arm linux中一些重要的宏及地…

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_OFFSET)

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

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

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

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

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

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

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

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