Re: [PATCH AUTOSEL 6.10 14/16] irqchip/gic-v3: Don't return errors from gic_acpi_match_gicc()

[Marc Zyngier]

On Sun, 28 Jul 2024 01:47:31 +0100,
Sasha Levin <sashal@xxxxxxxxxx> wrote:
> 
> From: James Morse <james.morse@xxxxxxx>
> 
> [ Upstream commit fa2dabe57220e6af78ed7a2f7016bf250a618204 ]
> 
> 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@xxxxxxx>
> Reviewed-by: Gavin Shan <gshan@xxxxxxxxxx>
> Tested-by: Miguel Luis <miguel.luis@xxxxxxxxxx>
> Signed-off-by: Russell King (Oracle) <rmk+kernel@xxxxxxxxxxxxxxx>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
> Reviewed-by: Marc Zyngier <maz@xxxxxxxxxx>
> Link: https://lore.kernel.org/r/20240529133446.28446-14-Jonathan.Cameron@xxxxxxxxxx
> Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

Please drop this. It has no purpose being backported to stable.

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.