From 14b6f00f8a4fdec5ccd45a0710284de301a61628 Mon Sep 17 00:00:00 2001 From: Nishanth Aravamudan Date: Mon, 28 Jan 2013 16:03:58 +0000 Subject: [PATCH] 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 25ebc45b93452d0bc60271f178237123c4b26808 ("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 Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/platforms/pseries/iommu.c | 88 +++++++++++++++++++--------------- 1 file changed, 50 insertions(+), 38 deletions(-) diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c index a8e99f9..1b2a174 100644 --- a/arch/powerpc/platforms/pseries/iommu.c +++ b/arch/powerpc/platforms/pseries/iommu.c @@ -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); } /* -- 2.7.4