[Skiboot] [PATCH] mambo/mambo_utils.tcl: Inject an MCE at a specified address

[Nicholas Piggin]

On Tue, 10 Apr 2018 21:25:18 +1000
Balbir Singh <bsingharora at gmail.com> wrote:

> Currently we don't support injecting an MCE on a specific address.
> This is useful for testing functionality like memcpy_mcsafe()
> (see https://patchwork.ozlabs.org/cover/893339/)
> 
> This patch refactors exc_mce into setup_mce and exc_mce. setup_mce
> is generally useful to setup a MCE context with variables DSISR,
> SRR1 and DAR. setup_mce supports setting up dsisr as a new
> function argument. It's useful when we want to set up both the
> cause and DSIR.

Hum, I actually have a patch sitting around that reworks this stuff
quite significantly for stop states (which mambo doesn't handle very
well). It doesn't look like there's a big conflict, but if I can send
it and get you to test and merge on top of it that would be good.

> 
> The core of the functionality is a routine called
> inject_mce_ue_on_addr, which takes an addr argument and injects
> an MCE (load/store with UE) when the specified address is accessed
> by code. This functionality can easily be enhanced to cover
> instruction UE's as well.
> 
> Signed-off-by: Balbir Singh <bsingharora at gmail.com>
> ---
>  external/mambo/mambo_utils.tcl | 29 ++++++++++++++++++++++++-----
>  1 file changed, 24 insertions(+), 5 deletions(-)
> 
> diff --git a/external/mambo/mambo_utils.tcl b/external/mambo/mambo_utils.tcl
> index 7a27f0f4..a9225e3e 100644
> --- a/external/mambo/mambo_utils.tcl
> +++ b/external/mambo/mambo_utils.tcl
> @@ -442,11 +442,12 @@ proc mce_trigger { args } {
>  #
>  # Default with no arguments is a recoverable i-side TLB multi-hit
>  # Other options:
> -# d_side=1 cause=0x80 - recoverable d-side SLB multi-hit
> +# d_side=1 dsisr=0x80 - recoverable d-side SLB multi-hit
> +# d_side=1 dsisr=0x8000, cause=0x1 - ue error on instruction fetch
>  # d_side=0 cause=0xd  - unrecoverable i-side async store timeout (POWER9 only)
>  # d_side=0 cause=0x1  - unrecoverable i-side ifetch
>  #
> -proc exc_mce { { d_side 0 } { cause 0x5 } { recoverable 1 } } {
> +proc setup_mce { { d_side 0 } {dsisr 0x5} { cause 0x5 } { recoverable 1 }} {
>      variable SRR1
>      variable DSISR
>      variable DAR
> @@ -466,11 +467,10 @@ proc exc_mce { { d_side 0 } { cause 0x5 } { recoverable 1 } } {
>          set msr_ri 0x0
>      }
>  
> -    # recoverable d-side SLB multihit
>      if { $d_side } {
>          set is_dside 1
> -        set SRR1_mc_cause 0x0
> -        set DSISR $cause
> +        set SRR1_mc_cause $cause
> +        set DSISR $dsisr
>          set DAR 0xdeadbeefdeadbeef
>      } else {
>          set is_dside 0

This doesn't seem right. ue error on ifetch is i-side which can not
set DSISR. I have the ifetch UE in the comment. What was wrong with
the original code here?

Thanks,
Nick