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Subject[PATCH v7 4/5] s390/vmcore: Implement remap_oldmem_pfn_range for s390
Date
From: Jan Willeke <willeke@de.ibm.com>

This patch introduces 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>
---
arch/s390/kernel/crash_dump.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)

diff --git a/arch/s390/kernel/crash_dump.c b/arch/s390/kernel/crash_dump.c
index bfb9cda..9769aa3 100644
--- a/arch/s390/kernel/crash_dump.c
+++ b/arch/s390/kernel/crash_dump.c
@@ -56,6 +56,32 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
}

/*
+ * 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
*/
int copy_from_oldmem(void *dest, void *src, size_t count)
--
1.8.2.3


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