summaryrefslogtreecommitdiff
path: root/kernel
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2015-09-08 14:35:59 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2015-09-08 14:35:59 -0700
commit12f03ee606914317e7e6a0815e53a48205c31dae (patch)
treef8579bf77d29b3921e1877e0ae12ec65b5ebc738 /kernel
parentd9241b22b58e012f26dd2244508d9f4837402af0 (diff)
parent004f1afbe199e6ab20805b95aefd83ccd24bc5c7 (diff)
Merge tag 'libnvdimm-for-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
Pull libnvdimm updates from Dan Williams: "This update has successfully completed a 0day-kbuild run and has appeared in a linux-next release. The changes outside of the typical drivers/nvdimm/ and drivers/acpi/nfit.[ch] paths are related to the removal of IORESOURCE_CACHEABLE, the introduction of memremap(), and the introduction of ZONE_DEVICE + devm_memremap_pages(). Summary: - Introduce ZONE_DEVICE and devm_memremap_pages() as a generic mechanism for adding device-driver-discovered memory regions to the kernel's direct map. This facility is used by the pmem driver to enable pfn_to_page() operations on the page frames returned by DAX ('direct_access' in 'struct block_device_operations'). For now, the 'memmap' allocation for these "device" pages comes from "System RAM". Support for allocating the memmap from device memory will arrive in a later kernel. - Introduce memremap() to replace usages of ioremap_cache() and ioremap_wt(). memremap() drops the __iomem annotation for these mappings to memory that do not have i/o side effects. The replacement of ioremap_cache() with memremap() is limited to the pmem driver to ease merging the api change in v4.3. Completion of the conversion is targeted for v4.4. - Similar to the usage of memcpy_to_pmem() + wmb_pmem() in the pmem driver, update the VFS DAX implementation and PMEM api to provide persistence guarantees for kernel operations on a DAX mapping. - Convert the ACPI NFIT 'BLK' driver to map the block apertures as cacheable to improve performance. - Miscellaneous updates and fixes to libnvdimm including support for issuing "address range scrub" commands, clarifying the optimal 'sector size' of pmem devices, a clarification of the usage of the ACPI '_STA' (status) property for DIMM devices, and other minor fixes" * tag 'libnvdimm-for-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (34 commits) libnvdimm, pmem: direct map legacy pmem by default libnvdimm, pmem: 'struct page' for pmem libnvdimm, pfn: 'struct page' provider infrastructure x86, pmem: clarify that ARCH_HAS_PMEM_API implies PMEM mapped WB add devm_memremap_pages mm: ZONE_DEVICE for "device memory" mm: move __phys_to_pfn and __pfn_to_phys to asm/generic/memory_model.h dax: drop size parameter to ->direct_access() nd_blk: change aperture mapping from WC to WB nvdimm: change to use generic kvfree() pmem, dax: have direct_access use __pmem annotation dax: update I/O path to do proper PMEM flushing pmem: add copy_from_iter_pmem() and clear_pmem() pmem, x86: clean up conditional pmem includes pmem: remove layer when calling arch_has_wmb_pmem() pmem, x86: move x86 PMEM API to new pmem.h header libnvdimm, e820: make CONFIG_X86_PMEM_LEGACY a tristate option pmem: switch to devm_ allocations devres: add devm_memremap libnvdimm, btt: write and validate parent_uuid ...
Diffstat (limited to 'kernel')
-rw-r--r--kernel/Makefile2
-rw-r--r--kernel/memremap.c190
-rw-r--r--kernel/resource.c61
3 files changed, 228 insertions, 25 deletions
diff --git a/kernel/Makefile b/kernel/Makefile
index d25ebea0453a..e0d7587e7684 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -99,6 +99,8 @@ obj-$(CONFIG_JUMP_LABEL) += jump_label.o
