Messages in this thread | | | Date | Wed, 26 Feb 2020 09:05:38 +0100 | From | Peter Zijlstra <> | Subject | Re: [patch 13/16] x86/entry: Move irqflags and context tracking to C for simple idtentries |
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On Tue, Feb 25, 2020 at 11:33:34PM +0100, Thomas Gleixner wrote:
> --- a/arch/x86/include/asm/idtentry.h > +++ b/arch/x86/include/asm/idtentry.h > @@ -7,14 +7,31 @@ > > #ifndef __ASSEMBLY__ > > +#ifdef CONFIG_CONTEXT_TRACKING > +static __always_inline void enter_from_user_context(void) > +{ > + CT_WARN_ON(ct_state() != CONTEXT_USER); > + user_exit_irqoff(); > +} > +#else > +static __always_inline void enter_from_user_context(void) { } > +#endif > + > /** > * idtentry_enter - Handle state tracking on idtentry > * @regs: Pointer to pt_regs of interrupted context > * > - * Place holder for now. > + * Invokes: > + * - The hardirq tracer to keep the state consistent as low level ASM > + * entry disabled interrupts. > + * > + * - Context tracking if the exception hit user mode > */ > static __always_inline void idtentry_enter(struct pt_regs *regs) > { > + trace_hardirqs_off(); > + if (user_mode(regs)) > + enter_from_user_context(); > }
So:
asm_exc_int3 exc_int3 idtentry_enter() enter_from_user_context if (context_tracking_enabled())
poke_int3_handler();
Is, AFAICT, completely buggered.
You can't have a static_branch before the poke_int3_handler that deals with text_poke.
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