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pseries/iommu: Remove DDW on kexec 

pseries/iommu: remove DDW on kexec

We currently insert a property in the device-tree when we successfully
configure DDW for a given slot. This was meant to be an optimization to
speed up kexec/kdump, so that we don't need to make the RTAS calls again
to re-configured DDW in the new kernel.

However, we end up tripping a plpar_tce_stuff failure on kexec/kdump
because we unconditionally parse the ibm,dma-window property for the
node at bus/dev setup time. This property contains the 32-bit DMA window
LIOBN, which is distinct from the DDW window's. We pass that LIOBN (via
iommu_table_init -> iommu_table_clear -> tce_free ->
tce_freemulti_pSeriesLP) to plpar_tce_stuff, which fails because that
32-bit window is no longer present after
25ebc45b93 ("powerpc/pseries/iommu: remove
default window before attempting DDW manipulation").

I believe the simplest, easiest-to-maintain fix is to just change our
initcall to, rather than detecting and updating the new kernel's DDW
knowledge, just remove all DDW configurations. When the drivers
re-initialize, we will set everything back up as it was before.

Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Nishanth Aravamudan 2013-01-28 16:03:58 +00:00 committed by Benjamin Herrenschmidt
parent a1dabadebb
commit 14b6f00f8a
1 changed files with 50 additions and 38 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

88
arch/powerpc/platforms/pseries/iommu.c
View File

@ -787,33 +787,68 @@ static u64 find_existing_ddw(struct device_node *pdn)
return dma_addr;
}
static void __restore_default_window(struct eeh_dev *edev,
u32 ddw_restore_token)
{
u32 cfg_addr;
u64 buid;
int ret;
/*
* Get the config address and phb buid of the PE window.
* Rely on eeh to retrieve this for us.
* Retrieve them from the pci device, not the node with the
* dma-window property
*/
cfg_addr = edev->config_addr;
if (edev->pe_config_addr)
cfg_addr = edev->pe_config_addr;
buid = edev->phb->buid;
do {
ret = rtas_call(ddw_restore_token, 3, 1, NULL, cfg_addr,
BUID_HI(buid), BUID_LO(buid));
} while (rtas_busy_delay(ret));
pr_info("ibm,reset-pe-dma-windows(%x) %x %x %x returned %d\n",
ddw_restore_token, cfg_addr, BUID_HI(buid), BUID_LO(buid), ret);
}
static int find_existing_ddw_windows(void)
{
int len;
struct device_node *pdn;
struct direct_window *window;
const struct dynamic_dma_window_prop *direct64;
const u32 *ddw_extensions;
if (!firmware_has_feature(FW_FEATURE_LPAR))
return 0;
for_each_node_with_property(pdn, DIRECT64_PROPNAME) {
direct64 = of_get_property(pdn, DIRECT64_PROPNAME, &len);
direct64 = of_get_property(pdn, DIRECT64_PROPNAME, NULL);
if (!direct64)
continue;
window = kzalloc(sizeof(*window), GFP_KERNEL);
if (!window || len < sizeof(struct dynamic_dma_window_prop)) {
kfree(window);
remove_ddw(pdn);
continue;
}
/*
* We need to ensure the IOMMU table is active when we
* return from the IOMMU setup so that the common code
* can clear the table or find the holes. To that end,
* first, remove any existing DDW configuration.
*/
remove_ddw(pdn);
window->device = pdn;
window->prop = direct64;
spin_lock(&direct_window_list_lock);
list_add(&window->list, &direct_window_list);
spin_unlock(&direct_window_list_lock);
/*
* Second, if we are running on a new enough level of
* firmware where the restore API is present, use it to
* restore the 32-bit window, which was removed in
* create_ddw.
* If the API is not present, then create_ddw couldn't
* have removed the 32-bit window in the first place, so
* removing the DDW configuration should be sufficient.
*/
ddw_extensions = of_get_property(pdn, "ibm,ddw-extensions",
NULL);
if (ddw_extensions && ddw_extensions[0] > 0)
__restore_default_window(of_node_to_eeh_dev(pdn),
ddw_extensions[1]);
}
return 0;
@ -886,30 +921,7 @@ static int create_ddw(struct pci_dev *dev, const u32 *ddw_avail,
static void restore_default_window(struct pci_dev *dev,
u32 ddw_restore_token)
{
struct eeh_dev *edev;
u32 cfg_addr;
u64 buid;
int ret;
/*
* Get the config address and phb buid of the PE window.
* Rely on eeh to retrieve this for us.
* Retrieve them from the pci device, not the node with the
* dma-window property
*/
edev = pci_dev_to_eeh_dev(dev);
cfg_addr = edev->config_addr;
if (edev->pe_config_addr)
cfg_addr = edev->pe_config_addr;
buid = edev->phb->buid;
do {
ret = rtas_call(ddw_restore_token, 3, 1, NULL, cfg_addr,
BUID_HI(buid), BUID_LO(buid));
} while (rtas_busy_delay(ret));
dev_info(&dev->dev,
"ibm,reset-pe-dma-windows(%x) %x %x %x returned %d\n",
ddw_restore_token, cfg_addr, BUID_HI(buid), BUID_LO(buid), ret);
__restore_default_window(pci_dev_to_eeh_dev(dev), ddw_restore_token);
}
/*