two virtual address pointing to same physical address

[Chan Kim]

In my previous email below, virtual address 0xc8000000 (for nocache region) and virtual adderss 0xc0540000 is pointing to the same physical address.
Is this situation normal? (in the kernel, two different virtual addresses pointing to the same physical address.)
Thanks in advance.
Chan



보낸 사람 : "Chan Kim" <ckim at etri.re.kr>
보낸 날짜 : 2014-05-14 21:54:03 ( +09:00 )
받는 사람 : kernelnewbies at kernelnewbies.org <kernelnewbies at kernelnewbies.org>
참조 : 
제목 : a question on nocache pool address which seems to have ended up as a nice comment?

Hi,
I was analyzing arch/sparc/mm/srmmu.c (linux 3.3)
In our system, the pgd table sits at c8000000 and the entry for c80000000 is at c8000320. (upper 8 bits is the index and *4 is the index address)
previously, I got srmmu_nocache_pool = c0540000. Does anybody know why __nocache_fix(0xc80000320) is c0540320?
This is equivalent to saying that nocache region 0xc8000000 is mapped to 0xc0540000 which is physical address 0x60540000.
I'm confused here..
I guess the virtual address 0xc8000000 which is in nocache region is rebased to previously allocated nocache physcial address 0x60540000 which is then equivalent to virtual address 0xc0540000. Having said that, it sounds perfectly correct.
another example of realizing something while asking.. Correct me if I'm wrong.
regards,
Chan
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