obj-$(CONFIG_CONTEXT_TRACKING) += context_tracking.o
obj-$(CONFIG_TORTURE_TEST) += torture.o
+obj-$(CONFIG_HAS_IOMEM) += memremap.o
+
$(obj)/configs.o: $(obj)/config_data.h
# config_data.h contains the same information as ikconfig.h but gzipped.
diff --git a/kernel/memremap.c b/kernel/memremap.c
new file mode 100644
index 000000000000..72b0c66628b6
--- /dev/null
+++ b/kernel/memremap.c
@@ -0,0 +1,190 @@
+/*
+ * Copyright(c) 2015 Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ */
+#include <linux/device.h>
+#include <linux/types.h>
+#include <linux/io.h>
+#include <linux/mm.h>
+#include <linux/memory_hotplug.h>
+
+#ifndef ioremap_cache
+/* temporary while we convert existing ioremap_cache users to memremap */
+__weak void __iomem *ioremap_cache(resource_size_t offset, unsigned long size)
+{
+ return ioremap(offset, size);
+}
+#endif
+
+/**
+ * memremap() - remap an iomem_resource as cacheable memory
+ * @offset: iomem resource start address
+ * @size: size of remap
+ * @flags: either MEMREMAP_WB or MEMREMAP_WT
+ *
+ * memremap() is "ioremap" for cases where it is known that the resource
+ * being mapped does not have i/o side effects and the __iomem
+ * annotation is not applicable.
+ *
+ * MEMREMAP_WB - matches the default mapping for "System RAM" on
+ * the architecture. This is usually a read-allocate write-back cache.
+ * Morever, if MEMREMAP_WB is specified and the requested remap region is RAM
+ * memremap() will bypass establishing a new mapping and instead return
+ * a pointer into the direct map.
+ *
+ * MEMREMAP_WT - establish a mapping whereby writes either bypass the
+ * cache or are written through to memory and never exist in a
+ * cache-dirty state with respect to program visibility. Attempts to
+ * map "System RAM" with this mapping type will fail.
+ */
+void *memremap(resource_size_t offset, size_t size, unsigned long flags)
+{
+ int is_ram = region_intersects(offset, size, "System RAM");
+ void *addr = NULL;
+
+ if (is_ram == REGION_MIXED) {
+ WARN_ONCE(1, "memremap attempted on mixed range %pa size: %#lx\n",
+ &offset, (unsigned long) size);
+ return NULL;
+ }
+
+ /* Try all mapping types requested until one returns non-NULL */
+ if (flags & MEMREMAP_WB) {
+ flags &= ~MEMREMAP_WB;
+ /*
+ * MEMREMAP_WB is special in that it can be satisifed
+ * from the direct map. Some archs depend on the
+ * capability of memremap() to autodetect cases where
+ * the requested range is potentially in "System RAM"
+ */
+ if (is_ram == REGION_INTERSECTS)
+ addr = __va(offset);
+ else
+ addr = ioremap_cache(offset, size);
+ }
+
+ /*
+ * If we don't have a mapping yet and more request flags are
+ * pending then we will be attempting to establish a new virtual
+ * address mapping. Enforce that this mapping is not aliasing
+ * "System RAM"
+ */
+ if (!addr && is_ram == REGION_INTERSECTS && flags) {
+ WARN_ONCE(1, "memremap attempted on ram %pa size: %#lx\n",
+ &offset, (unsigned long) size);
+ return NULL;
+ }
+
+ if (!addr && (flags & MEMREMAP_WT)) {
+ flags &= ~MEMREMAP_WT;
+ addr = ioremap_wt(offset, size);
+ }
+
+ return addr;
+}
+EXPORT_SYMBOL(memremap);
+
+void memunmap(void *addr)
+{
+ if (is_vmalloc_addr(addr))
+ iounmap((void __iomem *) addr);
+}
+EXPORT_SYMBOL(memunmap);
+
+static void devm_memremap_release(struct device *dev, void *res)
+{
+ memunmap(res);
+}
+
+static int devm_memremap_match(struct device *dev, void *res, void *match_data)
+{
+ return *(void **)res == match_data;
+}
+
+void *devm_memremap(struct device *dev, resource_size_t offset,
+ size_t size, unsigned long flags)
+{
+ void **ptr, *addr;
+
+ ptr = devres_alloc(devm_memremap_release, sizeof(*ptr), GFP_KERNEL);
+ if (!ptr)
+ return NULL;
+
+ addr = memremap(offset, size, flags);
+ if (addr) {
+ *ptr = addr;
+ devres_add(dev, ptr);
+ } else
+ devres_free(ptr);
+
+ return addr;
+}
+EXPORT_SYMBOL(devm_memremap);
+
+void devm_memunmap(struct device *dev, void *addr)
+{
+ WARN_ON(devres_destroy(dev, devm_memremap_release, devm_memremap_match,
+ addr));
