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[], unsigned long maxsize)
 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	if (maxsize)
 31		memsize = memsize ? min((unsigned long)memsize, maxsize) : maxsize;
 32	do {
 33		size = 0;
 34		type = tprot(addr);
 35		do {
 36			size += rzm;
 37			if (memsize && addr + size >= memsize)
 38				break;
 39		} while (type == tprot(addr + size));
 40		if (type == CHUNK_READ_WRITE || type == CHUNK_READ_ONLY) {
 41			if (memsize && (addr + size > memsize))
 42				size = memsize - addr;
 43			chunk[i].addr = addr;
 44			chunk[i].size = size;
 45			chunk[i].type = type;
 46			i++;
 47		}
 48		addr += size;
 49	} while (addr < memsize && i < MEMORY_CHUNKS);
 50}
 51
 52/**
 53 * detect_memory_layout - fill mem_chunk array with memory layout data
 54 * @chunk: mem_chunk array to be filled
 55 * @maxsize: maximum address where memory detection should stop
 56 *
 57 * Fills the passed in memory chunk array with the memory layout of the
 58 * machine. The array must have a size of at least MEMORY_CHUNKS and will
 59 * be fully initialized afterwards.
 60 * If the maxsize paramater has a value > 0 memory detection will stop at
 61 * that address. It is guaranteed that all chunks have an ending address
 62 * that is smaller than maxsize.
 63 * If maxsize is 0 all memory will be detected.
 64 */
 65void detect_memory_layout(struct mem_chunk chunk[], unsigned long maxsize)
 66{
 67	unsigned long flags, flags_dat, cr0;
 68
 69	memset(chunk, 0, MEMORY_CHUNKS * sizeof(struct mem_chunk));
 70	/*
 71	 * Disable IRQs, DAT and low address protection so tprot does the
 72	 * right thing and we don't get scheduled away with low address
 73	 * protection disabled.
 74	 */
 75	local_irq_save(flags);
 76	flags_dat = __arch_local_irq_stnsm(0xfb);
 77	/*
 78	 * In case DAT was enabled, make sure chunk doesn't reside in vmalloc
 79	 * space. We have disabled DAT and any access to vmalloc area will
 80	 * cause an exception.
 81	 * If DAT was disabled we are called from early ipl code.
 82	 */
 83	if (test_bit(5, &flags_dat)) {
 84		if (WARN_ON_ONCE(is_vmalloc_or_module_addr(chunk)))
 85			goto out;
 86	}
 87	__ctl_store(cr0, 0, 0);
 88	__ctl_clear_bit(0, 28);
 89	find_memory_chunks(chunk, maxsize);
 90	__ctl_load(cr0, 0, 0);
 91out:
 92	__arch_local_irq_ssm(flags_dat);
 93	local_irq_restore(flags);
 94}
 95EXPORT_SYMBOL(detect_memory_layout);
 96
 97/*
 98 * Create memory hole with given address and size.
 99 */
100void create_mem_hole(struct mem_chunk mem_chunk[], unsigned long addr,
101		     unsigned long size)
102{
103	int i;
104
105	for (i = 0; i < MEMORY_CHUNKS; i++) {
106		struct mem_chunk *chunk = &mem_chunk[i];
107
108		if (chunk->size == 0)
109			continue;
110		if (addr > chunk->addr + chunk->size)
111			continue;
112		if (addr + size <= chunk->addr)
113			continue;
114		/* Split */
115		if ((addr > chunk->addr) &&
116		    (addr + size < chunk->addr + chunk->size)) {
117			struct mem_chunk *new = chunk + 1;
118
119			memmove(new, chunk, (MEMORY_CHUNKS-i-1) * sizeof(*new));
120			new->addr = addr + size;
121			new->size = chunk->addr + chunk->size - new->addr;
122			chunk->size = addr - chunk->addr;
123			continue;
124		} else if ((addr <= chunk->addr) &&
125			   (addr + size >= chunk->addr + chunk->size)) {
126			memmove(chunk, chunk + 1, (MEMORY_CHUNKS-i-1) * sizeof(*chunk));
127			memset(&mem_chunk[MEMORY_CHUNKS-1], 0, sizeof(*chunk));
128		} else if (addr + size < chunk->addr + chunk->size) {
129			chunk->size =  chunk->addr + chunk->size - addr - size;
130			chunk->addr = addr + size;
131		} else if (addr > chunk->addr) {
132			chunk->size = addr - chunk->addr;
133		}
134	}
135}