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authorMichael Holzheu <holzheu@linux.vnet.ibm.com>2011-10-30 15:16:39 +0100
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2011-10-30 15:16:42 +0100
commit7f0bf656c66e4292e965c95fd9de55c72b6578bb (patch)
tree5940a3c7ce75d64deb03a0a4f2199f64c497c1bf /arch/s390/mm
parent1943f53c9ca182fa233e5a17e89ef8e421d7819e (diff)
downloadlinux-linaro-stable-7f0bf656c66e4292e965c95fd9de55c72b6578bb.tar.gz
[S390] Add real memory access functions
Add access function for real memory needed by s390 kdump backend. Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/mm')
-rw-r--r--arch/s390/mm/maccess.c56
1 files changed, 56 insertions, 0 deletions
diff --git a/arch/s390/mm/maccess.c b/arch/s390/mm/maccess.c
index 5dbbaa6e594c..1cb8427bedfb 100644
--- a/arch/s390/mm/maccess.c
+++ b/arch/s390/mm/maccess.c
@@ -11,6 +11,7 @@
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/errno.h>
+#include <linux/gfp.h>
#include <asm/system.h>
/*
@@ -60,6 +61,9 @@ long probe_kernel_write(void *dst, const void *src, size_t size)
return copied < 0 ? -EFAULT : 0;
}
+/*
+ * Copy memory in real mode (kernel to kernel)
+ */
int memcpy_real(void *dest, void *src, size_t count)
{
register unsigned long _dest asm("2") = (unsigned long) dest;
@@ -101,3 +105,55 @@ void copy_to_absolute_zero(void *dest, void *src, size_t count)
__ctl_load(cr0, 0, 0);
preempt_enable();
}
+
+/*
+ * Copy memory from kernel (real) to user (virtual)
+ */
+int copy_to_user_real(void __user *dest, void *src, size_t count)
+{
+ int offs = 0, size, rc;
+ char *buf;
+
+ buf = (char *) __get_free_page(GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+ rc = -EFAULT;
+ while (offs < count) {
+ size = min(PAGE_SIZE, count - offs);
+ if (memcpy_real(buf, src + offs, size))
+ goto out;
+ if (copy_to_user(dest + offs, buf, size))
+ goto out;
+ offs += size;
+ }
+ rc = 0;
+out:
+ free_page((unsigned long) buf);
+ return rc;
+}
+
+/*
+ * Copy memory from user (virtual) to kernel (real)
+ */
+int copy_from_user_real(void *dest, void __user *src, size_t count)
+{
+ int offs = 0, size, rc;
+ char *buf;
+
+ buf = (char *) __get_free_page(GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+ rc = -EFAULT;
+ while (offs < count) {
+ size = min(PAGE_SIZE, count - offs);
+ if (copy_from_user(buf, src + offs, size))
+ goto out;
+ if (memcpy_real(dest + offs, buf, size))
+ goto out;
+ offs += size;
+ }
+ rc = 0;
+out:
+ free_page((unsigned long) buf);
+ return rc;
+}