[PATCH v3] irqchip/gicv3-its: Don't allow devices whose ID is outside range

Shanker Donthineni
2016-03-01T12:55:19Z

We are not checking whether the requested device identifier fits into
the device table memory or not. The function its_create_device()
assumes that enough memory has been allocated for whole DevID space
(reported by ITS_TYPER.Devbits) during the ITS probe() and continues
to initialize ITS hardware.

This assumption is not perfect, sometimes we reduce memory size either
because of its size crossing MAX_ORDER-1 or BASERn max size limit. The
MAPD command fails if 'Device ID' is outside of device table range.

Add a simple validation check to avoid MAPD failures since we are
not handling ITS command errors. This change also helps to return an
error -ENOMEM instead of success to caller.

Reviewed-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Shanker Donthineni <shankerd@codeaurora.org>
---
[v1]->[v2]
Rebase to v4.5-rc6, edit commit text and simplify code changes.

[v2]->[v3]
Fix typo.

drivers/irqchip/irq-gic-v3-its.c | 24 ++++++++++++++++++++----
1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 43dfd15..6d986ac 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -55,6 +55,16 @@ struct its_collection {
};

/*
+ * The ITS_BASER structure - contains memory information and table
+ * entry size in bytes.
+ */
+struct its_baser {
+ void *base;
+ u32 order;
+ u32 entry_size;
+};
+
+/*
* The ITS structure - contains most of the infrastructure, with the
* top-level MSI domain, the command queue, the collections, and the
* list of devices writing to it.
@@ -66,14 +76,12 @@ struct its_node {
unsigned long phys_base;
struct its_cmd_block *cmd_base;
struct its_cmd_block *cmd_write;
- struct {
- void *base;
- u32 order;
- } tables[GITS_BASER_NR_REGS];
+ struct its_baser tables[GITS_BASER_NR_REGS];
struct its_collection *collections;
struct list_head its_device_list;
u64 flags;
u32 ite_size;
+ struct its_baser *device_table;
};

#define ITS_ITT_ALIGN SZ_256
@@ -860,6 +868,7 @@ static int its_alloc_tables(const char *node_name, struct its_node *its)
* For other tables, only allocate a single page.
*/
if (type == GITS_BASER_TYPE_DEVICE) {
+ its->device_table = &its->tables[i];
/*
* 'order' was initialized earlier to the default page
* granule of the the ITS. We can't have an allocation
@@ -874,6 +883,7 @@ static int its_alloc_tables(const char *node_name, struct its_node *its)
node_name, order);
}
}
+ its->tables[i].entry_size = entry_size;

retry_alloc_baser:
alloc_pages = (PAGE_ORDER_TO_SIZE(order) / psz);
@@ -1152,6 +1162,12 @@ static struct its_device *its_create_device(struct its_node *its, u32 dev_id,
int nr_ites;
int sz;

+ /* Don't allow 'dev_id' that exceeds single, flat table limit */
+ if (its->device_table &&
+ (dev_id >= (PAGE_ORDER_TO_SIZE(its->device_table->order) /
+ its->device_table->entry_size)))
+ return NULL;
+
dev = kzalloc(sizeof(*dev), GFP_KERNEL);
/*
* At least one bit of EventID is being used, hence a minimum
--
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