Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull s390 updates from Martin Schwidefsky:
 "Just a random collection of bug-fixes and cleanups, nothing new in
  this merge request."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (46 commits)
  s390/ap: Fix wrong or missing comments
  s390/ap: move receive callback to message struct
  s390/dasd: re-prioritize partition detection message
  s390/qeth: reshuffle initialization
  s390/qeth: cleanup drv attr usage
  s390/claw: cleanup drv attr usage
  s390/lcs: cleanup drv attr usage
  s390/ctc: cleanup drv attr usage
  s390/ccwgroup: remove ccwgroup_create_from_string
  s390/qeth: stop using struct ccwgroup driver for discipline callbacks
  s390/qeth: switch to ccwgroup_create_dev
  s390/claw: switch to ccwgroup_create_dev
  s390/lcs: switch to ccwgroup_create_dev
  s390/ctcm: switch to ccwgroup_create_dev
  s390/ccwgroup: exploit ccwdev_by_dev_id
  s390/ccwgroup: introduce ccwgroup_create_dev
  s390: fix race on TIF_MCCK_PENDING
  s390/barrier: make use of fast-bcr facility
  s390/barrier: cleanup barrier functions
  s390/claw: remove "eieio" calls
  ...

1 files changed, 67 insertions, 0 deletions

diff --git a/arch/s390/mm/maccess.c b/arch/s390/mm/maccess.c
index e1335dc..795a0a9 100644
--- a/arch/s390/mm/maccess.c
+++ b/arch/s390/mm/maccess.c
@@ -12,6 +12,7 @@
 #include <linux/types.h>
 #include <linux/errno.h>
 #include <linux/gfp.h>
+#include <linux/cpu.h>
 #include <asm/ctl_reg.h>
 
 /*
@@ -166,3 +167,69 @@ out:
 	free_page((unsigned long) buf);
 	return rc;
 }
+
+/*
+ * Check if physical address is within prefix or zero page
+ */
+static int is_swapped(unsigned long addr)
+{
+	unsigned long lc;
+	int cpu;
+
+	if (addr < sizeof(struct _lowcore))
+		return 1;
+	for_each_online_cpu(cpu) {
+		lc = (unsigned long) lowcore_ptr[cpu];
+		if (addr > lc + sizeof(struct _lowcore) - 1 || addr < lc)
+			continue;
+		return 1;
+	}
+	return 0;
+}
+
+/*
+ * Return swapped prefix or zero page address
+ */
+static unsigned long get_swapped(unsigned long addr)
+{
+	unsigned long prefix = store_prefix();
+
+	if (addr < sizeof(struct _lowcore))
+		return addr + prefix;
+	if (addr >= prefix && addr < prefix + sizeof(struct _lowcore))
+		return addr - prefix;
+	return addr;
+}
+
+/*
+ * Convert a physical pointer for /dev/mem access
+ *
+ * For swapped prefix pages a new buffer is returned that contains a copy of
+ * the absolute memory. The buffer size is maximum one page large.
+ */
+void *xlate_dev_mem_ptr(unsigned long addr)
+{
+	void *bounce = (void *) addr;
+	unsigned long size;
+
+	get_online_cpus();
+	preempt_disable();
+	if (is_swapped(addr)) {
+		size = PAGE_SIZE - (addr & ~PAGE_MASK);
+		bounce = (void *) __get_free_page(GFP_ATOMIC);
+		if (bounce)
+			memcpy_real(bounce, (void *) get_swapped(addr), size);
+	}
+	preempt_enable();
+	put_online_cpus();
+	return bounce;
+}
+
+/*
+ * Free converted buffer for /dev/mem access (if necessary)
+ */
+void unxlate_dev_mem_ptr(unsigned long addr, void *buf)
+{
+	if ((void *) addr != buf)
+		free_page((unsigned long) buf);
+}