From 50e0649e3f90fc7eed021277cd8fc574632d28b6 Mon Sep 17 00:00:00 2001
From: Marc Zyngier <marc.zyngier@arm.com>
Date: Tue, 26 Jun 2018 11:21:11 +0100
Subject: [PATCH] irqchip/gic-v3-its: Use pre-programmed redistributor tables
 with kdump kernels

commit c6e2ccb66d0c3b4fffc59932585e9f709ad59003 upstream

If using a kdump kernel, and that we cannot disable LPIs to install
our own tables, let's switch to using the already allocated tables.

This means that we'll change some of the initial kernel's memory,
but at least we'll be able to have LPIs in this secondary kernel.

Tested-by: Jeremy Linton <jeremy.linton@arm.com>
Tested-by: Bhupesh Sharma <bhsharma@redhat.com>
Tested-by: Lei Zhang <zhang.lei@jp.fujitsu.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Zou Cao <zoucao@linux.alibaba.com>
Reviewed-by: Baoyou Xie <xie.baoyou@linux.alibaba.com>
---
 drivers/irqchip/irq-gic-v3-its.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 750fcd44783c..bf1eab671118 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -19,6 +19,7 @@
 #include <linux/acpi_iort.h>
 #include <linux/bitmap.h>
 #include <linux/cpu.h>
+#include <linux/crash_dump.h>
 #include <linux/delay.h>
 #include <linux/dma-iommu.h>
 #include <linux/interrupt.h>
@@ -1991,8 +1992,15 @@ static void its_free_pending_table(struct page *pt)
 		   get_order(max_t(u32, LPI_PENDBASE_SZ, SZ_64K)));
 }
 
+/*
+ * Booting with kdump and LPIs enabled is generally fine.
+ */
 static bool enabled_lpis_allowed(void)
 {
+	/* Allow a kdump kernel */
+	if (is_kdump_kernel())
+		return true;
+
 	return false;
 }
 
-- 
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