Commit 18aa60ce authored Jan 26, 2016 by Marc Zyngier Committed by Thomas Gleixner Jan 26, 2016

irqchip/gic-v3-its: Recompute the number of pages on page size change



When the programming of a GITS_BASERn register fails because of
an unsupported ITS page size, we retry it with a smaller page size.
Unfortunately, we don't recompute the number of allocated ITS pages,
indicating the wrong value computed in the original allocation.

A convenient fix is to free the pages we allocated, update the
page size, and restart the allocation. This will ensure that
we always allocate the right amount in the case of a device
table, specially if we have to reduce the allocation order
to stay within the boundaries of the ITS maximum allocation.

Reported-and-tested-by: Ma Jun <majun258@huawei.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Jason Cooper <jason@lakedaemon.net>
Link: http://lkml.kernel.org/r/1453818255-1289-1-git-send-email-marc.zyngier@arm.com


Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

parent bb1a7931

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

+6 −2

Original line number	Diff line number	Diff line
		@@ -875,6 +875,7 @@ static int its_alloc_tables(const char node_name, struct its_node its)
		}

		alloc_size = (1 << order) * PAGE_SIZE;
		retry_alloc_baser:
		alloc_pages = (alloc_size / psz);
		if (alloc_pages > GITS_BASER_PAGES_MAX) {
		alloc_pages = GITS_BASER_PAGES_MAX;
		@@ -938,13 +939,16 @@ static int its_alloc_tables(const char node_name, struct its_node its)
		* size and retry. If we reach 4K, then
		* something is horribly wrong...
		*/
		free_pages((unsigned long)base, order);
		its->tables[i] = NULL;

		switch (psz) {
		case SZ_16K:
		psz = SZ_4K;
		goto retry_baser;
		goto retry_alloc_baser;
		case SZ_64K:
		psz = SZ_16K;
		goto retry_baser;
		goto retry_alloc_baser;
		}
		}