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![Christoph Hellwig](/assets/img/avatar_default.png)
This behaves like devm_memremap except that it ensures we have page structures available that can back the region. Signed-off-by: Christoph Hellwig <hch@lst.de> [djbw: catch attempts to remap RAM, drop flags] Signed-off-by: Dan Williams <dan.j.williams@intel.com>
190 lines
5.1 KiB
C
190 lines
5.1 KiB
C
/*
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* Copyright(c) 2015 Intel Corporation. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of version 2 of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*/
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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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#include <linux/memory_hotplug.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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/**
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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: either MEMREMAP_WB or MEMREMAP_WT
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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.
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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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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, "System RAM");
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void *addr = 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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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 = __va(offset);
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else
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addr = ioremap_cache(offset, size);
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}
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/*
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* If we don't have a mapping yet and more request flags are
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* pending 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) {
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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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flags &= ~MEMREMAP_WT;
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addr = ioremap_wt(offset, size);
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}
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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(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(devm_memremap_release, sizeof(*ptr), GFP_KERNEL);
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if (!ptr)
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return NULL;
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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 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_destroy(dev, devm_memremap_release, devm_memremap_match,
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addr));
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memunmap(addr);
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}
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EXPORT_SYMBOL(devm_memunmap);
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#ifdef CONFIG_ZONE_DEVICE
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struct page_map {
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struct resource res;
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};
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static void devm_memremap_pages_release(struct device *dev, void *res)
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{
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struct page_map *page_map = res;
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/* pages are dead and unused, undo the arch mapping */
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arch_remove_memory(page_map->res.start, resource_size(&page_map->res));
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}
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void *devm_memremap_pages(struct device *dev, struct resource *res)
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{
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int is_ram = region_intersects(res->start, resource_size(res),
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"System RAM");
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struct page_map *page_map;
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int error, nid;
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if (is_ram == REGION_MIXED) {
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WARN_ONCE(1, "%s attempted on mixed region %pr\n",
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__func__, res);
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return ERR_PTR(-ENXIO);
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}
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if (is_ram == REGION_INTERSECTS)
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return __va(res->start);
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page_map = devres_alloc(devm_memremap_pages_release,
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sizeof(*page_map), GFP_KERNEL);
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if (!page_map)
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return ERR_PTR(-ENOMEM);
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memcpy(&page_map->res, res, sizeof(*res));
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nid = dev_to_node(dev);
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if (nid < 0)
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nid = 0;
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error = arch_add_memory(nid, res->start, resource_size(res), true);
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if (error) {
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devres_free(page_map);
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return ERR_PTR(error);
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}
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devres_add(dev, page_map);
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return __va(res->start);
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}
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EXPORT_SYMBOL(devm_memremap_pages);
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#endif /* CONFIG_ZONE_DEVICE */
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