1 /*
2  * This file is subject to the terms and conditions of the GNU General Public
3  * License.  See the file "COPYING" in the main directory of this archive
4  * for more details.
5  *
6  * This file contains NUMA specific variables and functions which are used on
7  * NUMA machines with contiguous memory.
8  *
9  *                         2002/08/07 Erich Focht <efocht@ess.nec.de>
10  */
11 
12 #include <linux/cpu.h>
13 #include <linux/kernel.h>
14 #include <linux/mm.h>
15 #include <linux/node.h>
16 #include <linux/init.h>
17 #include <linux/memblock.h>
18 #include <linux/module.h>
19 #include <asm/mmzone.h>
20 #include <asm/numa.h>
21 
22 
23 /*
24  * The following structures are usually initialized by ACPI or
25  * similar mechanisms and describe the NUMA characteristics of the machine.
26  */
27 int num_node_memblks;
28 struct node_memblk_s node_memblk[NR_NODE_MEMBLKS];
29 struct node_cpuid_s node_cpuid[NR_CPUS] =
30 	{ [0 ... NR_CPUS-1] = { .phys_id = 0, .nid = NUMA_NO_NODE } };
31 
32 /*
33  * This is a matrix with "distances" between nodes, they should be
34  * proportional to the memory access latency ratios.
35  */
36 u8 numa_slit[MAX_NUMNODES * MAX_NUMNODES];
37 
__node_distance(int from,int to)38 int __node_distance(int from, int to)
39 {
40 	return slit_distance(from, to);
41 }
42 EXPORT_SYMBOL(__node_distance);
43 
44 /* Identify which cnode a physical address resides on */
45 int
paddr_to_nid(unsigned long paddr)46 paddr_to_nid(unsigned long paddr)
47 {
48 	int	i;
49 
50 	for (i = 0; i < num_node_memblks; i++)
51 		if (paddr >= node_memblk[i].start_paddr &&
52 		    paddr < node_memblk[i].start_paddr + node_memblk[i].size)
53 			break;
54 
55 	return (i < num_node_memblks) ? node_memblk[i].nid : (num_node_memblks ? -1 : 0);
56 }
57 EXPORT_SYMBOL(paddr_to_nid);
58 
59 #if defined(CONFIG_SPARSEMEM) && defined(CONFIG_NUMA)
numa_clear_node(int cpu)60 void numa_clear_node(int cpu)
61 {
62 	unmap_cpu_from_node(cpu, NUMA_NO_NODE);
63 }
64 
65 #ifdef CONFIG_MEMORY_HOTPLUG
66 /*
67  *  SRAT information is stored in node_memblk[], then we can use SRAT
68  *  information at memory-hot-add if necessary.
69  */
70 
memory_add_physaddr_to_nid(u64 addr)71 int memory_add_physaddr_to_nid(u64 addr)
72 {
73 	int nid = paddr_to_nid(addr);
74 	if (nid < 0)
75 		return 0;
76 	return nid;
77 }
78 EXPORT_SYMBOL(memory_add_physaddr_to_nid);
79 #endif
80 #endif
81