4.4-stable review patch. If anyone has any objections, please let me know.
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From: Marc Zyngier marc.zyngier@arm.com
commit 18aa60ce2751c95d3412ed06a58b8b6cfb6f88f2 upstream.
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.c... Signed-off-by: Thomas Gleixner tglx@linutronix.de Signed-off-by: Hanjun Guo hanjun.guo@linaro.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/irqchip/irq-gic-v3-its.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
--- a/drivers/irqchip/irq-gic-v3-its.c +++ b/drivers/irqchip/irq-gic-v3-its.c @@ -884,6 +884,7 @@ static int its_alloc_tables(const char * }
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; @@ -947,13 +948,16 @@ retry_baser: * 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; } }