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Message-ID: <f45820cf-3ea5-6f5a-7702-bb4b14811e56@redhat.com>
Date:   Tue, 19 Sep 2023 11:23:00 +1000
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Subject: Re: [RFC PATCH v2 28/35] arm64, irqchip/gic-v3, ACPI: Move MADT GICC
 enabled check into a helper
Content-Language: en-US
To:     James Morse <james.morse@arm.com>, linux-pm@vger.kernel.org,
        loongarch@lists.linux.dev, linux-acpi@vger.kernel.org,
        linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-riscv@lists.infradead.org, kvmarm@lists.linux.dev
Cc:     x86@kernel.org, Salil Mehta <salil.mehta@huawei.com>,
        Russell King <linux@armlinux.org.uk>,
        Jean-Philippe Brucker <jean-philippe@linaro.org>,
        jianyong.wu@arm.com, justin.he@arm.com
References: <20230913163823.7880-1-james.morse@arm.com>
 <20230913163823.7880-29-james.morse@arm.com>
From:   Gavin Shan <gshan@redhat.com>
In-Reply-To: <20230913163823.7880-29-james.morse@arm.com>
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On 9/14/23 02:38, James Morse wrote:
> ACPI, irqchip and the architecture code all inspect the MADT
> enabled bit for a GICC entry in the MADT.
> 
> The addition of an 'online capable' bit means all these sites need
> updating.
> 
> Move the current checks behind a helper to make future updates easier.
> 
> Signed-off-by: James Morse <james.morse@arm.com>
> ---
>   arch/arm64/kernel/smp.c       |  2 +-
>   drivers/acpi/processor_core.c |  2 +-
>   drivers/irqchip/irq-gic-v3.c  | 10 ++++------
>   include/linux/acpi.h          |  5 +++++
>   4 files changed, 11 insertions(+), 8 deletions(-)
> 

With Jonathan and Russell's comments addressed:

Reviewed-by: Gavin Shan <gshan@redhat.com>

> diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
> index 960b98b43506..8c8f55721786 100644
> --- a/arch/arm64/kernel/smp.c
> +++ b/arch/arm64/kernel/smp.c
> @@ -520,7 +520,7 @@ acpi_map_gic_cpu_interface(struct acpi_madt_generic_interrupt *processor)
>   {
>   	u64 hwid = processor->arm_mpidr;
>   
> -	if (!(processor->flags & ACPI_MADT_ENABLED)) {
> +	if (!acpi_gicc_is_usable(processor)) {
>   		pr_debug("skipping disabled CPU entry with 0x%llx MPIDR\n", hwid);
>   		return;
>   	}
> diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c
> index 7dd6dbaa98c3..b203cfe28550 100644
> --- a/drivers/acpi/processor_core.c
> +++ b/drivers/acpi/processor_core.c
> @@ -90,7 +90,7 @@ static int map_gicc_mpidr(struct acpi_subtable_header *entry,
>   	struct acpi_madt_generic_interrupt *gicc =
>   	    container_of(entry, struct acpi_madt_generic_interrupt, header);
>   
> -	if (!(gicc->flags & ACPI_MADT_ENABLED))
> +	if (!acpi_gicc_is_usable(gicc))
>   		return -ENODEV;
>   
>   	/* device_declaration means Device object in DSDT, in the
> diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
> index eedfa8e9f077..72d3cdebdad1 100644
> --- a/drivers/irqchip/irq-gic-v3.c
> +++ b/drivers/irqchip/irq-gic-v3.c
> @@ -2367,8 +2367,7 @@ gic_acpi_parse_madt_gicc(union acpi_subtable_headers *header,
>   	u32 size = reg == GIC_PIDR2_ARCH_GICv4 ? SZ_64K * 4 : SZ_64K * 2;
>   	void __iomem *redist_base;
>   
> -	/* GICC entry which has !ACPI_MADT_ENABLED is not unusable so skip */
> -	if (!(gicc->flags & ACPI_MADT_ENABLED))
> +	if (!acpi_gicc_is_usable(gicc))
>   		return 0;
>   
>   	redist_base = ioremap(gicc->gicr_base_address, size);
> @@ -2418,7 +2417,7 @@ 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 ((gicc->flags & ACPI_MADT_ENABLED) && gicc->gicr_base_address) {
> +	if (acpi_gicc_is_usable(gicc) && gicc->gicr_base_address) {
>   		acpi_data.enabled_rdists++;
>   		return 0;
>   	}
> @@ -2427,7 +2426,7 @@ static int __init gic_acpi_match_gicc(union acpi_subtable_headers *header,
>   	 * It's perfectly valid firmware can pass disabled GICC entry, driver
>   	 * should not treat as errors, skip the entry instead of probe fail.
>   	 */
> -	if (!(gicc->flags & ACPI_MADT_ENABLED))
> +	if (!acpi_gicc_is_usable(gicc))
>   		return 0;
>   
>   	return -ENODEV;
> @@ -2486,8 +2485,7 @@ static int __init gic_acpi_parse_virt_madt_gicc(union acpi_subtable_headers *hea
>   	int maint_irq_mode;
>   	static int first_madt = true;
>   
> -	/* Skip unusable CPUs */
> -	if (!(gicc->flags & ACPI_MADT_ENABLED))
> +	if (!acpi_gicc_is_usable(gicc))
>   		return 0;
>   
>   	maint_irq_mode = (gicc->flags & ACPI_MADT_VGIC_IRQ_MODE) ?
> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> index b7ab85857bb7..e3265a9eafae 100644
> --- a/include/linux/acpi.h
> +++ b/include/linux/acpi.h
> @@ -256,6 +256,11 @@ acpi_table_parse_cedt(enum acpi_cedt_type id,
>   int acpi_parse_mcfg (struct acpi_table_header *header);
>   void acpi_table_print_madt_entry (struct acpi_subtable_header *madt);
>   
> +static inline bool acpi_gicc_is_usable(struct acpi_madt_generic_interrupt *gicc)
> +{
> +	return (gicc->flags & ACPI_MADT_ENABLED);
> +}
> +
>   /* the following numa functions are architecture-dependent */
>   void acpi_numa_slit_init (struct acpi_table_slit *slit);
>   

Thanks,
Gavin