+ memunmap(addr);
+}
+EXPORT_SYMBOL(devm_memunmap);
+
+#ifdef CONFIG_ZONE_DEVICE
+struct page_map {
+ struct resource res;
+};
+
+static void devm_memremap_pages_release(struct device *dev, void *res)
+{
+ struct page_map *page_map = res;
+
+ /* pages are dead and unused, undo the arch mapping */
+ arch_remove_memory(page_map->res.start, resource_size(&page_map->res));
+}
+
+void *devm_memremap_pages(struct device *dev, struct resource *res)
+{
+ int is_ram = region_intersects(res->start, resource_size(res),
+ "System RAM");
+ struct page_map *page_map;
+ int error, nid;
+
+ if (is_ram == REGION_MIXED) {
+ WARN_ONCE(1, "%s attempted on mixed region %pr\n",
+ __func__, res);
+ return ERR_PTR(-ENXIO);
+ }
+
+ if (is_ram == REGION_INTERSECTS)
+ return __va(res->start);
+
+ page_map = devres_alloc(devm_memremap_pages_release,
+ sizeof(*page_map), GFP_KERNEL);
+ if (!page_map)
+ return ERR_PTR(-ENOMEM);
+
+ memcpy(&page_map->res, res, sizeof(*res));
+
+ nid = dev_to_node(dev);
+ if (nid < 0)
+ nid = 0;
+
+ error = arch_add_memory(nid, res->start, resource_size(res), true);
+ if (error) {
+ devres_free(page_map);
+ return ERR_PTR(error);
+ }
+
+ devres_add(dev, page_map);
+ return __va(res->start);
+}
+EXPORT_SYMBOL(devm_memremap_pages);
+#endif /* CONFIG_ZONE_DEVICE */
diff --git a/kernel/resource.c b/kernel/resource.c
index fed052a1bc9f..f150dbbe6f62 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -492,40 +492,51 @@ int __weak page_is_ram(unsigned long pfn)
}
EXPORT_SYMBOL_GPL(page_is_ram);
-/*
- * Search for a resouce entry that fully contains the specified region.
- * If found, return 1 if it is RAM, 0 if not.
- * If not found, or region is not fully contained, return -1
+/**
+ * region_intersects() - determine intersection of region with known resources
+ * @start: region start address
+ * @size: size of region
+ * @name: name of resource (in iomem_resource)
*
- * Used by the ioremap functions to ensure the user is not remapping RAM and is
- * a vast speed up over walking through the resource table page by page.
+ * Check if the specified region partially overlaps or fully eclipses a
+ * resource identified by @name. Return REGION_DISJOINT if the region
+ * does not overlap @name, return REGION_MIXED if the region overlaps
+ * @type and another resource, and return REGION_INTERSECTS if the
+ * region overlaps @type and no other defined resource. Note, that
+ * REGION_INTERSECTS is also returned in the case when the specified
+ * region overlaps RAM and undefined memory holes.
+ *
+ * region_intersect() is used by memory remapping functions to ensure
+ * the user is not remapping RAM and is a vast speed up over walking
+ * through the resource table page by page.
*/
-int region_is_ram(resource_size_t start, unsigned long size)
+int region_intersects(resource_size_t start, size_t size, const char *name)
{
- struct resource *p;
- resource_size_t end = start + size - 1;
unsigned long flags = IORESOURCE_MEM | IORESOURCE_BUSY;
- const char *name = "System RAM";
- int ret = -1;
+ resource_size_t end = start + size - 1;
+ int type = 0; int other = 0;
+ struct resource *p;
read_lock(&resource_lock);
for (p = iomem_resource.child; p ; p = p->sibling) {
- if (p->end < start)
- continue;
-
- if (p->start <= start && end <= p->end) {
- /* resource fully contains region */
- if ((p->flags != flags) || strcmp(p->name, name))
- ret = 0;
- else
- ret = 1;
- break;
- }
- if (end < p->start)
- break; /* not found */
+ bool is_type = strcmp(p->name, name) == 0 && p->flags == flags;
+
+ if (start >= p->start && start <= p->end)
+ is_type ? type++ : other++;
+ if (end >= p->start && end <= p->end)
+ is_type ? type++ : other++;
+ if (p->start >= start && p->end <= end)
+ is_type ? type++ : other++;
}
read_unlock(&resource_lock);
- return ret;
+
+ if (other == 0)
+ return type ? REGION_INTERSECTS : REGION_DISJOINT;
+
+ if (type)
+ return REGION_MIXED;
+
+ return REGION_DISJOINT;
}
void __weak arch_remove_reservations(struct resource *avail)