[PATCH v3 1/4] resource: Change __request_region to inherit from immediate parent

[PATCH v3 1/4] resource: Change __request_region to inherit from immediate parent

[Toshi Kani]

__request_region() sets 'flags' of a new resource from @parent
as it inherits the parent's attribute.  When a target resource
has a conflict, this function inserts the new resource entry
under the conflicted entry by updating @parent.  In this case,
the new resource entry needs to inherit attribute from the updated
parent.  This conflict is a typical case since __request_region()
is used to allocate a new resource from a specific resource range.

For instance, request_mem_region() calls __request_region() with
@parent set to &iomem_resource, which is the root entry of the
whole iomem range.  When this request results in inserting a new
entry "DEV-A" under "BUS-1", "DEV-A" needs to inherit from the
immediate parent "BUS-1" as it holds specific attribute for the
range.

root (&iomem_resource)
 :
 + "BUS-1"
    + "DEV-A"

Change __request_region() to set 'flags' and 'desc' of a new entry
from the immediate parent.

Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dan Williams <dan.j.williams@intel.com>
---
 kernel/resource.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/resource.c b/kernel/resource.c
index 4d46605..5a56e8f 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -1085,15 +1085,16 @@ struct resource * __request_region(struct resource *parent,
 	res->name = name;
 	res->start = start;
 	res->end = start + n - 1;
-	res->flags = resource_type(parent) | resource_ext_type(parent);
-	res->flags |= IORESOURCE_BUSY | flags;
-	res->desc = IORES_DESC_NONE;
 
 	write_lock(&resource_lock);
 
 	for (;;) {
 		struct resource *conflict;
 
+		res->flags = resource_type(parent) | resource_ext_type(parent);
+		res->flags |= IORESOURCE_BUSY | flags;
+		res->desc = parent->desc;
+
 		conflict = __request_resource(parent, res);
 		if (!conflict)
 			break;

[PATCH v3 2/4] resource: Add remove_resource interface

[Toshi Kani]

insert_resource() and insert_resource_conflict() are called
by resource producers to insert a new resource.  When there
is any conflict, they move conflicting resources down to the
children of the new resource.  There is no destructor of these
interfaces, however.

Add remove_resource(), which removes a resource previously
inserted by insert_resource() or insert_resource_conflict(),
and moves the children up to where they were before.

__release_resource() is changed to have @release_child, so
that this function can be used for remove_resource() as well.

Also add comments to clarify that these functions are intended
for producers of resources to avoid any confusion with
request/release_resource() for consumers.

Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dan Williams <dan.j.williams@intel.com>
---
 include/linux/ioport.h |    1 +
 kernel/resource.c      |   51 +++++++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 47 insertions(+), 5 deletions(-)

diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index afb4559..8017b8b 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -174,6 +174,7 @@ extern void reserve_region_with_split(struct resource *root,
 extern struct resource *insert_resource_conflict(struct resource *parent, struct resource *new);
 extern int insert_resource(struct resource *parent, struct resource *new);
 extern void insert_resource_expand_to_fit(struct resource *root, struct resource *new);
+extern int remove_resource(struct resource *old);
 extern void arch_remove_reservations(struct resource *avail);
 extern int allocate_resource(struct resource *root, struct resource *new,
 			     resource_size_t size, resource_size_t min,
diff --git a/kernel/resource.c b/kernel/resource.c
index 5a56e8f..effb6ee 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -233,9 +233,9 @@ static struct resource * __request_resource(struct resource *root, struct resour
 	}
 }
 
