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* [PATCH v3 12/14] powerpc/eeh: Rename eeh_{add_to|remove_from}_parent_pe()
From: Oliver O'Halloran @ 2020-07-25  8:12 UTC (permalink / raw)
  To: linuxppc-dev; +Cc: Oliver O'Halloran
In-Reply-To: <20200725081231.39076-1-oohall@gmail.com>

The naming of eeh_{add_to|remove_from}_parent_pe() doesn't really reflect
what they actually do. If the PE referred to be edev->pe_config_addr
already exists under that PHB then the edev is added to that PE. However,
if the PE doesn't exist the a new one is created for the edev.

The bulk of the implementation of eeh_add_to_parent_pe() covers that
second case. Similarly, most of eeh_remove_from_parent_pe() is
determining when it's safe to delete a PE.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
---
v2: no changes
v3: no changes
---
 arch/powerpc/include/asm/eeh.h               | 4 ++--
 arch/powerpc/kernel/eeh.c                    | 4 ++--
 arch/powerpc/kernel/eeh_driver.c             | 2 +-
 arch/powerpc/kernel/eeh_pe.c                 | 8 ++++----
 arch/powerpc/kernel/pci_dn.c                 | 2 +-
 arch/powerpc/platforms/powernv/eeh-powernv.c | 2 +-
 arch/powerpc/platforms/pseries/eeh_pseries.c | 8 ++++----
 7 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/arch/powerpc/include/asm/eeh.h b/arch/powerpc/include/asm/eeh.h
index 79de8624809a..ee5f354bc8b9 100644
--- a/arch/powerpc/include/asm/eeh.h
+++ b/arch/powerpc/include/asm/eeh.h
@@ -283,8 +283,8 @@ struct eeh_pe *eeh_phb_pe_get(struct pci_controller *phb);
 struct eeh_pe *eeh_pe_next(struct eeh_pe *pe, struct eeh_pe *root);
 struct eeh_pe *eeh_pe_get(struct pci_controller *phb,
 			  int pe_no, int config_addr);
-int eeh_add_to_parent_pe(struct eeh_dev *edev);
-int eeh_rmv_from_parent_pe(struct eeh_dev *edev);
+int eeh_pe_tree_insert(struct eeh_dev *edev);
+int eeh_pe_tree_remove(struct eeh_dev *edev);
 void eeh_pe_update_time_stamp(struct eeh_pe *pe);
 void *eeh_pe_traverse(struct eeh_pe *root,
 		      eeh_pe_traverse_func fn, void *flag);
diff --git a/arch/powerpc/kernel/eeh.c b/arch/powerpc/kernel/eeh.c
index f203ffc5c57d..94682382fc8c 100644
--- a/arch/powerpc/kernel/eeh.c
+++ b/arch/powerpc/kernel/eeh.c
@@ -1107,7 +1107,7 @@ void eeh_probe_device(struct pci_dev *dev)
 	 * FIXME: HEY MA, LOOK AT ME, NO LOCKING!
 	 */
 	if (edev->pdev && edev->pdev != dev) {
-		eeh_rmv_from_parent_pe(edev);
+		eeh_pe_tree_remove(edev);
 		eeh_addr_cache_rmv_dev(edev->pdev);
 		eeh_sysfs_remove_device(edev->pdev);
 
@@ -1186,7 +1186,7 @@ void eeh_remove_device(struct pci_dev *dev)
 	edev->in_error = false;
 	dev->dev.archdata.edev = NULL;
 	if (!(edev->pe->state & EEH_PE_KEEP))
-		eeh_rmv_from_parent_pe(edev);
+		eeh_pe_tree_remove(edev);
 	else
 		edev->mode |= EEH_DEV_DISCONNECTED;
 }
diff --git a/arch/powerpc/kernel/eeh_driver.c b/arch/powerpc/kernel/eeh_driver.c
index b84d3cb2532e..4197e4559f65 100644
--- a/arch/powerpc/kernel/eeh_driver.c
+++ b/arch/powerpc/kernel/eeh_driver.c
@@ -542,7 +542,7 @@ static void *eeh_pe_detach_dev(struct eeh_pe *pe, void *userdata)
 			continue;
 
 		edev->mode &= ~(EEH_DEV_DISCONNECTED | EEH_DEV_IRQ_DISABLED);
-		eeh_rmv_from_parent_pe(edev);
+		eeh_pe_tree_remove(edev);
 	}
 
 	return NULL;
diff --git a/arch/powerpc/kernel/eeh_pe.c b/arch/powerpc/kernel/eeh_pe.c
index f20fb0ee6aec..97bf09db2ecd 100644
--- a/arch/powerpc/kernel/eeh_pe.c
+++ b/arch/powerpc/kernel/eeh_pe.c
@@ -356,7 +356,7 @@ static struct eeh_pe *eeh_pe_get_parent(struct eeh_dev *edev)
 }
 
 /**
- * eeh_add_to_parent_pe - Add EEH device to parent PE
+ * eeh_pe_tree_insert - Add EEH device to parent PE
  * @edev: EEH device
  *
  * Add EEH device to the parent PE. If the parent PE already
@@ -364,7 +364,7 @@ static struct eeh_pe *eeh_pe_get_parent(struct eeh_dev *edev)
  * we have to create new PE to hold the EEH device and the new
  * PE will be linked to its parent PE as well.
  */
-int eeh_add_to_parent_pe(struct eeh_dev *edev)
+int eeh_pe_tree_insert(struct eeh_dev *edev)
 {
 	struct eeh_pe *pe, *parent;
 	struct pci_dn *pdn = eeh_dev_to_pdn(edev);
@@ -459,7 +459,7 @@ int eeh_add_to_parent_pe(struct eeh_dev *edev)
 }
 
 /**
- * eeh_rmv_from_parent_pe - Remove one EEH device from the associated PE
+ * eeh_pe_tree_remove - Remove one EEH device from the associated PE
  * @edev: EEH device
  *
  * The PE hierarchy tree might be changed when doing PCI hotplug.
@@ -467,7 +467,7 @@ int eeh_add_to_parent_pe(struct eeh_dev *edev)
  * during EEH recovery. So we have to call the function remove the
  * corresponding PE accordingly if necessary.
  */
-int eeh_rmv_from_parent_pe(struct eeh_dev *edev)
+int eeh_pe_tree_remove(struct eeh_dev *edev)
 {
 	struct eeh_pe *pe, *parent, *child;
 	bool keep, recover;
diff --git a/arch/powerpc/kernel/pci_dn.c b/arch/powerpc/kernel/pci_dn.c
index bf11ac8427ac..e99b7c547d7e 100644
--- a/arch/powerpc/kernel/pci_dn.c
+++ b/arch/powerpc/kernel/pci_dn.c
@@ -263,7 +263,7 @@ void remove_sriov_vf_pdns(struct pci_dev *pdev)
 				 * have a configured PE.
 				 */
 				if (edev->pe)
-					eeh_rmv_from_parent_pe(edev);
+					eeh_pe_tree_remove(edev);
 
 				pdn->edev = NULL;
 				kfree(edev);
diff --git a/arch/powerpc/platforms/powernv/eeh-powernv.c b/arch/powerpc/platforms/powernv/eeh-powernv.c
index 7cbb03a97a61..8c9fca773692 100644
--- a/arch/powerpc/platforms/powernv/eeh-powernv.c
+++ b/arch/powerpc/platforms/powernv/eeh-powernv.c
@@ -399,7 +399,7 @@ static struct eeh_dev *pnv_eeh_probe(struct pci_dev *pdev)
 	edev->pe_config_addr = phb->ioda.pe_rmap[config_addr];
 
 	/* Create PE */
-	ret = eeh_add_to_parent_pe(edev);
+	ret = eeh_pe_tree_insert(edev);
 	if (ret) {
 		eeh_edev_warn(edev, "Failed to add device to PE (code %d)\n", ret);
 		return NULL;
diff --git a/arch/powerpc/platforms/pseries/eeh_pseries.c b/arch/powerpc/platforms/pseries/eeh_pseries.c
index 67931fe5f341..88639b65daa3 100644
--- a/arch/powerpc/platforms/pseries/eeh_pseries.c
+++ b/arch/powerpc/platforms/pseries/eeh_pseries.c
@@ -71,8 +71,8 @@ void pseries_pcibios_bus_add_device(struct pci_dev *pdev)
 		struct eeh_dev *edev = pdn_to_eeh_dev(pdn);
 
 		edev->pe_config_addr =  (pdn->busno << 16) | (pdn->devfn << 8);
-		eeh_rmv_from_parent_pe(edev); /* Remove as it is adding to bus pe */
-		eeh_add_to_parent_pe(edev);   /* Add as VF PE type */
+		eeh_pe_tree_remove(edev); /* Remove as it is adding to bus pe */
+		eeh_pe_tree_insert(edev);   /* Add as VF PE type */
 	}
 #endif
 	eeh_probe_device(pdev);
@@ -315,14 +315,14 @@ void pseries_eeh_init_edev(struct pci_dn *pdn)
 
 		if (enable) {
 			eeh_add_flag(EEH_ENABLED);
-			eeh_add_to_parent_pe(edev);
+			eeh_pe_tree_insert(edev);
 		} else if (pdn->parent && pdn_to_eeh_dev(pdn->parent) &&
 			   (pdn_to_eeh_dev(pdn->parent))->pe) {
 			/* This device doesn't support EEH, but it may have an
 			 * EEH parent, in which case we mark it as supported.
 			 */
 			edev->pe_config_addr = pdn_to_eeh_dev(pdn->parent)->pe_config_addr;
-			eeh_add_to_parent_pe(edev);
+			eeh_pe_tree_insert(edev);
 		}
 		eeh_edev_dbg(edev, "EEH is %s on device (code %d)\n",
 			     (enable ? "enabled" : "unsupported"), ret);
-- 
2.26.2


^ permalink raw reply related

* [PATCH v3 13/14] powerpc/eeh: Drop pdn use in eeh_pe_tree_insert()
From: Oliver O'Halloran @ 2020-07-25  8:12 UTC (permalink / raw)
  To: linuxppc-dev; +Cc: Oliver O'Halloran
In-Reply-To: <20200725081231.39076-1-oohall@gmail.com>

This is mostly just to make the subsequent diffs less noisy. No functional
changes.

