irqchip/gic-v3-its: Use pre-programmed redistributor tables with kdump kernels

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>

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 6a9066411cbca01ef61f2fdd918429a10e9f43e6..83d5573f56e9cb927d5ee15ee1ef595b1a0da128 100644 (file)
--- 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>
@@ -1963,8 +1964,15 @@ static void its_free_pending_table(struct page *pt)
        free_pages((unsigned long)page_address(pt), get_order(LPI_PENDBASE_SZ));
 }
 
+/*
+ * 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;
 }