简介：这是armlinux中一些重要的宏及地址定义的详细页面，介绍了和linux,有关的知识、技巧、经验，和一些linux源码等。
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
118 textofs-y := 0x00008000
222 TEXT_OFFSET := $(textofs-y)
PAGE_OFFSE 内核镜像起始虚拟地址。值为0xC0000000
/arch/arm/configs/s3c2410_defconfig
CONFIG_PAGE_OFFSET=0xC0000000
./arch/arm/include/asm/memory.h
34 #define PAGE_OFFSET UL(CONFIG_PAGE_OFFSET)
PHYS_OFFSET RAM启始物理地址，对于2410来说值为0x30000000，RAM接在片选6上
arch/arm/mach-s3c2410/include/mach/memory.h
from arch/arm/mach-rpc/include/mach/memory.h
#define PHYS_OFFSET UL(0x30000000)
KERNEL_RAM_VADDR 内核在RAM中的虚拟地址。值为0xC0008000
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)
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
VMALLOC_START 0xc4800000
VMALLOC_END 0xe0000000
MODULES_VADDR 0xbf000000
MODULES_END 0xc0000000
./arch/arm/include/asm/memory.h
51 #define MODULES_VADDR (PAGE_OFFSET - 8*1024*1024)
61 #ifdef CONFIG_HIGHMEM
62 #define MODULES_END (PAGE_OFFSET - PMD_SIZE)
63 #else
64 #define MODULES_END (PAGE_OFFSET)
65 #endif
arch/arm/include/asm/highmem.h:6:#define PKMAP_BASE (PAGE_OFFSET - PMD_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)
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)
142 #define __phys_to_virt(x) ((x) - PHYS_OFFSET + PAGE_OFFSET)
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)
149 #define __pfn_to_phys(pfn) ((pfn) << PAGE_SHIFT)
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)))
155 #define phys_to_page(phys) (pfn_to_page(__phys_to_pfn(phys)))
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
