Hi Marc,
On 02/22/2016 09:57 PM, Shanker Donthineni wrote:
We are not checking whether the requested device identifier fits into
table or not. The ITS 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.
Signed-off-by: Shanker Donthineni <[email protected]>
---
This patch depends on
https://git.kernel.org/cgit/linux/kernel/git/maz/arm-platforms.git/commit/?h=irq/gic-4.5-fixes&id=2eca0d6ceea1f108b2d3ac81fb34698c4fd41006
drivers/irqchip/irq-gic-v3-its.c | 18 +++++++++++++++---
1 file changed, 15 insertions(+), 3 deletions(-)
diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index c0f227a..9bdcdf5 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -70,6 +70,7 @@ struct its_node {
struct {
void *base;
u32 order;
+ u32 entry_size;
} tables[GITS_BASER_NR_REGS];
struct its_collection *collections;
struct list_head its_device_list;
@@ -880,6 +881,7 @@ static int its_alloc_tables(const char *node_name, struct
its_node *its)
node_name, order);
}
}
+ its->tables[type].entry_size = entry_size;
retry_alloc_baser:
alloc_pages = (PAGE_ORDER_TO_SIZE(order) / psz);
@@ -896,8 +898,8 @@ retry_alloc_baser:
goto out_free;
}
- its->tables[i].base = base;
- its->tables[i].order = order;
+ its->tables[type].base = base;
+ its->tables[type].order = order;
retry_baser:
val = (virt_to_phys(base) |
@@ -947,7 +949,7 @@ retry_baser:
* something is horribly wrong...
*/
free_pages((unsigned long)base, order);
- its->tables[i].base = NULL;
+ its->tables[type].base = NULL;
switch (psz) {
case SZ_16K:
@@ -1152,12 +1154,22 @@ static struct its_device *its_create_device(struct
its_node *its, u32 dev_id,
unsigned long *lpi_map;
unsigned long flags;
u16 *col_map = NULL;
+ u8 type = GITS_BASER_TYPE_DEVICE;
+ u32 entry_size;
+ u32 order;
void *itt;
int lpi_base;
int nr_lpis;
int nr_ites;
int sz;
+ entry_size = its->tables[type].entry_size;
+ order = its->tables[type].order;
+
+ /* Don't allow 'dev_id' that exceeds single, flat table limit */
+ if (dev_id >= (PAGE_ORDER_TO_SIZE(order) / entry_size))
+ return NULL;
+
dev = kzalloc(sizeof(*dev), GFP_KERNEL);
/*
* At least one bit of EventID is being used, hence a minimum
ITS probe function tries to allocate maximum memory as much as possible
to cover whole DevID.
sparse which is reported (ITS_TYPER.Devbits) by HW. We might not be able
to allocate enough
memory for device table. We reduce memory allocation size for two
reasons either because of
crossing MAX_ORDER limit or max ITS_BASERn size.
1) According to ARM-GIC spec, we can assign maximum memory size 256
(ITS-Size) *
64K (ITS-PageSzie) Bytes to level-one (flat) device table.
DevID = flat_table_size / device_table_entry_size = 16 MBytes / 8
= 21bits (max)
2) Maximum 4Mbytes memory is possible on kernel using PAGE_SIZE=4K with
default
arch/arm64/defconfig (MAX_ORDER = 12).
DevID = flat_table_size / device_table_entry_size = 4 MBytes / 8 =
19bits (max)
Assuming: minimum device table entry size 8 Bytes.
I think it is a generic problem and this fail scenario happens if DevID
range is more than 21bits or
failed to allocate required memory size for device table.
Our ITS hardware is capable of supporting 32bit DevID space, so it
advertises ITS_TYPER.Devbits
field with value 31 causing this problem. I think we need some
protection in its_create_device() to
avoid this scenario.
I am planning to post an another patch to add support for
ITS-Indirection (two-level) table walk feature.
--
Shanker Donthineni
Qualcomm Technologies, Inc. on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux
Foundation Collaborative Project
