alistair23-linux/arch/x86/mm/numa_32.c
Petr Tesarik 85fc73a2cd x86: Fix the initialization of physnode_map
With DISCONTIGMEM, the mapping between a pfn and its owning node is
initialized using data provided by the BIOS. However, the initialization
may fail if the extents are not aligned to section boundary (64M).

The symptom of this bug is an early boot failure in pfn_to_page(),
as it tries to access NODE_DATA(__nid) using index from an unitialized
element of the physnode_map[] array.

While the bug is always present, it is more likely to be hit in kdump
kernels on large machines, because:

1. The memory map for a kdump kernel is specified as exactmap, and
   exactmap is more likely to be unaligned.

2. Large reservations are more likely to span across a 64M boundary.

[ hpa: fixed incorrect use of "pfn" instead of "start" ]

Signed-off-by: Petr Tesarik <ptesarik@suse.cz>
Link: http://lkml.kernel.org/r/20140201133019.32e56f86@hananiah.suse.cz
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2014-02-01 22:15:51 -08:00

105 lines
3.2 KiB
C

/*
* Written by: Patricia Gaughen <gone@us.ibm.com>, IBM Corporation
* August 2002: added remote node KVA remap - Martin J. Bligh
*
* Copyright (C) 2002, IBM Corp.
*
* All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/bootmem.h>
#include <linux/memblock.h>
#include <linux/module.h>
#include "numa_internal.h"
#ifdef CONFIG_DISCONTIGMEM
/*
* 4) physnode_map - the mapping between a pfn and owning node
* physnode_map keeps track of the physical memory layout of a generic
* numa node on a 64Mb break (each element of the array will
* represent 64Mb of memory and will be marked by the node id. so,
* if the first gig is on node 0, and the second gig is on node 1
* physnode_map will contain:
*
* physnode_map[0-15] = 0;
* physnode_map[16-31] = 1;
* physnode_map[32- ] = -1;
*/
s8 physnode_map[MAX_SECTIONS] __read_mostly = { [0 ... (MAX_SECTIONS - 1)] = -1};
EXPORT_SYMBOL(physnode_map);
void memory_present(int nid, unsigned long start, unsigned long end)
{
unsigned long pfn;
printk(KERN_INFO "Node: %d, start_pfn: %lx, end_pfn: %lx\n",
nid, start, end);
printk(KERN_DEBUG " Setting physnode_map array to node %d for pfns:\n", nid);
printk(KERN_DEBUG " ");
start = round_down(start, PAGES_PER_SECTION);
end = round_up(end, PAGES_PER_SECTION);
for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION) {
physnode_map[pfn / PAGES_PER_SECTION] = nid;
printk(KERN_CONT "%lx ", pfn);
}
printk(KERN_CONT "\n");
}
unsigned long node_memmap_size_bytes(int nid, unsigned long start_pfn,
unsigned long end_pfn)
{
unsigned long nr_pages = end_pfn - start_pfn;
if (!nr_pages)
return 0;
return (nr_pages + 1) * sizeof(struct page);
}
#endif
extern unsigned long highend_pfn, highstart_pfn;
void __init initmem_init(void)
{
x86_numa_init();
#ifdef CONFIG_HIGHMEM
highstart_pfn = highend_pfn = max_pfn;
if (max_pfn > max_low_pfn)
highstart_pfn = max_low_pfn;
printk(KERN_NOTICE "%ldMB HIGHMEM available.\n",
pages_to_mb(highend_pfn - highstart_pfn));
high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1;
#else
high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
#endif
printk(KERN_NOTICE "%ldMB LOWMEM available.\n",
pages_to_mb(max_low_pfn));
printk(KERN_DEBUG "max_low_pfn = %lx, highstart_pfn = %lx\n",
max_low_pfn, highstart_pfn);
printk(KERN_DEBUG "Low memory ends at vaddr %08lx\n",
(ulong) pfn_to_kaddr(max_low_pfn));
printk(KERN_DEBUG "High memory starts at vaddr %08lx\n",
(ulong) pfn_to_kaddr(highstart_pfn));
setup_bootmem_allocator();
}