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273 lines
7.2 KiB
273 lines
7.2 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Copyright (C) 2001-2008 Silicon Graphics, Inc. All rights reserved. |
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* |
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* A simple uncached page allocator using the generic allocator. This |
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* allocator first utilizes the spare (spill) pages found in the EFI |
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* memmap and will then start converting cached pages to uncached ones |
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* at a granule at a time. Node awareness is implemented by having a |
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* pool of pages per node. |
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*/ |
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#include <linux/types.h> |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/init.h> |
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#include <linux/errno.h> |
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#include <linux/string.h> |
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#include <linux/efi.h> |
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#include <linux/nmi.h> |
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#include <linux/genalloc.h> |
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#include <linux/gfp.h> |
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#include <linux/pgtable.h> |
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#include <asm/efi.h> |
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#include <asm/page.h> |
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#include <asm/pal.h> |
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#include <linux/atomic.h> |
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#include <asm/tlbflush.h> |
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struct uncached_pool { |
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struct gen_pool *pool; |
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struct mutex add_chunk_mutex; /* serialize adding a converted chunk */ |
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int nchunks_added; /* #of converted chunks added to pool */ |
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atomic_t status; /* smp called function's return status*/ |
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}; |
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#define MAX_CONVERTED_CHUNKS_PER_NODE 2 |
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struct uncached_pool uncached_pools[MAX_NUMNODES]; |
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static void uncached_ipi_visibility(void *data) |
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{ |
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int status; |
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struct uncached_pool *uc_pool = (struct uncached_pool *)data; |
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status = ia64_pal_prefetch_visibility(PAL_VISIBILITY_PHYSICAL); |
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if ((status != PAL_VISIBILITY_OK) && |
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(status != PAL_VISIBILITY_OK_REMOTE_NEEDED)) |
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atomic_inc(&uc_pool->status); |
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} |
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static void uncached_ipi_mc_drain(void *data) |
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{ |
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int status; |
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struct uncached_pool *uc_pool = (struct uncached_pool *)data; |
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status = ia64_pal_mc_drain(); |
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if (status != PAL_STATUS_SUCCESS) |
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atomic_inc(&uc_pool->status); |
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} |
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/* |
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* Add a new chunk of uncached memory pages to the specified pool. |
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* |
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* @pool: pool to add new chunk of uncached memory to |
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* @nid: node id of node to allocate memory from, or -1 |
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* |
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* This is accomplished by first allocating a granule of cached memory pages |
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* and then converting them to uncached memory pages. |
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*/ |
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static int uncached_add_chunk(struct uncached_pool *uc_pool, int nid) |
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{ |
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struct page *page; |
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int status, i, nchunks_added = uc_pool->nchunks_added; |
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unsigned long c_addr, uc_addr; |
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if (mutex_lock_interruptible(&uc_pool->add_chunk_mutex) != 0) |
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return -1; /* interrupted by a signal */ |
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if (uc_pool->nchunks_added > nchunks_added) { |
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/* someone added a new chunk while we were waiting */ |
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mutex_unlock(&uc_pool->add_chunk_mutex); |
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return 0; |
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} |
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if (uc_pool->nchunks_added >= MAX_CONVERTED_CHUNKS_PER_NODE) { |
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mutex_unlock(&uc_pool->add_chunk_mutex); |
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return -1; |
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} |
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/* attempt to allocate a granule's worth of cached memory pages */ |
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page = __alloc_pages_node(nid, |
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GFP_KERNEL | __GFP_ZERO | __GFP_THISNODE, |
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IA64_GRANULE_SHIFT-PAGE_SHIFT); |
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if (!page) { |
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mutex_unlock(&uc_pool->add_chunk_mutex); |
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return -1; |
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} |
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/* convert the memory pages from cached to uncached */ |
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c_addr = (unsigned long)page_address(page); |
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uc_addr = c_addr - PAGE_OFFSET + __IA64_UNCACHED_OFFSET; |
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/* |
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* There's a small race here where it's possible for someone to |
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* access the page through /dev/mem halfway through the conversion |
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* to uncached - not sure it's really worth bothering about |
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*/ |
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for (i = 0; i < (IA64_GRANULE_SIZE / PAGE_SIZE); i++) |
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SetPageUncached(&page[i]); |
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flush_tlb_kernel_range(uc_addr, uc_addr + IA64_GRANULE_SIZE); |
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status = ia64_pal_prefetch_visibility(PAL_VISIBILITY_PHYSICAL); |
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if (status == PAL_VISIBILITY_OK_REMOTE_NEEDED) { |
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atomic_set(&uc_pool->status, 0); |
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smp_call_function(uncached_ipi_visibility, uc_pool, 1); |
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if (atomic_read(&uc_pool->status)) |
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goto failed; |
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} else if (status != PAL_VISIBILITY_OK) |
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goto failed; |
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preempt_disable(); |
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flush_icache_range(uc_addr, uc_addr + IA64_GRANULE_SIZE); |
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/* flush the just introduced uncached translation from the TLB */ |
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local_flush_tlb_all(); |
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preempt_enable(); |
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status = ia64_pal_mc_drain(); |
