linux/debian/patches-rt/irqchip-gic-v3-its-Move-pending-table-allocation-to-.patch

From: Marc Zyngier <marc.zyngier@arm.com>
Date: Fri, 27 Jul 2018 13:38:54 +0100
Subject: [PATCH] irqchip/gic-v3-its: Move pending table allocation to init
 time
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.1-rt3.tar.xz

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 drivers/irqchip/irq-gic-v3-its.c   |   80 ++++++++++++++++++++++++-------------
 include/linux/irqchip/arm-gic-v3.h |    1 
 2 files changed, 53 insertions(+), 28 deletions(-)

--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -173,6 +173,7 @@ static DEFINE_RAW_SPINLOCK(vmovp_lock);
 static DEFINE_IDA(its_vpeid_ida);
 
 #define gic_data_rdist()		(raw_cpu_ptr(gic_rdists->rdist))
+#define gic_data_rdist_cpu(cpu)		(per_cpu_ptr(gic_rdists->rdist, cpu))
 #define gic_data_rdist_rd_base()	(gic_data_rdist()->rd_base)
 #define gic_data_rdist_vlpi_base()	(gic_data_rdist_rd_base() + SZ_128K)
 
@@ -1622,7 +1623,7 @@ static void its_free_prop_table(struct p
 		   get_order(LPI_PROPBASE_SZ));
 }
 
-static int __init its_alloc_lpi_tables(void)
+static int __init its_alloc_lpi_prop_table(void)
 {
 	phys_addr_t paddr;
 
@@ -1945,30 +1946,47 @@ static void its_free_pending_table(struc
 		   get_order(max_t(u32, LPI_PENDBASE_SZ, SZ_64K)));
 }
 
-static void its_cpu_init_lpis(void)
+static int __init allocate_lpi_tables(void)
 {
-	void __iomem *rbase = gic_data_rdist_rd_base();
-	struct page *pend_page;
-	u64 val, tmp;
+	int err, cpu;
 
-	/* If we didn't allocate the pending table yet, do it now */
-	pend_page = gic_data_rdist()->pend_page;
-	if (!pend_page) {
-		phys_addr_t paddr;
+	err = its_alloc_lpi_prop_table();
+	if (err)
+		return err;
+
+	/*
+	 * We allocate all the pending tables anyway, as we may have a
+	 * mix of RDs that have had LPIs enabled, and some that
+	 * don't. We'll free the unused ones as each CPU comes online.
+	 */
+	for_each_possible_cpu(cpu) {
+		struct page *pend_page;
 
 		pend_page = its_allocate_pending_table(GFP_NOWAIT);
 		if (!pend_page) {
-			pr_err("Failed to allocate PENDBASE for CPU%d\n",
-			       smp_processor_id());
-			return;
+			pr_err("Failed to allocate PENDBASE for CPU%d\n", cpu);
+			return -ENOMEM;
 		}
 
-		paddr = page_to_phys(pend_page);
-		pr_info("CPU%d: using LPI pending table @%pa\n",
-			smp_processor_id(), &paddr);
-		gic_data_rdist()->pend_page = pend_page;
+		gic_data_rdist_cpu(cpu)->pend_page = pend_page;
 	}
 
+	return 0;
+}
+
+static void its_cpu_init_lpis(void)
+{
+	void __iomem *rbase = gic_data_rdist_rd_base();
+	struct page *pend_page;
+	phys_addr_t paddr;
+	u64 val, tmp;
+
+	if (gic_data_rdist()->lpi_enabled)
+		return;
+
+	pend_page = gic_data_rdist()->pend_page;
+	paddr = page_to_phys(pend_page);
+
 	/* set PROPBASE */
 	val = (page_to_phys(gic_rdists->prop_page) |
 	       GICR_PROPBASER_InnerShareable |
@@ -2020,6 +2038,10 @@ static void its_cpu_init_lpis(void)
 
 	/* Make sure the GIC has seen the above */
 	dsb(sy);
+	gic_data_rdist()->lpi_enabled = true;
+	pr_info("GICv3: CPU%d: using LPI pending table @%pa\n",
+		smp_processor_id(),
+		&paddr);
 }
 
 static void its_cpu_init_collection(struct its_node *its)
@@ -3498,16 +3520,6 @@ static int redist_disable_lpis(void)
 	u64 timeout = USEC_PER_SEC;
 	u64 val;
 
-	/*
-	 * If coming via a CPU hotplug event, we don't need to disable
-	 * LPIs before trying to re-enable them. They are already
-	 * configured and all is well in the world. Detect this case
-	 * by checking the allocation of the pending table for the
-	 * current CPU.
-	 */
-	if (gic_data_rdist()->pend_page)
-		return 0;
-
 	if (!gic_rdists_supports_plpis()) {
 		pr_info("CPU%d: LPIs not supported\n", smp_processor_id());
 		return -ENXIO;
@@ -3517,7 +3529,18 @@ static int redist_disable_lpis(void)
 	if (!(val & GICR_CTLR_ENABLE_LPIS))
 		return 0;
 
-	pr_warn("CPU%d: Booted with LPIs enabled, memory probably corrupted\n",
+	/*
+	 * If coming via a CPU hotplug event, we don't need to disable
+	 * LPIs before trying to re-enable them. They are already
+	 * configured and all is well in the world.
+	 */
+	if (gic_data_rdist()->lpi_enabled)
+		return 0;
+
+	/*
+	 * From that point on, we only try to do some damage control.
+	 */
+	pr_warn("GICv3: CPU%d: Booted with LPIs enabled, memory probably corrupted\n",
 		smp_processor_id());
 	add_taint(TAINT_CRAP, LOCKDEP_STILL_OK);
 
@@ -3773,7 +3796,8 @@ int __init its_init(struct fwnode_handle
 	}
 
 	gic_rdists = rdists;
-	err = its_alloc_lpi_tables();
+
+	err = allocate_lpi_tables();
 	if (err)
 		return err;
 
--- a/include/linux/irqchip/arm-gic-v3.h
+++ b/include/linux/irqchip/arm-gic-v3.h
@@ -585,6 +585,7 @@ struct rdists {
 		void __iomem	*rd_base;
 		struct page	*pend_page;
 		phys_addr_t	phys_base;
+		bool		lpi_enabled;
 	} __percpu		*rdist;
 	struct page		*prop_page;
 	u64			flags;