One thing that needs calling out is the removal of the "config_addr"
variable and replacing it with edev->bdfn. The contents of edev->bdfn are
the same, however it's worth pointing out that what RTAS calls a
"config_addr" isn't the same as the bdfn. The config_addr is supposed to
be: <bus><devfn><reg> with each field being an 8 bit number. Various parts
of the EEH code use BDFN and "config_addr" as interchangeable quantities
even though they aren't really.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
---
v2: no changes
v3: no changes
---
 arch/powerpc/kernel/eeh_pe.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/arch/powerpc/kernel/eeh_pe.c b/arch/powerpc/kernel/eeh_pe.c
index 97bf09db2ecd..898205829a8f 100644
--- a/arch/powerpc/kernel/eeh_pe.c
+++ b/arch/powerpc/kernel/eeh_pe.c
@@ -366,9 +366,8 @@ static struct eeh_pe *eeh_pe_get_parent(struct eeh_dev *edev)
  */
 int eeh_pe_tree_insert(struct eeh_dev *edev)
 {
+	struct pci_controller *hose = edev->controller;
 	struct eeh_pe *pe, *parent;
-	struct pci_dn *pdn = eeh_dev_to_pdn(edev);
-	int config_addr = (pdn->busno << 8) | (pdn->devfn);
 
 	/* Check if the PE number is valid */
 	if (!eeh_has_flag(EEH_VALID_PE_ZERO) && !edev->pe_config_addr) {
@@ -382,7 +381,7 @@ int eeh_pe_tree_insert(struct eeh_dev *edev)
 	 * PE should be composed of PCI bus and its subordinate
 	 * components.
 	 */
-	pe = eeh_pe_get(pdn->phb, edev->pe_config_addr, config_addr);
+	pe = eeh_pe_get(hose, edev->pe_config_addr, edev->bdfn);
 	if (pe) {
 		if (pe->type & EEH_PE_INVALID) {
 			list_add_tail(&edev->entry, &pe->edevs);
@@ -416,15 +415,15 @@ int eeh_pe_tree_insert(struct eeh_dev *edev)
 
 	/* Create a new EEH PE */
 	if (edev->physfn)
-		pe = eeh_pe_alloc(pdn->phb, EEH_PE_VF);
+		pe = eeh_pe_alloc(hose, EEH_PE_VF);
 	else
-		pe = eeh_pe_alloc(pdn->phb, EEH_PE_DEVICE);
+		pe = eeh_pe_alloc(hose, EEH_PE_DEVICE);
 	if (!pe) {
 		pr_err("%s: out of memory!\n", __func__);
 		return -ENOMEM;
 	}
 	pe->addr	= edev->pe_config_addr;
-	pe->config_addr	= config_addr;
+	pe->config_addr	= edev->bdfn;
 
 	/*
 	 * Put the new EEH PE into hierarchy tree. If the parent
@@ -434,10 +433,10 @@ int eeh_pe_tree_insert(struct eeh_dev *edev)
 	 */
 	parent = eeh_pe_get_parent(edev);
 	if (!parent) {
-		parent = eeh_phb_pe_get(pdn->phb);
+		parent = eeh_phb_pe_get(hose);
 		if (!parent) {
 			pr_err("%s: No PHB PE is found (PHB Domain=%d)\n",
-				__func__, pdn->phb->global_number);
+				__func__, hose->global_number);
 			edev->pe = NULL;
 			kfree(pe);
 			return -EEXIST;
-- 
2.26.2


^ permalink raw reply related

* [PATCH v3 14/14] powerpc/eeh: Move PE tree setup into the platform
From: Oliver O'Halloran @ 2020-07-25  8:12 UTC (permalink / raw)
  To: linuxppc-dev; +Cc: Alexey Kardashevskiy, Oliver O'Halloran
In-Reply-To: <20200725081231.39076-1-oohall@gmail.com>

The EEH core has a concept of a "PE tree" to support PowerNV. The PE tree
follows the PCI bus structures because a reset asserted on an upstream
bridge will be propagated to the downstream bridges. On pseries there's a
1-1 correspondence between what the guest sees are a PHB and a PE so the
"tree" is really just a single node.

Current the EEH core is reponsible for setting up this PE tree which it
does by traversing the pci_dn tree. The structure of the pci_dn tree
matches the bus tree on PowerNV which leads to the PE tree being "correct"
this setup method doesn't make a whole lot of sense and it's actively
confusing for the pseries case where it doesn't really do anything.

We want to remove the dependence on pci_dn anyway so this patch move
choosing where to insert a new PE into the platform code rather than
being part of the generic EEH code. For PowerNV this simplifies the
tree building logic and removes the use of pci_dn. For pseries we
keep the existing logic. I'm not really convinced it does anything
due to the 1-1 PE-to-PHB correspondence so every device under that
PHB should be in the same PE, but I'd rather not remove it entirely
until we've had a chance to look at it more deeply.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
v2: Reworked pseries PE setup slightly
v3: no changes
---
 arch/powerpc/include/asm/eeh.h               |  2 +-
 arch/powerpc/kernel/eeh_pe.c                 | 70 ++++++--------------
 arch/powerpc/platforms/powernv/eeh-powernv.c | 27 +++++++-
 arch/powerpc/platforms/pseries/eeh_pseries.c | 66 +++++++++++++++---
 4 files changed, 102 insertions(+), 63 deletions(-)

diff --git a/arch/powerpc/include/asm/eeh.h b/arch/powerpc/include/asm/eeh.h
index ee5f354bc8b9..d5f369bcd130 100644
--- a/arch/powerpc/include/asm/eeh.h
+++ b/arch/powerpc/include/asm/eeh.h
@@ -283,7 +283,7 @@ struct eeh_pe *eeh_phb_pe_get(struct pci_controller *phb);
 struct eeh_pe *eeh_pe_next(struct eeh_pe *pe, struct eeh_pe *root);
 struct eeh_pe *eeh_pe_get(struct pci_controller *phb,
 			  int pe_no, int config_addr);
-int eeh_pe_tree_insert(struct eeh_dev *edev);
+int eeh_pe_tree_insert(struct eeh_dev *edev, struct eeh_pe *new_pe_parent);
 int eeh_pe_tree_remove(struct eeh_dev *edev);
 void eeh_pe_update_time_stamp(struct eeh_pe *pe);
 void *eeh_pe_traverse(struct eeh_pe *root,
diff --git a/arch/powerpc/kernel/eeh_pe.c b/arch/powerpc/kernel/eeh_pe.c
index 898205829a8f..ea2f8b362d18 100644
--- a/arch/powerpc/kernel/eeh_pe.c
+++ b/arch/powerpc/kernel/eeh_pe.c
@@ -318,53 +318,20 @@ struct eeh_pe *eeh_pe_get(struct pci_controller *phb,
 	return pe;
 }
 
-/**
- * eeh_pe_get_parent - Retrieve the parent PE
- * @edev: EEH device
- *
- * The whole PEs existing in the system are organized as hierarchy
- * tree. The function is used to retrieve the parent PE according
- * to the parent EEH device.
- */
-static struct eeh_pe *eeh_pe_get_parent(struct eeh_dev *edev)
-{
-	struct eeh_dev *parent;
-	struct pci_dn *pdn = eeh_dev_to_pdn(edev);
-
-	/*
-	 * It might have the case for the indirect parent
-	 * EEH device already having associated PE, but
-	 * the direct parent EEH device doesn't have yet.
-	 */
-	if (edev->physfn)
-		pdn = pci_get_pdn(edev->physfn);
-	else
-		pdn = pdn ? pdn->parent : NULL;
-	while (pdn) {
-		/* We're poking out of PCI territory */
-		parent = pdn_to_eeh_dev(pdn);
-		if (!parent)
-			return NULL;
-
-		if (parent->pe)
-			return parent->pe;
-
-		pdn = pdn->parent;
-	}
-
-	return NULL;
-}
-
 /**
  * eeh_pe_tree_insert - Add EEH device to parent PE
  * @edev: EEH device
+ * @new_pe_parent: PE to create additional PEs under
  *
- * Add EEH device to the parent PE. If the parent PE already
- * exists, the PE type will be changed to EEH_PE_BUS. Otherwise,
- * we have to create new PE to hold the EEH device and the new
- * PE will be linked to its parent PE as well.
+ * Add EEH device to the PE in edev->pe_config_addr. If a PE already
+ * exists with that address then @edev is added to that PE. Otherwise
+ * a new PE is created and inserted into the PE tree as a child of
+ * @new_pe_parent.
+ *
+ * If @new_pe_parent is NULL then the new PE will be inserted under
+ * directly under the the PHB.
  */
-int eeh_pe_tree_insert(struct eeh_dev *edev)
+int eeh_pe_tree_insert(struct eeh_dev *edev, struct eeh_pe *new_pe_parent)
 {
 	struct pci_controller *hose = edev->controller;
 	struct eeh_pe *pe, *parent;
@@ -399,7 +366,7 @@ int eeh_pe_tree_insert(struct eeh_dev *edev)
 			}
 
 			eeh_edev_dbg(edev,
-				     "Added to device PE (parent: PE#%x)\n",
+				     "Added to existing PE (parent: PE#%x)\n",
 				     pe->parent->addr);
 		} else {
 			/* Mark the PE as type of PCI bus */
@@ -431,10 +398,9 @@ int eeh_pe_tree_insert(struct eeh_dev *edev)
 	 * to PHB directly. Otherwise, we have to associate the
 	 * PE with its parent.
 	 */
-	parent = eeh_pe_get_parent(edev);
-	if (!parent) {
-		parent = eeh_phb_pe_get(hose);
-		if (!parent) {
+	if (!new_pe_parent) {
+		new_pe_parent = eeh_phb_pe_get(hose);
+		if (!new_pe_parent) {
 			pr_err("%s: No PHB PE is found (PHB Domain=%d)\n",
 				__func__, hose->global_number);
 			edev->pe = NULL;
@@ -442,17 +408,19 @@ int eeh_pe_tree_insert(struct eeh_dev *edev)
 			return -EEXIST;
 		}
 	}
-	pe->parent = parent;
+
+	/* link new PE into the tree */
+	pe->parent = new_pe_parent;
+	list_add_tail(&pe->child, &new_pe_parent->child_list);
 
 	/*
 	 * Put the newly created PE into the child list and
 	 * link the EEH device accordingly.
 	 */
-	list_add_tail(&pe->child, &parent->child_list);
 	list_add_tail(&edev->entry, &pe->edevs);
 	edev->pe = pe;
-	eeh_edev_dbg(edev, "Added to device PE (parent: PE#%x)\n",
-		     pe->parent->addr);
+	eeh_edev_dbg(edev, "Added to new (parent: PE#%x)\n",
+		     new_pe_parent->addr);
 
 	return 0;
 }
diff --git a/arch/powerpc/platforms/powernv/eeh-powernv.c b/arch/powerpc/platforms/powernv/eeh-powernv.c
index 8c9fca773692..9af8c3b98853 100644
--- a/arch/powerpc/platforms/powernv/eeh-powernv.c
+++ b/arch/powerpc/platforms/powernv/eeh-powernv.c
@@ -338,6 +338,28 @@ static int pnv_eeh_find_ecap(struct pci_dn *pdn, int cap)
 	return 0;
 }
 
+static struct eeh_pe *pnv_eeh_get_upstream_pe(struct pci_dev *pdev)
+{
+	struct pci_controller *hose = pdev->bus->sysdata;
+	struct pnv_phb *phb = hose->private_data;
+	struct pci_dev *parent = pdev->bus->self;
+
+#ifdef CONFIG_PCI_IOV
+	/* for VFs we use the PF's PE as the upstream PE */
+	if (pdev->is_virtfn)
+		parent = pdev->physfn;
+#endif
+
+	/* otherwise use the PE of our parent bridge */
+	if (parent) {
+		struct pnv_ioda_pe *ioda_pe = pnv_ioda_get_pe(parent);
+
+		return eeh_pe_get(phb->hose, ioda_pe->pe_number, 0);
+	}
+
+	return NULL;
+}
+
 /**
  * pnv_eeh_probe - Do probe on PCI device
  * @pdev: pci_dev to probe
@@ -350,6 +372,7 @@ static struct eeh_dev *pnv_eeh_probe(struct pci_dev *pdev)
 	struct pci_controller *hose = pdn->phb;
 	struct pnv_phb *phb = hose->private_data;
 	struct eeh_dev *edev = pdn_to_eeh_dev(pdn);
+	struct eeh_pe *upstream_pe;
 	uint32_t pcie_flags;
 	int ret;
 	int config_addr = (pdn->busno << 8) | (pdn->devfn);
@@ -398,8 +421,10 @@ static struct eeh_dev *pnv_eeh_probe(struct pci_dev *pdev)
 
 	edev->pe_config_addr = phb->ioda.pe_rmap[config_addr];
 
