Messages in this thread | | | From | Linus Torvalds <> | Date | Wed, 7 Feb 2018 09:37:53 -0800 | Subject | Re: [PATCH tip-pti 2/2] x86/entry: interleave XOR register clearing with PUSH/MOV instructions |
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On Wed, Feb 7, 2018 at 9:05 AM, Linus Torvalds <torvalds@linux-foundation.org> wrote: > > The other thing we need to do is to just pass down the system call > number as an argument instead of reloading it.
.. we may also want to disable some debug things.
For example, if you enable KASAN, it does insane things for do_syscall(). I realize that nobody is supposed to care about performance for KASAN, but still...
So one of the issues with do_syscall() is simply that _because_ it was the rare case only, the code simply was never even looked at. But if y ou look at the straight-line case, do_syscall_64() really doesn't look too bad apart from the argument reloading that I do think is largely fixable.
Linus
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