Messages in this thread | | | Subject | Re: Why system call need to copy the date from the userspace before using it | Date | Wed, 13 Apr 2005 07:59:54 -0400 | From | Hacksaw <> |
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>>Why not use it directly >Some of these reasons are:
It seems like you gave reason why userland pointers shouldn't be trusted, not why userland data should be copied into kernel land. All the problems you mentioned would have to be solved by the kernel regardless of copying the data around.
Ummm... Except for the who's mapped now problem. That's pretty weird. I guess that's something that comes with trying to use tons of RAM in a 32 bit system.
I thought the big issue was the need to lock the page(s) during the call, and maybe some tricky races which made the idea difficult. -- The key is realizing the whole world is stupid and being happy anyway http://www.hacksaw.org -- http://www.privatecircus.com -- KB1FVD
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