Messages in this thread | | | Date | Tue, 7 Nov 2023 17:29:58 +0100 | Subject | Re: [PATCH v2 1/2] arm64: Move Mediatek GIC quirk handling from irqchip to core | From | AngeloGioacchino Del Regno <> |
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Il 07/11/23 16:26, Douglas Anderson ha scritto: > In commit 44bd78dd2b88 ("irqchip/gic-v3: Disable pseudo NMIs on > Mediatek devices w/ firmware issues") we added a method for detecting > Mediatek devices with broken firmware and disabled pseudo-NMI. While > that worked, it didn't address the problem at a deep enough level. > > The fundamental issue with this broken firmware is that it's not > saving and restoring several important GICR registers. The current > list is believed to be: > * GICR_NUM_IPRIORITYR > * GICR_CTLR > * GICR_ISPENDR0 > * GICR_ISACTIVER0 > * GICR_NSACR > > Pseudo-NMI didn't work because it was the only thing (currently) in > the kernel that relied on the broken registers, so forcing pseudo-NMI > off was an effective fix. However, it could be observed that calling > system_uses_irq_prio_masking() on these systems still returned > "true". That caused confusion and led to the need for > commit a07a59415217 ("arm64: smp: avoid NMI IPIs with broken MediaTek > FW"). It's worried that the incorrect value returned by > system_uses_irq_prio_masking() on these systems will continue to > confuse future developers. > > Let's fix the issue a little more completely by disabling IRQ > priorities at a deeper level in the kernel. Once we do this we can > revert some of the other bits of code dealing with this quirk. > > This includes a partial revert of commit 44bd78dd2b88 > ("irqchip/gic-v3: Disable pseudo NMIs on Mediatek devices w/ firmware > issues"). This isn't a full revert because it leaves some of the > changes to the "quirks" structure around in case future code needs it. > > Suggested-by: Mark Rutland <mark.rutland@arm.com> > Signed-off-by: Douglas Anderson <dianders@chromium.org> > --- > > Changes in v2: > - Just detect the quirk once at init time. > - Fixed typo in subject: s/GiC/GIC. > - Squash in ("Remove Mediatek pseudo-NMI firmware quirk handling"). > > arch/arm64/kernel/cpufeature.c | 46 ++++++++++++++++++++++++++++------ > drivers/irqchip/irq-gic-v3.c | 22 +--------------- > 2 files changed, 39 insertions(+), 29 deletions(-) > > diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c > index f6b2e2906fc9..928124ea2e96 100644 > --- a/arch/arm64/kernel/cpufeature.c > +++ b/arch/arm64/kernel/cpufeature.c > @@ -999,6 +999,37 @@ static void init_32bit_cpu_features(struct cpuinfo_32bit *info) > init_cpu_ftr_reg(SYS_MVFR2_EL1, info->reg_mvfr2); > } > > +#ifdef CONFIG_ARM64_PSEUDO_NMI > +static bool enable_pseudo_nmi; > + > +static int __init early_enable_pseudo_nmi(char *p) > +{ > + return kstrtobool(p, &enable_pseudo_nmi); > +} > +early_param("irqchip.gicv3_pseudo_nmi", early_enable_pseudo_nmi); > + > +static __init void detect_system_supports_pseudo_nmi(void) > +{ > + struct device_node *np; > + > + if (!enable_pseudo_nmi) > + return; > + > + /* > + * Detect broken Mediatek firmware that doesn't properly save and
s/Mediatek/MediaTek/g
Apart from that,
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
On MT8195, MT8192, MT8186: Tested-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
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