+	upstream_pe = pnv_eeh_get_upstream_pe(pdev);
+
 	/* Create PE */
-	ret = eeh_pe_tree_insert(edev);
+	ret = eeh_pe_tree_insert(edev, upstream_pe);
 	if (ret) {
 		eeh_edev_warn(edev, "Failed to add device to PE (code %d)\n", ret);
 		return NULL;
diff --git a/arch/powerpc/platforms/pseries/eeh_pseries.c b/arch/powerpc/platforms/pseries/eeh_pseries.c
index 88639b65daa3..8169f3e996fc 100644
--- a/arch/powerpc/platforms/pseries/eeh_pseries.c
+++ b/arch/powerpc/platforms/pseries/eeh_pseries.c
@@ -68,11 +68,16 @@ void pseries_pcibios_bus_add_device(struct pci_dev *pdev)
 	pseries_eeh_init_edev(pdn);
 #ifdef CONFIG_PCI_IOV
 	if (pdev->is_virtfn) {
+		/*
+		 * FIXME: This really should be handled by choosing the right
+		 *        parent PE in in pseries_eeh_init_edev().
+		 */
+		struct eeh_pe *physfn_pe = pci_dev_to_eeh_dev(pdev->physfn)->pe;
 		struct eeh_dev *edev = pdn_to_eeh_dev(pdn);
 
 		edev->pe_config_addr =  (pdn->busno << 16) | (pdn->devfn << 8);
 		eeh_pe_tree_remove(edev); /* Remove as it is adding to bus pe */
-		eeh_pe_tree_insert(edev);   /* Add as VF PE type */
+		eeh_pe_tree_insert(edev, physfn_pe);   /* Add as VF PE type */
 	}
 #endif
 	eeh_probe_device(pdev);
@@ -218,6 +223,43 @@ static int pseries_eeh_find_ecap(struct pci_dn *pdn, int cap)
 	return 0;
 }
 
+/**
+ * pseries_eeh_pe_get_parent - Retrieve the parent PE
+ * @edev: EEH device
+ *
+ * The whole PEs existing in the system are organized as hierarchy
+ * tree. The function is used to retrieve the parent PE according
+ * to the parent EEH device.
+ */
+static struct eeh_pe *pseries_eeh_pe_get_parent(struct eeh_dev *edev)
+{
+	struct eeh_dev *parent;
+	struct pci_dn *pdn = eeh_dev_to_pdn(edev);
+
+	/*
+	 * It might have the case for the indirect parent
+	 * EEH device already having associated PE, but
+	 * the direct parent EEH device doesn't have yet.
+	 */
+	if (edev->physfn)
+		pdn = pci_get_pdn(edev->physfn);
+	else
+		pdn = pdn ? pdn->parent : NULL;
+	while (pdn) {
+		/* We're poking out of PCI territory */
+		parent = pdn_to_eeh_dev(pdn);
+		if (!parent)
+			return NULL;
+
+		if (parent->pe)
+			return parent->pe;
+
+		pdn = pdn->parent;
+	}
+
+	return NULL;
+}
+
 /**
  * pseries_eeh_init_edev - initialise the eeh_dev and eeh_pe for a pci_dn
  *
@@ -301,6 +343,8 @@ void pseries_eeh_init_edev(struct pci_dn *pdn)
 	if (ret) {
 		eeh_edev_dbg(edev, "EEH failed to enable on device (code %d)\n", ret);
 	} else {
+		struct eeh_pe *parent;
+
 		/* Retrieve PE address */
 		edev->pe_config_addr = pseries_eeh_get_pe_addr(pdn);
 		pe.addr = edev->pe_config_addr;
@@ -313,16 +357,18 @@ void pseries_eeh_init_edev(struct pci_dn *pdn)
 		if (ret > 0 && ret != EEH_STATE_NOT_SUPPORT)
 			enable = 1;
 
-		if (enable) {
+		/* This device doesn't support EEH, but it may have an
+		 * EEH parent. In this case any error on the device will
+		 * freeze the PE of it's upstream bridge, so added it to
+		 * the upstream PE.
+		 */
+		parent = pseries_eeh_pe_get_parent(edev);
+		if (parent && !enable)
+			edev->pe_config_addr = parent->addr;
+
+		if (enable || parent) {
 			eeh_add_flag(EEH_ENABLED);
-			eeh_pe_tree_insert(edev);
-		} else if (pdn->parent && pdn_to_eeh_dev(pdn->parent) &&
-			   (pdn_to_eeh_dev(pdn->parent))->pe) {
-			/* This device doesn't support EEH, but it may have an
-			 * EEH parent, in which case we mark it as supported.
-			 */
-			edev->pe_config_addr = pdn_to_eeh_dev(pdn->parent)->pe_config_addr;
-			eeh_pe_tree_insert(edev);
+			eeh_pe_tree_insert(edev, parent);
 		}
 		eeh_edev_dbg(edev, "EEH is %s on device (code %d)\n",
 			     (enable ? "enabled" : "unsupported"), ret);
-- 
2.26.2


^ permalink raw reply related

* [PATCH -next] powerpc/papr_scm: Make some symbols static
From: Wei Yongjun @ 2020-07-25  9:19 UTC (permalink / raw)
  To: Hulk Robot, Michael Ellerman, Aneesh Kumar K.V, Dan Williams,
	Vaibhav Jain, Santosh Sivaraj
  Cc: linuxppc-dev, Wei Yongjun, linux-kernel

The sparse tool complains as follows:

arch/powerpc/platforms/pseries/papr_scm.c:97:1: warning:
 symbol 'papr_nd_regions' was not declared. Should it be static?
arch/powerpc/platforms/pseries/papr_scm.c:98:1: warning:
 symbol 'papr_ndr_lock' was not declared. Should it be static?

Those variables are not used outside of papr_scm.c, so this
commit marks them static.

Fixes: 85343a8da2d9 ("powerpc/papr/scm: Add bad memory ranges to nvdimm bad ranges")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
---
 arch/powerpc/platforms/pseries/papr_scm.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c
index 8fd441d32487..3d1235a76ba9 100644
--- a/arch/powerpc/platforms/pseries/papr_scm.c
+++ b/arch/powerpc/platforms/pseries/papr_scm.c
@@ -94,8 +94,8 @@ struct papr_scm_priv {
 	u64 health_bitmap;
 };
 
-LIST_HEAD(papr_nd_regions);
-DEFINE_MUTEX(papr_ndr_lock);
+static LIST_HEAD(papr_nd_regions);
+static DEFINE_MUTEX(papr_ndr_lock);
 
 static int drc_pmem_bind(struct papr_scm_priv *p)
 {


^ permalink raw reply related

* Re: [PATCH v2] powerpc/uaccess: simplify the get_fs() set_fs() logic
From: Michael Ellerman @ 2020-07-25 11:22 UTC (permalink / raw)
  To: Christophe Leroy, Benjamin Herrenschmidt, Paul Mackerras
  Cc: linuxppc-dev, linux-kernel
In-Reply-To: <dd2876b808ea38eb7b7f760ecd6ce06096c61fb5.1580295551.git.christophe.leroy@c-s.fr>

Hi Christophe,

Unfortunately this would collide messily with "uaccess: remove
segment_eq" in linux-next, so I'll ask you to do a respin based on that,
some comments below.

Christophe Leroy <christophe.leroy@c-s.fr> writes:
> On powerpc, we only have USER_DS and KERNEL_DS
>
> Today, this is managed as an 'unsigned long' data space limit
> which is used to compare the passed address with, plus a bit
> in the thread_info flags that is set whenever modifying the limit
> to enable the verification in addr_limit_user_check()
>
> The limit is either the last address of user space when USER_DS is
> set, and the last address of address space when KERNEL_DS is set.
> In both cases, the limit is a compiletime constant.
>
> get_fs() returns the limit, which is part of thread_info struct
> set_fs() updates the limit then set the TI_FSCHECK flag.
> addr_limit_user_check() check the flag, and if it is set it checks
> the limit is the user limit, then unsets the TI_FSCHECK flag.
>
> In addition, when the flag is set the syscall exit work is involved.
> This exit work is heavy compared to normal syscall exit as it goes
> through normal exception exit instead of the fast syscall exit.
>
> Rename this TI_FSCHECK flag to TIF_KERNEL_DS flag which tells whether
> KERNEL_DS or USER_DS is set. Get mm_segment_t be redifined as a bool
> struct that is either false (for USER_DS) or true (for KERNEL_DS).
> When TIF_KERNEL_DS is set, the limit is ~0UL. Otherwise it is
> TASK_SIZE_USER (resp TASK_SIZE_USER64 on PPC64). When KERNEL_DS is
> set, there is no range to check. Define TI_FSCHECK as an alias to
> TIF_KERNEL_DS.

I'd rather avoid the "DS" name any more than we have to. Maybe it means
"data space" but that's not a very common term.

The generic helper these days is called uaccess_kernel(), which returns
true when uaccess routines are allowed to access the kernel.

So calling it TIF_UACCESS_KERNEL would work I think?

The bool could be called uaccess_kernel.
And END_OF_USER_DS could be USER_ADDR_MAX.

> On exit, involve exit work when the bit is set, i.e. when KERNEL_DS
> is set. addr_limit_user_check() will clear the bit and kill the
> user process.

I guess this is safe. The check was added to make sure we never return
to userspace with KERNEL_DS set, but using the actual TIF flag to
determine the address limit should be equally safe, and avoid the
overhead of the check in the good case.

