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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-06-10 05:30:17 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-06-10 05:30:17 -0300
commitd635711daa98be86d4c7fd01499c34f566b54ccb (patch)
treeaa5cc3760a27c3d57146498cb82fa549547de06c /kernel/memremap.c
parentc91265cd0efb83778f015b4d4b1129bd2cfd075e (diff)
Linux-libre 4.6.2-gnu
Diffstat (limited to 'kernel/memremap.c')
-rw-r--r--kernel/memremap.c45
1 files changed, 28 insertions, 17 deletions
diff --git a/kernel/memremap.c b/kernel/memremap.c
index 6cf54615a..a6d382312 100644
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -41,13 +41,15 @@ static void *try_ram_remap(resource_size_t offset, size_t size)
* memremap() - remap an iomem_resource as cacheable memory
* @offset: iomem resource start address
* @size: size of remap
- * @flags: either MEMREMAP_WB or MEMREMAP_WT
+ * @flags: any of MEMREMAP_WB, MEMREMAP_WT and MEMREMAP_WC
*
* 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.
+ * annotation is not applicable. In the case of multiple flags, the different
+ * mapping types will be attempted in the order listed below until one of
+ * them succeeds.
*
- * MEMREMAP_WB - matches the default mapping for "System RAM" on
+ * 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
@@ -56,13 +58,21 @@ static void *try_ram_remap(resource_size_t offset, size_t size)
* 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.
+ * map System RAM with this mapping type will fail.
+ *
+ * MEMREMAP_WC - establish a writecombine mapping, whereby writes may
+ * be coalesced together (e.g. in the CPU's write buffers), but is otherwise
+ * uncached. 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");
+ int is_ram = region_intersects(offset, size,
+ IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);
void *addr = NULL;
+ if (!flags)
+ return NULL;
+
if (is_ram == REGION_MIXED) {
WARN_ONCE(1, "memremap attempted on mixed range %pa size: %#lx\n",
&offset, (unsigned long) size);
@@ -71,12 +81,11 @@ void *memremap(resource_size_t offset, size_t size, unsigned long flags)
/* 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"
+ * the requested range is potentially in System RAM.
*/
if (is_ram == REGION_INTERSECTS)
addr = try_ram_remap(offset, size);
@@ -85,21 +94,22 @@ void *memremap(resource_size_t offset, size_t size, unsigned long flags)
}
/*
- * If we don't have a mapping yet and more request flags are
- * pending then we will be attempting to establish a new virtual
+ * If we don't have a mapping yet and other request flags are
+ * present then we will be attempting to establish a new virtual
* address mapping. Enforce that this mapping is not aliasing
- * "System RAM"
+ * System RAM.
*/
- if (!addr && is_ram == REGION_INTERSECTS && flags) {
+ if (!addr && is_ram == REGION_INTERSECTS && flags != MEMREMAP_WB) {
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;
+ if (!addr && (flags & MEMREMAP_WT))
addr = ioremap_wt(offset, size);
- }
+
+ if (!addr && (flags & MEMREMAP_WC))
+ addr = ioremap_wc(offset, size);
return addr;
}
@@ -279,7 +289,8 @@ void *devm_memremap_pages(struct device *dev, struct resource *res,
align_start = res->start & ~(SECTION_SIZE - 1);
align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE)
- align_start;
- is_ram = region_intersects(align_start, align_size, "System RAM");
+ is_ram = region_intersects(align_start, align_size,
+ IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);
if (is_ram == REGION_MIXED) {
WARN_ONCE(1, "%s attempted on mixed region %pr\n",
@@ -389,7 +400,7 @@ struct vmem_altmap *to_vmem_altmap(unsigned long memmap_start)
/*
* 'memmap_start' is the virtual address for the first "struct
* page" in this range of the vmemmap array. In the case of
- * CONFIG_SPARSE_VMEMMAP a page_to_pfn conversion is simple
+ * CONFIG_SPARSEMEM_VMEMMAP a page_to_pfn conversion is simple
* pointer arithmetic, so we can perform this to_vmem_altmap()
* conversion without concern for the initialization state of
* the struct page fields.
@@ -398,7 +409,7 @@ struct vmem_altmap *to_vmem_altmap(unsigned long memmap_start)
struct dev_pagemap *pgmap;
/*
- * Uncoditionally retrieve a dev_pagemap associated with the
+ * Unconditionally retrieve a dev_pagemap associated with the
* given physical address, this is only for use in the
* arch_{add|remove}_memory() for setting up and tearing down
* the memmap.