From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Wed, 5 Aug 2015 17:04:01 -0300
Subject: Initial import

---
 arch/s390/mm/page-states.c | 114 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 114 insertions(+)
 create mode 100644 arch/s390/mm/page-states.c

(limited to 'arch/s390/mm/page-states.c')

diff --git a/arch/s390/mm/page-states.c b/arch/s390/mm/page-states.c
new file mode 100644
index 000000000..a90d45e9d
--- /dev/null
+++ b/arch/s390/mm/page-states.c
@@ -0,0 +1,114 @@
+/*
+ * Copyright IBM Corp. 2008
+ *
+ * Guest page hinting for unused pages.
+ *
+ * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/mm.h>
+#include <linux/gfp.h>
+#include <linux/init.h>
+
+#define ESSA_SET_STABLE		1
+#define ESSA_SET_UNUSED		2
+
+static int cmma_flag = 1;
+
+static int __init cmma(char *str)
+{
+	char *parm;
+
+	parm = strstrip(str);
+	if (strcmp(parm, "yes") == 0 || strcmp(parm, "on") == 0) {
+		cmma_flag = 1;
+		return 1;
+	}
+	cmma_flag = 0;
+	if (strcmp(parm, "no") == 0 || strcmp(parm, "off") == 0)
+		return 1;
+	return 0;
+}
+__setup("cmma=", cmma);
+
+void __init cmma_init(void)
+{
+	register unsigned long tmp asm("0") = 0;
+	register int rc asm("1") = -EOPNOTSUPP;
+
+	if (!cmma_flag)
+		return;
+	asm volatile(
+		"       .insn rrf,0xb9ab0000,%1,%1,0,0\n"
+		"0:     la      %0,0\n"
+		"1:\n"
+		EX_TABLE(0b,1b)
+		: "+&d" (rc), "+&d" (tmp));
+	if (rc)
+		cmma_flag = 0;
+}
+
+static inline void set_page_unstable(struct page *page, int order)
+{
+	int i, rc;
+
+	for (i = 0; i < (1 << order); i++)
+		asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"
+			     : "=&d" (rc)
+			     : "a" (page_to_phys(page + i)),
+			       "i" (ESSA_SET_UNUSED));
+}
+
+void arch_free_page(struct page *page, int order)
+{
+	if (!cmma_flag)
+		return;
+	set_page_unstable(page, order);
+}
+
+static inline void set_page_stable(struct page *page, int order)
+{
+	int i, rc;
+
+	for (i = 0; i < (1 << order); i++)
+		asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"
+			     : "=&d" (rc)
+			     : "a" (page_to_phys(page + i)),
+			       "i" (ESSA_SET_STABLE));
+}
+
+void arch_alloc_page(struct page *page, int order)
+{
+	if (!cmma_flag)
+		return;
+	set_page_stable(page, order);
+}
+
+void arch_set_page_states(int make_stable)
+{
+	unsigned long flags, order, t;
+	struct list_head *l;
+	struct page *page;
+	struct zone *zone;
+
+	if (!cmma_flag)
+		return;
+	if (make_stable)
+		drain_local_pages(NULL);
+	for_each_populated_zone(zone) {
+		spin_lock_irqsave(&zone->lock, flags);
+		for_each_migratetype_order(order, t) {
+			list_for_each(l, &zone->free_area[order].free_list[t]) {
+				page = list_entry(l, struct page, lru);
+				if (make_stable)
+					set_page_stable(page, order);
+				else
+					set_page_unstable(page, order);
+			}
+		}
+		spin_unlock_irqrestore(&zone->lock, flags);
+	}
+}
-- 
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