linux-kernel - [irqchip: irq/irqchip-next] irqchip/gic-v4: Disable redistributors' view of the VPE table at boot time

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Message-ID: <163966828357.23020.3431040692428134241.tip-bot2@tip-bot2>
Date:   Thu, 16 Dec 2021 15:24:43 -0000
From:   "irqchip-bot for Marc Zyngier" <tip-bot2@...utronix.de>
To:     linux-kernel@...r.kernel.org
Cc:     Jay Chen <jkchen@...ux.alibaba.com>, Marc Zyngier <maz@...nel.org>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        tglx@...utronix.de
Subject: [irqchip: irq/irqchip-next] irqchip/gic-v4: Disable redistributors'
 view of the VPE table at boot time

The following commit has been merged into the irq/irqchip-next branch of irqchip:

Commit-ID:     79a7f77b9b154d572bd9d2f1eecf58c4d018d8e2
Gitweb:        https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms/79a7f77b9b154d572bd9d2f1eecf58c4d018d8e2
Author:        Marc Zyngier <maz@...nel.org>
AuthorDate:    Thu, 16 Dec 2021 14:32:27 
Committer:     Marc Zyngier <maz@...nel.org>
CommitterDate: Thu, 16 Dec 2021 15:19:52 

irqchip/gic-v4: Disable redistributors' view of the VPE table at boot time

Jay Chen reported that using a kdump kernel on a GICv4.1 system
results in a RAS error being delivered when the secondary kernel
configures the ITS's view of the new VPE table.

As it turns out, that's because each RD still has a pointer to
the previous instance of the VPE table, and that particular
implementation is very upset by seeing two bits of the HW that
should point to the same table with different values.

To solve this, let's invalidate any reference that any RD has to
the VPE table when discovering the RDs. The ITS can then be
programmed as expected.

Reported-by: Jay Chen <jkchen@...ux.alibaba.com>
Signed-off-by: Marc Zyngier <maz@...nel.org>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@....com>
Link: https://lore.kernel.org/r/20211214064716.21407-1-jkchen@linux.alibaba.com
Link: https://lore.kernel.org/r/20211216144804.1578566-1-maz@kernel.org
---
 drivers/irqchip/irq-gic-v3.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index daec330..8639752 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -920,6 +920,22 @@ static int __gic_update_rdist_properties(struct redist_region *region,
 {
 	u64 typer = gic_read_typer(ptr + GICR_TYPER);
 
+	/* Boot-time cleanip */
+	if ((typer & GICR_TYPER_VLPIS) && (typer & GICR_TYPER_RVPEID)) {
+		u64 val;
+
+		/* Deactivate any present vPE */
+		val = gicr_read_vpendbaser(ptr + SZ_128K + GICR_VPENDBASER);
+		if (val & GICR_VPENDBASER_Valid)
+			gicr_write_vpendbaser(GICR_VPENDBASER_PendingLast,
+					      ptr + SZ_128K + GICR_VPENDBASER);
+
+		/* Mark the VPE table as invalid */
+		val = gicr_read_vpropbaser(ptr + SZ_128K + GICR_VPROPBASER);
+		val &= ~GICR_VPROPBASER_4_1_VALID;
+		gicr_write_vpropbaser(val, ptr + SZ_128K + GICR_VPROPBASER);
+	}
+
 	gic_data.rdists.has_vlpis &= !!(typer & GICR_TYPER_VLPIS);
 
 	/* RVPEID implies some form of DirectLPI, no matter what the doc says... :-/ */