cheers


> diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
> index 8387698bd5b6..e9e3c3b0f05e 100644
> --- a/arch/powerpc/include/asm/processor.h
> +++ b/arch/powerpc/include/asm/processor.h
> @@ -84,7 +84,7 @@ void start_thread(struct pt_regs *regs, unsigned long fdptr, unsigned long sp);
>  void release_thread(struct task_struct *);
>  
>  typedef struct {
> -	unsigned long seg;
> +	bool is_kernel_ds;
>  } mm_segment_t;
>  
>  #define TS_FPR(i) fp_state.fpr[i][TS_FPROFFSET]
> @@ -148,7 +148,6 @@ struct thread_struct {
>  	unsigned long	ksp_vsid;
>  #endif
>  	struct pt_regs	*regs;		/* Pointer to saved register state */
> -	mm_segment_t	addr_limit;	/* for get_fs() validation */
>  #ifdef CONFIG_BOOKE
>  	/* BookE base exception scratch space; align on cacheline */
>  	unsigned long	normsave[8] ____cacheline_aligned;
> @@ -289,7 +288,6 @@ struct thread_struct {
>  #define INIT_THREAD { \
>  	.ksp = INIT_SP, \
>  	.ksp_limit = INIT_SP_LIMIT, \
> -	.addr_limit = KERNEL_DS, \
>  	.pgdir = swapper_pg_dir, \
>  	.fpexc_mode = MSR_FE0 | MSR_FE1, \
>  	SPEFSCR_INIT \
> @@ -298,7 +296,6 @@ struct thread_struct {
>  #define INIT_THREAD  { \
>  	.ksp = INIT_SP, \
>  	.regs = (struct pt_regs *)INIT_SP - 1, /* XXX bogus, I think */ \
> -	.addr_limit = KERNEL_DS, \
>  	.fpexc_mode = 0, \
>  	.fscr = FSCR_TAR | FSCR_EBB \
>  }
> diff --git a/arch/powerpc/include/asm/thread_info.h b/arch/powerpc/include/asm/thread_info.h
> index a2270749b282..a681ce624ab7 100644
> --- a/arch/powerpc/include/asm/thread_info.h
> +++ b/arch/powerpc/include/asm/thread_info.h
> @@ -69,7 +69,7 @@ struct thread_info {
>  #define INIT_THREAD_INFO(tsk)			\
>  {						\
>  	.preempt_count = INIT_PREEMPT_COUNT,	\
> -	.flags =	0,			\
> +	.flags =	_TIF_KERNEL_DS,		\
>  }
>  
>  #define THREAD_SIZE_ORDER	(THREAD_SHIFT - PAGE_SHIFT)
> @@ -90,7 +90,8 @@ void arch_setup_new_exec(void);
>  #define TIF_SYSCALL_TRACE	0	/* syscall trace active */
>  #define TIF_SIGPENDING		1	/* signal pending */
>  #define TIF_NEED_RESCHED	2	/* rescheduling necessary */
> -#define TIF_FSCHECK		3	/* Check FS is USER_DS on return */
> +#define TIF_KERNEL_DS		3	/* KERNEL_DS is set */
> +#define TIF_FSCHECK	TIF_KERNEL_DS
>  #define TIF_SYSCALL_EMU		4	/* syscall emulation active */
>  #define TIF_RESTORE_TM		5	/* need to restore TM FP/VEC/VSX */
>  #define TIF_PATCH_PENDING	6	/* pending live patching update */
> @@ -130,7 +131,7 @@ void arch_setup_new_exec(void);
>  #define _TIF_SYSCALL_TRACEPOINT	(1<<TIF_SYSCALL_TRACEPOINT)
>  #define _TIF_EMULATE_STACK_STORE	(1<<TIF_EMULATE_STACK_STORE)
>  #define _TIF_NOHZ		(1<<TIF_NOHZ)
> -#define _TIF_FSCHECK		(1<<TIF_FSCHECK)
> +#define _TIF_KERNEL_DS		(1 << TIF_KERNEL_DS)
>  #define _TIF_SYSCALL_EMU	(1<<TIF_SYSCALL_EMU)
>  #define _TIF_SYSCALL_DOTRACE	(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
>  				 _TIF_SECCOMP | _TIF_SYSCALL_TRACEPOINT | \
> @@ -139,7 +140,7 @@ void arch_setup_new_exec(void);
>  #define _TIF_USER_WORK_MASK	(_TIF_SIGPENDING | _TIF_NEED_RESCHED | \
>  				 _TIF_NOTIFY_RESUME | _TIF_UPROBE | \
>  				 _TIF_RESTORE_TM | _TIF_PATCH_PENDING | \
> -				 _TIF_FSCHECK)
> +				 _TIF_KERNEL_DS)
>  #define _TIF_PERSYSCALL_MASK	(_TIF_RESTOREALL|_TIF_NOERROR)
>  
>  /* Bits in local_flags */
> diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h
> index c92fe7fe9692..391c3a26f980 100644
> --- a/arch/powerpc/include/asm/uaccess.h
> +++ b/arch/powerpc/include/asm/uaccess.h
> @@ -21,43 +21,44 @@
>  
>  #define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
>  
> -#define KERNEL_DS	MAKE_MM_SEG(~0UL)
> -#ifdef __powerpc64__
> -/* We use TASK_SIZE_USER64 as TASK_SIZE is not constant */
> -#define USER_DS		MAKE_MM_SEG(TASK_SIZE_USER64 - 1)
> -#else
> -#define USER_DS		MAKE_MM_SEG(TASK_SIZE - 1)
> -#endif
> +#define KERNEL_DS	MAKE_MM_SEG(true)
> +#define USER_DS		MAKE_MM_SEG(false)
> +
> +#define get_fs()	(MAKE_MM_SEG(test_thread_flag(TIF_KERNEL_DS)))
>  
> -#define get_fs()	(current->thread.addr_limit)
> +#define segment_eq(a, b)	((a).is_kernel_ds == (b).is_kernel_ds)
>  
>  static inline void set_fs(mm_segment_t fs)
>  {
> -	current->thread.addr_limit = fs;
> -	/* On user-mode return check addr_limit (fs) is correct */
> -	set_thread_flag(TIF_FSCHECK);
> +	update_thread_flag(TIF_KERNEL_DS, segment_eq(fs, KERNEL_DS));
>  }
>  
> -#define segment_eq(a, b)	((a).seg == (b).seg)
> -
> -#define user_addr_max()	(get_fs().seg)
> +#define user_addr_max()	(segment_eq(get_fs(), KERNEL_DS) ? ~0UL : END_OF_USER_DS - 1)
>  
>  #ifdef __powerpc64__
> +
> +#define END_OF_USER_DS		TASK_SIZE_USER64
> +
>  /*
>   * This check is sufficient because there is a large enough
>   * gap between user addresses and the kernel addresses
>   */
>  #define __access_ok(addr, size, segment)	\
> -	(((addr) <= (segment).seg) && ((size) <= (segment).seg))
> +	segment_eq(segment, KERNEL_DS) ?	\
> +	1 : (addr) < END_OF_USER_DS && ((size) < END_OF_USER_DS)
>  
>  #else
>  
> +#define END_OF_USER_DS		TASK_SIZE
> +
>  static inline int __access_ok(unsigned long addr, unsigned long size,
>  			mm_segment_t seg)
>  {
> -	if (addr > seg.seg)
> +	if (segment_eq(seg, KERNEL_DS))
> +		return 1;
> +	if (addr >= END_OF_USER_DS)
>  		return 0;
> -	return (size == 0 || size - 1 <= seg.seg - addr);
> +	return addr + size <= END_OF_USER_DS;
>  }
>  
>  #endif
> diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
> index c077acb983a1..bf005dd9407e 100644
> --- a/arch/powerpc/lib/sstep.c
> +++ b/arch/powerpc/lib/sstep.c
> @@ -110,7 +110,7 @@ static nokprobe_inline long address_ok(struct pt_regs *regs,
>  		return 1;
>  	if (__access_ok(ea, 1, USER_DS))
>  		/* Access overlaps the end of the user region */
> -		regs->dar = USER_DS.seg;
> +		regs->dar = END_OF_USER_DS;
>  	else
>  		regs->dar = ea;
>  	return 0;
> -- 
> 2.25.0

^ permalink raw reply

* Re: [PATCH v3 5/6] powerpc/pseries: implement paravirt qspinlocks for SPLPAR
From: Peter Zijlstra @ 2020-07-25 17:26 UTC (permalink / raw)
  To: Waiman Long
  Cc: linux-arch, Boqun Feng, virtualization, linuxppc-dev,
	Nicholas Piggin, linux-kernel, Ingo Molnar, kvm-ppc, Will Deacon
In-Reply-To: <8532332b-85dd-661b-cf72-81a8ceb70747@redhat.com>

On Fri, Jul 24, 2020 at 03:10:59PM -0400, Waiman Long wrote:
> On 7/24/20 4:16 AM, Will Deacon wrote:
> > On Thu, Jul 23, 2020 at 08:47:59PM +0200, peterz@infradead.org wrote:
> > > On Thu, Jul 23, 2020 at 02:32:36PM -0400, Waiman Long wrote:
> > > > BTW, do you have any comment on my v2 lock holder cpu info qspinlock patch?
> > > > I will have to update the patch to fix the reported 0-day test problem, but
> > > > I want to collect other feedback before sending out v3.
> > > I want to say I hate it all, it adds instructions to a path we spend an
> > > aweful lot of time optimizing without really getting anything back for
> > > it.
> > > 
> > > Will, how do you feel about it?
> > I can see it potentially being useful for debugging, but I hate the
> > limitation to 256 CPUs. Even arm64 is hitting that now.
> 
> After thinking more about that, I think we can use all the remaining bits in
> the 16-bit locked_pending. Reserving 1 bit for locked and 1 bit for pending,
> there are 14 bits left. So as long as NR_CPUS < 16k (requirement for 16-bit
> locked_pending), we can put all possible cpu numbers into the lock. We can
> also just use smp_processor_id() without additional percpu data.

That sounds horrific, wouldn't that destroy the whole point of using a
byte for pending?

> > Also, you're talking ~1% gains here. I think our collective time would
> > be better spent off reviewing the CNA series and trying to make it more
> > deterministic.
> 
> I thought you guys are not interested in CNA. I do want to get CNA merged,
> if possible. Let review the current version again and see if there are ways
> we can further improve it.

It's not a lack of interrest. We were struggling with the fairness
issues and the complexity of the thing. I forgot the current state of
matters, but at one point UNLOCK was O(n) in waiters, which is, of
course, 'unfortunate'.

I'll have to look up whatever notes remain, but the basic idea of
keeping remote nodes on a secondary list is obviously breaking all sorts
of fairness. After that they pile on a bunch of hacks to fix the worst
of them, but it feels exactly like that, a bunch of hacks.

One of the things I suppose we ought to do is see if some of the ideas
of phase-fair locks can be applied to this.

That coupled with a chronic lack of time for anything :-(

^ permalink raw reply

* Re: [PATCH v3 5/6] powerpc/pseries: implement paravirt qspinlocks for SPLPAR
From: Waiman Long @ 2020-07-25 17:36 UTC (permalink / raw)
  To: Peter Zijlstra
  Cc: linux-arch, Boqun Feng, virtualization, linuxppc-dev,
	Nicholas Piggin, linux-kernel, Ingo Molnar, kvm-ppc, Will Deacon
In-Reply-To: <20200725172630.GF10769@hirez.programming.kicks-ass.net>

On 7/25/20 1:26 PM, Peter Zijlstra wrote:
> On Fri, Jul 24, 2020 at 03:10:59PM -0400, Waiman Long wrote:
>> On 7/24/20 4:16 AM, Will Deacon wrote:
>>> On Thu, Jul 23, 2020 at 08:47:59PM +0200, peterz@infradead.org wrote:
>>>> On Thu, Jul 23, 2020 at 02:32:36PM -0400, Waiman Long wrote:
>>>>> BTW, do you have any comment on my v2 lock holder cpu info qspinlock patch?
>>>>> I will have to update the patch to fix the reported 0-day test problem, but
>>>>> I want to collect other feedback before sending out v3.
>>>> I want to say I hate it all, it adds instructions to a path we spend an
>>>> aweful lot of time optimizing without really getting anything back for
>>>> it.
>>>>
>>>> Will, how do you feel about it?
>>> I can see it potentially being useful for debugging, but I hate the
>>> limitation to 256 CPUs. Even arm64 is hitting that now.
>> After thinking more about that, I think we can use all the remaining bits in
>> the 16-bit locked_pending. Reserving 1 bit for locked and 1 bit for pending,
>> there are 14 bits left. So as long as NR_CPUS < 16k (requirement for 16-bit
>> locked_pending), we can put all possible cpu numbers into the lock. We can
>> also just use smp_processor_id() without additional percpu data.
> That sounds horrific, wouldn't that destroy the whole point of using a
> byte for pending?
You are right. I realized that later on and had sent a follow-up mail to 
correct that.
>>> Also, you're talking ~1% gains here. I think our collective time would
>>> be better spent off reviewing the CNA series and trying to make it more
>>> deterministic.
>> I thought you guys are not interested in CNA. I do want to get CNA merged,
>> if possible. Let review the current version again and see if there are ways
>> we can further improve it.
> It's not a lack of interrest. We were struggling with the fairness
> issues and the complexity of the thing. I forgot the current state of
> matters, but at one point UNLOCK was O(n) in waiters, which is, of
> course, 'unfortunate'.
>
> I'll have to look up whatever notes remain, but the basic idea of
> keeping remote nodes on a secondary list is obviously breaking all sorts
> of fairness. After that they pile on a bunch of hacks to fix the worst
> of them, but it feels exactly like that, a bunch of hacks.
>
> One of the things I suppose we ought to do is see if some of the ideas
> of phase-fair locks can be applied to this.
That could be a possible solution to ensure better fairness.
>
> That coupled with a chronic lack of time for anything :-(
>
That is always true and I feel this way too:-)

Cheers,
Longman


^ permalink raw reply

* Re: [PATCH 1/2] lockdep: improve current->(hard|soft)irqs_enabled synchronisation with actual irq state
From: Peter Zijlstra @ 2020-07-25 20:26 UTC (permalink / raw)
  To: Nicholas Piggin
  Cc: linux-arch, Alexey Kardashevskiy, linuxppc-dev, linux-kernel,
	Ingo Molnar, Will Deacon
In-Reply-To: <20200723105615.1268126-1-npiggin@gmail.com>

On Thu, Jul 23, 2020 at 08:56:14PM +1000, Nicholas Piggin wrote:
> diff --git a/arch/powerpc/include/asm/hw_irq.h b/arch/powerpc/include/asm/hw_irq.h
> index 3a0db7b0b46e..35060be09073 100644
> --- a/arch/powerpc/include/asm/hw_irq.h
> +++ b/arch/powerpc/include/asm/hw_irq.h
> @@ -200,17 +200,14 @@ static inline bool arch_irqs_disabled(void)
>  #define powerpc_local_irq_pmu_save(flags)			\
>  	 do {							\
>  		raw_local_irq_pmu_save(flags);			\
> -		trace_hardirqs_off();				\
> +		if (!raw_irqs_disabled_flags(flags))		\
> +			trace_hardirqs_off();			\
>  	} while(0)

So one problem with the above is something like this:

	raw_local_irq_save();
	<NMI>
	  powerpc_local_irq_pmu_save();

that would now no longer call into tracing/lockdep at all. As a
consequence, lockdep and tracing would show the NMI ran with IRQs
enabled, which is exceptionally weird..

