va instead.

139  */

140 #ifndef __virt_to_phys

141 #define __virt_to_phys(x)       ((x) - PAGE_OFFSET + PHYS_OFFSET)//物理地址和虚拟地址
142 #define __phys_to_virt(x)       ((x) - PHYS_OFFSET + PAGE_OFFSET)//之间转换的宏
143 #endif

144

145 /*

146  * Convert a physical address to a Page Frame Number and back

147  */

148 #define __phys_to_pfn(paddr)    ((paddr) >> PAGE_SHIFT)
//物理地址和页帧号之间
149 #define __pfn_to_phys(pfn)      ((pfn) << PAGE_SHIFT)  
//转换的宏
150

151 /*

152  * Convert a page to/from a physical address

153  */

154 #define page_to_phys(page)      (__pfn_to_phys(page_to_pfn(page)))//页地址和物理地址
155 #define phys_to_page(phys)      (pfn_to_page(__phys_to_pfn(phys)))//之间的转换宏依赖于内存模型。

201 /*

202  * Drivers should NOT use these either.

203  */

204 #define __pa(x)                 __virt_to_phys((unsigned long)(x))

205 #define __va(x)                 ((void *)__phys_to_virt((unsigned long)(x)))

206 #define pfn_to_kaddr(pfn)       __va((pfn) << PAGE_SHIFT)

207

208 /*

209  * Virtual <-> DMA view memory address translations

210  * Again, these are *only* valid on the kernel direct mapped RAM

211  * memory.  Use of these is *deprecated* (and that doesn't mean

212  * use the __ prefixed forms instead.)  See dma-mapping.h.

213  */

214 #ifndef __virt_to_bus

215 #define __virt_to_bus   __virt_to_phys

216 #define __bus_to_virt   __phys_to_virt

217 #define __pfn_to_bus(x) __pfn_to_phys(x)

218 #define __bus_to_pfn(x) __phys_to_pfn(x)

219 #endif



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