s390/mem_detect: move memory detection code to mm folder

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

2 files changed, 146 insertions, 1 deletions

diff --git a/arch/s390/mm/Makefile b/arch/s390/mm/Makefile
index 640bea12303c..839592ca265c 100644
--- a/arch/s390/mm/Makefile
+++ b/arch/s390/mm/Makefile
@@ -3,7 +3,7 @@
 #
 
 obj-y		:= init.o fault.o extmem.o mmap.o vmem.o pgtable.o maccess.o
-obj-y		+= page-states.o gup.o extable.o pageattr.o
+obj-y		+= page-states.o gup.o extable.o pageattr.o mem_detect.o
 
 obj-$(CONFIG_CMM)		+= cmm.o
 obj-$(CONFIG_HUGETLB_PAGE)	+= hugetlbpage.o
diff --git a/arch/s390/mm/mem_detect.c b/arch/s390/mm/mem_detect.c
new file mode 100644
index 000000000000..22d502e885ed
--- /dev/null
+++ b/arch/s390/mm/mem_detect.c
@@ -0,0 +1,145 @@
+/*
+ * Copyright IBM Corp. 2008, 2009
+ *
+ * Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <asm/ipl.h>
+#include <asm/sclp.h>
+#include <asm/setup.h>
+
+#define ADDR2G (1ULL << 31)
+
+static void find_memory_chunks(struct mem_chunk chunk[])
+{
+	unsigned long long memsize, rnmax, rzm;
+	unsigned long addr = 0, size;
+	int i = 0, type;
+
+	rzm = sclp_get_rzm();
+	rnmax = sclp_get_rnmax();
+	memsize = rzm * rnmax;
+	if (!rzm)
+		rzm = 1ULL << 17;
+	if (sizeof(long) == 4) {
+		rzm = min(ADDR2G, rzm);
+		memsize = memsize ? min(ADDR2G, memsize) : ADDR2G;
+	}
+	do {
+		size = 0;
+		type = tprot(addr);
+		do {
+			size += rzm;
+			if (memsize && addr + size >= memsize)
+				break;
+		} while (type == tprot(addr + size));
+		if (type == CHUNK_READ_WRITE || type == CHUNK_READ_ONLY) {
+			chunk[i].addr = addr;
+			chunk[i].size = size;
+			chunk[i].type = type;
+			i++;
+		}
+		addr += size;
+	} while (addr < memsize && i < MEMORY_CHUNKS);
+}
+
+void detect_memory_layout(struct mem_chunk chunk[])
+{
+	unsigned long flags, cr0;
+
+	memset(chunk, 0, MEMORY_CHUNKS * sizeof(struct mem_chunk));
+	/* Disable IRQs, DAT and low address protection so tprot does the
+	 * right thing and we don't get scheduled away with low address
+	 * protection disabled.
+	 */
+	flags = __arch_local_irq_stnsm(0xf8);
+	__ctl_store(cr0, 0, 0);
+	__ctl_clear_bit(0, 28);
+	find_memory_chunks(chunk);
+	__ctl_load(cr0, 0, 0);
+	arch_local_irq_restore(flags);
+}
+EXPORT_SYMBOL(detect_memory_layout);
+
+/*
+ * Move memory chunks array from index "from" to index "to"
+ */
+static void mem_chunk_move(struct mem_chunk chunk[], int to, int from)
+{
+	int cnt = MEMORY_CHUNKS - to;
+
+	memmove(&chunk[to], &chunk[from], cnt * sizeof(struct mem_chunk));
+}
+
+/*
+ * Initialize memory chunk
+ */
+static void mem_chunk_init(struct mem_chunk *chunk, unsigned long addr,
+			   unsigned long size, int type)
+{
+	chunk->type = type;
+	chunk->addr = addr;
+	chunk->size = size;
+}
+
+/*
+ * Create memory hole with given address, size, and type
+ */
+void create_mem_hole(struct mem_chunk chunk[], unsigned long addr,
+		     unsigned long size, int type)
+{
+	unsigned long lh_start, lh_end, lh_size, ch_start, ch_end, ch_size;
+	int i, ch_type;
+
+	for (i = 0; i < MEMORY_CHUNKS; i++) {
+		if (chunk[i].size == 0)
+			continue;
+
+		/* Define chunk properties */
+		ch_start = chunk[i].addr;
+		ch_size = chunk[i].size;
+		ch_end = ch_start + ch_size - 1;
+		ch_type = chunk[i].type;
+
+		/* Is memory chunk hit by memory hole? */
+		if (addr + size <= ch_start)
+			continue; /* No: memory hole in front of chunk */
+		if (addr > ch_end)
+			continue; /* No: memory hole after chunk */
+
+		/* Yes: Define local hole properties */
+		lh_start = max(addr, chunk[i].addr);
+		lh_end = min(addr + size - 1, ch_end);
+		lh_size = lh_end - lh_start + 1;
+
+		if (lh_start == ch_start && lh_end == ch_end) {
+			/* Hole covers complete memory chunk */
+			mem_chunk_init(&chunk[i], lh_start, lh_size, type);
+		} else if (lh_end == ch_end) {
+			/* Hole starts in memory chunk and convers chunk end */
+			mem_chunk_move(chunk, i + 1, i);
+			mem_chunk_init(&chunk[i], ch_start, ch_size - lh_size,
+				       ch_type);
+			mem_chunk_init(&chunk[i + 1], lh_start, lh_size, type);
+			i += 1;
+		} else if (lh_start == ch_start) {
+			/* Hole ends in memory chunk */
+			mem_chunk_move(chunk, i + 1, i);
+			mem_chunk_init(&chunk[i], lh_start, lh_size, type);
+			mem_chunk_init(&chunk[i + 1], lh_end + 1,
+				       ch_size - lh_size, ch_type);
+			break;
+		} else {
+			/* Hole splits memory chunk */
+			mem_chunk_move(chunk, i + 2, i);
+			mem_chunk_init(&chunk[i], ch_start,
+				       lh_start - ch_start, ch_type);
+			mem_chunk_init(&chunk[i + 1], lh_start, lh_size, type);
+			mem_chunk_init(&chunk[i + 2], lh_end + 1,
+				       ch_end - lh_end, ch_type);
+			break;
+		}
+	}
+}