From: Jan Willeke <willeke@de.ibm.com>
Date: Wed, 11 Sep 2013 21:24:52 +0000 (-0700)
Subject: s390/vmcore: implement remap_oldmem_pfn_range for s390
X-Git-Tag: v3.12-rc1~52^2~64
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=23df79da8eb97757e39af7625665c1c5cecc610b;p=linux.git

s390/vmcore: implement remap_oldmem_pfn_range for s390

Introduce the s390 specific way to map pages from oldmem.  The memory area
below OLDMEM_SIZE is mapped with offset OLDMEM_BASE.  The other old memory
is mapped directly.

Signed-off-by: Jan Willeke <willeke@de.ibm.com>
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/arch/s390/kernel/crash_dump.c b/arch/s390/kernel/crash_dump.c
index 0c9a897a1fb5..3e776158b330 100644
--- a/arch/s390/kernel/crash_dump.c
+++ b/arch/s390/kernel/crash_dump.c
@@ -98,6 +98,32 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
 	return (rc == 0) ? csize : rc;
 }
 
+/*
+ * Remap "oldmem"
+ *
+ * For the kdump reserved memory this functions performs a swap operation:
+ * [0 - OLDMEM_SIZE] is mapped to [OLDMEM_BASE - OLDMEM_BASE + OLDMEM_SIZE]
+ */
+int remap_oldmem_pfn_range(struct vm_area_struct *vma, unsigned long from,
+			   unsigned long pfn, unsigned long size, pgprot_t prot)
+{
+	unsigned long size_old;
+	int rc;
+
+	if (pfn < OLDMEM_SIZE >> PAGE_SHIFT) {
+		size_old = min(size, OLDMEM_SIZE - (pfn << PAGE_SHIFT));
+		rc = remap_pfn_range(vma, from,
+				     pfn + (OLDMEM_BASE >> PAGE_SHIFT),
+				     size_old, prot);
+		if (rc || size == size_old)
+			return rc;
+		size -= size_old;
+		from += size_old;
+		pfn += size_old >> PAGE_SHIFT;
+	}
+	return remap_pfn_range(vma, from, pfn, size, prot);
+}
+
 /*
  * Copy memory from old kernel
  */