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Currently, kernel/memremap.c contains generic code for supporting memremap() (CONFIG_HAS_IOMEM) and devm_memremap_pages() (CONFIG_ZONE_DEVICE). This causes ongoing build maintenance problems as additions to memremap.c, especially for the ZONE_DEVICE case, need to be careful about being placed in ifdef guards. Remove the need for these ifdef guards by moving the ZONE_DEVICE support functions to their own compilation unit. Cc: "Jérôme Glisse" <jglisse@redhat.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
168 lines
4.7 KiB
C
168 lines
4.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#include <linux/device.h>
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#include <linux/types.h>
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#include <linux/io.h>
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#include <linux/mm.h>
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#ifndef ioremap_cache
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/* temporary while we convert existing ioremap_cache users to memremap */
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__weak void __iomem *ioremap_cache(resource_size_t offset, unsigned long size)
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{
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return ioremap(offset, size);
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}
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#endif
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#ifndef arch_memremap_wb
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static void *arch_memremap_wb(resource_size_t offset, unsigned long size)
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{
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return (__force void *)ioremap_cache(offset, size);
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}
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#endif
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#ifndef arch_memremap_can_ram_remap
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static bool arch_memremap_can_ram_remap(resource_size_t offset, size_t size,
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unsigned long flags)
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{
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return true;
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}
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#endif
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static void *try_ram_remap(resource_size_t offset, size_t size,
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unsigned long flags)
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{
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unsigned long pfn = PHYS_PFN(offset);
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/* In the simple case just return the existing linear address */
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if (pfn_valid(pfn) && !PageHighMem(pfn_to_page(pfn)) &&
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arch_memremap_can_ram_remap(offset, size, flags))
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return __va(offset);
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return NULL; /* fallback to arch_memremap_wb */
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}
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/**
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* memremap() - remap an iomem_resource as cacheable memory
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* @offset: iomem resource start address
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* @size: size of remap
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* @flags: any of MEMREMAP_WB, MEMREMAP_WT, MEMREMAP_WC,
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* MEMREMAP_ENC, MEMREMAP_DEC
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*
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* memremap() is "ioremap" for cases where it is known that the resource
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* being mapped does not have i/o side effects and the __iomem
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* annotation is not applicable. In the case of multiple flags, the different
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* mapping types will be attempted in the order listed below until one of
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* them succeeds.
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*
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* MEMREMAP_WB - matches the default mapping for System RAM on
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* the architecture. This is usually a read-allocate write-back cache.
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* Morever, if MEMREMAP_WB is specified and the requested remap region is RAM
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* memremap() will bypass establishing a new mapping and instead return
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* a pointer into the direct map.
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*
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* MEMREMAP_WT - establish a mapping whereby writes either bypass the
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* cache or are written through to memory and never exist in a
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* cache-dirty state with respect to program visibility. Attempts to
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* map System RAM with this mapping type will fail.
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*
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* MEMREMAP_WC - establish a writecombine mapping, whereby writes may
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* be coalesced together (e.g. in the CPU's write buffers), but is otherwise
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* uncached. Attempts to map System RAM with this mapping type will fail.
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*/
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void *memremap(resource_size_t offset, size_t size, unsigned long flags)
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{
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int is_ram = region_intersects(offset, size,
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IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);
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void *addr = NULL;
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if (!flags)
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return NULL;
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if (is_ram == REGION_MIXED) {
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WARN_ONCE(1, "memremap attempted on mixed range %pa size: %#lx\n",
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&offset, (unsigned long) size);
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return NULL;
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}
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/* Try all mapping types requested until one returns non-NULL */
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if (flags & MEMREMAP_WB) {
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/*
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* MEMREMAP_WB is special in that it can be satisifed
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* from the direct map. Some archs depend on the
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* capability of memremap() to autodetect cases where
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* the requested range is potentially in System RAM.
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*/
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if (is_ram == REGION_INTERSECTS)
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addr = try_ram_remap(offset, size, flags);
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if (!addr)
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addr = arch_memremap_wb(offset, size);
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}
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/*
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* If we don't have a mapping yet and other request flags are
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* present then we will be attempting to establish a new virtual
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* address mapping. Enforce that this mapping is not aliasing
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* System RAM.
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*/
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if (!addr && is_ram == REGION_INTERSECTS && flags != MEMREMAP_WB) {
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WARN_ONCE(1, "memremap attempted on ram %pa size: %#lx\n",
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&offset, (unsigned long) size);
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return NULL;
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}
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if (!addr && (flags & MEMREMAP_WT))
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addr = ioremap_wt(offset, size);
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if (!addr && (flags & MEMREMAP_WC))
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addr = ioremap_wc(offset, size);
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return addr;
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}
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EXPORT_SYMBOL(memremap);
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void memunmap(void *addr)
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{
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if (is_vmalloc_addr(addr))
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iounmap((void __iomem *) addr);
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}
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EXPORT_SYMBOL(memunmap);
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static void devm_memremap_release(struct device *dev, void *res)
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{
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memunmap(*(void **)res);
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}
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static int devm_memremap_match(struct device *dev, void *res, void *match_data)
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{
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return *(void **)res == match_data;
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}
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void *devm_memremap(struct device *dev, resource_size_t offset,
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size_t size, unsigned long flags)
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{
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void **ptr, *addr;
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ptr = devres_alloc_node(devm_memremap_release, sizeof(*ptr), GFP_KERNEL,
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dev_to_node(dev));
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if (!ptr)
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return ERR_PTR(-ENOMEM);
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addr = memremap(offset, size, flags);
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if (addr) {
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*ptr = addr;
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devres_add(dev, ptr);
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} else {
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devres_free(ptr);
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return ERR_PTR(-ENXIO);
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}
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return addr;
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}
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EXPORT_SYMBOL(devm_memremap);
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void devm_memunmap(struct device *dev, void *addr)
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{
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WARN_ON(devres_release(dev, devm_memremap_release,
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devm_memremap_match, addr));
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}
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EXPORT_SYMBOL(devm_memunmap);
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