Similar problem with:

	raw_local_irq_disable();
	local_irq_save()

Now, most architectures today seem to do what x86 also did:

	<NMI>
	  trace_hardirqs_off()
	  ...
	  if (irqs_unmasked(regs))
	    trace_hardirqs_on()
	</NMI>

Which is 'funny' when it interleaves like:

	local_irq_disable();
	...
	local_irq_enable()
	  trace_hardirqs_on();
	  <NMI/>
	  raw_local_irq_enable();

Because then it will undo the trace_hardirqs_on() we just did. With the
result that both tracing and lockdep will see a hardirqs-disable without
a matching enable, while the hardware state is enabled.

Which is exactly the state Alexey seems to have ran into.

Now, x86, and at least arm64 call nmi_enter() before
trace_hardirqs_off(), but AFAICT Power never did that, and that's part
of the problem. nmi_enter() does lockdep_off() and that _used_ to also
kill IRQ tracking.

Now, my patch changed that, it makes IRQ tracking not respect
lockdep_off(). And that exposed x86 (and everybody else :/) to the same
problem you have.

And this is why I made x86 look at software state in NMIs. Because then
it all works out. For bonus points, trace_hardirqs_*() also has some
do-it-once logic for tracing.



Anyway, it's Saturday evening, time for a beer. I'll stare at this more
later.

^ permalink raw reply

* [PATCH] selftests/powerpc: Skip vmx/vsx tests on older CPUs
From: Michael Ellerman @ 2020-07-26  0:34 UTC (permalink / raw)
  To: linuxppc-dev

These tests use VSX or newer VMX instructions, so need to be skipped
on older CPUs to avoid SIGILL'ing.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 tools/testing/selftests/powerpc/math/Makefile      | 8 ++++----
 tools/testing/selftests/powerpc/math/vmx_preempt.c | 3 +++
 tools/testing/selftests/powerpc/math/vmx_signal.c  | 3 +++
 tools/testing/selftests/powerpc/math/vmx_syscall.c | 7 ++++++-
 tools/testing/selftests/powerpc/math/vsx_preempt.c | 2 ++
 5 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/tools/testing/selftests/powerpc/math/Makefile b/tools/testing/selftests/powerpc/math/Makefile
index 4e2049d2fd8d..fcc91c205984 100644
--- a/tools/testing/selftests/powerpc/math/Makefile
+++ b/tools/testing/selftests/powerpc/math/Makefile
@@ -11,9 +11,9 @@ $(OUTPUT)/fpu_syscall: fpu_asm.S
 $(OUTPUT)/fpu_preempt: fpu_asm.S
 $(OUTPUT)/fpu_signal:  fpu_asm.S
 
-$(OUTPUT)/vmx_syscall: vmx_asm.S
-$(OUTPUT)/vmx_preempt: vmx_asm.S
-$(OUTPUT)/vmx_signal: vmx_asm.S
+$(OUTPUT)/vmx_syscall: vmx_asm.S ../utils.c
+$(OUTPUT)/vmx_preempt: vmx_asm.S ../utils.c
+$(OUTPUT)/vmx_signal: vmx_asm.S ../utils.c
 
 $(OUTPUT)/vsx_preempt: CFLAGS += -mvsx
-$(OUTPUT)/vsx_preempt: vsx_asm.S
+$(OUTPUT)/vsx_preempt: vsx_asm.S ../utils.c
diff --git a/tools/testing/selftests/powerpc/math/vmx_preempt.c b/tools/testing/selftests/powerpc/math/vmx_preempt.c
index 2e059f154e77..6761d6ce30ec 100644
--- a/tools/testing/selftests/powerpc/math/vmx_preempt.c
+++ b/tools/testing/selftests/powerpc/math/vmx_preempt.c
@@ -57,6 +57,9 @@ int test_preempt_vmx(void)
 	int i, rc, threads;
 	pthread_t *tids;
 
+	// vcmpequd used in vmx_asm.S is v2.07
+	SKIP_IF(!have_hwcap2(PPC_FEATURE2_ARCH_2_07));
+
 	threads = sysconf(_SC_NPROCESSORS_ONLN) * THREAD_FACTOR;
 	tids = malloc(threads * sizeof(pthread_t));
 	FAIL_IF(!tids);
diff --git a/tools/testing/selftests/powerpc/math/vmx_signal.c b/tools/testing/selftests/powerpc/math/vmx_signal.c
index 785a48e0976f..b340a5c4e79d 100644
--- a/tools/testing/selftests/powerpc/math/vmx_signal.c
+++ b/tools/testing/selftests/powerpc/math/vmx_signal.c
@@ -96,6 +96,9 @@ int test_signal_vmx(void)
 	void *rc_p;
 	pthread_t *tids;
 
+	// vcmpequd used in vmx_asm.S is v2.07
+	SKIP_IF(!have_hwcap2(PPC_FEATURE2_ARCH_2_07));
+
 	threads = sysconf(_SC_NPROCESSORS_ONLN) * THREAD_FACTOR;
 	tids = malloc(threads * sizeof(pthread_t));
 	FAIL_IF(!tids);
diff --git a/tools/testing/selftests/powerpc/math/vmx_syscall.c b/tools/testing/selftests/powerpc/math/vmx_syscall.c
index 9ee293cc868e..03c78dfe3444 100644
--- a/tools/testing/selftests/powerpc/math/vmx_syscall.c
+++ b/tools/testing/selftests/powerpc/math/vmx_syscall.c
@@ -49,9 +49,14 @@ int test_vmx_syscall(void)
 	 * Setup an environment with much context switching
 	 */
 	pid_t pid2;
-	pid_t pid = fork();
+	pid_t pid;
 	int ret;
 	int child_ret;
+
+	// vcmpequd used in vmx_asm.S is v2.07
+	SKIP_IF(!have_hwcap2(PPC_FEATURE2_ARCH_2_07));
+
+	pid = fork();
 	FAIL_IF(pid == -1);
 
 	pid2 = fork();
diff --git a/tools/testing/selftests/powerpc/math/vsx_preempt.c b/tools/testing/selftests/powerpc/math/vsx_preempt.c
index 63de9c6e2cd3..d1601bb889d4 100644
--- a/tools/testing/selftests/powerpc/math/vsx_preempt.c
+++ b/tools/testing/selftests/powerpc/math/vsx_preempt.c
@@ -92,6 +92,8 @@ int test_preempt_vsx(void)
 	int i, rc, threads;
 	pthread_t *tids;
 
+	SKIP_IF(!have_hwcap(PPC_FEATURE_HAS_VSX));
+
 	threads = sysconf(_SC_NPROCESSORS_ONLN) * THREAD_FACTOR;
 	tids = malloc(threads * sizeof(pthread_t));
 	FAIL_IF(!tids);
-- 
2.25.1


^ permalink raw reply related

* [PATCH 5/9] powerpc: hw_breakpoint.h: delete duplicated word
From: Randy Dunlap @ 2020-07-26  0:38 UTC (permalink / raw)
  To: linux-kernel; +Cc: Randy Dunlap, Paul Mackerras, linuxppc-dev
In-Reply-To: <20200726003809.20454-1-rdunlap@infradead.org>

Drop the repeated word "the".

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@lists.ozlabs.org
---
 arch/powerpc/include/asm/hw_breakpoint.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- linux-next-20200720.orig/arch/powerpc/include/asm/hw_breakpoint.h
+++ linux-next-20200720/arch/powerpc/include/asm/hw_breakpoint.h
@@ -17,7 +17,7 @@ struct arch_hw_breakpoint {
 	u16		hw_len; /* length programmed in hw */
 };
 
-/* Note: Don't change the the first 6 bits below as they are in the same order
+/* Note: Don't change the first 6 bits below as they are in the same order
  * as the dabr and dabrx.
  */
 #define HW_BRK_TYPE_READ		0x01

^ permalink raw reply

* [PATCH 3/9] powerpc: cputime.h: delete duplicated word
From: Randy Dunlap @ 2020-07-26  0:38 UTC (permalink / raw)
  To: linux-kernel; +Cc: Randy Dunlap, Paul Mackerras, linuxppc-dev
In-Reply-To: <20200726003809.20454-1-rdunlap@infradead.org>

Drop the repeated word "use".

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@lists.ozlabs.org
---
 arch/powerpc/include/asm/cputime.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- linux-next-20200720.orig/arch/powerpc/include/asm/cputime.h
+++ linux-next-20200720/arch/powerpc/include/asm/cputime.h
@@ -67,7 +67,7 @@ static inline void arch_vtime_task_switc
 
 /*
  * account_cpu_user_entry/exit runs "unreconciled", so can't trace,
- * can't use use get_paca()
+ * can't use get_paca()
  */
 static notrace inline void account_cpu_user_entry(void)
 {

^ permalink raw reply

* [PATCH 4/9] powerpc: epapr_hcalls.h: delete duplicated words
From: Randy Dunlap @ 2020-07-26  0:38 UTC (permalink / raw)
  To: linux-kernel; +Cc: Randy Dunlap, Paul Mackerras, linuxppc-dev
In-Reply-To: <20200726003809.20454-1-rdunlap@infradead.org>

Drop the repeated words "file" and "the".

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@lists.ozlabs.org
---
 arch/powerpc/include/asm/epapr_hcalls.h |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- linux-next-20200720.orig/arch/powerpc/include/asm/epapr_hcalls.h
+++ linux-next-20200720/arch/powerpc/include/asm/epapr_hcalls.h
@@ -37,7 +37,7 @@
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-/* A "hypercall" is an "sc 1" instruction.  This header file file provides C
+/* A "hypercall" is an "sc 1" instruction.  This header file provides C
  * wrapper functions for the ePAPR hypervisor interface.  It is inteded
  * for use by Linux device drivers and other operating systems.
  *
@@ -246,7 +246,7 @@ static inline unsigned int ev_int_get_ma
  * ev_int_eoi - signal the end of interrupt processing
  * @interrupt: the interrupt number
  *
- * This function signals the end of processing for the the specified
+ * This function signals the end of processing for the specified
  * interrupt, which must be the interrupt currently in service. By
  * definition, this is also the highest-priority interrupt.
  *

^ permalink raw reply

* [PATCH 0/9] powerpc: delete duplicated words
From: Randy Dunlap @ 2020-07-26  0:38 UTC (permalink / raw)
  To: linux-kernel; +Cc: Randy Dunlap, Paul Mackerras, linuxppc-dev

Drop duplicated words in arch/powerpc/ header files.

Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@lists.ozlabs.org

 arch/powerpc/include/asm/book3s/64/mmu-hash.h |    2 +-
 arch/powerpc/include/asm/book3s/64/radix-4k.h |    2 +-
 arch/powerpc/include/asm/cputime.h            |    2 +-
 arch/powerpc/include/asm/epapr_hcalls.h       |    4 ++--
 arch/powerpc/include/asm/hw_breakpoint.h      |    2 +-
 arch/powerpc/include/asm/ppc_asm.h            |    2 +-
 arch/powerpc/include/asm/reg.h                |    2 +-
 arch/powerpc/include/asm/smu.h                |    2 +-
 arch/powerpc/platforms/powernv/pci.h          |    2 +-
 9 files changed, 10 insertions(+), 10 deletions(-)

^ permalink raw reply

* [PATCH 1/9] powerpc: book3s: mmu-hash.h: delete duplicated word
From: Randy Dunlap @ 2020-07-26  0:38 UTC (permalink / raw)
  To: linux-kernel; +Cc: Randy Dunlap, Paul Mackerras, linuxppc-dev
In-Reply-To: <20200726003809.20454-1-rdunlap@infradead.org>

Drop the repeated word "below".

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@lists.ozlabs.org
---
 arch/powerpc/include/asm/book3s/64/mmu-hash.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- linux-next-20200720.orig/arch/powerpc/include/asm/book3s/64/mmu-hash.h
+++ linux-next-20200720/arch/powerpc/include/asm/book3s/64/mmu-hash.h
@@ -793,7 +793,7 @@ static inline unsigned long get_vsid(uns
 }
 
 /*
- * For kernel space, we use context ids as below
+ * For kernel space, we use context ids as
  * below. Range is 512TB per context.
  *
  * 0x00001 -  [ 0xc000000000000000 - 0xc001ffffffffffff]

^ permalink raw reply

* [PATCH 2/9] powerpc: book3s: radix-4k.h: delete duplicated word
From: Randy Dunlap @ 2020-07-26  0:38 UTC (permalink / raw)
  To: linux-kernel; +Cc: Randy Dunlap, Paul Mackerras, linuxppc-dev
In-Reply-To: <20200726003809.20454-1-rdunlap@infradead.org>

Drop the repeated word "per".

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@lists.ozlabs.org
---
 arch/powerpc/include/asm/book3s/64/radix-4k.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- linux-next-20200720.orig/arch/powerpc/include/asm/book3s/64/radix-4k.h
+++ linux-next-20200720/arch/powerpc/include/asm/book3s/64/radix-4k.h
@@ -11,7 +11,7 @@
 #define RADIX_PGD_INDEX_SIZE  13  // size: 8B << 13 = 64KB, maps 2^13 x 512GB =   4PB
 
 /*
- * One fragment per per page
+ * One fragment per page
  */
 #define RADIX_PTE_FRAG_SIZE_SHIFT  (RADIX_PTE_INDEX_SIZE + 3)
 #define RADIX_PTE_FRAG_NR	(PAGE_SIZE >> RADIX_PTE_FRAG_SIZE_SHIFT)

^ permalink raw reply

* [PATCH 6/9] powerpc: ppc_asm.h: delete duplicated word
From: Randy Dunlap @ 2020-07-26  0:38 UTC (permalink / raw)
  To: linux-kernel; +Cc: Randy Dunlap, Paul Mackerras, linuxppc-dev
In-Reply-To: <20200726003809.20454-1-rdunlap@infradead.org>

Drop the repeated word "in".

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@lists.ozlabs.org
---
 arch/powerpc/include/asm/ppc_asm.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- linux-next-20200720.orig/arch/powerpc/include/asm/ppc_asm.h
+++ linux-next-20200720/arch/powerpc/include/asm/ppc_asm.h
@@ -774,7 +774,7 @@ END_FTR_SECTION_NESTED(CPU_FTR_CELL_TB_B
 #define FIXUP_ENDIAN
 #else
 /*
- * This version may be used in in HV or non-HV context.
+ * This version may be used in HV or non-HV context.
  * MSR[EE] must be disabled.
  */
 #define FIXUP_ENDIAN						   \

^ permalink raw reply

* [PATCH 7/9] powerpc: reg.h: delete duplicated word
From: Randy Dunlap @ 2020-07-26  0:38 UTC (permalink / raw)
  To: linux-kernel; +Cc: Randy Dunlap, Paul Mackerras, linuxppc-dev
In-Reply-To: <20200726003809.20454-1-rdunlap@infradead.org>

Drop the repeated word "a".

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@lists.ozlabs.org
---
 arch/powerpc/include/asm/reg.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- linux-next-20200720.orig/arch/powerpc/include/asm/reg.h
+++ linux-next-20200720/arch/powerpc/include/asm/reg.h
@@ -1472,7 +1472,7 @@ static inline void update_power8_hid0(un
 {
 	/*
 	 *  The HID0 update on Power8 should at the very least be
-	 *  preceded by a a SYNC instruction followed by an ISYNC
+	 *  preceded by a SYNC instruction followed by an ISYNC
 	 *  instruction
 	 */
 	asm volatile("sync; mtspr %0,%1; isync":: "i"(SPRN_HID0), "r"(hid0));

^ permalink raw reply

* [PATCH 8/9] powerpc: smu.h: delete duplicated word
From: Randy Dunlap @ 2020-07-26  0:38 UTC (permalink / raw)
  To: linux-kernel; +Cc: Randy Dunlap, Paul Mackerras, linuxppc-dev
In-Reply-To: <20200726003809.20454-1-rdunlap@infradead.org>

Drop the repeated word "the".

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@lists.ozlabs.org
---
 arch/powerpc/include/asm/smu.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- linux-next-20200720.orig/arch/powerpc/include/asm/smu.h
+++ linux-next-20200720/arch/powerpc/include/asm/smu.h
@@ -108,7 +108,7 @@
  /*
   * i2c commands
   *
-  * To issue an i2c command, first is to send a parameter block to the
+  * To issue an i2c command, first is to send a parameter block to
   * the SMU. This is a command of type 0x9a with 9 bytes of header
   * eventually followed by data for a write:
   *

^ permalink raw reply

* [PATCH 9/9] powerpc: powernv: pci.h: delete duplicated word
From: Randy Dunlap @ 2020-07-26  0:38 UTC (permalink / raw)
  To: linux-kernel; +Cc: Randy Dunlap, Paul Mackerras, linuxppc-dev
In-Reply-To: <20200726003809.20454-1-rdunlap@infradead.org>

Drop the repeated word "for".

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@lists.ozlabs.org
---
 arch/powerpc/platforms/powernv/pci.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- linux-next-20200720.orig/arch/powerpc/platforms/powernv/pci.h
+++ linux-next-20200720/arch/powerpc/platforms/powernv/pci.h
@@ -87,7 +87,7 @@ struct pnv_ioda_pe {
 	bool			tce_bypass_enabled;
 	uint64_t		tce_bypass_base;
 
-	/* MSIs. MVE index is identical for for 32 and 64 bit MSI
+	/* MSIs. MVE index is identical for 32 and 64 bit MSI
 	 * and -1 if not supported. (It's actually identical to the
 	 * PE number)
 	 */

^ permalink raw reply

* [PATCH v3 0/3] powerpc/pseries: IPI doorbell improvements
From: Nicholas Piggin @ 2020-07-26  3:51 UTC (permalink / raw)
  To: linuxppc-dev
  Cc: kvm-ppc, Nicholas Piggin, Anton Blanchard, Cédric Le Goater,
	David Gibson

Since v2:
- Fixed ppc32 compile error
- Tested-by from Cedric

Nicholas Piggin (3):
  powerpc: inline doorbell sending functions
  powerpc/pseries: Use doorbells even if XIVE is available
  powerpc/pseries: Add KVM guest doorbell restrictions

 arch/powerpc/include/asm/dbell.h     | 67 ++++++++++++++++++++++++++--
 arch/powerpc/include/asm/firmware.h  |  6 +++
 arch/powerpc/include/asm/kvm_para.h  | 26 ++---------
 arch/powerpc/kernel/Makefile         |  5 +--
 arch/powerpc/kernel/dbell.c          | 55 -----------------------
 arch/powerpc/kernel/firmware.c       | 19 ++++++++
 arch/powerpc/platforms/pseries/smp.c | 62 +++++++++++++++++--------
 7 files changed, 138 insertions(+), 102 deletions(-)

-- 
2.23.0


^ permalink raw reply

* [PATCH v3 1/3] powerpc: inline doorbell sending functions
From: Nicholas Piggin @ 2020-07-26  3:51 UTC (permalink / raw)
  To: linuxppc-dev
  Cc: kvm-ppc, Nicholas Piggin, Anton Blanchard, Cédric Le Goater,
	David Gibson
In-Reply-To: <20200726035155.1424103-1-npiggin@gmail.com>

These are only called in one place for a given platform, so inline them
for performance.

Tested-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 arch/powerpc/include/asm/dbell.h | 67 ++++++++++++++++++++++++++++++--
 arch/powerpc/kernel/dbell.c      | 55 --------------------------
 2 files changed, 64 insertions(+), 58 deletions(-)

diff --git a/arch/powerpc/include/asm/dbell.h b/arch/powerpc/include/asm/dbell.h
index 4ce6808deed3..1f04f3de96ba 100644
--- a/arch/powerpc/include/asm/dbell.h
+++ b/arch/powerpc/include/asm/dbell.h
@@ -13,6 +13,11 @@
 
 #include <asm/ppc-opcode.h>
 #include <asm/feature-fixups.h>
+#ifdef CONFIG_KVM
+#include <asm/kvm_ppc.h>
+#else
+static inline void kvmppc_set_host_ipi(int cpu) {}
+#endif
 
 #define PPC_DBELL_MSG_BRDCAST	(0x04000000)
 #define PPC_DBELL_TYPE(x)	(((x) & 0xf) << (63-36))
@@ -87,9 +92,6 @@ static inline void ppc_msgsync(void)
 
 #endif /* CONFIG_PPC_BOOK3S */
 
-extern void doorbell_global_ipi(int cpu);
-extern void doorbell_core_ipi(int cpu);
-extern int doorbell_try_core_ipi(int cpu);
 extern void doorbell_exception(struct pt_regs *regs);
 
 static inline void ppc_msgsnd(enum ppc_dbell type, u32 flags, u32 tag)
@@ -100,4 +102,63 @@ static inline void ppc_msgsnd(enum ppc_dbell type, u32 flags, u32 tag)
 	_ppc_msgsnd(msg);
 }
 
+#ifdef CONFIG_SMP
+
+/*
+ * Doorbells must only be used if CPU_FTR_DBELL is available.
+ * msgsnd is used in HV, and msgsndp is used in !HV.
+ *
+ * These should be used by platform code that is aware of restrictions.
+ * Other arch code should use ->cause_ipi.
+ *
+ * doorbell_global_ipi() sends a dbell to any target CPU.
+ * Must be used only by architectures that address msgsnd target
+ * by PIR/get_hard_smp_processor_id.
+ */
+static inline void doorbell_global_ipi(int cpu)
+{
+	u32 tag = get_hard_smp_processor_id(cpu);
+
+	kvmppc_set_host_ipi(cpu);
+	/* Order previous accesses vs. msgsnd, which is treated as a store */
+	ppc_msgsnd_sync();
+	ppc_msgsnd(PPC_DBELL_MSGTYPE, 0, tag);
+}
+
+/*
+ * doorbell_core_ipi() sends a dbell to a target CPU in the same core.
+ * Must be used only by architectures that address msgsnd target
+ * by TIR/cpu_thread_in_core.
+ */
+static inline void doorbell_core_ipi(int cpu)
+{
+	u32 tag = cpu_thread_in_core(cpu);
+
+	kvmppc_set_host_ipi(cpu);
+	/* Order previous accesses vs. msgsnd, which is treated as a store */
+	ppc_msgsnd_sync();
+	ppc_msgsnd(PPC_DBELL_MSGTYPE, 0, tag);
+}
+
+/*
+ * Attempt to cause a core doorbell if destination is on the same core.
+ * Returns 1 on success, 0 on failure.
+ */
+static inline int doorbell_try_core_ipi(int cpu)
+{
+	int this_cpu = get_cpu();
+	int ret = 0;
+
+	if (cpumask_test_cpu(cpu, cpu_sibling_mask(this_cpu))) {
+		doorbell_core_ipi(cpu);
+		ret = 1;
+	}
+
+	put_cpu();
+
+	return ret;
+}
+
+#endif /* CONFIG_SMP */
+
 #endif /* _ASM_POWERPC_DBELL_H */
diff --git a/arch/powerpc/kernel/dbell.c b/arch/powerpc/kernel/dbell.c
index f17ff1200eaa..52680cf07c9d 100644
--- a/arch/powerpc/kernel/dbell.c
+++ b/arch/powerpc/kernel/dbell.c
@@ -18,61 +18,6 @@
 
