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Commit f54b97ed authored by Marc Zyngier's avatar Marc Zyngier Committed by Jason Cooper
Browse files

irqchip: gicv3-its: Allocate enough memory for the full range of DeviceID 



The ITS table allocator is only allocating a single page per table.
This works fine for most things, but leads to silent lack of
interrupt delivery if we end-up with a device that has an ID that is
out of the range defined by a single page of memory. Even worse, depending
on the page size, behaviour changes, which is not a very good experience.

A solution is actually to allocate memory for the full range of ID that
the ITS supports. A massive waste memory wise, but at least a safe bet.

Tested on a Phytium SoC.

Tested-by: default avatarChen Baozi <chenbaozi@kylinos.com.cn>
Acked-by: default avatarChen Baozi <chenbaozi@kylinos.com.cn>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Link: https://lkml.kernel.org/r/1425659870-11832-3-git-send-email-marc.zyngier@arm.com


Signed-off-by: default avatarJason Cooper <jason@lakedaemon.net>
parent 16acae72

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

+21 −4
Original line number Original line Diff line number Diff line
@@ -806,14 +806,31 @@ static int its_alloc_tables(struct its_node *its) 
		u64 val = readq_relaxed(its->base + GITS_BASER + i * 8);

		u64 val = readq_relaxed(its->base + GITS_BASER + i * 8);

		u64 type = GITS_BASER_TYPE(val);

		u64 type = GITS_BASER_TYPE(val);

		u64 entry_size = GITS_BASER_ENTRY_SIZE(val);

		u64 entry_size = GITS_BASER_ENTRY_SIZE(val);

		int order = 0;

		int alloc_size;

		u64 tmp;

		u64 tmp;

		void *base;

		void *base;





		if (type == GITS_BASER_TYPE_NONE)

		if (type == GITS_BASER_TYPE_NONE)

			continue;

			continue;





		/* We're lazy and only allocate a single page for now */

		/*

		base = (void *)get_zeroed_page(GFP_KERNEL);

		 * Allocate as many entries as required to fit the

		 * range of device IDs that the ITS can grok... The ID

		 * space being incredibly sparse, this results in a

		 * massive waste of memory.

		 *

		 * For other tables, only allocate a single page.

		 */

		if (type == GITS_BASER_TYPE_DEVICE) {

			u64 typer = readq_relaxed(its->base + GITS_TYPER);

			u32 ids = GITS_TYPER_DEVBITS(typer);



			order = get_order((1UL << ids) * entry_size);

		}



		alloc_size = (1 << order) * PAGE_SIZE;

		base = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);

		if (!base) {

		if (!base) {

			err = -ENOMEM;

			err = -ENOMEM;

			goto out_free;

			goto out_free;
@@ -841,7 +858,7 @@ retry_baser: 
			break;

			break;

		}

		}





		val |= (PAGE_SIZE / psz) - 1;

		val |= (alloc_size / psz) - 1;





		writeq_relaxed(val, its->base + GITS_BASER + i * 8);

		writeq_relaxed(val, its->base + GITS_BASER + i * 8);

		tmp = readq_relaxed(its->base + GITS_BASER + i * 8);

		tmp = readq_relaxed(its->base + GITS_BASER + i * 8);
@@ -882,7 +899,7 @@ retry_baser: 
		}

		}





		pr_info("ITS: allocated %d %s @%lx (psz %dK, shr %d)\n",

		pr_info("ITS: allocated %d %s @%lx (psz %dK, shr %d)\n",

			(int)(PAGE_SIZE / entry_size),

			(int)(alloc_size / entry_size),

			its_base_type_string[type],

			its_base_type_string[type],

			(unsigned long)virt_to_phys(base),

			(unsigned long)virt_to_phys(base),

			psz / SZ_1K, (int)shr >> GITS_BASER_SHAREABILITY_SHIFT);

			psz / SZ_1K, (int)shr >> GITS_BASER_SHAREABILITY_SHIFT);

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

+2 −0
Original line number Original line Diff line number Diff line
@@ -166,6 +166,8 @@ 




#define GITS_TRANSLATER			0x10040

#define GITS_TRANSLATER			0x10040





#define GITS_TYPER_DEVBITS_SHIFT	13

#define GITS_TYPER_DEVBITS(r)		((((r) >> GITS_TYPER_DEVBITS_SHIFT) & 0x1f) + 1)

#define GITS_TYPER_PTA			(1UL << 19)

#define GITS_TYPER_PTA			(1UL << 19)





#define GITS_CBASER_VALID		(1UL << 63)

#define GITS_CBASER_VALID		(1UL << 63)