Re: [PATCH RFC v4 10/15] irqchip/gic-v3: Don't return errors from gic_acpi_match_gicc()

On Wed, 31 Jan 2024 16:50:27 +0000
Russell King (Oracle) <[email protected]> wrote:

> From: James Morse <[email protected]>
> 
> 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 <[email protected]>
> Reviewed-by: Gavin Shan <[email protected]>
> Signed-off-by: Russell King (Oracle) <[email protected]>
Does what it says on the tin.

Reviewed-by: Jonathan Cameron <[email protected]>