Commit 11e37d35 authored by Marc Zyngier's avatar Marc Zyngier
Browse files

irqchip/gic-v3-its: Move pending table allocation to init time 



Pending tables for the redistributors are currently allocated
one at a time as each CPU boots. This is causing some grief
for Linux/RT (allocation from within a CPU hotplug notifier is
frown upon).

Let's move this allocation to take place at init time, when we
only have a single CPU. It means we're allocating memory for CPUs
that are not online yet, but most system will boot all of their
CPUs anyway, so that's not completely wasted.

Tested-by: default avatarJeremy Linton <jeremy.linton@arm.com>
Tested-by: default avatarBhupesh Sharma <bhsharma@redhat.com>
Tested-by: default avatarLei Zhang <zhang.lei@jp.fujitsu.com>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent 053be485

drivers/irqchip/irq-gic-v3-its.c

+52 −28
Original line number Diff line number Diff line
@@ -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)
@@ -1625,7 +1626,7 @@ static void its_free_prop_table(struct page *prop_page) 
		   get_order(LPI_PROPBASE_SZ));

}



static int __init its_alloc_lpi_tables(void)

static int __init its_setup_lpi_prop_table(void)

{

	phys_addr_t paddr;
@@ -1944,29 +1945,46 @@ static void its_free_pending_table(struct page *pt) 
	free_pages((unsigned long)page_address(pt), get_order(LPI_PENDBASE_SZ));

}



static void its_cpu_init_lpis(void)

static int __init allocate_lpi_tables(void)

{

	void __iomem *rbase = gic_data_rdist_rd_base();

	int err, cpu;



	err = its_setup_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;

	u64 val, tmp;



	/* If we didn't allocate the pending table yet, do it now */

	pend_page = gic_data_rdist()->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;

	}



	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;



		pend_page = its_allocate_pending_table(GFP_NOWAIT);

		if (!pend_page) {

			pr_err("Failed to allocate PENDBASE for CPU%d\n",

			       smp_processor_id());

	if (gic_data_rdist()->lpi_enabled)

		return;

		}



	pend_page = gic_data_rdist()->pend_page;

	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;

	}



	/* set PROPBASE */

	val = (page_to_phys(gic_rdists->prop_page) |
@@ -2019,6 +2037,10 @@ 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)
@@ -3497,16 +3519,6 @@ 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;
@@ -3516,7 +3528,18 @@ 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);
@@ -3772,7 +3795,8 @@ int __init its_init(struct fwnode_handle *handle, struct rdists *rdists, 
	}



	gic_rdists = rdists;

	err = its_alloc_lpi_tables();



	err = allocate_lpi_tables();

	if (err)

		return err;

include/linux/irqchip/arm-gic-v3.h

+1 −0
Original line number Diff line number Diff line
@@ -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;

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