--- /dev/null
+From f03574f2d5b2d6229dcdf2d322848065f72953c7 Mon Sep 17 00:00:00 2001
+From: Dave Hansen <dave@linux.vnet.ibm.com>
+Date: Wed, 30 Jan 2013 16:56:16 -0800
+Subject: x86-32, mm: Rip out x86_32 NUMA remapping code
+
+From: Dave Hansen <dave@linux.vnet.ibm.com>
+
+commit f03574f2d5b2d6229dcdf2d322848065f72953c7 upstream.
+
+[was already included in 3.0, but I missed the patch hunk for
+ arch/x86/mm/numa_32.c - gregkh]
+
+This code was an optimization for 32-bit NUMA systems.
+
+It has probably been the cause of a number of subtle bugs over
+the years, although the conditions to excite them would have
+been hard to trigger. Essentially, we remap part of the kernel
+linear mapping area, and then sometimes part of that area gets
+freed back in to the bootmem allocator. If those pages get
+used by kernel data structures (say mem_map[] or a dentry),
+there's no big deal. But, if anyone ever tried to use the
+linear mapping for these pages _and_ cared about their physical
+address, bad things happen.
+
+For instance, say you passed __GFP_ZERO to the page allocator
+and then happened to get handed one of these pages, it zero the
+remapped page, but it would make a pte to the _old_ page.
+There are probably a hundred other ways that it could screw
+with things.
+
+We don't need to hang on to performance optimizations for
+these old boxes any more. All my 32-bit NUMA systems are long
+dead and buried, and I probably had access to more than most
+people.
+
+This code is causing real things to break today:
+
+ https://lkml.org/lkml/2013/1/9/376
+
+I looked in to actually fixing this, but it requires surgery
+to way too much brittle code, as well as stuff like
+per_cpu_ptr_to_phys().
+
+[ hpa: Cc: this for -stable, since it is a memory corruption issue.
+ However, an alternative is to simply mark NUMA as depends BROKEN
+ rather than EXPERIMENTAL in the X86_32 subclause... ]
+
+Link: http://lkml.kernel.org/r/20130131005616.1C79F411@kernel.stglabs.ibm.com
+Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
+Cc: Jiri Slaby <jslaby@suse.cz>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ arch/x86/mm/numa_32.c | 161 --------------------------------------------------
+ 1 file changed, 161 deletions(-)
+
+--- a/arch/x86/mm/numa_32.c
++++ b/arch/x86/mm/numa_32.c
+@@ -73,167 +73,6 @@ unsigned long node_memmap_size_bytes(int
+
+ extern unsigned long highend_pfn, highstart_pfn;
+
+-#define LARGE_PAGE_BYTES (PTRS_PER_PTE * PAGE_SIZE)
+-
+-static void *node_remap_start_vaddr[MAX_NUMNODES];
+-void set_pmd_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags);
+-
+-/*
+- * Remap memory allocator
+- */
+-static unsigned long node_remap_start_pfn[MAX_NUMNODES];
+-static void *node_remap_end_vaddr[MAX_NUMNODES];
+-static void *node_remap_alloc_vaddr[MAX_NUMNODES];
+-
+-/**
+- * alloc_remap - Allocate remapped memory
+- * @nid: NUMA node to allocate memory from
+- * @size: The size of allocation
+- *
+- * Allocate @size bytes from the remap area of NUMA node @nid. The
+- * size of the remap area is predetermined by init_alloc_remap() and
+- * only the callers considered there should call this function. For
+- * more info, please read the comment on top of init_alloc_remap().
+- *
+- * The caller must be ready to handle allocation failure from this
+- * function and fall back to regular memory allocator in such cases.
+- *
+- * CONTEXT:
+- * Single CPU early boot context.
+- *
+- * RETURNS:
+- * Pointer to the allocated memory on success, %NULL on failure.
