Messages in this thread Patch in this message | | | Date | Sat, 24 Feb 2024 10:30:04 +0000 | From | Marc Zyngier <> | Subject | Re: [PATCH 2/3] irqchip/gic-v3-its: Spin off GICv4 init into a separate function |
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On Mon, 19 Feb 2024 18:58:07 +0000, Oliver Upton <oliver.upton@linux.dev> wrote: > > Burying the GICv4 redistributor initialization into the routine for LPIs > is a bit confusing, and can lead to sillies where unexpected codepaths > may not fully initialize the RD. > > Hoist it out of its_cpu_init_lpis() into a dedicated function. > > Signed-off-by: Oliver Upton <oliver.upton@linux.dev> > --- > drivers/irqchip/irq-gic-v3-its.c | 32 +++++++++++++++++++++----------- > 1 file changed, 21 insertions(+), 11 deletions(-) > > diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c > index 0022852ce494..63d1743f08cc 100644 > --- a/drivers/irqchip/irq-gic-v3-its.c > +++ b/drivers/irqchip/irq-gic-v3-its.c > @@ -3173,8 +3173,25 @@ static void its_cpu_init_lpis(void) > writel_relaxed(val, rbase + GICR_CTLR); > > out: > - if (gic_rdists->has_vlpis && !gic_rdists->has_rvpeid) { > + /* Make sure the GIC has seen the above */ > + dsb(sy);
So having hoisted the dsb() here...
> + gic_data_rdist()->flags |= RD_LOCAL_LPI_ENABLED; > + pr_info("GICv3: CPU%d: using %s LPI pending table @%pa\n", > + smp_processor_id(), > + gic_data_rdist()->flags & RD_LOCAL_PENDTABLE_PREALLOCATED ? > + "reserved" : "allocated", > + &paddr); > +} > + > +static void its_cpu_init_vlpis(void) > +{ > + /* No vLPIs? No problem. */ > + if (!gic_rdists->has_vlpis) > + return; > + > + if (!gic_rdists->has_rvpeid) { > void __iomem *vlpi_base = gic_data_rdist_vlpi_base(); > + u64 val; > > /* > * It's possible for CPU to receive VLPIs before it is > @@ -3193,7 +3210,8 @@ static void its_cpu_init_lpis(void) > * ancient programming gets left in and has possibility of > * corrupting memory. > */ > - val = its_clear_vpend_valid(vlpi_base, 0, 0); > + its_clear_vpend_valid(vlpi_base, 0, 0); > + return;
I'm not sure about the necessity of this return statement. allocate_vpe_l1_table() checks for rvpeid already, so it should be fine to carry on.
> } > > if (allocate_vpe_l1_table()) { > @@ -3205,15 +3223,6 @@ static void its_cpu_init_lpis(void) > gic_rdists->has_rvpeid = false; > gic_rdists->has_vlpis = false; > } > - > - /* Make sure the GIC has seen the above */ > - dsb(sy);
.. we're now missing a dsb affecting the VPE table programming, as we expect things to take effect immediately.
> - gic_data_rdist()->flags |= RD_LOCAL_LPI_ENABLED; > - pr_info("GICv3: CPU%d: using %s LPI pending table @%pa\n", > - smp_processor_id(), > - gic_data_rdist()->flags & RD_LOCAL_PENDTABLE_PREALLOCATED ? > - "reserved" : "allocated", > - &paddr); > } > > static void its_cpu_init_collection(struct its_node *its) > @@ -5265,6 +5274,7 @@ int its_cpu_init(void) > return ret; > > its_cpu_init_lpis(); > + its_cpu_init_vlpis(); > its_cpu_init_collections(); > } >
I'm otherwise OK with the idea of splitting things up.
Thanks,
M.
-- Without deviation from the norm, progress is not possible.
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