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这是2.6.28entry-32.S中的部分代码:
#define SAVE_ALL \
cld; \
pushl %fs; \
CFI_ADJUST_CFA_OFFSET 4;\
/*CFI_REL_OFFSET fs, 0;*/\
pushl %es; \
CFI_ADJUST_CFA_OFFSET 4;\
/*CFI_REL_OFFSET es, 0;*/\
pushl %ds; \
CFI_ADJUST_CFA_OFFSET 4;\
/*CFI_REL_OFFSET ds, 0;*/\
pushl %eax; \
CFI_ADJUST_CFA_OFFSET 4;\
CFI_REL_OFFSET eax, 0;\
pushl %ebp; \
CFI_ADJUST_CFA_OFFSET 4;\
CFI_REL_OFFSET ebp, 0;\
pushl %edi; \
CFI_ADJUST_CFA_OFFSET 4;\
CFI_REL_OFFSET edi, 0;\
pushl %esi; \
CFI_ADJUST_CFA_OFFSET 4;\
CFI_REL_OFFSET esi, 0;\
pushl %edx; \
CFI_ADJUST_CFA_OFFSET 4;\
CFI_REL_OFFSET edx, 0;\
pushl %ecx; \
CFI_ADJUST_CFA_OFFSET 4;\
CFI_REL_OFFSET ecx, 0;\
pushl %ebx; \
CFI_ADJUST_CFA_OFFSET 4;\
CFI_REL_OFFSET ebx, 0;\
movl $(__USER_DS), %edx; \
movl %edx, %ds; \
movl %edx, %es; \
movl $(__KERNEL_PERCPU), %edx; \
movl %edx, %fs
请问每个pushl 后面的CFI_ADJUST_CFA_OFFSET的作用是什么阿?
在2.4版本里边没有看见过。
谢谢 |
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