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Re: [PATCH] ppc/pnv: Fix NMI system reset SRR1 value
From: |
David Gibson |
Subject: |
Re: [PATCH] ppc/pnv: Fix NMI system reset SRR1 value |
Date: |
Thu, 7 May 2020 23:51:54 +1000 |
On Thu, May 07, 2020 at 09:48:24PM +1000, Nicholas Piggin wrote:
> Commit a77fed5bd926 ("ppc/pnv: Add support for NMI interface") got the
> SRR1 setting wrong for sresets that hit outside of power-save states.
>
> Fix this, better documenting the source for the bit definitions.
>
> Fixes: a77fed5bd926 ("ppc/pnv: Add support for NMI interface") got the
> Cc: Cédric Le Goater <address@hidden>
> Cc: David Gibson <address@hidden>
> Signed-off-by: Nicholas Piggin <address@hidden>
Applied to ppc-for-5.1, thanks.
> ---
>
> Thanks to Cedric for pointing out concerns with a previous MCE patch
> that unearthed this as well. Linux does not actually care what these
> SRR1[42:45] bits look like for non-powersave sresets, but we should
> follow documented behaviour as far as possible.
>
> hw/ppc/pnv.c | 26 ++++++++++++++++++++------
> 1 file changed, 20 insertions(+), 6 deletions(-)
>
> diff --git a/hw/ppc/pnv.c b/hw/ppc/pnv.c
> index a3b7a8d0ff..1b4748ce6d 100644
> --- a/hw/ppc/pnv.c
> +++ b/hw/ppc/pnv.c
> @@ -1986,12 +1986,26 @@ static void pnv_cpu_do_nmi_on_cpu(CPUState *cs,
> run_on_cpu_data arg)
>
> cpu_synchronize_state(cs);
> ppc_cpu_do_system_reset(cs);
> - /*
> - * SRR1[42:45] is set to 0100 which the ISA defines as implementation
> - * dependent. POWER processors use this for xscom triggered interrupts,
> - * which come from the BMC or NMI IPIs.
> - */
> - env->spr[SPR_SRR1] |= PPC_BIT(43);
> + if (env->spr[SPR_SRR1] & PPC_BITMASK(46, 47)) {
> + /*
> + * Power-save wakeups, as indicated by non-zero SRR1[46:47] put the
> + * wakeup reason in SRR1[42:45], system reset is indicated with 0b0100
> + * (PPC_BIT(43)).
> + */
> + if (!(env->spr[SPR_SRR1] & PPC_BIT(43))) {
> + warn_report("ppc_cpu_do_system_reset does not set system reset
> wakeup reason");
> + env->spr[SPR_SRR1] |= PPC_BIT(43);
> + }
> + } else {
> + /*
> + * For non-powersave system resets, SRR1[42:45] are defined to be
> + * implementation-dependent. The POWER9 User Manual specifies that
> + * an external (SCOM driven, which may come from a BMC nmi command or
> + * another CPU requesting a NMI IPI) system reset exception should be
> + * 0b0010 (PPC_BIT(44)).
> + */
> + env->spr[SPR_SRR1] |= PPC_BIT(44);
> + }
> }
>
> static void pnv_nmi(NMIState *n, int cpu_index, Error **errp)
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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