 #ifdef CONFIG_SMP
 
-/*
- * Doorbells must only be used if CPU_FTR_DBELL is available.
- * msgsnd is used in HV, and msgsndp is used in !HV.
- *
- * These should be used by platform code that is aware of restrictions.
- * Other arch code should use ->cause_ipi.
- *
- * doorbell_global_ipi() sends a dbell to any target CPU.
- * Must be used only by architectures that address msgsnd target
- * by PIR/get_hard_smp_processor_id.
- */
-void doorbell_global_ipi(int cpu)
-{
-	u32 tag = get_hard_smp_processor_id(cpu);
-
-	kvmppc_set_host_ipi(cpu);
-	/* Order previous accesses vs. msgsnd, which is treated as a store */
-	ppc_msgsnd_sync();
-	ppc_msgsnd(PPC_DBELL_MSGTYPE, 0, tag);
-}
-
-/*
- * doorbell_core_ipi() sends a dbell to a target CPU in the same core.
- * Must be used only by architectures that address msgsnd target
- * by TIR/cpu_thread_in_core.
- */
-void doorbell_core_ipi(int cpu)
-{
-	u32 tag = cpu_thread_in_core(cpu);
-
-	kvmppc_set_host_ipi(cpu);
-	/* Order previous accesses vs. msgsnd, which is treated as a store */
-	ppc_msgsnd_sync();
-	ppc_msgsnd(PPC_DBELL_MSGTYPE, 0, tag);
-}
-
-/*
- * Attempt to cause a core doorbell if destination is on the same core.
- * Returns 1 on success, 0 on failure.
- */
-int doorbell_try_core_ipi(int cpu)
-{
-	int this_cpu = get_cpu();
-	int ret = 0;
-
-	if (cpumask_test_cpu(cpu, cpu_sibling_mask(this_cpu))) {
-		doorbell_core_ipi(cpu);
-		ret = 1;
-	}
-
-	put_cpu();
-
-	return ret;
-}
-
 void doorbell_exception(struct pt_regs *regs)
 {
 	struct pt_regs *old_regs = set_irq_regs(regs);
-- 
2.23.0


^ permalink raw reply related

* [PATCH v3 2/3] powerpc/pseries: Use doorbells even if XIVE is available
From: Nicholas Piggin @ 2020-07-26  3:51 UTC (permalink / raw)
  To: linuxppc-dev
  Cc: kvm-ppc, Nicholas Piggin, Anton Blanchard, Cédric Le Goater,
	David Gibson
In-Reply-To: <20200726035155.1424103-1-npiggin@gmail.com>

KVM supports msgsndp in guests by trapping and emulating the
instruction, so it was decided to always use XIVE for IPIs if it is
available. However on PowerVM systems, msgsndp can be used and gives
better performance. On large systems, high XIVE interrupt rates can
have sub-linear scaling, and using msgsndp can reduce the load on
the interrupt controller.

So switch to using core local doorbells even if XIVE is available.
This reduces performance for KVM guests with an SMT topology by
about 50% for ping-pong context switching between SMT vCPUs. An
option vector (or dt-cpu-ftrs) could be defined to disable msgsndp
to get KVM performance back.

Tested-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 arch/powerpc/platforms/pseries/smp.c | 54 ++++++++++++++++++----------
 1 file changed, 36 insertions(+), 18 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/smp.c b/arch/powerpc/platforms/pseries/smp.c
index 6891710833be..67e6ad5076ce 100644
--- a/arch/powerpc/platforms/pseries/smp.c
+++ b/arch/powerpc/platforms/pseries/smp.c
@@ -188,13 +188,16 @@ static int pseries_smp_prepare_cpu(int cpu)
 	return 0;
 }
 
-static void smp_pseries_cause_ipi(int cpu)
+/* Cause IPI as setup by the interrupt controller (xics or xive) */
+static void (*ic_cause_ipi)(int cpu) __ro_after_init;
+
+/* Use msgsndp doorbells target is a sibling, else use interrupt controller */
+static void dbell_or_ic_cause_ipi(int cpu)
 {
-	/* POWER9 should not use this handler */
 	if (doorbell_try_core_ipi(cpu))
 		return;
 
-	icp_ops->cause_ipi(cpu);
+	ic_cause_ipi(cpu);
 }
 
 static int pseries_cause_nmi_ipi(int cpu)
@@ -218,26 +221,41 @@ static int pseries_cause_nmi_ipi(int cpu)
 	return 0;
 }
 
-static __init void pSeries_smp_probe_xics(void)
-{
-	xics_smp_probe();
-
-	if (cpu_has_feature(CPU_FTR_DBELL) && !is_secure_guest())
-		smp_ops->cause_ipi = smp_pseries_cause_ipi;
-	else
-		smp_ops->cause_ipi = icp_ops->cause_ipi;
-}
-
 static __init void pSeries_smp_probe(void)
 {
 	if (xive_enabled())
-		/*
-		 * Don't use P9 doorbells when XIVE is enabled. IPIs
-		 * using MMIOs should be faster
-		 */
 		xive_smp_probe();
 	else
-		pSeries_smp_probe_xics();
+		xics_smp_probe();
+
+	/* No doorbell facility, must use the interrupt controller for IPIs */
+	if (!cpu_has_feature(CPU_FTR_DBELL))
+		return;
+
+	/* Doorbells can only be used for IPIs between SMT siblings */
+	if (!cpu_has_feature(CPU_FTR_SMT))
+		return;
+
+	/*
+	 * KVM emulates doorbells by disabling FSCR[MSGP] so msgsndp faults
+	 * to the hypervisor which then reads the instruction from guest
+	 * memory. This can't be done if the guest is secure, so don't use
+	 * doorbells in secure guests.
+	 *
+	 * Under PowerVM, FSCR[MSGP] is enabled so doorbells could be used
+	 * by secure guests if we distinguished this from KVM.
+	 */
+	if (is_secure_guest())
+		return;
+
+	/*
+	 * The guest can use doobells for SMT sibling IPIs, which stay in
+	 * the core rather than going to the interrupt controller. This
+	 * tends to be slower under KVM where doorbells are emulated, but
+	 * faster for PowerVM where they're enabled.
+	 */
+	ic_cause_ipi = smp_ops->cause_ipi;
+	smp_ops->cause_ipi = dbell_or_ic_cause_ipi;
 }
 
 static struct smp_ops_t pseries_smp_ops = {
-- 
2.23.0


^ permalink raw reply related

* [PATCH v3 3/3] powerpc/pseries: Add KVM guest doorbell restrictions
From: Nicholas Piggin @ 2020-07-26  3:51 UTC (permalink / raw)
  To: linuxppc-dev
  Cc: kvm-ppc, Nicholas Piggin, Anton Blanchard, Cédric Le Goater,
	David Gibson
In-Reply-To: <20200726035155.1424103-1-npiggin@gmail.com>

KVM guests have certain restrictions and performance quirks when using
doorbells. This patch moves the EPAPR KVM guest test so it can be shared
with PSERIES, and uses that in doorbell setup code to apply the KVM
guest quirks and  improves IPI performance for two cases:

 - PowerVM guests may now use doorbells even if they are secure.

 - KVM guests no longer use doorbells if XIVE is available.

There is a valid complaint that "KVM guest" is not a very reasonable
thing to test for, it's preferable for the hypervisor to advertise
particular behaviours to the guest so they could change if the
hypervisor implementation or configuration changes. However in this case
we were already assuming a KVM guest worst case, so this patch is about
containing those quirks. If KVM later advertises fast doorbells, we
should test for that and override the quirks.

Tested-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 arch/powerpc/include/asm/firmware.h  |  6 +++++
 arch/powerpc/include/asm/kvm_para.h  | 26 +++----------------
 arch/powerpc/kernel/Makefile         |  5 ++--
 arch/powerpc/kernel/firmware.c       | 19 ++++++++++++++
 arch/powerpc/platforms/pseries/smp.c | 38 +++++++++++++++++-----------
 5 files changed, 53 insertions(+), 41 deletions(-)

diff --git a/arch/powerpc/include/asm/firmware.h b/arch/powerpc/include/asm/firmware.h
index 6003c2e533a0..f67efbaba17f 100644
--- a/arch/powerpc/include/asm/firmware.h
+++ b/arch/powerpc/include/asm/firmware.h
@@ -132,6 +132,12 @@ extern int ibm_nmi_interlock_token;
 
 extern unsigned int __start___fw_ftr_fixup, __stop___fw_ftr_fixup;
 
+#if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_KVM_GUEST)
+bool is_kvm_guest(void);
+#else
+static inline bool is_kvm_guest(void) { return false; }
+#endif
+
 #ifdef CONFIG_PPC_PSERIES
 void pseries_probe_fw_features(void);
 #else
diff --git a/arch/powerpc/include/asm/kvm_para.h b/arch/powerpc/include/asm/kvm_para.h
index 9c1f6b4b9bbf..744612054c94 100644
--- a/arch/powerpc/include/asm/kvm_para.h
+++ b/arch/powerpc/include/asm/kvm_para.h
@@ -8,35 +8,15 @@
 #ifndef __POWERPC_KVM_PARA_H__
 #define __POWERPC_KVM_PARA_H__
 
-#include <uapi/asm/kvm_para.h>
-
-#ifdef CONFIG_KVM_GUEST
-
-#include <linux/of.h>
-
-static inline int kvm_para_available(void)
-{
-	struct device_node *hyper_node;
-
-	hyper_node = of_find_node_by_path("/hypervisor");
-	if (!hyper_node)
-		return 0;
+#include <asm/firmware.h>
 
-	if (!of_device_is_compatible(hyper_node, "linux,kvm"))
-		return 0;
-
-	return 1;
-}
-
-#else
+#include <uapi/asm/kvm_para.h>
 
 static inline int kvm_para_available(void)
 {
-	return 0;
+	return IS_ENABLED(CONFIG_KVM_GUEST) && is_kvm_guest();
 }
 
