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/arch/s390/kernel/mem_detect.c

https://bitbucket.org/thekraven/iscream_thunderc-2.6.35
C | 64 lines | 49 code | 6 blank | 9 comment | 13 complexity | 9f0aa3bf2d6231d18a06289c46346067 MD5 | raw file
Possible License(s): GPL-2.0, LGPL-2.0, AGPL-1.0
 1/*
 2 * Copyright IBM Corp. 2008, 2009
 3 *
 4 * Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
 5 */
 6
 7#include <linux/kernel.h>
 8#include <linux/module.h>
 9#include <asm/ipl.h>
10#include <asm/sclp.h>
11#include <asm/setup.h>
12
13#define ADDR2G (1ULL << 31)
14
15static void find_memory_chunks(struct mem_chunk chunk[])
16{
17	unsigned long long memsize, rnmax, rzm;
18	unsigned long addr = 0, size;
19	int i = 0, type;
20
21	rzm = sclp_get_rzm();
22	rnmax = sclp_get_rnmax();
23	memsize = rzm * rnmax;
24	if (!rzm)
25		rzm = 1ULL << 17;
26	if (sizeof(long) == 4) {
27		rzm = min(ADDR2G, rzm);
28		memsize = memsize ? min(ADDR2G, memsize) : ADDR2G;
29	}
30	do {
31		size = 0;
32		type = tprot(addr);
33		do {
34			size += rzm;
35			if (memsize && addr + size >= memsize)
36				break;
37		} while (type == tprot(addr + size));
38		if (type == CHUNK_READ_WRITE || type == CHUNK_READ_ONLY) {
39			chunk[i].addr = addr;
40			chunk[i].size = size;
41			chunk[i].type = type;
42			i++;
43		}
44		addr += size;
45	} while (addr < memsize && i < MEMORY_CHUNKS);
46}
47
48void detect_memory_layout(struct mem_chunk chunk[])
49{
50	unsigned long flags, cr0;
51
52	memset(chunk, 0, MEMORY_CHUNKS * sizeof(struct mem_chunk));
53	/* Disable IRQs, DAT and low address protection so tprot does the
54	 * right thing and we don't get scheduled away with low address
55	 * protection disabled.
56	 */
57	flags = __raw_local_irq_stnsm(0xf8);
58	__ctl_store(cr0, 0, 0);
59	__ctl_clear_bit(0, 28);
60	find_memory_chunks(chunk);
61	__ctl_load(cr0, 0, 0);
62	__raw_local_irq_ssm(flags);
63}
64EXPORT_SYMBOL(detect_memory_layout);