diff mbox series

[v10,13/19] irqchip/gic-v3: Don't return errors from gic_acpi_match_gicc()

Message ID 20240529133446.28446-14-Jonathan.Cameron@huawei.com (mailing list archive)
State Handled Elsewhere, archived
Headers show
Series ACPI/arm64: add support for virtual cpu hotplug | expand

Commit Message

Jonathan Cameron May 29, 2024, 1:34 p.m. UTC
From: James Morse <james.morse@arm.com>

gic_acpi_match_gicc() is only called via gic_acpi_count_gicr_regions().
It should only count the number of enabled redistributors, but it
also tries to sanity check the GICC entry, currently returning an
error if the Enabled bit is set, but the gicr_base_address is zero.

Adding support for the online-capable bit to the sanity check will
complicate it, for no benefit. The existing check implicitly depends on
gic_acpi_count_gicr_regions() previous failing to find any GICR regions
(as it is valid to have gicr_base_address of zero if the redistributors
are described via a GICR entry).

Instead of complicating the check, remove it. Failures that happen at
this point cause the irqchip not to register, meaning no irqs can be
requested. The kernel grinds to a panic() pretty quickly.

Without the check, MADT tables that exhibit this problem are still
caught by gic_populate_rdist(), which helpfully also prints what went
wrong:
| CPU4: mpidr 100 has no re-distributor!

Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Tested-by: Miguel Luis <miguel.luis@oracle.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 drivers/irqchip/irq-gic-v3.c | 13 ++-----------
 1 file changed, 2 insertions(+), 11 deletions(-)

Comments

Jonathan Cameron June 19, 2024, 8:11 a.m. UTC | #1
On Wed, 29 May 2024 14:34:40 +0100
Jonathan Cameron <Jonathan.Cameron@huawei.com> wrote:

> From: James Morse <james.morse@arm.com>
> 
> gic_acpi_match_gicc() is only called via gic_acpi_count_gicr_regions().
> It should only count the number of enabled redistributors, but it
> also tries to sanity check the GICC entry, currently returning an
> error if the Enabled bit is set, but the gicr_base_address is zero.
> 
> Adding support for the online-capable bit to the sanity check will
> complicate it, for no benefit. The existing check implicitly depends on
> gic_acpi_count_gicr_regions() previous failing to find any GICR regions
> (as it is valid to have gicr_base_address of zero if the redistributors
> are described via a GICR entry).
> 
> Instead of complicating the check, remove it. Failures that happen at
> this point cause the irqchip not to register, meaning no irqs can be
> requested. The kernel grinds to a panic() pretty quickly.
> 
> Without the check, MADT tables that exhibit this problem are still
> caught by gic_populate_rdist(), which helpfully also prints what went
> wrong:
> | CPU4: mpidr 100 has no re-distributor!
> 
> Signed-off-by: James Morse <james.morse@arm.com>
> Reviewed-by: Gavin Shan <gshan@redhat.com>
> Tested-by: Miguel Luis <miguel.luis@oracle.com>
> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Sorry. I managed not to pick up Marc's RB form v8 and this patch is unchanged.
https://lore.kernel.org/all/87jzkktaui.wl-maz@kernel.org/

Hopefully whoever picks this up is using tooling (b4 or similar) that will get it from
here.

Reviewed-by: Marc Zyngier <maz@kernel.org>

So just patch 14 waiting for Marc to take another glance.


> ---
>  drivers/irqchip/irq-gic-v3.c | 13 ++-----------
>  1 file changed, 2 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
> index 6fb276504bcc..10af15f93d4d 100644
> --- a/drivers/irqchip/irq-gic-v3.c
> +++ b/drivers/irqchip/irq-gic-v3.c
> @@ -2415,19 +2415,10 @@ static int __init gic_acpi_match_gicc(union acpi_subtable_headers *header,
>  	 * If GICC is enabled and has valid gicr base address, then it means
>  	 * GICR base is presented via GICC
>  	 */
> -	if (acpi_gicc_is_usable(gicc) && gicc->gicr_base_address) {
> +	if (acpi_gicc_is_usable(gicc) && gicc->gicr_base_address)
>  		acpi_data.enabled_rdists++;
> -		return 0;
> -	}
>  
> -	/*
> -	 * It's perfectly valid firmware can pass disabled GICC entry, driver
> -	 * should not treat as errors, skip the entry instead of probe fail.
> -	 */
> -	if (!acpi_gicc_is_usable(gicc))
> -		return 0;
> -
> -	return -ENODEV;
> +	return 0;
>  }
>  
>  static int __init gic_acpi_count_gicr_regions(void)
diff mbox series

Patch

diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index 6fb276504bcc..10af15f93d4d 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -2415,19 +2415,10 @@  static int __init gic_acpi_match_gicc(union acpi_subtable_headers *header,
 	 * If GICC is enabled and has valid gicr base address, then it means
 	 * GICR base is presented via GICC
 	 */
-	if (acpi_gicc_is_usable(gicc) && gicc->gicr_base_address) {
+	if (acpi_gicc_is_usable(gicc) && gicc->gicr_base_address)
 		acpi_data.enabled_rdists++;
-		return 0;
-	}
 
-	/*
-	 * It's perfectly valid firmware can pass disabled GICC entry, driver
-	 * should not treat as errors, skip the entry instead of probe fail.
-	 */
-	if (!acpi_gicc_is_usable(gicc))
-		return 0;
-
-	return -ENODEV;
+	return 0;
 }
 
 static int __init gic_acpi_count_gicr_regions(void)