+- */
+-void *alloc_remap(int nid, unsigned long size)
+-{
+- void *allocation = node_remap_alloc_vaddr[nid];
+-
+- size = ALIGN(size, L1_CACHE_BYTES);
+-
+- if (!allocation || (allocation + size) > node_remap_end_vaddr[nid])
+- return NULL;
+-
+- node_remap_alloc_vaddr[nid] += size;
+- memset(allocation, 0, size);
+-
+- return allocation;
+-}
+-
+-#ifdef CONFIG_HIBERNATION
+-/**
+- * resume_map_numa_kva - add KVA mapping to the temporary page tables created
+- * during resume from hibernation
+- * @pgd_base - temporary resume page directory
+- */
+-void resume_map_numa_kva(pgd_t *pgd_base)
+-{
+- int node;
+-
+- for_each_online_node(node) {
+- unsigned long start_va, start_pfn, nr_pages, pfn;
+-
+- start_va = (unsigned long)node_remap_start_vaddr[node];
+- start_pfn = node_remap_start_pfn[node];
+- nr_pages = (node_remap_end_vaddr[node] -
+- node_remap_start_vaddr[node]) >> PAGE_SHIFT;
+-
+- printk(KERN_DEBUG "%s: node %d\n", __func__, node);
+-
+- for (pfn = 0; pfn < nr_pages; pfn += PTRS_PER_PTE) {
+- unsigned long vaddr = start_va + (pfn << PAGE_SHIFT);
+- pgd_t *pgd = pgd_base + pgd_index(vaddr);
+- pud_t *pud = pud_offset(pgd, vaddr);
+- pmd_t *pmd = pmd_offset(pud, vaddr);
+-
+- set_pmd(pmd, pfn_pmd(start_pfn + pfn,
+- PAGE_KERNEL_LARGE_EXEC));
+-
+- printk(KERN_DEBUG "%s: %08lx -> pfn %08lx\n",
+- __func__, vaddr, start_pfn + pfn);
+- }
+- }
+-}
+-#endif
+-
+-/**
+- * init_alloc_remap - Initialize remap allocator for a NUMA node
+- * @nid: NUMA node to initizlie remap allocator for
+- *
+- * NUMA nodes may end up without any lowmem. As allocating pgdat and
+- * memmap on a different node with lowmem is inefficient, a special
+- * remap allocator is implemented which can be used by alloc_remap().
+- *
+- * For each node, the amount of memory which will be necessary for
+- * pgdat and memmap is calculated and two memory areas of the size are
+- * allocated - one in the node and the other in lowmem; then, the area
+- * in the node is remapped to the lowmem area.
+- *
+- * As pgdat and memmap must be allocated in lowmem anyway, this
+- * doesn't waste lowmem address space; however, the actual lowmem
+- * which gets remapped over is wasted. The amount shouldn't be
+- * problematic on machines this feature will be used.
+- *
+- * Initialization failure isn't fatal. alloc_remap() is used
+- * opportunistically and the callers will fall back to other memory
+- * allocation mechanisms on failure.
+- */
+-void __init init_alloc_remap(int nid, u64 start, u64 end)
+-{
+- unsigned long start_pfn = start >> PAGE_SHIFT;
+- unsigned long end_pfn = end >> PAGE_SHIFT;
+- unsigned long size, pfn;
+- u64 node_pa, remap_pa;
+- void *remap_va;
+-
+- /*
+- * The acpi/srat node info can show hot-add memroy zones where
+- * memory could be added but not currently present.
+- */
+- printk(KERN_DEBUG "node %d pfn: [%lx - %lx]\n",
+- nid, start_pfn, end_pfn);
+-
+- /* calculate the necessary space aligned to large page size */
+- size = node_memmap_size_bytes(nid, start_pfn, end_pfn);
+- size += ALIGN(sizeof(pg_data_t), PAGE_SIZE);
+- size = ALIGN(size, LARGE_PAGE_BYTES);
+-
+- /* allocate node memory and the lowmem remap area */
+- node_pa = memblock_find_in_range(start, end, size, LARGE_PAGE_BYTES);
+- if (node_pa == MEMBLOCK_ERROR) {
+- pr_warning("remap_alloc: failed to allocate %lu bytes for node %d\n",
+- size, nid);
+- return;
+- }
+- memblock_x86_reserve_range(node_pa, node_pa + size, "KVA RAM");
+-
+- remap_pa = memblock_find_in_range(min_low_pfn << PAGE_SHIFT,
+- max_low_pfn << PAGE_SHIFT,
+- size, LARGE_PAGE_BYTES);
+- if (remap_pa == MEMBLOCK_ERROR) {
+- pr_warning("remap_alloc: failed to allocate %lu bytes remap area for node %d\n",
+- size, nid);
+- memblock_x86_free_range(node_pa, node_pa + size);
+- return;
+- }
+- memblock_x86_reserve_range(remap_pa, remap_pa + size, "KVA PG");
+- remap_va = phys_to_virt(remap_pa);
+-
+- /* perform actual remap */
+- for (pfn = 0; pfn < size >> PAGE_SHIFT; pfn += PTRS_PER_PTE)
+- set_pmd_pfn((unsigned long)remap_va + (pfn << PAGE_SHIFT),
+- (node_pa >> PAGE_SHIFT) + pfn,
+- PAGE_KERNEL_LARGE);
+-
+- /* initialize remap allocator parameters */
+- node_remap_start_pfn[nid] = node_pa >> PAGE_SHIFT;
+- node_remap_start_vaddr[nid] = remap_va;
+- node_remap_end_vaddr[nid] = remap_va + size;
+- node_remap_alloc_vaddr[nid] = remap_va;
+-
+- printk(KERN_DEBUG "remap_alloc: node %d [%08llx-%08llx) -> [%p-%p)\n",
+- nid, node_pa, node_pa + size, remap_va, remap_va + size);
+-}
+-
+ void __init initmem_init(void)
+ {
+ x86_numa_init();
projects / thirdparty / kernel / stable-queue.git / commitdiff
