[PATCH] irqchip/gic-v3: Fix GIC_LINE_NR accessor

[PATCH] irqchip/gic-v3: Fix GIC_LINE_NR accessor

[Zenghui Yu]

As per GIC spec, ITLinesNumber indicates the maximum SPI INTID that
the GIC implementation supports. And the maximum SPI INTID an
implementation might support is 1019 (field value 11111).

max(GICD_TYPER_SPIS(...), 1020) is not what we actually want for
GIC_LINE_NR. Fix it to min(GICD_TYPER_SPIS(...), 1020).

Signed-off-by: Zenghui Yu <yuzenghui@huawei.com>
---

Hi Marc,

I still see "GICv3: 992 SPIs implemented" on the host. I go back to
https://patchwork.kernel.org/patch/11078623/ and it seems that we
failed to make the GIC_LINE_NR correct at that time.

 drivers/irqchip/irq-gic-v3.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index 7b0c96b9e02f..f4a49aef5ca4 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -59,7 +59,7 @@ static struct gic_chip_data gic_data __read_mostly;
 static DEFINE_STATIC_KEY_TRUE(supports_deactivate_key);
 
 #define GIC_ID_NR	(1U << GICD_TYPER_ID_BITS(gic_data.rdists.gicd_typer))
-#define GIC_LINE_NR	max(GICD_TYPER_SPIS(gic_data.rdists.gicd_typer), 1020U)
+#define GIC_LINE_NR	min(GICD_TYPER_SPIS(gic_data.rdists.gicd_typer), 1020U)
 #define GIC_ESPI_NR	GICD_TYPER_ESPIS(gic_data.rdists.gicd_typer)
 
 /*
-- 
2.19.1

Re: [PATCH] irqchip/gic-v3: Fix GIC_LINE_NR accessor

[Marc Zyngier]

On 18/09/2019 07:57, Zenghui Yu wrote:
> As per GIC spec, ITLinesNumber indicates the maximum SPI INTID that
> the GIC implementation supports. And the maximum SPI INTID an
> implementation might support is 1019 (field value 11111).
> 
> max(GICD_TYPER_SPIS(...), 1020) is not what we actually want for
> GIC_LINE_NR. Fix it to min(GICD_TYPER_SPIS(...), 1020).
> 
> Signed-off-by: Zenghui Yu <yuzenghui@huawei.com>
> ---
> 
> Hi Marc,
> 
> I still see "GICv3: 992 SPIs implemented" on the host. I go back to
> https://patchwork.kernel.org/patch/11078623/ and it seems that we
> failed to make the GIC_LINE_NR correct at that time.

Ah, nice catch. Clearly, I didn't have my head screwed on properly when
I wrote this. I'll take this in for the next round of fixes.

Thanks,

	M.
-- 
Jazz is not dead, it just smells funny...

[tip: irq/urgent] irqchip/gic-v3: Fix GIC_LINE_NR accessor

[tip-bot2 for Zenghui Yu]

The following commit has been merged into the irq/urgent branch of tip:

Commit-ID:     c107d613f9204ff9c7624c229938153d7492c56e
Gitweb:        https://git.kernel.org/tip/c107d613f9204ff9c7624c229938153d7492c56e
Author:        Zenghui Yu <yuzenghui@huawei.com>
AuthorDate:    Wed, 18 Sep 2019 06:57:30 
Committer:     Marc Zyngier <maz@kernel.org>
CommitterDate: Wed, 18 Sep 2019 11:42:23 +01:00

irqchip/gic-v3: Fix GIC_LINE_NR accessor

As per GIC spec, ITLinesNumber indicates the maximum SPI INTID that
the GIC implementation supports. And the maximum SPI INTID an
implementation might support is 1019 (field value 11111).

max(GICD_TYPER_SPIS(...), 1020) is not what we actually want for
GIC_LINE_NR. Fix it to min(GICD_TYPER_SPIS(...), 1020).

Signed-off-by: Zenghui Yu <yuzenghui@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/1568789850-14080-1-git-send-email-yuzenghui@huawei.com
---
 drivers/irqchip/irq-gic-v3.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index 422664a..1edc993 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -59,7 +59,7 @@ static struct gic_chip_data gic_data __read_mostly;
 static DEFINE_STATIC_KEY_TRUE(supports_deactivate_key);
 
 #define GIC_ID_NR	(1U << GICD_TYPER_ID_BITS(gic_data.rdists.gicd_typer))
-#define GIC_LINE_NR	max(GICD_TYPER_SPIS(gic_data.rdists.gicd_typer), 1020U)
+#define GIC_LINE_NR	min(GICD_TYPER_SPIS(gic_data.rdists.gicd_typer), 1020U)
 #define GIC_ESPI_NR	GICD_TYPER_ESPIS(gic_data.rdists.gicd_typer)
 
 /*