Re: My ARM64 boot just broke (undefined instruction)

John F Carr wrote on Thu, Feb 02, 2023 at 03:57:07PM +0000: 
> > On Feb 2, 2023, at 05:13, Martin Cracauer <cracauer@cons.org> wrote:
> > 
> > I am getting a new boot panic on 14-current.
> > 
> > Platform:
> > - Apple Mac M1 mini
> > - QEMU 7.2.0 to arm64
> > - Last working kernel: Jan 25 main-n260242-f5924ad8fde4
> > - kern config GENERIC-NODEBUG
> > 
> > [...]
> > generic_timer0: <ARM Generic Timer> irq 34,35,36 on acpi0
> > Undefined instruction: d53be228
> 
> That opcode disassembles to
>   mrs    x8, CNTP_CTL_EL0
> The instruction is in function get_ctrl in sys/arm/arm/generic_timer.c.
> 
> Three possibilities:
> 
> 1. Apple didn't implement the CNTP_CTL_EL0 register to spec.
> 2. qemu does not handle privileged access properly.
> 3. There is something non-obvious wrong with the change below.  Copying its author Andrew Turner.  You could try reverting it.

Thank you, John.  I have confirmed that reverting the diff below
solves the problem for me.

Martin
 
> commit c57694ce94712ce1fe0341ae51d70446a7dbbfa2
> Author: Andrew Turner <andrew@FreeBSD.org>
> Date:   Sat Jan 28 17:36:24 2023 +0000
> 
>     Disable the arm physical timer when an irq exists
>          Some firmware leaves the timers enabled. Ensure they are disabled if
>     there are any physical timer interrupt resources to ensure we don't
>     receive any unexpected interrupts from them.
> 
> diff --git a/sys/arm/arm/generic_timer.c b/sys/arm/arm/generic_timer.c
> index 2527af9b9068..0556643032c2 100644
> --- a/sys/arm/arm/generic_timer.c
> +++ b/sys/arm/arm/generic_timer.c
> @@ -521,7 +521,8 @@ arm_tmr_attach(device_t dev)
>         if (sc->res[GT_VIRT] != NULL)
>                 arm_tmr_disable(false);
>         /* And the physical */
> -       if (sc->physical)
> +       if (sc->res[GT_PHYS_SECURE] != NULL ||
> +           sc->res[GT_PHYS_NONSECURE] != NULL)
>                 arm_tmr_disable(true);
> 

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Martin Cracauer <cracauer@cons.org>   http://www.cons.org/cracauer/