/* * Copyright (C) 2001-2006 Silicon Graphics, Inc. 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. * * A simple uncached page allocator using the generic allocator. This * allocator first utilizes the spare (spill) pages found in the EFI * memmap and will then start converting cached pages to uncached ones * at a granule at a time. Node awareness is implemented by having a * pool of pages per node. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include extern void __init efi_memmap_walk_uc(efi_freemem_callback_t, void *); #define MAX_UNCACHED_GRANULES 5 static int allocated_granules; struct gen_pool *uncached_pool[MAX_NUMNODES]; static void uncached_ipi_visibility(void *data) { int status; status = ia64_pal_prefetch_visibility(PAL_VISIBILITY_PHYSICAL); if ((status != PAL_VISIBILITY_OK) && (status != PAL_VISIBILITY_OK_REMOTE_NEEDED)) printk(KERN_DEBUG "pal_prefetch_visibility() returns %i on " "CPU %i\n", status, raw_smp_processor_id()); } static void uncached_ipi_mc_drain(void *data) { int status; status = ia64_pal_mc_drain(); if (status) printk(KERN_WARNING "ia64_pal_mc_drain() failed with %i on " "CPU %i\n", status, raw_smp_processor_id()); } /* * Add a new chunk of uncached memory pages to the specified pool. * * @pool: pool to add new chunk of uncached memory to * @nid: node id of node to allocate memory from, or -1 * * This is accomplished by first allocating a granule of cached memory pages * and then converting them to uncached memory pages. */ static int uncached_add_chunk(struct gen_pool *pool, int nid) { struct page *page; int status, i; unsigned long c_addr, uc_addr; if (allocated_granules >= MAX_UNCACHED_GRANULES) return -1; /* attempt to allocate a granule's worth of cached memory pages */ page = alloc_pages_node(nid, GFP_KERNEL | __GFP_ZERO, IA64_GRANULE_SHIFT-PAGE_SHIFT); if (!page) return -1; /* convert the memory pages from cached to uncached */ c_addr = (unsigned long)page_address(page); uc_addr = c_addr - PAGE_OFFSET + __IA64_UNCACHED_OFFSET; /* * There's a small race here where it's possible for someone to * access the page through /dev/mem halfway through the conversion * to uncached - not sure it's really worth bothering about */ for (i = 0; i < (IA64_GRANULE_SIZE / PAGE_SIZE); i++) SetPageUncached(&page[i]); flush_tlb_kernel_range(uc_addr, uc_adddr + IA64_GRANULE_SIZE); status = ia64_pal_prefetch_visibility(PAL_VISIBILITY_PHYSICAL); if (!status) { status = smp_call_function(uncached_ipi_visibility, NULL, 0, 1); if (status) goto failed; } preempt_disable(); if (ia64_platform_is("sn2")) sn_flush_all_caches(uc_addr, IA64_GRANULE_SIZE); else flush_icache_range(uc_addr, uc_addr + IA64_GRANULE_SIZE); /* flush the just introduced uncached translation from the TLB */ local_flush_tlb_all(); preempt_enable(); ia64_pal_mc_drain(); status = smp_call_function(uncached_ipi_mc_drain, NULL, 0, 1); if (status) goto failed; /* * The chunk of memory pages has been converted to uncached so now we * can add it to the pool. */ status = gen_pool_add(pool, uc_addr, IA64_GRANULE_SIZE, nid); if (status) goto failed; allocated_granules++; return 0; /* failed to convert or add the chunk so give it back to the kernel */ failed: for (i = 0; i < (IA64_GRANULE_SIZE / PAGE_SIZE); i++) ClearPageUncached(&page[i]); free_pages(c_addr, IA64_GRANULE_SHIFT-PAGE_SHIFT); return -1; } /* * uncached_alloc_page * * @starting_nid: node id of node to start with, or -1 * * Allocate 1 uncached page. Allocates on the requested node. If no * uncached pages are available on the requested node, roundrobin starting * with the next higher node. */ unsigned long uncached_alloc_page(int starting_nid) { unsigned long uc_addr; struct gen_pool *pool; int nid; if (unlikely(starting_nid >= MAX_NUMNODES)) return 0; if (starting_nid < 0) starting_nid = numa_node_id(); nid = starting_nid; do { if (!node_online(nid)) continue; pool = uncached_pool[nid]; if (pool == NULL) continue; do { uc_addr = gen_pool_alloc(pool, PAGE_SIZE); if (uc_addr != 0) return uc_addr; } while (uncached_add_chunk(pool, nid) == 0); } while ((nid = (nid + 1) % MAX_NUMNODES) != starting_nid); return 0; } EXPORT_SYMBOL(uncached_alloc_page); /* * uncached_free_page * * @uc_addr: uncached address of page to free * * Free a single uncached page. */ void uncached_free_page(unsigned long uc_addr) { int nid = paddr_to_nid(uc_addr - __IA64_UNCACHED_OFFSET); struct gen_pool *pool = uncached_pool[nid]; if (unlikely(pool == NULL)) return; if ((uc_addr & (0XFUL << 60)) != __IA64_UNCACHED_OFFSET) panic("uncached_free_page invalid address %lx\n", uc_addr); gen_pool_free(pool, uc_addr, PAGE_SIZE); } EXPORT_SYMBOL(uncached_free_page); /* * uncached_build_memmap, * * @uc_start: uncached starting address of a chunk of uncached memory * @uc_end: uncached ending address of a chunk of uncached memory * @arg: ignored, (NULL argument passed in on call to efi_memmap_walk_uc()) * * Called at boot time to build a map of pages that can be used for * memory special operations. */ static int __init uncached_build_memmap(unsigned long uc_start, unsigned long uc_end, void *arg) { int nid = paddr_to_nid(uc_start - __IA64_UNCACHED_OFFSET); struct gen_pool *pool = uncached_pool[nid]; size_t size = uc_end - uc_start; touch_softlockup_watchdog(); if (pool != NULL) { memset((char *)uc_start, 0, size); (void) gen_pool_add(pool, uc_start, size, nid); } return 0; } static int __init uncached_init(void) { int nid; for_each_online_node(nid) { uncached_pool[nid] = gen_pool_create(PAGE_SHIFT, nid); } efi_memmap_walk_uc(uncached_build_memmap, NULL); return 0; } __initcall(uncached_init);