Messages in this thread | | | Date | Fri, 30 Aug 2013 13:03:31 -0400 | From | Steven Rostedt <> | Subject | Re: x86-32: Early microcode loading stumbles over disabled DYNAMIC_FTRACE |
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On Fri, 30 Aug 2013 09:35:18 -0700 "H. Peter Anvin" <hpa@zytor.com> wrote:
> On 08/30/2013 08:51 AM, Steven Rostedt wrote: > > > > It does when dynamic tracing is enabled. But this issue is with static > > tracing, there's no code modification, thus all functions call > > mcount/__fentry__ and we need to look at a variable to determine if we > > should trace or not. > > > > And of course global variables are a no-no without special handling in > pre-paging mode. Sigh. > > You *could* bail out of the calling address is < PAGE_OFFSET. >
We could do that too, as static tracing already gives us high overhead, I'm not sure how much more overhead another check like this even matters.
Who uses static tracing? I only use it to test that it still works ;-)
-- Steve
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