-static int __release_resource(struct resource *old)
+static int __release_resource(struct resource *old, bool release_child)
 {
-	struct resource *tmp, **p;
+	struct resource *tmp, **p, *chd;
 
 	p = &old->parent->child;
 	for (;;) {
@@ -243,7 +243,17 @@ static int __release_resource(struct resource *old)
 		if (!tmp)
 			break;
 		if (tmp == old) {
-			*p = tmp->sibling;
+			if (release_child || !(tmp->child)) {
+				*p = tmp->sibling;
+			} else {
+				for (chd = tmp->child;; chd = chd->sibling) {
+					chd->parent = tmp->parent;
+					if (!(chd->sibling))
+						break;
+				}
+				*p = tmp->child;
+				chd->sibling = tmp->sibling;
+			}
 			old->parent = NULL;
 			return 0;
 		}
@@ -325,7 +335,7 @@ int release_resource(struct resource *old)
 	int retval;
 
 	write_lock(&resource_lock);
-	retval = __release_resource(old);
+	retval = __release_resource(old, true);
 	write_unlock(&resource_lock);
 	return retval;
 }
@@ -679,7 +689,7 @@ static int reallocate_resource(struct resource *root, struct resource *old,
 		old->start = new.start;
 		old->end = new.end;
 	} else {
-		__release_resource(old);
+		__release_resource(old, true);
 		*old = new;
 		conflict = __request_resource(root, old);
 		BUG_ON(conflict);
@@ -825,6 +835,9 @@ static struct resource * __insert_resource(struct resource *parent, struct resou
  * entirely fit within the range of the new resource, then the new
  * resource is inserted and the conflicting resources become children of
  * the new resource.
+ *
+ * This function is intended for producers of resources, such as FW modules
+ * and bus drivers.
  */
 struct resource *insert_resource_conflict(struct resource *parent, struct resource *new)
 {
@@ -842,6 +855,9 @@ struct resource *insert_resource_conflict(struct resource *parent, struct resour
  * @new: new resource to insert
  *
  * Returns 0 on success, -EBUSY if the resource can't be inserted.
+ *
+ * This function is intended for producers of resources, such as FW modules
+ * and bus drivers.
  */
 int insert_resource(struct resource *parent, struct resource *new)
 {
@@ -885,6 +901,31 @@ void insert_resource_expand_to_fit(struct resource *root, struct resource *new)
 	write_unlock(&resource_lock);
 }
 
+/**
+ * remove_resource - Remove a resource in the resource tree
+ * @old: resource to remove
+ *
+ * Returns 0 on success, -EINVAL if the resource is not valid.
+ *
+ * This function removes a resource previously inserted by insert_resource()
+ * or insert_resource_conflict(), and moves the children (if any) up to
+ * where they were before.  insert_resource() and insert_resource_conflict()
+ * insert a new resource, and move any conflicting resources down to the
+ * children of the new resource.
+ *
+ * insert_resource(), insert_resource_conflict() and remove_resource() are
+ * intended for producers of resources, such as FW modules and bus drivers.
+ */
+int remove_resource(struct resource *old)
+{
+	int retval;
+
+	write_lock(&resource_lock);
+	retval = __release_resource(old, false);
+	write_unlock(&resource_lock);
+	return retval;
+}
+
 static int __adjust_resource(struct resource *res, resource_size_t start,
 				resource_size_t size)
 {

[PATCH v3 3/4] resource: Export insert_resource and remove_resource

[Toshi Kani]

insert_resource() and remove_resouce() are called by producers
of resources, such as FW modules and bus drivers.  These modules
may be implemented as loadable modules.

Export insert_resource() and remove_resouce() so that they can
be called from such modules.

link: https://lkml.org/lkml/2016/3/8/872
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dan Williams <dan.j.williams@intel.com>
---
 kernel/resource.c |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/resource.c b/kernel/resource.c
index effb6ee..2e78ead 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -866,6 +866,7 @@ int insert_resource(struct resource *parent, struct resource *new)
 	conflict = insert_resource_conflict(parent, new);
 	return conflict ? -EBUSY : 0;
 }
+EXPORT_SYMBOL_GPL(insert_resource);
 
 /**
  * insert_resource_expand_to_fit - Insert a resource into the resource tree
@@ -925,6 +926,7 @@ int remove_resource(struct resource *old)
 	write_unlock(&resource_lock);
 	return retval;
 }
+EXPORT_SYMBOL_GPL(remove_resource);
 
 static int __adjust_resource(struct resource *res, resource_size_t start,
 				resource_size_t size)

[PATCH v3 4/4] ACPI: Change NFIT driver to insert new resource

[Toshi Kani]

ACPI 6 defines persistent memory (PMEM) ranges in multiple
firmware interfaces, e820, EFI, and ACPI NFIT table.  This EFI
change, however, leads to hit a bug in the grub bootloader, which
treats EFI_PERSISTENT_MEMORY type as regular memory and corrupts
stored user data [1].