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if (status != PAL_STATUS_SUCCESS) |
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goto failed; |
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atomic_set(&uc_pool->status, 0); |
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smp_call_function(uncached_ipi_mc_drain, uc_pool, 1); |
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if (atomic_read(&uc_pool->status)) |
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goto failed; |
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/* |
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* The chunk of memory pages has been converted to uncached so now we |
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* can add it to the pool. |
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*/ |
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status = gen_pool_add(uc_pool->pool, uc_addr, IA64_GRANULE_SIZE, nid); |
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if (status) |
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goto failed; |
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uc_pool->nchunks_added++; |
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mutex_unlock(&uc_pool->add_chunk_mutex); |
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return 0; |
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/* failed to convert or add the chunk so give it back to the kernel */ |
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failed: |
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for (i = 0; i < (IA64_GRANULE_SIZE / PAGE_SIZE); i++) |
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ClearPageUncached(&page[i]); |
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free_pages(c_addr, IA64_GRANULE_SHIFT-PAGE_SHIFT); |
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mutex_unlock(&uc_pool->add_chunk_mutex); |
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return -1; |
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} |
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/* |
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* uncached_alloc_page |
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* |
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* @starting_nid: node id of node to start with, or -1 |
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* @n_pages: number of contiguous pages to allocate |
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* |
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* Allocate the specified number of contiguous uncached pages on the |
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* the requested node. If not enough contiguous uncached pages are available |
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* on the requested node, roundrobin starting with the next higher node. |
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*/ |
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unsigned long uncached_alloc_page(int starting_nid, int n_pages) |
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{ |
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unsigned long uc_addr; |
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struct uncached_pool *uc_pool; |
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int nid; |
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if (unlikely(starting_nid >= MAX_NUMNODES)) |
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return 0; |
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if (starting_nid < 0) |
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starting_nid = numa_node_id(); |
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nid = starting_nid; |
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do { |
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if (!node_state(nid, N_HIGH_MEMORY)) |
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continue; |
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uc_pool = &uncached_pools[nid]; |
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if (uc_pool->pool == NULL) |
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continue; |
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do { |
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uc_addr = gen_pool_alloc(uc_pool->pool, |
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n_pages * PAGE_SIZE); |
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if (uc_addr != 0) |
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return uc_addr; |
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} while (uncached_add_chunk(uc_pool, nid) == 0); |
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} while ((nid = (nid + 1) % MAX_NUMNODES) != starting_nid); |
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return 0; |
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} |
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EXPORT_SYMBOL(uncached_alloc_page); |
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/* |
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* uncached_free_page |
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* |
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* @uc_addr: uncached address of first page to free |
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* @n_pages: number of contiguous pages to free |
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* |
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* Free the specified number of uncached pages. |
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*/ |
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void uncached_free_page(unsigned long uc_addr, int n_pages) |
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{ |
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int nid = paddr_to_nid(uc_addr - __IA64_UNCACHED_OFFSET); |
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struct gen_pool *pool = uncached_pools[nid].pool; |
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if (unlikely(pool == NULL)) |
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return; |
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if ((uc_addr & (0XFUL << 60)) != __IA64_UNCACHED_OFFSET) |
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panic("uncached_free_page invalid address %lx\n", uc_addr); |
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gen_pool_free(pool, uc_addr, n_pages * PAGE_SIZE); |
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} |
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EXPORT_SYMBOL(uncached_free_page); |
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/* |
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* uncached_build_memmap, |
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* |
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* @uc_start: uncached starting address of a chunk of uncached memory |
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* @uc_end: uncached ending address of a chunk of uncached memory |
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* @arg: ignored, (NULL argument passed in on call to efi_memmap_walk_uc()) |
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* |
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* Called at boot time to build a map of pages that can be used for |
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* memory special operations. |
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*/ |
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static int __init uncached_build_memmap(u64 uc_start, u64 uc_end, void *arg) |
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{ |
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int nid = paddr_to_nid(uc_start - __IA64_UNCACHED_OFFSET); |
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struct gen_pool *pool = uncached_pools[nid].pool; |
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size_t size = uc_end - uc_start; |
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touch_softlockup_watchdog(); |
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if (pool != NULL) { |
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memset((char *)uc_start, 0, size); |
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(void) gen_pool_add(pool, uc_start, size, nid); |
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} |
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return 0; |
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} |
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static int __init uncached_init(void) |
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{ |
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int nid; |
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for_each_node_state(nid, N_ONLINE) { |
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uncached_pools[nid].pool = gen_pool_create(PAGE_SHIFT, nid); |
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mutex_init(&uncached_pools[nid].add_chunk_mutex); |
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} |
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efi_memmap_walk_uc(uncached_build_memmap, NULL); |
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return 0; |
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} |
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__initcall(uncached_init);
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