From: Marc Zyngier <marc.zyngier@arm.com>
Date: Fri, 27 Jul 2018 13:38:54 +0100
Subject: irqchip/gic-v3-its: Move pending table allocation to init time
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git
Git-commit: 2afd91698e241202cfb80ec14586c65e93cd0be9
Patch-mainline: Queued in subsystem maintainer repository
References: SLE Realtime Extension

[ Upstream commit 4a0819bb25d12d39c0390636122eefba232596c1 ]

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
[bigeasy: backport commit effe377d415 ("irqchip/gic-v3-its: Move pending
          table allocation to init time")]
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Mike Galbraith <mgalbraith@suse.de>
---
 drivers/irqchip/irq-gic-v3-its.c |   56 +++++++++++++++++----------------------
 1 file changed, 25 insertions(+), 31 deletions(-)

--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -1989,14 +1989,12 @@ static int its_alloc_collections(struct
 	return 0;
 }
 
-static struct page *its_allocate_pending_table(unsigned int cpu)
+static struct page *its_allocate_pending_table(gfp_t gfp_flags)
 {
 	struct page *pend_page;
-	unsigned int order;
 
-	order = get_order(LPI_PENDBASE_SZ);
-	pend_page = alloc_pages_node(cpu_to_node(cpu), GFP_KERNEL | __GFP_ZERO,
-				     order);
+	pend_page = alloc_pages(gfp_flags | __GFP_ZERO,
+				get_order(LPI_PENDBASE_SZ));
 	if (!pend_page)
 		return NULL;
 
@@ -2027,7 +2025,7 @@ static bool enabled_lpis_allowed(void)
 	return gic_check_reserved_range(addr, LPI_PROPBASE_SZ);
 }
 
-static int __init allocate_lpi_tables(void)
+static int __init allocate_lpi_prop_table(void)
 {
 	u64 val;
 	int err, cpu;
@@ -2067,25 +2065,31 @@ static int __init allocate_lpi_tables(vo
 	return 0;
 }
 
-static int its_alloc_pend_page(unsigned int cpu)
+static int __init allocate_lpi_tables(void)
 {
-	struct page *pend_page;
-	phys_addr_t paddr;
+	int err, cpu;
 
-	pend_page = gic_data_rdist_cpu(cpu)->pend_page;
-	if (pend_page)
-		return 0;
+	err = its_alloc_lpi_prop_table();
+	if (err)
+		return err;
 
-	pend_page = its_allocate_pending_table(cpu);
-	if (!pend_page) {
-		pr_err("Failed to allocate PENDBASE for CPU%d\n",
-		       smp_processor_id());
-		return -ENOMEM;
+	/*
+	 * 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", cpu);
+			return -ENOMEM;
+		}
+
+		gic_data_rdist_cpu(cpu)->pend_page = pend_page;
 	}
 
-	paddr = page_to_phys(pend_page);
-	pr_info("CPU%d: using LPI pending table @%pa\n", cpu, &paddr);
-	gic_data_rdist_cpu(cpu)->pend_page = pend_page;
 	return 0;
 }
 
@@ -2981,7 +2985,7 @@ static int its_vpe_init(struct its_vpe *
 		return vpe_id;
 
 	/* Allocate VPT */
-	vpt_page = its_allocate_pending_table(raw_smp_processor_id());
+	vpt_page = its_allocate_pending_table(GFP_KERNEL);
 	if (!vpt_page) {
 		its_vpe_id_free(vpe_id);
 		return -ENOMEM;
@@ -3847,16 +3851,6 @@ int __init its_init(struct fwnode_handle
 	if (err)
 		return err;
 
-	err = cpuhp_setup_state(CPUHP_BP_PREPARE_DYN, "irqchip/arm/gicv3:prepare",
-				its_alloc_pend_page, NULL);
-	if (err < 0) {
-		pr_warn("ITS: Can't register CPU-hoplug callback.\n");
-		return err;
-	}
-	err = its_alloc_pend_page(smp_processor_id());
-	if (err < 0)
-		return err;
-
 	list_for_each_entry(its, &its_nodes, entry)
 		has_v4 |= its->is_v4;