Messages in this thread | | | Date | Wed, 28 May 2014 12:44:38 +0100 | From | Will Deacon <> | Subject | Re: [PATCH v5 2/2] arm64: enable context tracking |
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Hi Larry,
On Mon, May 26, 2014 at 07:56:13PM +0100, Larry Bassel wrote: > Make calls to ct_user_enter when the kernel is exited > and ct_user_exit when the kernel is entered (in el0_da, > el0_ia, el0_svc, el0_irq and all of the "error" paths). > > These macros expand to function calls which will only work > properly if el0_sync and related code has been rearranged > (in a previous patch of this series). > > The calls to ct_user_exit are made after hw debugging has been > enabled (enable_dbg_and_irq). > > The call to ct_user_enter is made at the beginning of the > kernel_exit macro. > > This patch is based on earlier work by Kevin Hilman. > Save/restore optimizations were also done by Kevin.
Apologies if we've discussed this before (it rings a bell), but why are we penalising the fast syscall path with this? Shouldn't TIF_NOHZ contribute to out _TIF_WORK_MASK, then we could do the tracking on the syscall slow path?
I think that would tidy up your mov into x19 too.
Also -- how do you track ret_from_fork in the child with these patches?
Will
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