Therefore, BIOS may set generic reserved type in e820 and EFI to
cover PMEM ranges.  The kernel can initialize PMEM ranges from
ACPI NFIT table alone.

This scheme causes a problem in the iomem table, though.  On x86,
for instance, e820_reserve_resources() initializes top-level entries
(iomem_resource.child) from the e820 table at early boot-time.
This creates "reserved" entry for a PMEM range, which does not allow
region_intersects() to check with PMEM type.

Change acpi_nfit_register_region() to call acpi_nfit_insert_resource(),
which calls insert_resource() to insert a PMEM entry from NFIT when
the iomem table does not have a PMEM entry already.  That is, when
a PMEM range is marked as reserved type in e820, it inserts
"Persistent Memory" entry, which results as follows.

 + "Persistent Memory"
    + "reserved"

This allows the EINJ driver, which calls region_intersects() to check
PMEM ranges, to work continuously even if BIOS sets reserved type
(or sets nothing) to PMEM ranges in e820 and EFI.

[1]: https://lists.gnu.org/archive/html/grub-devel/2015-11/msg00209.html
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
---
 drivers/acpi/nfit.c |   48 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c
index 35947ac..d5c78f2 100644
--- a/drivers/acpi/nfit.c
+++ b/drivers/acpi/nfit.c
@@ -1571,6 +1571,48 @@ static int ars_status_process_records(struct nvdimm_bus *nvdimm_bus,
 	return 0;
 }
 
+static void acpi_nfit_remove_resource(void *data)
+{
+	struct resource *res = data;
+
+	remove_resource(res);
+}
+
+static int acpi_nfit_insert_resource(struct acpi_nfit_desc *acpi_desc,
+		struct nd_region_desc *ndr_desc)
+{
+	struct resource *res, *nd_res = ndr_desc->res;
+	int is_pmem, ret;
+
+	/* No operation if the region is already registered as PMEM */
+	is_pmem = region_intersects(nd_res->start, resource_size(nd_res),
+				IORESOURCE_MEM, IORES_DESC_PERSISTENT_MEMORY);
+	if (is_pmem == REGION_INTERSECTS)
+		return 0;
+
+	res = devm_kzalloc(acpi_desc->dev, sizeof(*res), GFP_KERNEL);
+	if (!res)
+		return -ENOMEM;
+
+	res->name = "Persistent Memory";
+	res->start = nd_res->start;
+	res->end = nd_res->end;
+	res->flags = IORESOURCE_MEM;
+	res->desc = IORES_DESC_PERSISTENT_MEMORY;
+
+	ret = insert_resource(&iomem_resource, res);
+	if (ret)
+		return ret;
+
+	ret = devm_add_action(acpi_desc->dev, acpi_nfit_remove_resource, res);
+	if (ret) {
+		remove_resource(res);
+		return ret;
+	}
+
+	return 0;
+}
+
 static int acpi_nfit_find_poison(struct acpi_nfit_desc *acpi_desc,
 		struct nd_region_desc *ndr_desc)
 {
@@ -1788,6 +1830,12 @@ static int acpi_nfit_register_region(struct acpi_nfit_desc *acpi_desc,
 
 	nvdimm_bus = acpi_desc->nvdimm_bus;
 	if (nfit_spa_type(spa) == NFIT_SPA_PM) {
+		rc = acpi_nfit_insert_resource(acpi_desc, ndr_desc);
+		if (rc)
+			dev_warn(acpi_desc->dev,
+				"failed to insert pmem resource to iomem: %d\n",
+				rc);
+
 		rc = acpi_nfit_find_poison(acpi_desc, ndr_desc);
 		if (rc) {
 			dev_err(acpi_desc->dev,