-#endif
-
 static inline unsigned int kvm_arch_para_features(void)
 {
 	unsigned long r;
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index 244542ae2a91..852164439dcb 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -45,11 +45,10 @@ obj-y				:= cputable.o syscalls.o \
 				   signal.o sysfs.o cacheinfo.o time.o \
 				   prom.o traps.o setup-common.o \
 				   udbg.o misc.o io.o misc_$(BITS).o \
-				   of_platform.o prom_parse.o
+				   of_platform.o prom_parse.o firmware.o
 obj-y				+= ptrace/
 obj-$(CONFIG_PPC64)		+= setup_64.o \
-				   paca.o nvram_64.o firmware.o note.o \
-				   syscall_64.o
+				   paca.o nvram_64.o note.o syscall_64.o
 obj-$(CONFIG_COMPAT)		+= sys_ppc32.o signal_32.o
 obj-$(CONFIG_VDSO32)		+= vdso32/
 obj-$(CONFIG_PPC_WATCHDOG)	+= watchdog.o
diff --git a/arch/powerpc/kernel/firmware.c b/arch/powerpc/kernel/firmware.c
index cc4a5e3f51f1..fe48d319d490 100644
--- a/arch/powerpc/kernel/firmware.c
+++ b/arch/powerpc/kernel/firmware.c
@@ -11,8 +11,27 @@
 
 #include <linux/export.h>
 #include <linux/cache.h>
+#include <linux/of.h>
 
 #include <asm/firmware.h>
 
+#ifdef CONFIG_PPC64
 unsigned long powerpc_firmware_features __read_mostly;
 EXPORT_SYMBOL_GPL(powerpc_firmware_features);
+#endif
+
+#if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_KVM_GUEST)
+bool is_kvm_guest(void)
+{
+	struct device_node *hyper_node;
+
+	hyper_node = of_find_node_by_path("/hypervisor");
+	if (!hyper_node)
+		return 0;
+
+	if (!of_device_is_compatible(hyper_node, "linux,kvm"))
+		return 0;
+
+	return 1;
+}
+#endif
diff --git a/arch/powerpc/platforms/pseries/smp.c b/arch/powerpc/platforms/pseries/smp.c
index 67e6ad5076ce..7af0003b40b6 100644
--- a/arch/powerpc/platforms/pseries/smp.c
+++ b/arch/powerpc/platforms/pseries/smp.c
@@ -236,24 +236,32 @@ static __init void pSeries_smp_probe(void)
 	if (!cpu_has_feature(CPU_FTR_SMT))
 		return;
 
-	/*
-	 * KVM emulates doorbells by disabling FSCR[MSGP] so msgsndp faults
-	 * to the hypervisor which then reads the instruction from guest
-	 * memory. This can't be done if the guest is secure, so don't use
-	 * doorbells in secure guests.
-	 *
-	 * Under PowerVM, FSCR[MSGP] is enabled so doorbells could be used
-	 * by secure guests if we distinguished this from KVM.
-	 */
-	if (is_secure_guest())
-		return;
+	if (is_kvm_guest()) {
+		/*
+		 * KVM emulates doorbells by disabling FSCR[MSGP] so msgsndp
+		 * faults to the hypervisor which then reads the instruction
+		 * from guest memory, which tends to be slower than using XIVE.
+		 */
+		if (xive_enabled())
+			return;
+
+		/*
+		 * XICS hcalls aren't as fast, so we can use msgsndp (which
+		 * also helps exercise KVM emulation), however KVM can't
+		 * emulate secure guests because it can't read the instruction
+		 * out of their memory.
+		 */
+		if (is_secure_guest())
+			return;
+	}
 
 	/*
-	 * The guest can use doobells for SMT sibling IPIs, which stay in
-	 * the core rather than going to the interrupt controller. This
-	 * tends to be slower under KVM where doorbells are emulated, but
-	 * faster for PowerVM where they're enabled.
+	 * Under PowerVM, FSCR[MSGP] is enabled as guest vCPU siblings are
+	 * gang scheduled on the same physical core, so doorbells are always
+	 * faster than the interrupt controller, and they can be used by
+	 * secure guests.
 	 */
+
 	ic_cause_ipi = smp_ops->cause_ipi;
 	smp_ops->cause_ipi = dbell_or_ic_cause_ipi;
 }
-- 
2.23.0


^ permalink raw reply related

* Re: [PATCH 1/2] lockdep: improve current->(hard|soft)irqs_enabled synchronisation with actual irq state
From: Nicholas Piggin @ 2020-07-26  4:14 UTC (permalink / raw)
  To: Peter Zijlstra
  Cc: linux-arch, Alexey Kardashevskiy, Will Deacon, linux-kernel,
	Ingo Molnar, linuxppc-dev
In-Reply-To: <20200725202617.GI10769@hirez.programming.kicks-ass.net>

Excerpts from Peter Zijlstra's message of July 26, 2020 6:26 am:
> On Thu, Jul 23, 2020 at 08:56:14PM +1000, Nicholas Piggin wrote:
>> diff --git a/arch/powerpc/include/asm/hw_irq.h b/arch/powerpc/include/asm/hw_irq.h
>> index 3a0db7b0b46e..35060be09073 100644
>> --- a/arch/powerpc/include/asm/hw_irq.h
>> +++ b/arch/powerpc/include/asm/hw_irq.h
>> @@ -200,17 +200,14 @@ static inline bool arch_irqs_disabled(void)
>>  #define powerpc_local_irq_pmu_save(flags)			\
>>  	 do {							\
>>  		raw_local_irq_pmu_save(flags);			\
>> -		trace_hardirqs_off();				\
>> +		if (!raw_irqs_disabled_flags(flags))		\
>> +			trace_hardirqs_off();			\
>>  	} while(0)
> 
> So one problem with the above is something like this:
> 
> 	raw_local_irq_save();
> 	<NMI>
> 	  powerpc_local_irq_pmu_save();
> 
> that would now no longer call into tracing/lockdep at all. As a
> consequence, lockdep and tracing would show the NMI ran with IRQs
> enabled, which is exceptionally weird..

powerpc perf NMIs will trace_hardirqs_off() if they were enabled,
and trace_hardirqs_on() at exit in that case too.

Machine check and system reset (like x86's "nmi") don't, but that's
deliberate to avoid any tracing in those cases which often causes
more problems than it's worth (and we have flags to prevent ftrace,
etc too for those cases).

> Similar problem with:
> 
> 	raw_local_irq_disable();
> 	local_irq_save()
> 
> Now, most architectures today seem to do what x86 also did:
> 
> 	<NMI>
> 	  trace_hardirqs_off()
> 	  ...
> 	  if (irqs_unmasked(regs))
> 	    trace_hardirqs_on()
> 	</NMI>
> 
> Which is 'funny' when it interleaves like:
> 
> 	local_irq_disable();
> 	...
> 	local_irq_enable()
> 	  trace_hardirqs_on();
> 	  <NMI/>
> 	  raw_local_irq_enable();
> 
> Because then it will undo the trace_hardirqs_on() we just did. With the
> result that both tracing and lockdep will see a hardirqs-disable without
> a matching enable, while the hardware state is enabled.

Seems like an arch problem -- why not disable if it was enabled only?
I guess the local_irq tracing calls are a mess so maybe they copied 
those.

> Which is exactly the state Alexey seems to have ran into.

No his was what I said, the interruptee's trace_hardirqs_on() in
local_irq_enable getting lost because the NMI's local_irq_disable
always disables, but the enable doesn't re-enable.

It's all just weird asymmetrical special case hacks AFAIKS, the
code should just be symmetric and lockdep handle it's own weirdness.

> 
> Now, x86, and at least arm64 call nmi_enter() before
> trace_hardirqs_off(), but AFAICT Power never did that, and that's part
> of the problem. nmi_enter() does lockdep_off() and that _used_ to also
> kill IRQ tracking.

Power does do nmi_enter -- __perf_event_interrupt()

        nmi = perf_intr_is_nmi(regs);
        if (nmi)
                nmi_enter();
        else
                irq_enter();

Thanks,
Nick

> Now, my patch changed that, it makes IRQ tracking not respect
> lockdep_off(). And that exposed x86 (and everybody else :/) to the same
> problem you have.
> 
> And this is why I made x86 look at software state in NMIs. Because then
> it all works out. For bonus points, trace_hardirqs_*() also has some
> do-it-once logic for tracing.
> 
> 
> 
> Anyway, it's Saturday evening, time for a beer. I'll stare at this more
> later.
> 

^ permalink raw reply

* Re: [PATCH 1/2] lockdep: improve current->(hard|soft)irqs_enabled synchronisation with actual irq state
From: Alexey Kardashevskiy @ 2020-07-26  7:40 UTC (permalink / raw)
  To: Nicholas Piggin, Peter Zijlstra
  Cc: linux-arch, Will Deacon, Ingo Molnar, linuxppc-dev, linux-kernel
In-Reply-To: <1595568105.4eodjnxzwp.astroid@bobo.none>



On 24/07/2020 15:59, Nicholas Piggin wrote:
> Excerpts from Alexey Kardashevskiy's message of July 24, 2020 2:16 pm:
>>
>>
>> On 23/07/2020 23:11, Nicholas Piggin wrote:
>>> Excerpts from Peter Zijlstra's message of July 23, 2020 9:40 pm:
>>>> On Thu, Jul 23, 2020 at 08:56:14PM +1000, Nicholas Piggin wrote:
>>>>
>>>>> diff --git a/arch/powerpc/include/asm/hw_irq.h b/arch/powerpc/include/asm/hw_irq.h
>>>>> index 3a0db7b0b46e..35060be09073 100644
>>>>> --- a/arch/powerpc/include/asm/hw_irq.h
>>>>> +++ b/arch/powerpc/include/asm/hw_irq.h
>>>>> @@ -200,17 +200,14 @@ static inline bool arch_irqs_disabled(void)
>>>>>  #define powerpc_local_irq_pmu_save(flags)			\
>>>>>  	 do {							\
>>>>>  		raw_local_irq_pmu_save(flags);			\
>>>>> -		trace_hardirqs_off();				\
>>>>> +		if (!raw_irqs_disabled_flags(flags))		\
>>>>> +			trace_hardirqs_off();			\
>>>>>  	} while(0)
>>>>>  #define powerpc_local_irq_pmu_restore(flags)			\
>>>>>  	do {							\
>>>>> -		if (raw_irqs_disabled_flags(flags)) {		\
>>>>> -			raw_local_irq_pmu_restore(flags);	\
>>>>> -			trace_hardirqs_off();			\
>>>>> -		} else {					\
>>>>> +		if (!raw_irqs_disabled_flags(flags))		\
>>>>>  			trace_hardirqs_on();			\
>>>>> -			raw_local_irq_pmu_restore(flags);	\
>>>>> -		}						\
>>>>> +		raw_local_irq_pmu_restore(flags);		\
>>>>>  	} while(0)
>>>>
>>>> You shouldn't be calling lockdep from NMI context!
>>>
>>> After this patch it doesn't.
>>>
>>> trace_hardirqs_on/off implementation appears to expect to be called in NMI 
>>> context though, for some reason.
>>>
>>>> That is, I recently
>>>> added suport for that on x86:
>>>>
>>>>   https://lkml.kernel.org/r/20200623083721.155449112@infradead.org
>>>>   https://lkml.kernel.org/r/20200623083721.216740948@infradead.org
>>>>
>>>> But you need to be very careful on how you order things, as you can see
>>>> the above relies on preempt_count() already having been incremented with
>>>> NMI_MASK.
>>>
>>> Hmm. My patch seems simpler.
>>
>> And your patches fix my error while Peter's do not:
>>
>>
>> IRQs not enabled as expected
>> WARNING: CPU: 0 PID: 1377 at /home/aik/p/kernel/kernel/softirq.c:169
>> __local_bh_enable_ip+0x118/0x190
> 
> I think they would have needed some powerpc bits as well. 

True, there is quite a lot to repeat of what x86 does, I was in a hurry
and did not think it through :)

> But I don't
> see a reason we can't merge my patches, at least they fix this case and
> don't seem to make things worse in any way.

True. Or we could keep these lockdep_stats::redundant_softirqs_on/etc
and make powerpc_local_irq_pmu_restore()/local_irq_restore() call
trace_hardirqs_on() always and let lockdep do reference counting, may be?


-- 
Alexey

^ permalink raw reply


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