ARM Linux下的swapper_pg_dir全局变量在哪里定义

swapper_pg_dir在arch/arm/kernel/head.S文件中定义。具体代码如下：

 

 

在arch/arm/kernel/head.S文件中定义。

 26 #error "PHYS_OFFSET must be at an even 2MiB boundary!"
 27 #endif
 28
 29 #define KERNEL_RAM_VADDR (PAGE_OFFSET + TEXT_OFFSET)//PAGE_OFFSET 虚拟地址的起始地址（通常为0xC0000000）。
 30 #define KERNEL_RAM_PADDR (PHYS_OFFSET + TEXT_OFFSET)//PHYS_OFFSET 物理地址（DDR）的起始地址
 31
 32
 33 /*
 34 * swapper_pg_dir is the virtual address of the initial page table.
 35 * We place the page tables 16K below KERNEL_RAM_VADDR. Therefore, we must
 36 * make sure that KERNEL_RAM_VADDR is correctly set. Currently, we expect
 37 * the least significant 16 bits to be 0x8000, but we could probably
 38 * relax this restriction to KERNEL_RAM_VADDR >= PAGE_OFFSET + 0x4000.
 39 */
 40 #if (KERNEL_RAM_VADDR & 0xffff) != 0x8000
 41 #error KERNEL_RAM_VADDR must start at 0xXXXX8000
 42 #endif
 43
 44 .globl swapper_pg_dir
 45 .equ swapper_pg_dir, KERNEL_RAM_VADDR - 0x4000
 46
 47 .macro pgtbl, rd
 48 ldr \rd, =(KERNEL_RAM_PADDR - 0x4000)
 49 .endm

TEXT_OFFSET在arch/arm/Makefile文件中定义：

 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)